Inhibitory effect of ephedrannins A and B from roots of Ephedra sinica STAPF on melanogenesis.

BACKGROUND: Melanogenesis, a process producing the pigment melanin in human skin, eyes and hair, is a major physiological response against various environmental stresses, in particular exposure to ultraviolet radiation, and its pathway is regulated by a key enzyme, tyrosinase. In this study, we evaluated the effects of ephedrannins A and B, which are polyphenols from the roots of Ephedra sinica, commonly used in herbalism in oriental countries, on mushroom tyrosinase and melanogenesis in B16F10 melanoma cells. METHODS: Their effects on mushroom tyrosinase were determined via kinetic studies using a spectrophotometric analysis and those on melanin and tyrosinase production in melanoma cells treated with α-MSH (melanin stimulating hormone) were examined using PCR and ELISA. RESULTS: Both ephedrannins A and B exhibited concentration-dependent inhibitory effects on L-tyrosine oxidation by mushroom tyrosinase, and the inhibition mechanism was competitive and reversible with L-tyrosine as the substrate. In addition, melanin production in melanoma cells was also suppressed in a concentration-dependent manner by ephedrannins A and B without significant effects on cell proliferation at the concentrations tested. Both compounds showed inhibitory effects on melanin production by suppressing the transcription of tyrosinase in the cells. CONCLUSION: Both compounds exhibited significant inhibitory effects, but the inhibition by ephedrannin B was much more effective than that by ephedrannin A. Both ephedrannins A and B may be good candidates for a whitening agent for skin. GENERAL SIGNIFICANCE: This is the first report that describes effective inhibition of melanin production by ephedrannins A and B isolated from Ephedra roots.

Ephedrannin A and B from roots of Ephedra sinica inhibit lipopolysaccharide-induced inflammatory mediators by suppressing nuclear factor-κB activation in RAW 264.7 macrophages.

Ephedra sinica is a traditional Chinese medicinal herb and has pharmacological functions including anti-inflammatory effects. However, the active ingredients from Ephedra roots have not been characterized. Here, two active constituents were isolated and their structures and mechanisms of action were defined. Active constituents from Ephedra roots were isolated by continuous solvent-extractions and column chromatography. Their structures were determined by use of multiple types of spectrometry. The mechanisms of action were examined using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells through PCR, ELISA, electrophoretic mobility shift assays, and immunocytochemistry. Two active constituents, ephedrannin A and B, belonging to the A-type proanthocyanidin family were identified. Both ephedrannin A and B effectively suppressed the transcription of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). These compounds exerted their anti-inflammatory actions on LPS-stimulated macrophages by suppressing the translocation of nuclear factor-kappa B (NF-κB) and the phosphorylation of p38 mitogen-activated protein (MAP) kinase. Ephedrannin A and B both exhibited strong anti-inflammatory effects, however, the optimal dose of ephedrannin B was 10 times lower than that of ephedrannin A. This is the first report describing effective anti-inflammatory activity for ephedrannin A and B isolated from Ephedra roots. Ephedrannin B may be a good candidate for delaying the progression of human inflammatory diseases and warrants further studies.