Cytotoxic and anti-metastatic activities of phenolic compounds from Dendrobium ellipsophyllum

Phenolic compounds isolated from Dendrobium ellipsophyllum Tang & Wang (Orchidaceae) have been shown to possess potential pharmacological activity; however, their anticancer as well as anti-metastasis activities are largely unknown. The aim of the present study was to isolate active compounds from D. ellipsophyllum and to explore the possible effects of phenolic compounds isolated from the plant for cytotoxic as well as anti-metastatic properties.

The compounds were isolated by using chromatographic techniques including silica gel and Sephadex LH20. Each of the isolates was evaluated for their cytotoxicity on H292 human lung cancer cell lines by 2,3-Bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. The cytotoxic compounds were further evaluated for apoptosis-inducing and anoikis-sensitizing effects.

Ten phenolic compounds were isolated, 5,7-dihydroxy-chromen-4-one (1:); 4,5-dihydroxy-2,3-dimethoxy-9,10-dihydrophenanthrene (2:); moscatilin (3:), 4,4'-dihydroxy-3,5-dimethoxybibenzyl (4:); 4,5,4'-trihydroxy-3,3'-dimethoxybibenzyl (5:); (2S)-homoeriodictyol (6:); (2S)-eriodictyol (7:); chrysoeriol (8:); phloretic acid (9:); and luteolin (10:). Compounds 4:, 5:, 8: and 10: exhibited appreciable cytotoxic activity with 50% inhibitory concentration values less than 250 μM. These compounds also showed potential apoptosis induction and anoikis-sensitizing effect at non-toxic concentrations.

Compounds 4:, 5:, 8: and 10: are responsible for cytotoxic and anti-metastatic activities of D. ellipsophyllum.