This is for those people who are new to the story or for those who still struggling with the concept of what Novogen and Marshall Edwards are all about.

The story has its roots in the very beginnings of life … in particular, a crucial step that enabled simple, single-cell organisms to develop into higher forms of life through harnessing nitrogen gas and converting it into protein.

PROTEIN

At the heart of this story is the need of all life forms to make protein. Carbohydrates (sugars) and fats are essentially ‘dumb’ components of the body, serving largely passive roles such as structural supports (eg. the cytoskeletons of cells) and providing energy sources. Proteins, on the other hand, are far more ‘intelligent’ in nature, regulating the millions of different functions that underwrite the survival of an individual cell and allow collections of cells to cooperate and to work together. An individual cell, whether it is a simple single-cell organism such as a bacteria, or part of a more complex structure such as plant, or part of an even more sophisticated structure such as a mammal, has roughly the same complement of proteins. The more sophisticated the cell’s function, the more proteins it will need, but the underlying task of keeping the cell alive and functioning and dividing takes about the same several thousand different types of proteins whether it be a cell in the leaf of a plant involved in photosynthesis, or a heart muscle cell in an animal contracting thousands of times a day in order to maintain a heart-beat. The more complex an organism becomes, the more protein it needs…not just because of the greater number of cells, but because of the growing task of integrating the function of more cells. As life evolved and became more complex, it needed to develop an increasingly greater range of proteins. In this way, muscles could be developed to permit complicated movement and to provide greater strength, nerves could be insulated to allow electrical currents to pass down them to provide greater control over body movements, chemical signals such as hormones and cytokines could be made to allow the body to develop more sophisticated functions, antibodies could be developed to protect against infections, the brain with its intricate neural pathways and chemical transmitters could be assembled, and muscular organs such as the heart and blood vessels could be formed, along with blood, to ensure that all parts of this more complex organism could be nourished.

Each of the tens of thousands of different types of protein in our body has a limited life-span, which in many cases is only seconds. Proteins are in a constant state of flux, being constantly broken down and reassembled, but always with a net loss from the body. The constant shedding of hair and skin cells alone accounts for a significant loss or protein on a daily basis. To service this loss, an adult human needs between about 45 -70 g of protein daily in the diet of women and men respectively, and that needs to be provided in the form of amino acids, the building blocks of proteins.

Amino acids, as shown below, comprise atoms of carbon (C), hydrogen (H), oxygen (O) and nitrogen (N).

Amino acid structure. [R=different additional chemical group defining different amino acids].

There are 20 different kinds of amino acids (eg. cystine, methionine, arginine etc.), the difference stemming from a different form of chemical grouping attaching to the underlying C-H-O-N skeleton.

Protein is created by stringing together individual amino acids like a string of pearls in chains that involve anything from just a dozen or so amino acids, up to many thousands. By assembling the 20 different amino acids in varying sequences, and then attaching these different sequences together in varying lengths, the number of different proteins that can be created is virtually endless.

This is where proteins differ from carbohydrates and fats and why proteins are far more ‘intelligent’ than those other two molecules. Carbohydrates are made up of hundreds or thousands of individual sugar molecules such as glucose or fructose, and fats from individual fatty acids. But carbohydrates and fats are built up like blocks of Lego in relatively rigid structures, and just as with a box of thousands of separate pieces of Lego the potential number of final structures is almost endless. But these final structures remain rigid and therefore limited in what they can achieve other than providing a supporting structure.

Proteins, on the other hand, once the amino acid chain has been assembled, then undergo a series of twists and turns that impart a high degree of flexibility to the chain. The first step is that the amino acid chain is twisted to create a helix (think of the DNA helix that we are familiar with). Then that helix is folded in a way that is unique to each protein, with the final shape of the protein being its distinguishing feature. In the same way that a length of string could be dropped to the floor a million times and never produce twice the same shaped bundle on the floor, so the body is able to create the tens of thousands of different proteins that it needs.

The ability to twist and turn and change shape is what gives protein the ability to ‘think’ for itself and to perform highly sophisticated functions, and it is the presence of nitrogen in the amino acid chain that imparts this flexibility in the first place.

THE NITROGEN CYCLE

We obviously could not survive without the presence of carbon, hydrogen and oxygen, as the basic elements of life. But it is the ability of the body to access nitrogen that is responsible for you being able to read these words now and not just an unsophisticated bug in a pond trying to stop becoming someone else’s dinner.

Accessing all the carbon, hydrogen and oxygen that we need has never been a problem for any life form. These three elements are in everything that we eat and they are readily available to our bodies from that food. Hydrogen and oxygen are also available in the form of water, and all three elements are available as gases in the air we breathe.

Nitrogen, on the other hand, has always been something of a problem. And this is despite it being the most abundant element in our environment. Nitrogen accounts for 78% of the air that we breathe and it is the most abundant gas in Earth’s atmosphere, with 33,000 tonnes of nitrogen above every acre on the surface of our planet. But despite this abundance, nitrogen unfortunately is just too chemically stable in a gaseous state for animals to access it directly from air.

