By Dr. Daniela Vergara
Have you ever wondered why some Cannabis sativa buds are bright red or purple? Today we will continue our discussion on flavonoids which are the compounds that help give the plant its bold colors. Please read our previous post on purple C. sativa
Besides the well-known cannabinoids like THC (tetrahydrocannabinol) and CBD (cannabidiol), C. sativa also contains other important compounds called flavonoids. These chemicals not only make the plant look beautiful, but they may also work together with cannabinoids and terpenes to produce an effect [1].
What Are Flavonoids?
Flavonoids are a type of phenolic compound found in many plants. They’re known for their wide range of colors and are common in plant-based foods too.
Phenol is a simple chemical made of a carbon ring with an -OH (hydroxyl) group attached. It’s the basic building block for many plant compounds like flavonoids.
Flavonoids are considered some of the most important plant phenols in our diet and are one of the largest groups of natural compounds in the plant world [2].
Flavonoids and colors
The word “flavonoid” comes from the Latin word flavus, meaning yellow—because many flavonoids give plants yellow tones. But flavonoids can also add red, purple, and other colors.
Flavonoids are colorful compounds, but we don’t always see them because their colors can be hidden by other pigments. For example, green chlorophyll (which helps with photosynthesis) and yellow-orange carotenoids are not flavonoids, so not all plant pigments come from flavonoids. However, when buds are red or purple, that usually means flavonoids are present.
What Do Flavonoids Do?
Flavonoids are found in thousands of plants and have many jobs. One of their main roles is to act as pigments, especially in flower petals [3]. Over 4,000 natural flavonoids have been identified [2]. Some studies also suggest that flavonoids help protect plants from ultraviolet (UV) light and from diseases [3].
In C. sativa, flavonoids help give each variety its unique look and may even affect how it makes us feel, but research needs to confirm that. Some colorful C. sativa types—like Purple Haze or Purple Urkle get their deep hues from these compounds.
Flavonoid classification
In addition to C. sativa, flavonoids are also found in fruits, vegetables, and many other plants we eat. We’ve previously talked about anthocyanins, a type of flavonoid that turns some C. sativa flowers purple.
Flavonoids are usually attached to sugar molecules and are grouped into 13 classes based on their chemical structure [2]:
- Flavonols – Found in many plants; includes quercetin and kaempferol
- Flavones – Includes apigenin, luteolin, and cannflavins A, B, and C, which are found in cannabis
- Flavanones – Found in citrus fruits; includes naringenin and hesperetin
- Isoflavones – Found in soy products; includes genistein and daidzein
- Anthocyanidins – Give red, blue, or purple color to foods like blueberries and blackberries [4]
Chemical Structure
Flavonoids are organic compounds (contain carbon atoms) made of 15 carbon atoms and two benzene rings [2, 3].
Flavonoids in Cannabis sativa
Several flavonoids have been found in C. sativa, with some of the most well-known being flavones like vitexin, orientin, luteolin, and apigenin, and flavonols like kaempferol and quercetin [5].
One of the first flavonoids identified in C. sativa was cannflavin [6]. It was later found that this compound can be divided into several types: cannflavins A, B, and C [7, 8]. However, it is estimated that besides the main cannflavin A, B, and C, C. sativa may produce more than 20 types of flavonoids including orientin, vitexin, apigenin, luteolin, kaempferol, and quercetin [5].
Cannflavins A and B have been found in young hemp plants with low cannabinoid levels [9] and also in homemade cannabis tinctures [10].
Flavonoids and their role
While flavonoids are well studied in other plants and foods, it’s still unknown about how they interact with the rest of the compounds in C. sativa and more research is needed.
Flavonoids are natural antioxidants that may help prevent or treat many diseases. They are being studied for their anti-cancer and antiviral effects. Some research shows they may help fight viruses like HIV, herpes, the flu, and polio [2].
Flavonoids have antioxidant, possibly anti-cancer effects [11], and may reduce inflammation [6] by blocking inflammation signals in the body like prostaglandin E2 and leukotrienes [9, 11].
Well-Known Flavonoids in Plants
There are many flavonoids found in nature. One of the most studied is quercetin, which may help fight cancer. It’s one of the most common flavonoids in fruits, along with kaempferol and myricetin [2].
Another important one is apigenin, which is found in fruits, vegetables, and also in C. sativa [2, 5]. Apigenin may affect the GABA receptor in the brain (just like THC and CBD), which could explain why it may have calming or relaxing effects [12]. It’s also being studied for helping treat many types of cancer, including breast, lung, prostate, colon, liver, and more [2].
So, remember, when you consume cannabis you are consuming much more than THC, and hopefully in a near future we will know more about how flavonoids affect users and their health.
References
1. Zager, J.J., et al., Gene networks underlying cannabinoid and terpenoid accumulation in cannabis. Plant physiology, 2019. 180(4): p. 1877-1897.
2. Bhuyan, D.J. and A. Basu, Phenolic compounds potential health benefits and toxicity, in Utilisation of bioactive compounds from agricultural and food waste. 2017, CRC Press. p. 27-59.
3. Falcone Ferreyra, M.L., S. Rius, and P. Casati, Flavonoids: biosynthesis, biological functions, and biotechnological applications. Frontiers in Plant Science, 2012. 3(222).
4. Bautista, J.L., S. Yu, and L. Tian, Flavonoids in Cannabis sativa: Biosynthesis, bioactivities, and biotechnology. ACS omega, 2021. 6(8): p. 5119-5123.
5. Vanhoenacker, G., et al., Chemotaxonomic features associated with flavonoids of cannabinoid-free cannabis (Cannabis sativa subsp sativa L.) in relation to hops (Humulus lupulus L.). Natural Product Letters, 2002. 16(1): p. 57-63.
6. Barrett, M., D. Gordon, and F. Evans, Isolation from Cannabis sativa L. of cannflavin—a novel inhibitor of prostaglandin production. Biochemical pharmacology, 1985. 34(11): p. 2019-2024.
7. Barrett, M., A. Scutt, and F. Evans, Cannflavin A and B, prenylated flavones from Cannabis sativa L. Experientia, 1986. 42(4): p. 452-453.
8. Rea, K.A., et al., Biosynthesis of cannflavins A and B from Cannabis sativa L. Phytochemistry, 2019. 164: p. 162-171.
9. Werz, O., et al., Cannflavins from hemp sprouts, a novel cannabinoid-free hemp food product, target microsomal prostaglandin E2 synthase-1 and 5-lipoxygenase. PharmaNutrition, 2014. 2(3): p. 53-60.
10. Peschel, W., Quality control of traditional cannabis tinctures: pattern, markers, and stability. Scientia pharmaceutica, 2016. 84(3): p. 567-584.
11. Moreau, M., et al., Flavonoid derivative of cannabis demonstrates therapeutic potential in preclinical models of metastatic pancreatic cancer. Frontiers in oncology, 2019. 9: p. 660.
12. Losi, G., et al., Apigenin modulates GABAergic and glutamatergic transmission in cultured cortical neurons. European journal of pharmacology, 2004. 502(1-2): p. 41-46.
