luteolin

Luteolin is a naturally occurring flavone, a subclass of polyphenols, with the chemical formula C15H10O6. It possesses a flavone skeleton comprising two phenyl rings (A and B) and a heterocyclic ring (C). Luteolin is found in a variety of plant foods and herbs, including celery, parsley, thyme, green pepper, and chamomile, as well as in certain fruits such as oranges and apples. The compound is extracted for use in botanical supplements and natural product research.

Biological investigations have documented antioxidant, anti-inflammatory, anticancer, and neuroprotective activities for luteolin. Its antioxidant effect is partly due to the ability to scavenge free radicals and to upregulate endogenous antioxidant enzymes like glutathione peroxidase. Anti-inflammatory actions involve inhibition of nuclear factor kappa‑B (NF‑κB) signalling, reduction of pro‑inflammatory cytokines (IL‑6, TNF‑α), and suppression of cyclo‑oxygenase‑2 expression. In cancer cell models, luteolin induces apoptosis via mitochondrial pathways, arrests cell cycles, and inhibits angiogenesis through down‑regulation of vascular endothelial growth factor. Neuroprotective studies suggest that luteolin mitigates oxidative stress and excitotoxicity in neuronal cultures and improves cognitive performance in animal models of Alzheimer’s disease.

In laboratory settings, luteolin was found to inhibit specific protein kinases such as mitogen‑activated protein kinases (MAPKs), phosphoinositide 3‑kinase (PI3K), and protein kinase C (PKC). This wide range of targets contributes to its diverse pharmacological profile. Toxicological data indicate that luteolin is relatively safe at dietary concentrations; however, high‑dose supplementation may lead to gastrointestinal discomfort and mild hepatotoxicity in pre‑clinical studies. Ongoing clinical trials aim to clarify its therapeutic potential in conditions such as inflammatory bowel disease, metabolic syndrome, and certain cancers, but large‑scale human evidence remains limited.