For any life form to access nitrogen requires it to be converted into a solid state in a process known as nitrogen-fixing. This is the so-called nitrogen cycle that is so critical to life on Earth.

The nitrogen cycle has two main steps. The first step is to convert nitrogen gas in the air into salts such as ammonia (NH4+) and nitrate (NO3-) salts that then occur in water and soil. Part of this fixing process occurs during thunderstorms when electricity produces ammonia in the air that washes onto the ground with rain as ammonium salts. But most nitrogen fixation occurs through the action of bacteria in the soil that take nitrogen that diffuses into the soil and convert it into ammonia and nitrate salts.

The second step in the cycle is to move this fixed nitrogen from the soil into the plant, which the roots of the plant do in the normal process of taking up water and trace elements. Once absorbed, the plant is able to use the nitrogen in the salt to manufacture amino acids, which then are assembled into the thousands of different proteins that plants require to survive. In turn, when that plant is eaten by an animal, those plant proteins are broken down by the animal’s digestive system into the constituent amino acids, which are absorbed intact into the body and eventually reassembled by the animal into its own proteins.

HUMANS, PLANTS & DIETARY PROTEIN

Moving on now to how we humans fit into this nitrogen cycle. The 45-70 g of protein that we need to replace daily means that we need a total of about 8-12 g of nitrogen, the great majority of which needs to be supplied in the form of amino acids.

The fruits and most of the vegetables that we eat have protein levels somewhere between 0.5 g (eg. carrot) and 3.0 g (eg. broccoli) protein for every 100 g of plant material. The level is somewhat higher in grains (eg. wheat is 12%, and rice is 7%).

For herbivorous animals, such relatively modest levels of plant protein present no problem. The digestive systems of herbivores is adapted to consuming large quantities of plant material, and, for these animals, a diet based totally on a plant such as grass where the protein level might be only 1%, is still able to provide perfectly adequate amounts of amino acids in the diet. But it does mean eating fairly large amounts of plant material.

For omnivores such as humans, however, the situation is very different. The human digestive system was never adapted to eating large amounts of plant material. We don’t have four stomachs like ruminants, and that large fermentation tank that horses use to hold large amounts of grass, the caecum, is nothing more than a vestigial bit of tissue in humans known as the appendix. If an adult man was to rely solely on plants such as cereals, fruits and vegetables to obtain the recommended 70 g of dietary protein each day, he would need to consume in theory between about 3.0 and 3.5 kg of plant material each day (assuming an average 2.0% protein content), an amount of material that would be well beyond the capacity of most of us. You could get away with eating a smaller amount of cereals and grains (about 0.5 kg wheat flour or almost 1 kg of rice), but even that would still be a considerable challenge for most of us. And these are only theoretical amounts…in practical terms we would need to consume even larger amounts (about 50% more) since plant protein generally has relatively poor digestibility in omnivores. Whereas herbivores can pretty much extract all the protein out of plant material, our lack of vigorous fermentation activity in our gut limits the extent to which we can breakdown plant material to its various constituents such as amino acids.

So relying on fruits and vegetables and cereals for dietary protein would not meet the daily protein requirements for most humans. We simply could not eat enough plant material to meet that need. Of course, one way around that problem is to eat another animal that has already done the hard yards of concentrating plant amino acids into meat, and a mixture of plant protein and animal protein is the very basis of the hunter-gatherer diet that has served as the dietary environment for the development of man over the past few hundreds of thousands of years. That long period of development means that we still have the body and metabolism and physiology of hunter-gatherers that was designed on the basis of our protein needs being met through a blend of plants and animal products.

But the problem with this scenario in the modern world is that we have shifted the proportion of plant protein to animal protein in the diet to an enormous degree over the last 150 years. Technology has meant that modern man has become surrounded by animal protein to the extent that the modern Western diet derives at least 90% of its daily protein from animal products (meat, fish, eggs, dairy etc). The reality is that this is an entirely artificial situation. Meat is a luxury and always has been for humans since the dawn of our development. Up until the last 150 years or so, our hunter-gather background by and large was far more gathering than hunting to the extent that animal protein would only have provided about half or less of the daily protein needs. And given the pressures now facing the world in terms of population density and the relative environmental costs of animal versus plant production, it seems almost inevitable that that balance is going to have to shift back to a situation where meat becomes an incidental rather than the dominant source of dietary protein.

So if early man didn’t have the luxury of catching an animal daily, and didn’t have refrigeration to store the occasional kill, and didn’t have a gut designed to ferment large amounts of vegetables and grains, then how did he supplement his protein needs? The answer is the same way that vegetarians and a considerable proportion of the world’s population obtain a large proportion of their dietary protein today. It comes down to a specialised group of plants that are programmed to manufacture high amounts of protein and to present that protein in a readily digestible form for animals such as humans.

These plants are known as the Family Fabaceae, or more simply as….. legumes, and they play a key and often overlooked part in the nitrogen cycle.

