Flavonoids by Jillian Thayer
There are hundreds of phytochemicals residing within cannabis; well over five hundred compounds have been documented and researched (Gonçalves et al., 2019). These include phytocannabinoids, various kinds of terpenes, flavonoids, fatty acids, and many others. The first two constituents garner the most attention, but lately there has been an increased interest for studying cannabis flavonoids. Thanks in large part to the loosening of rules and regulations, as well as increased public interest, this has brought about a revival for studying this plant for its medicinal applications. Researchers and consumers alike want to know what other therapeutic constituents exist within cannabis, so they can be utilized for more applications. There is still a lot of information to uncover from this plant’s phytochemistry and scientists have been eagerly wanting to reveal more information about cannabis. This will be the topic of focus for this blog: a brief explanation as to what flavonoids are, examining the role they play in plant health and human wellness, and how cannabis flavonoids add more intrigue for the industry.
What is a Flavonoid
A flavonoid is a plant constituent with a polyphenolic (compounds containing numerous phenol groups) structure that contains fifteen carbon atoms and is water soluble. Phenolic phytochemicals are extremely widespread throughout the plant kingdom with over 10,000 different structures presented (Andre, Hausman, & Guerriero, 2016). Flavonoids are a particular class of phytochemicals that virtually exist within all plants, as ”secondary metabolites having a polyphenolic structure, widely found in fruits and vegetables” (Panche et al., 2016). Flavonoid classification can be broken down even further by different subgroups such as flavones and flavonols among many others. We readily see flavonoids in many of our favorite fruits and vegetables because these compounds are highly concentrated within the skin of these food sources. They are also present in many medicinal plants. These organic compounds grant them their flavor and color.
Flavonoid Properties for Plant Health and Human Wellness
Secondary metabolites play an important function in the overall health of the plant, but these compounds are not involved with the plant’s growth, development, or reproduction. An example of a secondary metabolite are flavonoids, for these function as a survival mechanism for plants. Due to this complex phytochemistry which offers protective qualities for plants, this constituent has been sought after and capitalized upon by the nutraceutical, pharmaceutical, and cosmetic industries as essential components for various applications. Some flavonoids have been studied extensively for their healing properties, such as flavones, as some researchers argue they “have demonstrated many potentially beneficial activities in animal studies and human trials” and therefore need to be explored to better understand their role they exhibit in our health (Hostetler, Ralston, & Schwartz, 2017). Moreover, scientists and manufacturers are interested in this class of compounds not only for medicinal applications, but also to utilize them as pesticides in agricultural practices (Panche, Diwan, & Chandra, 2016). We can easily see flavonoids as they show up as plant pigments, but the knowledge of why flavonoids are ubiquitous in plants and how it pertains to our health may not be as apparent.
Plant Functions: Protection, Attraction, and Interaction
Flavonoids display many different biological roles for plants in terms of their physiology and development. They function as a form of protection from abiotic and biotic stresses (such as heat, UV radiation, or pathogens and herbivores respectively). In the case of insect and herbivore pressure, plants can release certain chemicals that deter animals from eating the plant by altering its flavor and reducing its nutritive value, as well as discourage egg laying (Mierziak, Kostyn, & Kulma, 2014). On the other hand, plants can attract insects with the help of flavonoids, showcased by their vibrant colors, which encourages pollination. Plants also employ the use of flavonoids as way of protecting themselves against UV rays by functioning as a screen to block the radiation because they are present throughout the epidermis and hypodermis layers; this protects the vulnerable organs and tissues (Mierziak, Kostyn, & Kulma, 2014). Flavonoids are also able to interact with their environment through signal molecules which helps plants maintain symbiotic relationships with soil bacteria. Another way plants are able to interact with other plants is by inhibiting germination and growth from a competing plant via flavonoids, although scientists have not been able to fully understand the mechanism by which this occurs.
Many people have heard that one’s diet should consist of eating an array of different colored produce, commonly referred to as eating the rainbow. The reasoning behind this is due to the incredible properties these compounds hold for us. We require an assortment of nutrients to function optimally and flavonoids are believed to provide a multitude of attributes we need to support our natural systems. Benefits like decreasing inflammation, reducing damage caused by free radicals, as well as other protective qualities can all be attributed to flavonoids. Flavonoids have been documented to exhibit some pharmacological activities evidenced by some in vitro trials, but none have yet to include human studies to fully investigate these properties as flavonoids exhibit poor bioavailability and are therefore difficult to study. Nonetheless, many industries take advantage of this plant compound to incorporate natural wellness into many goods like cosmetics, food, beverage, and even agricultural pesticides (Panche, Diwan, & Chandra, 2016). We can easily take advantage of the qualities offered by flavonoids by simply eating organic produce as well as by utilizing medicinal plants. They are an integral component to our diet.
The Next Big Thing
There are several flavonoids found within the cannabis species. Twenty compounds have been identified, which mostly come from the flavone and flavonol subclasses (Andre, Hausman, & Guerriero, 2016). Some flavonoids found in cannabis, such as apigenin, luteolin, and quercetin, are also present in other fruits, vegetables, and medicinal plants. Chemically speaking, the flavone subgroup is a significant type of flavonoid; they appear as glucosides in leaves, flowers, and fruits (Panche, Diwan, & Chandra, 2016). Additionally, the flavonol subclass is present in many fruits and vegetables. These kinds of flavonoids are present in high THC and high CBD plant varieties. In addition to the commonly shared flavonoids, researchers have been able to identify flavonoids that are unique to cannabis.
