What are cannabis flavonoids and what do they do?

Flavonoids are a group of secondary plant metabolites responsible for pigmentation, whose main power lies in their antioxidant and anti-inflammatory properties. Found in plants, vegetables, and fruits, these phytonutrients are essential for the survival and development of these organisms.

This type of polyphenol has become one of the most studied natural compounds in science in recent years, due to its biological properties against cancer, cardiovascular diseases, and other chronic conditions.

What are flavonoids?

Derived from the Latin word flavus (yellow), flavonoids are associated with UV protection, attracting pollinating insects, and light capture. They also regulate the cell cycle and defend plants against herbivores.

The first scientific observation was made in 1664 when English physicist, chemist, and philosopher Robert Boyle briefly described the effects of flower pigmentation. Nearly 300 years later, Nobel laureate in Physiology and Medicine Szent-Györgyi identified the first flavonoid by isolating a substance called citrin from lemon peel.

Flavonoids are the most abundant subgroup of polyphenols in the plant kingdom, and research is divided into basic and applied studies. Applied research includes metabolic engineering of flavonoids, which allows manipulation of DNA to control biosynthesis. This has enabled innovations in flower coloration, improved nutritional potential of foods, suppression of pollen fertility, and increased pharmaceutical potential of plants.

What is the structure of flavonoids?

Flavonoids have a phenolic structure consisting of two benzene rings connected by a three-carbon chain, forming a C6-C3-C6 structure.

Different types of flavonoids are distinguished by the saturation and substituents of the C-ring, while individual compounds differ in the substitution of the A and B rings. In plants, flavonoids appear in free form or as glycosides.

Functions of flavonoids in plants

Flavonoids perform various defensive, generative, and protective functions in plants and other organisms. The primary function is protection against ultraviolet light, as flavonoids accumulate in surface layers to absorb up to 90% of UV radiation.

They also provide coloration in plants, vegetables, fruits, and other structures, act as herbivore protectors, and regulate auxin hormone transport. As highlighted in this article and in our post What are polyphenols?, the antioxidant function of flavonoids depends on their ability to scavenge free radicals.

Effects and benefits of flavonoids

Historically used in traditional Chinese medicine for their antioxidant nature, flavonoids have anti-inflammatory properties that support the immune system. They can also regulate blood pressure, blood sugar levels, and enhance cognitive performance.

In humans, they have been associated with inhibiting cancer cell growth, strengthening cardiac muscles, improving circulation, increasing capillary resilience, and preventing blood clots. They also protect the liver, stomach, and help reduce cholesterol.

Medicinal properties of flavonoids

The main medicinal properties are antioxidant, anti-inflammatory, anticancer, and neuroprotective. Studies have highlighted the following benefits:

• Antioxidant 
• Anti-inflammatory
• Anti-hemorrhagic
• Anti-allergic
• Antiviral
• Antibacterial
• Vasodilatory
• Hepatoprotective
• Anti-platelet aggregation
• Anti-neoplastic

How are they classified?

As with most secondary metabolites, flavonoids can be classified in various ways. According to the International Union of Pure and Applied Chemistry (IUPAC), classification is based on metabolic pathways and molecular structure. They are divided into flavonoids, isoflavonoids, and neoflavonoids.

Within flavonoids, there are flavones, flavonols, flavandiols, chalcones, anthocyanins, condensed tannins, aurones, dihydroflavonols, and flavanones.

• Flavones: including tricetin, apigenin, and luteolin.
• Flavonols: including quercetin, myricetin, and kaempferol.
• Flavandiols: including leucocyanidin, leucopelargonidin, and leucodelphinidin.
• Chalcones: promote pollination.
• Anthocyanins: water-soluble pigments responsible for coloration.
• Condensed tannins: anthocyanidins found in tea plants.
• Aurones: responsible for pigmentation in various plants.
• Dihydroflavonols: including dihydromyricetin, dihydroquercetin, and dihydrokaempferol.
• Flavanones: highly concentrated in citrus fruits like oranges.

Role of flavonoids in cannabis plants

Different cannabis seed strains (available in our online Grow Shop) contain a variety of flavonoids, alongside cannabinoids and terpenes. Flavonoids represent roughly 10% of the plant’s total compounds and can account for up to 2.5% of the dry weight in flowers and leaves. As antioxidants, they may inhibit P450 enzymes along with cannabidiol to help form tetrahydrocannabinol (THC) in cannabis plants.

The well-known “entourage effect” relies on the synergistic interaction of cannabis flavonoids with cannabinoids and terpenes, producing various therapeutic benefits for multiple diseases and chronic pain.

Flavonoids are typically found in leaves and stems, as seeds and roots do not contain them. Cannabis contains 23 unique types of flavonoids.

The most important include cannaflavins A, B, and C, beta-sitosterol, quercetin, and apigenin:

• Cannaflavins A, B, and C: A has effects stronger than aspirin, while B and C also have medicinal properties but are less studied.
• Beta-sitosterol: reduces cholesterol levels and prevents coronary diseases.
• Quercetin: known for anti-inflammatory and antioxidant properties.
• Apigenin: offers anticancer, anti-inflammatory, and antioxidant benefits.
• Vitexin and Isovitexin: inhibit arthritis and hypothyroidism.
• Orientin and luteolin: also found in tea plants; have anti-inflammatory, anticancer, and antibacterial properties.
• Kaempferol: possesses anti-inflammatory and antioxidant properties, helping prevent cancer and coronary diseases.

A fundamental part of plant development

For all the reasons explained above, it is necessary to highlight the amount of flavonoids present in cannabis. They are therefore a fundamental part of strengthening and ensuring the proper development and growth of these valuable plants.

Other foods that contain different types of flavonoids include cocoa, oranges, parsley, wine, onions, apples, Brussels sprouts, and green tea.

Clearly, further research and study is needed to gain a more accurate understanding of these natural compounds and their relationship with the positive effects they can have on different organisms. Even so, there is no doubt that these benefits have historically been exploited by humans and animals through the consumption of plants, vegetables, and fruits. For this reason, we should consider them a basic element in structuring our nutritional diet.