What distinguishes legumes from all other plants is their ability to concentrate ammonia and nitrate salts from the soil to an extent far beyond that of other plants. They do so because of a special symbiotic relationship with certain soil-dwelling bacteria known as Rhizobium spp. Whereas the soil bacteria that fix nitrogen into ammonia and nitrate salts for grasses, cereals and vegetables etc function completely independently of the plant, the Rhizobium bacteria work cooperatively with the plant. The bacteria are attracted to the roots of the legume plant where they form colonies on the roots in the form of nodules. Pull any legume from the ground and what you will see is a myriad of greyish-white nodules covering the root system.

These nodules are little powerhouses of nitrogen production, feeding the legume directly with large amounts of nitrogen which it readily turns into amino acids and then proteins. The legume is no different to any other plant such as wheat or a banana plant or a cauliflower in the amount of protein that it requires to grow and survive…that is, it is not making all this extra protein for its own benefit. The legume is making this protein as part of the earth’s nitrogen cycle in order to supplement the fixation and utilisation of atmospheric nitrogen. When the legume ultimately dies and decomposes, the high level of fixed nitrogen in the plant is returned to the soil.

LEGUMES IN THE HUMAN DIET

There are upwards of 20,000 different types of legumes in the world ranging from trees such as acacia (or wattles), through to flowering garden plants such as sweet peas and lupins, through to fodder crops such as clovers, all of them serving Nature by enriching the soil with nitrogen in a way that all other plants cannot do. But from this vast family of leguminous plants, the ones that we are interested in here are those whose seeds are used as food by humans. These legumes are known as pulses, but probably better known generically as ‘beans’. Pulses play an important role in human nutrition because their protein content is comparable on a weight basis to that of meat, particularly the seed where levels typically are between 20-25% by weight, but may go as high as 36%.

Common pulses eaten by humans

Far East

• soy bean
• adzuki bean
• mung bean
• lablab bean (hyacinth bean)
• Kudzu (Japanese arrowroot)

India

• chick peas (also known as Bengal gram and garbanzo bean)
• horse gram, black gram
• lentils (red, brown, white varieties)
• pigeon pea
• lablab bean

Africa

• peanut (groundnut)
• black-eyed bean (cowpea)
• pigeon pea

France, Italy

• cannellini
• flageolet bean
• borlotti bean
• haricot (navy bean)
• broad bean
• pea

Mediterranean & Middle East

• chick peas
• lentils
• ful medames
• broad bean
• fenugreek

Central & Latin Americas

• red kidney bean (also known as chili bean)
• lima bean
• black bean
• butter bean
• yam bean

Based on the amount and type of pulses eaten, the typical daily isoflavone consumption has been estimated as follows:

Isoflavone consumption mg / day

Japan – 38.2
China – 10.6
India – 1.2
USA- 0.012
Spain- 0.01
UK- 0.0055
Sweden- 0.0002
Finland – 0.0001

LEGUMES & ISOFLAVONES

Eating legumes does more than provide protein. It is a rich source of two other dietary components….fermentable sugars and isoflavones. The effects of the fermentable sugars are well known, aptly captured in the campfire scene in the movie, Blazing Saddles. This effect alone would be enough to justify including legumes in the diet……promoting fermentation in the large bowel encourages the growth of healthy bowel bacteria, something that legumes do better than any other type of plant. But what the campfire scene didn’t show was the presence in the cowboys’ blood of high levels of chemicals known as isoflavones, a direct effect of eating beans. Isoflavones and their biological effects on the human body are at the heart of the Novogen story.

Most people have heard of flavones (also known as flavonoids). These are the most common family of chemicals found in plants. Over 4000 different flavones have been identified, and the typical Western diet containing an average amount of fruit and vegetables delivers somewhere up to about 1 gram (about half a teaspoonful) of flavones daily. Flavones are the work-horse chemicals in plants, serving functions as diverse as providing the bright colours of flowers and leaves, to hormonal functions, to helping fight predators, and to protecting the plant against stresses. They are particularly strong anti-oxidants and scavengers of free radicals in plants, functions for which they are best known in terms of their health benefits for humans.

Isoflavones are close chemical cousins of the flavones, seeming to be a later development of flavones in terms of plant evolution. Their chemical structure is virtually a mirror image of flavones, a similarity that allows isoflavones to perform pretty much the same range of functions in the plant as flavones, but with just enough difference to allow them to do some things that flavones cannot do, one of these being an ability to communicate with Rhizobium bacteria in the soil. A key role of isoflavones in legumes is to diffuse out of the roots of the legume into the soil where they attract bacteria to the plant’s roots, and then to instruct those bacteria to proliferate and to form colonies and to start their nitrogen-fixing activity. The important contribution that legumes make to the Earth’s nitrogen cycle comes down completely to this humble group of isoflavones.

Over 1200 different isoflavones have been identified. Probably the best known of these is rotenone, an isoflavone that acts to repel insecticidal attack on legumes, and which has been commercialised for many years as a home garden insect spray. The vast majority of these 1200 isoflavones occur in legumes at trace levels only and for that reason do not figure large in the human diet, and therefore, or in this story.