There are two unique flavonoids derived from the class of flavones and are termed “cannflavin A and B.” There have not been as many studies on the flavonoids found within this plant species, but there is heightened interest in these unique compounds, especially due to their non-psychoactive and therapeutic role they display (Pellati et al., 2018). According to a study conducted in 1985 by Dr. Barrett, of the Department of Pharmacology, Institute of Basic Medical Sciences, Royal College of Surgeons of England, and and her colleagues, they found that not only do these cannflavins exist, but they demonstrated anti-inflammatory properties that were thirty times more effective than that of aspirin (Rea et al., 2019). This knowledge is intriguing and inspires further exploration to discover more of the plant therapeutics.
The Entourage Effect is the belief that the different chemical components work together synergistically in order to promote a more holistic effect. Those who advocate for the existence of the Entourage Effect point to the research that shows that there are other molecules present in cannabis which offer effects similar to the activity of the cannabinoids (Russo, 2019). The anti-inflammatory activity presented by the flavonoids found within cannabis helps to support this whole-plant synergy theory. Scientists have not been able to confirm this activity because there is too much chemical variability and many nuances in the cultivation, which makes it very difficult to conduct scientific experiments. However, there are many cannabis researchers who advocate that it does exist pointing to the various studied components that elucidate the whole spectrum is superior to isolated parts meant for consumption. Unfortunately, flavonoids do not make up a significant portion of cannabis phytochemistry, accounting for about 2.5% of its dry weight where they’re found only in the leaves and the flowers (Fundacion Canna, n.d.). This makes it difficult to extract and utilize these compounds. However, this further highlights the need to consume the plant in a holistic way in different preparations .
Future Potential, More to Discover
There are many important roles flavonoids exhibit in maintaining plant health, from protecting itself, from the elements and predators to attracting pollinators, which ensures reproduction. Humans are closely tied to nature; this is where we derive our food, medicine, and fiber, among other materials. Flavonoids contribute many properties that provide a multitude of benefits in the medical, cosmetic, and agricultural fields.
There is still much to learn about this subject in terms of how this may be applied to the cannabis industry; we are merely in the nascent stages of discovery. Much of the focus has been centered on cannabinoids and terpenes, but the flavonoid constituent is not to be overlooked. Most people are aware of the benefits to be had by consuming produce that is brightly and richly colored in order to support their health and physiological functions; this also includes consuming medicinal plants that promote similar actions. Even though these molecules exist in small amounts in the plant, it still offers a great deal of research potential to extrapolate therapeutic uses and benefits of flavonoids.
Andre, C. M., Hausman, J. F., & Guerriero, G. (2016). Cannabis sativa: The Plant of the Thousand and One Molecules. Frontiers in Plant Science, 7(19), 1-13. https://doi.org/10.3389/fpls.2016.00019
Fundación Canna. (n.d.). Flavonoids. Retrieved from https://www.fundacion-canna.es/en/flavonoids
Gonçalves, J., Rosado, T., Soares, S., Simão, A. Y., Caramelo, D., Luís, ., Fernández, N., Barroso, M., Gallardo, E., & Duarte, A. P. (2019). Cannabis and Its Secondary Metabolites: Their Use as Therapeutic Drugs, Toxicological Aspects, and Analytical Determination. Medicines, 6(1), 31. https://doi.org/10.3390/medicines6010031
Hostetler, G. L., Ralston, R. A., & Schwartz, S.J. (2017). Flavones: Food Sources, Bioavailability, Metabolism, and Bioactivity. Advances in Nutrition, 8(3). 423–435. https://doi.org/10.3945/an.116.012948
Mierziak, J., Kostyn, K., & Kulma, A. (2014). Flavonoids as important molecules of plant interactions with the environment. Molecules, 19(10), 16240–16265. https://doi.org/10.3390/molecules191016240
Panche, A. N., Diwan, A. D., & Chandra, S. R. (2016). Flavonoids: an overview. Journal of Nutritional Science, 5, 1-15. https://doi.org/10.1017/jns.2016.41
Pellati, F., Brighenti, V., Sperlea, J., Marchetti, L., Bertelli, D., & Benvenuti, S. (2018). New Methods for the Comprehensive Analysis of Bioactive Compounds in Cannabis sativa L. (hemp). Molecules, 23(10), 2639. https://doi.org/10.3390/molecules23102639
Rea, K. A., Casaretto, J. A., Al-Abdul-Wahidb, M. S., Sukumarana, A., Geddes-McAlistera, J., Rothstein, S. J., & Akhtara, T. A. (2019). Biosynthesis of cannflavins A and B from Cannabis sativa L. Phytochemistry, 164, 162-171. https://doi.org/10.1016/j.phytochem.2019.05.009
Russo E. B. (2019). The Case for the Entourage Effect and Conventional Breeding of Clinical Cannabis: No “Strain,” No Gain. Frontiers in plant science, 9, 1969. https://doi.org/10.3389/fpls.2018.01969