Natural phenanthrenes and their biological activity.

Biaryls in nature: a multi-facetted class of stereochemically, biosynthetically, and pharmacologically intriguing secondary metabolites.

Nudol, a phenanthrene of the orchids Eulophia nuda, Eria carinata and Eria stricta

Two substituted bibenzyls and a dihydrophenanthrene from Cymbidium Aloifolium

A methanol extract from the whole plant of Dendrobium formosum Roxb. ex Lindl., Orchidaceae, showed inhibitory potential against α-glucosidase and pancreatic lipase enzymes. Chromatographic separation of the extract resulted in the isolation of twelve phenolic compounds. The structures of these compounds were determined through analysis of NMR and HR-ESI-MS data. All of the isolates were evaluated for their α-glucosidase and pancreatic lipase inhibitory activities, as well as glucose uptake stimulatory effect. Among the isolates, 5-methoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone (12) showed the highest α-glucosidase and pancreatic lipase inhibitory effects with an IC50 values of 126.88 ± 0.66 μM and 69.45 ± 10.14 μM, respectively. An enzyme kinetics study was conducted by the Lineweaver-Burk plot method. The kinetics studies revealed that compound 12 was a non-competitive inhibitor of α-glucosidase and pancreatic lipase enzymes. Moreover, lusianthridin at 1 and 10 μg/ml and moscatilin at 100 μg/ml showed glucose uptake stimulatory effect without toxicity on L6 myotubes. This study is the first report on the phytochemical constituents and anti-diabetic and anti-obesity activities of D. formosum.

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Nabanita Datta

Papers

Coelonin, A 9,10-dihydrophenanthrene from the orchids Coelogyne ochracea and Coelogyne elata