The ability to regulate Rhizobium activity is limited to a small group of isoflavones, the four main ones being genistein, daidzein, formononetin and biochanin. The fact that these four isoflavones are essential to the nitrogen-fixing activity of legumes means that they are present in all legumes, and are present at relatively high levels.

Genistein, daidzein and formononetin derive their names from the botanical names of the Mediterranean plants from which they were first isolated. Biochanin takes its name from the Indian word ‘channa’ which is the foodstuff derived from ground chick pea or lentil sprouts. These sprouts are very rich in biochanin, so named because it was a compound with biological properties (bio) from channa (chanin).

These four isoflavones are so prominent in pulses that it is estimated that people who use pulses for a reasonable proportion of their daily dietary protein consume between about 20 – 150 mg of these four isoflavones in total each day depending on the type of pulse consumed. At the lower end of this range are some North African diets where various types of lower quality beans are used, while at the higher end is a diet typical of Northern Japan where soybeans (rich source of isoflavones) are consumed in relatively high amounts.

ISOFLAVONES & HUMAN BIOLOGY

What makes this group of four isoflavones the cornerstone of the Novogen story is that they are biologically active in animals and in humans in particular.

This cross-over of function from plants to animals is no happy accident of Nature, any more than is our reliance on plants for vitamins such as vitamin C. There is a very substantial (and important) difference between plants as a source of ingredients that we rely on for everyday health, and the use of plants as herbal medicines. Valerian is an example of herbal medicine, where a chemical in the root of a plant rarely encountered by humans has been discovered by accident to have a specific biological effect in humans. In the case of valerian root extract, that effect is on neurotransmitter function, purportedly providing relief for sleeplessness and depression. Valerian root (or almost any medicinal herb for that matter) is not a regular part of the human diet in the sense that the active medicinal ingredient of any of these plants has played any part in human evolution. The body’s homeostasis, by which we mean the way the body’s internal environment is maintained in a healthy and integrated state, has developed quite happily without any regular input from such medicinal herbs.

Isoflavones, on the other hand, along with flavones such as quercetin, plus a range of vitamins and other common plant chemicals, have been part of the human diet on a regular basis for much of human evolution.

It defies belief that compounds with significant biological activity in the body would not have had those activities incorporated or allowed for in our development in the same way that other plant-derived compounds such as vitamins have been incorporated.

Take genistein as an example. This simple compound has been shown to have the following effects in animals and humans:

• it is a mild estrogen and a moderately active anti-estrogen;
• it inhibits the production of testosterone;
• it has moderate anti-cancer activity against most forms of human cancer;
• it is anti-angiogenic (inhibits the production of abnormal blood vessels);
• it is mildly anti-inflammatory.
  

Superficially it may be challenging to believe that a compound used by a plant to attract and up-regulate soil-dwelling bacteria to its roots can (a) have any biological effect in animals, (b) produce effects in animals completely unrelated to its effects in plants, and (c) have such a broad range of effects in animals. But dig a bit deeper, and it really is not that strange.

(i) Isoflavones are the precursors of human steroidal hormones.

Isoflavones are the ancient ancestors of animal steroidal hormones, and that relationship retains sufficient chemical similarity for them to interact.

Again, this is no happy accident. In the process of higher life forms evolving from plants, all of the thousands of different biochemical processes that go to make up a sophisticated organism like the human body had their origins in the various biochemical assembly lines found in plants. Human biochemical processes weren’t created de novo from dust…they were adapted from existing plant biochemical processes, being refined and modified as required. The underlying biochemical processes that ensure the survival, function and growth of a plant cell differ little from those in a human cell. The differences lie more in the specialised functions of the human cell that evolved over millennia.The chemical link between isoflavones and steroids is that they both are based on two adjoining 6-carbon rings known as phenolic rings as shown below. For this reason, isoflavones and steroids are described chemically as being diphenolics, and to that extent belong to the same chemical family.

Diphenolic structure

The difference between the two diphenolics lies in their additional structures.

Steroid

Isoflavone

Plants have the capacity to manufacture both types of diphenolics …. both flavones/isoflavones and steroids….the manufacturing process for steroids simply being an extension of the manufacturing process for the simpler flavones/isoflavones. But for whatever reason, plants chose to rely predominantly on flavones/isoflavones for their hormonal needs. As a result, steroid levels in plants normally are at little more than trace levels. A significant exception is the Mexican yam that contains relatively high levels of the steroid, diosgenin, which served as the original starting material that enabled large scale manufacture of the estrogen in the oral contraceptive pill back in the 1960s.

