Abstract:
The MeOH extracts of Dendrobium pullchellum Roxb. Ex Lind1. And D. ellipsophyllum Tang & wang (Orchidaceae) showed significant cytotoxic activity against human lung cancer cells. Phytochemical study of the whole plant of D. pullchellum Roxb. Ex Lind1 led to the isolation of seven phenolic compounds, namely, chrysotobibenzyl, chrysotoxine, crepidatin, moscatilin, fimbriatone, (-) –shikimic acid and liriodendrin. The whole plant of D. ellipsophyllum Tang & wang yielded ten phenolic compounds indluding moscatilin, 5,7-dihydroxy-chromen-4-one, 4,5-dihydroxy-2,3-dimethoxy-9,10-dihydrophenanthrene, 4,4’-dihydroxy-3,5-dimethoxybibenzyl, 4,5,4’-trihydroxy-3,3’-dimethoxybibenzyl, (2S)-homoeriodictyol, (2S)-eriodictyol, chrysoeriol, phloretic acid and luteolin. The structures of all these isolates were determined by extensive spectroscopic studies, including comparison of their MS and NMR properties with previously reported data. Each of these isolates was evaluated for cytotoxic and anti-metastatic activities against human lung cancer cells. It was found that chrysotobibenzyl, chrysotoxine, crepidatin, moscatilin, 4,4’-dihydroxy-3,5-dimethoxybibenzyl, 4,5,4’-trihydroxy-3,3’-dimethoxybibenzyl, chrosoeriol and luteolin exhibited appreciable cytotoxic and anti-metastatic effects. Moscatilin, the strongest cytotoxic compound, was further evaluated for its mechanisms of action on human lung cancer cell migration and invasion. The present study demonstrates that the inhibitory effect of moscatilin was associated with an attenuation of endogenous reactive oxygen species (ROS), in which hydroxyl radical (OH*) was identified as a dominant species in the suppression of filopodia formation.
