Biological and Phytochemical Studies on Some Medicinal Orchids of Nepal

Abstract

Biological and phytochemical screenings of some orchid species growing in Nepal were studied. The ethanolic extracts of orchid species were tested against both gram positive and gram negative standard bacterial strains viz. Vibrio cholerae, Staphylococcusaureus, Klebsiella pneumoniae, Bacillus subtilis and Escherichia coli. All orchid extracts showed good bacterial Zone of Inhibition(ZOI) against Staphylococcus aureus. The crude extracts of Pholidota imbricata and Coelogyne cristatawere shown highest activity against Vibrio cholerae (ZOI -14 mm) and Staphylococcus aureus(ZOI –14 mm) respectively. The MIC and MBC value of the extracts of Pholidota imbricata and Coelogyne cristata were found to be 62.5 mg/ml and 31.25 mg/ml, 125 mg/ml and 250 mg/ml respectively. Only Pholidota imbricata and Pholidota articulata extracts were shown fairly good activity but all others extracts were shown very less activity or even failed to show any activity against fungal organisms viz.Candida albicans, Rhizopus stolonifer and Mucor spp. From the ethanolic extracts of orchid species, phytocon stituents detected qualitatively were Alkaloids, Terpenoides, Flavonoides, Tannins, Reducing sugars and Cynonogenicglycosides.