In the process of developing higher life-forms, it was the steroid pathway that was adapted for the more sophisticated animal hormonal functions such as reproduction (estrogen, progesterone, testosterone), water balance (aldosterone), and stress and inflammation (cortisone). In so doing, the biological function of these hormones became substantially more specific and more potent compared to the flavones and isoflavones with their broad range of functions in plants. This has parallels with that of beta-carotene and vitamin A. Beta-carotene is a perfectly adequate vitamin for plants. Animals, however, with their substantially higher metabolic rates required a more potent form of the vitamin, and so developed the capacity to convert plant beta-carotene into vitamin A. The result being that vitamin A is about 1000-times more potent as an anti-oxidant than beta-carotene. But not all beta-carotene is converted in the body into vitamin A, and the body uses both substances in an inter-convertible way. It is just that vitamin A is providing the bulk of the vitamin activity because of its much greater potency. Beta-carotene for this reason is referred to as a pro-vitamin in the sense that it is a much weaker version of vitamin A.

In the same way, isoflavones can be considered to be pro-hormones, capable of doing everything that a steroid hormone can do, only much weaker.

The ability of genistein to act either as an estrogen or an anti-estrogen is a good example of this pro-hormone effect. Estrogen activity is based on an estrogen hormone interacting with the estrogen receptors that are present on all cells. The figure on the left below shows graphically what happens when an estrogen hormone (in this case estradiol) makes contact with the receptor. The receptor itself is like any other large protein….very convoluted and folded, although the actual site where the hormone needs to dock is in a very specific part of the protein and involves two adjacent folds of the protein. The hormone needs to bridge these two folds and lock them together in a rigid way that is called receptor stabilisation. In the case of the estrogen receptor, the key to stabilisation is the binding to the receptor of the two terminal hydroxyl (OH) groups on estradiol as shown below. But because the estrogen receptor has been designed for estradiol, maximum stabilisation only occurs when the distance between the two OH groups exactly matches that of estradiol. When that happens and the two protein strands that comprise the docking site are held exactly the required distance apart and in exactly the right plane, then the receptor releases a trigger that initiates a series of chemical events that eventually yield an estrogenic response.

But chemicals other than estradiol can trigger an estrogenic response, and the reason for this is that the triggering of the estrogen receptor is not an all-or-nothing effect. If the hormone entering the receptor looks sufficiently like estradiol to the extent that it has two terminal hydroxyl groups that can interact with the docking site and stabilise the docking site, then it will still activate the receptor, but just not as powerfully as estradiol. Other steroidal hormones such as testosterone and cortisone are just too distant in their shape to stabilise the receptor to any extent, but there are certain other steroidal hormones that are estrogenic. The body makes three main forms of estrogen – estradiol, estrone and estriol. Estradiol is the most powerful estrogen of these three hormones, with estrone being about 30% as potent and estriol about 1% as potent. Estradiol is the dominant estrogen before menopause, and estrone and estriol dominate after menopause. Estrone and estriol are providing an estrogenic effect even though they are triggering the estrogen receptor to a much weaker extent that estradiol.

Genistein is like estradiol in having the necessary two terminal OH groups and an overall shape that closely resembles estradiol. For that reason, genistein is able to enter the receptor (as shown below),but like estriol, is sufficiently different to estradiol that it only activates the receptor weakly.

Genistein is about one-tenth as potent as estriol, the weakest steroidal estrogen in the body, which makes it about 1,000th as strong as estradiol. While this might sound too weak to be of any biological significance, it is worth remembering that the blood of people who eat even just a moderate amount of pulses on a regular basis will contain isoflavones such as genistein to levels about 10,000x that of steroidal estrogens. The 4 main isoflavones, genistein, daidzein, formononetin and biochanin, are all approximately equally estrogenic.

The three diagrams below show an estrogen receptor with the classic, ribbon-like, folded structure of a large protein. The diagram on the left shows what happens when estradiol interacts with the receptor. The trigger (yellow arm) is released, setting off a series of events within the cell that lead eventually to an estrogenic response. The diagram in the middle shows the effect of an anti-estrogen drug entering the receptor, completely blocking the site but preventing the release of the trigger. The third diagram shows what happens when genistein interacts with the receptor site. The trigger arm is released to a substantially lesser degree than with estradiol, resulting in a much milder estrogenic response, but slightly more than with the an ti-estrogen drug.

Estrogen Receptor

+ estradiol

+ anti-estrogen drug

+ isoflavone

Paradoxically, this weak estrogenic activity also means that weak estrogens such as genistein can also behave as anti-estrogens, blocking the effect of stronger estrogens such as estradiol. This is a fairly common biological phenomenon known as competitive-inhibition. This essentially means that when two chemicals with strikingly different strengths compete for the same receptor, then the ability of the weaker chemical to occupy even a small proportion of the binding sites means that the collective effect of the stronger chemical is reduced, compared to a situation where it was on its own.

[This pro-hormone estrogenic role of isoflavones has important implications for human health, particularly women’s health, and is the subject of a book that will shortly be available for download on this website].

