Flavonoids

Trifolirhizin possesses potential anti-inflammatory and anti-cancer activities, it inhibits acetylcholine mediated airway smooth muscle (ASM) contraction or directly relaxes pre-contracted ASM independent of β 2 -adrenoceptors. Trifolirhizin may be a a candidate as skin-whitening agents, it exerts varying degrees of inhibition on tyrosinase-dependent melanin biosynthesis.

Didymin is a citrus-derived natural compound that kills p53 wild-type as well as drug-resistant p53-mutant neuroblastoma cells in culture, it induces apoptosis by inhibiting N-Myc and upregulating RKIP in neuroblastoma. Didymin possesses antioxidant, anti-inflammation and anti-cancer properties.

Brazilin, isolated from Caesalpinia sappan has been known as a natural red pigment, exhibits the inhibitory effect on lipopolysaccharide (LPS)-stimulated NO production in a dose-dependent manner (IC50=24.3 microM), might be associated with the regulation of transcription factors NF-kappaB and AP-1; inducible isoform of nitric oxide synthase (NOS) plays an important role in inflammation and carcinogenesis, suggests that the suppressive effect of iNOS gene expression by brazilin might provide one possible mechanism for its anti-inflammatory and cancer chemopreventive activity.

Tectorigenin (Tg) and tectoridin (Td) are the major compounds isolated from the rhizomes of iridaceous plant Belamcanda chinensis which is well known as a chinese traditional medicine for the treatment of inflammatory diseases; Tectorigenin inhibits IFN-γ/LPS-induced inflammatory responses in murine macrophage RAW 264.7 cells, it appears to have the potential to prevent inflammation.