The biochemistry and medical significance of the flavonoids.

Epidemiological evidence suggests that flavonoids may play an important role in the decreased risk of chronic diseases associated with a diet rich in plant-derived foods. Flavonoids are also common constituents of plants used in traditional medicine to treat a wide range of diseases. The purpose of this article is to summarize the distribution and biological activities of one of the most common flavonoids: luteolin. This flavonoid and its glycosides are widely distributed in the plant kingdom; they are present in many plant families and have been identified in Bryophyta, Pteridophyta, Pinophyta and Magnoliophyta. Dietary sources of luteolin include, for instance, carrots, peppers, celery, olive oil, peppermint, thyme, rosemary and oregano. Preclinical studies have shown that this flavone possesses a variety of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial and anticancer activities. The ability of luteolin to inhibit angiogenesis, to induce apoptosis, to prevent carcinogenesis in animal models, to reduce tumor growth in vivo and to sensitize tumor cells to the cytotoxic effects of some anticancer drugs suggests that this flavonoid has cancer chemopreventive and chemotherapeutic potential. Modulation of ROS levels, inhibition of topoisomerases I and II, reduction of NF-kappaB and AP-1 activity, stabilization of p53, and inhibition of PI3K, STAT3, IGF1R and HER2 are possible mechanisms involved in the biological activities of luteolin.

Distribution and biological activities of the flavonoid luteolin.

Bioactive Benzofuran derivatives: A review

Therapeutic orchids: traditional uses and recent advances--an overview.

Natural phenanthrenes and their biological activity.

Bi-bicyclic and bi-tricyclic compounds from Dendrobium thyrsiflorum.

Tribulusamides A (1) and B (2), new lignanamides embracing two cinnamic amide parts joined in a cis configuration, were isolated from the fruits of Tribulus terrestris, together with four known compounds, N-trans-feruloyltyramine (3), terrestriamide (4), N-trans-coumaroyltyramine (5), and beta-sitosterol. The structures were elucidated by 2D-NMR spectroscopy. Addition of compounds 1-5, especially 1 and 2, to primary cultured mouse hepatocytes significantly prevented cell death induced by D-galactosamine (D-GalN)/tumor necrosis factor alpha (TNF-alpha).

Tribulusamide A and B, new hepatoprotective lignanamides from the fruits of Tribulus terrestris: indications of cytoprotective activity in murine hepatocyte culture

A nets aporphinoid alkaloid, trivially named linderaline (1), along with eight known isoquinoline alkaloids as (-)-pallidine (2), protosinomenine (3), laudanosoline 3',4'-dimethyl ether (4), boldine (5), norisoboldine (6), laurolitsine (7), pronuciferine (8) and reticulline (9) were isolated from ethanol extract of the dried root of Lindera aggregata (Sims) Kosterm. Their structures were established on the basis of the spectral analysis. Compounds 2, 3, 4, 6, 8 were found from the plant for the first time.

Zheng-Tao Wang

Papers

Bi-bicyclic and bi-tricyclic compounds from Dendrobium thyrsiflorum.

Tribulusamide A and B, new hepatoprotective lignanamides from the fruits of Tribulus terrestris: indications of cytoprotective activity in murine hepatocyte culture

Isoquinoline Alkaloids from Lindera aggregata

Cytotoxic sesquiterpenes from Ligularia platyglossa

A sesquiterpene lactone glucoside from Ixeris denticulata f. pinnatipartita.