While we have used the estrogen receptor-binding effect of isoflavones as an example of their hormonal effect in humans, the same principle applies to other steroid hormone effects such as male sex hormone activity, water-balance and anti-inflammation. When you consider some of the hormonal roles that isoflavones and flavones have in plants ….roles such regulating reproduction (flowering, seed production) and the response of plants to stress (drought, heat) and physical injuries….it is easy to see the ancestral link between those plant roles and that of steroidal hormones in animal reproduction and inflammation (stress, tissue damage).

It is worth emphasising at this point that these pro-hormone effects of isoflavones are limited to those of steroidal hormones. The other class of hormones in the human body, the peptide hormones (eg.insulin, growth hormone etc), are not steroids and therefore are chemically distinct from isoflavones.

(ii) Non-hormone effects

As important as the pro-hormone effects of isoflavones are to human health, they seem unlikely to have anything to do with the anti-cancer functions of isoflavones, the subject that is at the heart of this discussion. The ability of genistein to stop virtually all types of human cancer cells from growing and then to cause them to die, points to a function far more fundamental than the pro-steroidal hormone function. It is a function that reflects the workhorse role with diverse functions of isoflavones in plants, as opposed to the highly specialised function in animals of steroidal hormones such as estradiol that are not known to have any other functions in the body other than to activate the estrogen receptor.

A good example of this difference in function between isoflavones and steroids is the effect on smooth muscle cells. Smooth muscle cells (SMC) occur throughout the body in organs and tissues wherever contraction is required. Two such areas are in the walls of blood vessels and in the prostate gland. In blood vessels, the state of contraction of the vascular SMC is the means by which the body regulates blood pressure; in the prostate; the contraction of the prostate SMC is what expels the prostatic fluid to mix with the sperm at the time of ejaculation. SMC, like all other cells in the body, express estrogen receptors and therefore respond to both estradiol and isoflavones such as genistein.

Estradiol plays an important role in the body in maintaining low blood pressure, which it does via a direct effect on the vascular SMC. Activation of the estrogen receptor directly causes the SMC in the wall of blood vessels to relax. Genistein has exactly the same effect.…a pure and simple hormonal effect in both cases.
But then there is the effect of steroids and isoflavones on SMC in the process of angiogenesis. Angiogenesis is a normal biological process whereby new blood vessels are made to support new tissue as, for example, in a wound, where the in-growth of new capillaries into the wound space is an integral part of the repair process. The resulting blood vessels are completely normal in their behaviour, supporting the repair process and then dying off once repair is complete. This is in contrast to the angiogenesis that accompanies a rapidly dividing cancer…the SMC that proliferate as part of the growth of new capillaries in this situation are far from normal. Just like the cancer they are supporting, the SMC and the blood vessels in this form of angiogenesis grow in an entirely unregulated way.

Genistein is a potent inhibitor of angiogenesis where it is in association with cancer, causing the abnormal SMC to die. Estradiol has no such effect, so this effect clearly is independent of the estrogen receptor. Also, genistein’s anti-angiogenic effect is limited to abnormal blood vessel development…genistein has no effect on the normal process of angiogenesis in wound repair.
Much the same dichotomy of action occurs in the prostate. Prostate SMC play an important role in forcing prostatic fluid out of the gland at the time of ejaculation, but they also have a far more subtle role to play, and that is to support the integrity of the glandular cells in the prostate. See the Prostate Musing elsewhere for a more in depth look at this relationship, but suffice to say here that abnormal behaviour of prostate SMC is thought to be associated with the development of prostate cancer.

Genistein kills prostate SMC that are behaving abnormally, in the same way that it does to vascular SMC. Again, genistein has no such effect on normal prostate SMC and also, again, estradiol has no inhibitory effect on abnormal prostate SMC.

But perhaps the most striking difference in behaviour of the two compounds comes in their effect on human breast cancer cells.

Estradiol stimulates the growth of breast cancer cells, particularly those that are expressing estrogen receptors. Genistein kills human breast cancer cells, regardless of whether they are or are not expressing estrogen receptors.

This ability of genistein to induce death in cancer cells appears to be part of a broader ability to induce death in cells that are behaving abnormally. The cells don’t have to be overtly cancerous to be sensitive to isoflavones, just abnormal as in the case of the prostate SMC and vascular SMC in angiogenesis associated with cancer.

This non-hormonal action appears to have its roots in the primitiveness of isoflavones and the fact that isoflavones regulate a range of fairly primitive biological functions in plants, one of those functions being one of the most basic activities of all living cells ….the way that oxygen is imported into a cell and the way that waste hydrogen is expelled from the cell in return. This two-way pump mechanism is referred to as the reduction-oxidation (or redox) potential across the cell membrane. [See the NOX Musing for a more detailed discussion of this pump and its role in cancer].

It appears that changes in the redox pump are associated with abnormal change in the behaviour of cells. Whether the pump changes in response to the abnormal behaviour or whether it causes the abnormal behaviour is not clear. But irrespective of the link, isoflavones such as genistein appear to be able to detect this change and to direct the changed cell to die. In this way, isoflavones appear to have been given a critically important role in Nature as a surveillance mechanism for abnormal cell function. It would seem that this role is not confined to isoflavones, with some flavones and certain other plant chemicals having the same capacity, but it does seem that the isoflavones such as genistein have it to a much greater extent.

