Increasing resistance of microorganisms to antibiotics and other orthodox drugs has directed modern day research towards discovering more organic and more potent bioactive molecules preferentially, from plant sources. Since time immemorial medicinal plants that grow on high altitude Himalayan climate have been used for treatment of several infections and ailments as documented on various ethno-botanical research findings. The antioxidant and antibacterial properties of phytochemical extracts make them attractive alternative medicines. Therefore, this research studied the phytochemical constituents of Aconitum spicatum, Dactylorhizahatagirea, Rheum australe, Jurnea dolomiaea, Aconitum gammiei, Paris polyphylla and Gentiana spp.extracts and their antioxidant, antibacterial and cytotoxic potential. The extracts were tested against four different pathogenic microorganisms (Staphylococcus aureus, Bacillus subtillis, Klebsiella pneumonia, andEnterobacter) by using disc-diffusion method. Radical scavenging capacity of the extracts was estimated using DPPH(1,1-diphenyl-2-picrylhydrazyl) assay; and Brine-shrimp lethality assay was performed to investigate the cytotoxicity of the extracts.
Out of seven plant extracts, Rheum australe showed considerable antimicrobial activity against the test pathogen Klebsiella pneumoniaewith 14.5 mm Zone of inhibition. Gentiana spp and Rheum australe showed an effective antioxidant activity comparable to the standard Ascorbic acid (EC50 13.6 & 18.9 respectively). Except the extract from Dactylorhiza hatagirea, all other plant extracts showed promising cytotoxicity against Artemia salina hatched under laboratory conditions.
The antimicrobial and antioxidant activities of different plant extract obtained in this study can be attributed to the bioactive secondary metabolites present in varying degrees. Phytochemical analysis and positive antibacterial susceptibility test further suggests exploration of these plant constituents as broad spectrum antibiotics. The information provided herein provides scientific basis for the ethno-botanical knowledge of local community. Moreover, the cytotoxicity produced by these extracts manifest their importance in further study for anti-proliferative activities and development of plant based drugs.
