In vitro: |
PLoS One. 2010 Oct 28;5(10):e13713. | Antioxidant biomarkers from Vanda coerulea stems reduce irradiated HaCaT PGE-2 production as a result of COX-2 inhibition.[Pubmed: 21060890] | METHODS AND RESULTS:
Bio-guided fractionation and phytochemical analysis led to the isolation of five stilbenoids: imbricatin (1) methoxycoelonin (2) gigantol (3) Flavidin (4) and coelonin (5). Stilbenoids (1-3) were the most concentrated in crude hydro-alcoholic stem extract and were considered as Vanda coerulea stem biomarkers.
CONCLUSIONS:
Dihydro-phenanthropyran (1) and dihydro-phenanthrene (2) displayed the best DPPH/(•)OH radical scavenging activities as well as HaCaT intracellular antioxidant properties (using DCFH-DA probe: IC(50) 8.8 μM and 9.4 μM, respectively) compared to bibenzyle (3) (IC(50) 20.6 μM). In turn, the latter showed a constant inhibition of PGE-2 production, stronger than stilbenoids (1) and (2) (IC(50) 12.2 μM and 19.3 μM, respectively).
Western blot analysis revealed that stilbenoids (1-3) inhibited COX-2 expression at 23 μM. Interestingly, stilbenoids (1) and (2) but not (3) were able to inhibit human recombinant COX-2 activity. | Bioorg Med Chem. 2004 Oct 1;12(19):5141-6. | Antioxidant activities of flavidin in different in vitro model systems.[Pubmed: 15351397] | Flavidin was isolated from Orchidaceae species and purified by silica gel column chromatography. METHODS AND RESULTS: The structure was identified using physical and spectral ((1)H, (13)C NMR, and mass) data. Antioxidant potency of Flavidin was investigated employing various established in vitro model systems viz., beta-carotene-linoleate, 1,1-diphenyl-2-picryl hydrazyl (DPPH), phosphomolybdenum method, and scavenging of hydrogen peroxide methods. Flavidin showed very good antioxidant activity (90.2%) and almost equivalent to that of BHA at 50ppm level by beta-carotene-linoleate method. Radical scavenging activity of Flavidin was compared with BHA at 5, 10, 20, and 40ppm concentration and Flavidin showed more radical scavenging activity than BHA at all the tested concentrations. Furthermore, Flavidin showed very good antioxidant capacity by the formation of phosphomolybdenum complex method. Besides this, Flavidin showed effective hydrogen peroxide scavenging activity. CONCLUSIONS: The data obtained in the in vitro models clearly establish the antioxidant potency of Flavidin. However, comprehensive studies need to be conducted to ascertain the in vivo safety of Flavidin in experimental animal models. This is the first report on antioxidant activity of 9,10-dihydro-5H-phenanthro-(4,5 bcd)-pyrans/Flavidin type of compounds. |
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