FROM ISOFLAVONES TO ISOFLAVONOID DRUGS

The basis of the Novogen anti-cancer drug technology is to take the naturally-occurring phenomenon that is genistein and its non-hormonal anti-cancer actions, and to convert that into synthetic drugs with far greater potency and specificity.

The approach is classic pharmaceutical chemistry ….take an existing naturally-occurring compound, alter the chemical structure to produce new compounds, and then subject those compounds to a battery of tests to confirm their anti-cancer activity.

The first isoflavonoid drug from the Novogen laboratories was phenoxodiol, the result of a relatively modest alteration to the genistein structure.

Genistein to Phenoxodiol

Phenoxodiol retained two important characteristics of genistein:

• it was active against virtually all forms of human cancer;

• it had no adverse effects on non-cancer cells.

Phenoxodiol considerably improved on genistein in

• being up to 100x more potent against cancer cells;

• being unmodified in the body without loss of activity.

Aside from making phenoxodiol a much more useful drug candidate than genistein, the structural changes also changed the way the cancer cells were being switched off and ultimately made to die. Thus it was not just a matter of retaining a particular biological function and accentuating that function through the structural change. What the change had done was to create a drug that was acting in a materially different way to the naturally-occurring compound.

That outcome led to the realisation that the technology platform was more than just an opportunity to create increasingly more potent drugs based on the same action. The opportunity was to use synthetic chemistry to create a family of drugs with differing mechanisms of action and, therefore, perhaps differing targets.

Hundreds of new compounds were created empirically along lines of increasing complexity as shown in the three figures below. By testing these compounds for anti-cancer activity, a pattern progressively emerged of the way in which the basic isoflavonoid molecule could be manipulated in order to change its anti-cancer behaviour, its specificity and its potency.

Fig.A. Starting isoflavonoid structure.

Fig. B. Simple modification at one point (triphendiol)

Fig.C. Complex modification.

From this position of trial-and-error, Novogen developed the capacity to predictively design a new class of anti-cancer drugs. As the following diagram shows, computer-aided design is being employed to determine those parts of the isoflavonoid skeleton are able to be manipulated in order to increase anti-cancer activity, and the sorts of manipulation that are most likely to be successful. This intellectual property is at the heart of the Company’s future.

The Company has the potential to create a family of anti-cancer drugs with selective uses. Rather than the current one-size-fits-all approach to chemotherapy, the Novogen approach is to provide a range of drugs for specific purposes.

Phenoxodiol.

This was the first Novogen isoflavonoid drug selected to be taken into the clinic.

Phenoxodiol blocks cancer cell division and then induces cell death through both apoptotic and necrotic processes. The signal transduction pathways involved (primarily involving inhibition of sphingosine kinase and XIAP) are relatively well defined.

Phenoxodiol displays anti-cancer activity in pre-clinical studies against almost all forms of human cancer to the extent that it appears to be relatively non-selective in its anti-cancer activity. Despite showing no outstanding predilection for any one particular cancer type, phenoxodiol has tracked along the following four lines of development.

1. f there is one form of cancer more sensitive than others to phenoxodiol it would appear to be squamous cell carcinomas, the type of cancer commonly found in the mouth, oesophagus, cervix, vagina and skin. Its current trialling as a monotherapy in the treatment of cervical and vaginal cancers stems from this observation.
2. Phenoxodiol shows a range of biological functions that are particularly relevant to prostate cancer. This characteristic is being evaluated currently where phenoxodiol is being used as a monotherapy in the treatment of early-stage prostatic carcinoma.
3. Phenoxodiol displays a potent ability to synergise the anti-cancer effects of a range of standard chemotoxics including platinum and taxane drugs. This is behind the testing of the drug in current clinical studies as a means of restoring sensitivity to either carboplatin or docetaxol in late-stage ovarian carcinomas.
4. Phenoxodiol is transported in blood in a conjugated (glucuronidated or sulphated) form. This makes phenoxodiol (and most likely all other monomeric forms of Novogen isoflavonoid drugs) unsuitable for the treatment of leukaemias and colorectal cancers.

Triphendiol.

Triphendiol (previously known as NV-196) is the second Novogen isoflavonoid drug to enter the clinic.

Triphendiol appears to parallel phenoxodiol in that:

• it appears to have a similar mode of action;
• it is highly selective for cancer cells;
• it acts against a broad range of cancer cell types;
• it acts synergistically with standard chemotoxic drugs and restores sensitivity to those drugs;
• it appears in the blood in a conjugated form.

Despite these similiarities, triphendiol is far from being simply a slightly different version of phenoxodiol. Triphendiol clearly has a different set of cancer targets as evidenced by its considerably greater activity against pancreatic carcinoma, cholangiocarcinoma (cancer of the biliary system), and melanoma. The link between these three cancer types is not immediately clear, but it does point to a common signal transduction pathway target.

