Luteolin, 3',4',5,7-tetrahydroxyflavone, is a common flavonoid that exists in many types of plants including fruits, vegetables, and medicinal herbs. Plants rich in luteolin have been used in Chinese traditional medicine for treating various diseases such as hypertension, inflammatory disorders, and cancer. Luteolin possesses a variety of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial and anticancer activities. Numerous studies have shown that luteolin possesses beneficial neuroprotective effects both in vitro and in vivo.

Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g. tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries and grapes) and in plants or botanical products commonly used in traditional medicine (e.g. Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Numerous preclinical studies have shown that kaempferol and some glycosides of kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, anti-osteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities.

Quercitrin is known as a bio flavonoid antioxidant and was investigated extensively in its antioxidant potential in streptrozotocin (STZ)-induced diabetic rats. Quercitrin is also a constituent of the dye quercitron. Quercitrin can be found in Tartary buckwheat and in oaks species such as white oak or European red oak. Quercitrin has potential anti-inflammation effect that is used to treat heart and vascular conditions. Quercitrin offers protection against brain injury in mice by inhibiting oxidative stress and inflammation. Quercitrin also prevented CCl4 induced cerebral function disorders associated with its ability to inhibit the activities of monoamine oxidase (MAO), acetylcholine esterase (AChE) and the N-methyl-d-aspartate receptor 2B subunit (NR2B). Quercitrin suppressed the release of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). Quercitrin may be a potential candidate to be developed as a neuroprotective agent. Quercitrin has been used previously as an antibacterial agent and has been shown to inhibit the oxidation of low-density lipoproteins and prevent an allergic reaction. It was demonstrated that quercitrin exerts protective effects against H2O2-induced dysfunction in lung fibroblast cells. Quercitrin has antiproliferative and apoptotic effects on lung cancer cells by modulating the immune response. There were significant increases in caspase-3 activity, loss of MMP, and increases in the apoptotic cell population in response to quercitrin in DLD-1 colon cancer cells in a time- and dose-dependent manner. These results revealed that quercitrin has antiproliferative and apoptotic effects on colon cancer cells. Quercitrin activity supported with in vivo analyses could be a biomarker candicate for early colorectal carcinoma.

Fisetin, a natural flavonoid found in various fruits, vegetables, and nuts, has various biological properties, including anti-inflammatory, anti-oxidant, neuroprotective in cell culture and in animal models relevant to human diseases. Fisetin can be also a promising agent for the treatment of uveal melanoma. Besides, it is a therapeutic agent for respiratory inflammatory diseases such as chronic obstructive pulmonary disease (COPD), where fisetin inhibits the TNF-α-activated IKK/NF-κB cascade by targeting PKCδ. In vitro and in vivo experiments have revealed that fisetin possesses significant therapeutic effects against diabetic complications and atherosclerosis, where it can suppress vascular inflammatory processes.

Myricetin is a member of the flavonoid class of polyphenolic compounds with antioxidant properties. It occurs naturally in a wide variety of plants. Myricetin has demonstrated anti-inflammatory, antioxidative, anti-non-enzymatic glycation and anti-hyperlipidemia in a number of cellular and animal models. It has been investigated for potential therapeutic effects against cancers and diabetes.

Luteolin, 3',4',5,7-tetrahydroxyflavone, is a common flavonoid that exists in many types of plants including fruits, vegetables, and medicinal herbs. Plants rich in luteolin have been used in Chinese traditional medicine for treating various diseases such as hypertension, inflammatory disorders, and cancer. Luteolin possesses a variety of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial and anticancer activities. Numerous studies have shown that luteolin possesses beneficial neuroprotective effects both in vitro and in vivo.