Triphendiol was granted orphan Drug status by the FDA in 2008 for the treatment of pancreatic cancer, cholangiocarcinoma and Stage IIb-IV malignant melanoma.

NV-128

This is the third isoflavonoid drug to be selected for development, although it remains in its pre-clinical phase.

NV-128 represents a particularly exciting opportunity as the drug is reported to kill ovarian cancer stem cells in addition to ovarian cancer cells. Phenoxodiol and triphendiol appear not to have this effect on the stem cells. NV-128 appears to be working through a different mechanism to that of phenoxodiol, suggesting an entirely new class of anti-cancer drug.

WRAP UP

The Novogen anti-cancer drug technology platform offers a unique and rational means of treating cancer. Rational, because it is based on a natural phenomenon that is being harnessed and expanded; unique, because it offers the potential to develop specific therapies for specific types of cancer.

Isoflavones are arguably the great undiscovered player in human health. As plant compounds with significant biological activity in humans, their presence in the human diet at relatively high levels over thousands of years makes it extraordinarily unlikely that those activities would have been sidelined or ignored. Human development has taken place along side of these compounds, not despite their presence. Rather, it seems certain that those functions have become incorporated into human homeostasis to the point that we have become dependent on them.

One of those key functions is that of pro-hormones, working in tandem with the body’s own steroidal hormones to provide a balance across a wide range of bodily functions. For a woman in her 30s interested in avoiding cyclical mastalgia or endometriosis, or a woman in her 60s interested in avoiding osteoporosis, or a man in his 70s interested in helping to lower blood pressure, then this pro-hormone effect is highly relevant.

But we are interested here in cancer, and that comes down to a different function of isoflavones…their ability to detect pre-carcinogenic change and to eliminate those abnormal cells. We can only speculate on the evolutionary basis of this function, but it seems likely that it relates to a role in plants designed to detect and eliminate cells behaving abnormally. The basis of this abnormality appears to lie in fairly fundamental biochemical processes of life such as the way in which cells respire oxygen and discard waste hydrogen. Why and how such fundamental mechanisms can change is poorly understood, particularly in relation to cancer. Nevertheless, such fundamental changes do occur and isoflavones appear able to detect those changes and to induce the cancer cell to undergo apoptosis.

The Novogen technology platform is built on this phenomenon. Building on the naturally-occurring isoflavone chemical structure, the Company has created new chemical entities with stronger and differing abilities to kill cancer cells. One of the most remarkable developments is the finding that just minor changes in chemical structure produce drugs with a particular predilection for specific types of cancer. What makes this remarkable is that with few exceptions, markers have not been identified that distinguish one form of cancer from another, let alone the Holy Grail of distinguishing a normal cell from a cancer cell. Despite an intense effort in this regard over the last decade, little has come of it other than the identification of the BRCA 1 and 2 genes in about 15% of breast cancer cases (leading to the development of Herceptin), and the presence of the Philadelphia chromosome in chronic myeloid leukemia (leading to the development of Gleevec).

The biotech industry is highly skilled at developing new drugs if the target is known (so called rational drug design).That is behind the current intense effort to identify either a marker that is specific to cancer or markers that are specific to a particular cancer type. You need the lock in order to design the key. Novogen technology is delivering the keys, and in so doing, is pointing to hitherto unknown cancer locks. Work with phenoxodiol has led to the identification of one of those locks (tNOX), but even the fact that the full range of locks has yet to be identified does not diminish the exciting opportunity that the Company holds.

I foresee the technology platform yielding a family of drugs that will offer the oncologist a range of treatment options well beyond what is available now. The two drugs currently in the clinic represent just the start of this opportunity.

Phenoxodiol should be an important addition to the oncology world for its ability to restore sensitivity of cancer cells to commonly-used standard chemotoxic drugs as carboplatin and docetaxol should see it being used across a wide range of different cancer types where such drugs are used, despite the initial regulatory approval being sought for ovarian cancer. In this application, phenoxodiol will be unique. But beyond this general application, it has the potential to become a standard therapy in early-stage prostate cancer and in squamous cell carcinomas such as cervical and vaginal cancers, all cancers for which there currently are few effective therapeutic options.

Triphendiol looks destined to become a treatment for cholangiocarcinoma and pancreatic cancer in combination with gemcitabine.

The therapeutic applications of NV-128 are yet to be disclosed, but my educated guess is that it will be the different forms of lung cancer in particular, and, more generally, those forms of cancer where cancer stem cells form important components of ongoing tumour growth.

The most likely scenario, however, is that these (and future isoflavonoid drugs) will be used in combination. Combination chemotherapy of 2 or more isoflavonoid drugs with their differing molecular targets and differing cellular targets within a tumour mass, would offer the opportunity of successfully hitting a range of different phenotypes within the one tumour mass, and of reducing the likelihood of chemo-resistance developing.

This entry was posted Friday, October 16th, 2009 at 12:07 pm and is filed under Musings. Both comments and pings are currently closed.