Phytochemical analysis of some medicinal plants indigenous to Nepal and study of antioxidant, antimicrobial and cytotoxicity Phytochemical analysis of some medicinal plants indigenous to Nepal and study of antioxidant, antimicrobial and cytotoxicity Phytochemical analysis of some medicinal plants indigenous to Nepal and study of antioxidant, antimicrobial and cytotoxicity effect of their extracts on various cell lines.M. Sc. Thesis effect of their extracts on various cell lines

Abstract

Plants and plant-based products are the bases of many of the modern pharmaceuticals aswell as traditional health care systemwe use today for various ailments especially thecountry like Nepal. Keeping therefore in view, the growing interest of the use of herbaldrugs, the present study was undertaken with a view to evaluate thephytochemical andpharmacological activities of thestem ofRheumaustraleandTinospora cordifoliaand fruitpart ofDatura stramonium. In this research plants were subjected to both chemical and biological assays. The resultsofphytochemical screening showed presence of all the necessary primary and secondarymetabolites except tannins and resins. The total flavonoid content in crudemethanolicextract of T.cordifolia was found to be highest i.e.9.350±0.286 mg QE/g. Similarly thehighest phenol content was also foundabout 39.2±2.173mg/g in methanolic extract ofT.cordifolia.The free radical-scavenging activity of the extracts was tested through DPPH-method and the results were compared with Ascorbic acid. During our experiment, it wasnoted that the IC value of the standard antioxidant Ascorbic acid was found to be41.69±2.309and the extracts exhibited a concentration-dependent antiradical activity byinhibiting DPPH- radical. Of the different extracts, crudemethanol extract of Tinosporacordifoliaexhibited the highest free radical scavenging activity of 87.5% followed by themethanolic extract ofDatura stramonium(85.39%) andRheumaustrale(80.67%). Whilethehexane and the chloroformcrude extractexhibited moderate level free radical scavengingactivity.CrudeMethanolic and chloroformextractof all the three plant demonstrated thesignificant activity onKlebsiella pneumoniaandStaphylococcus aureusrespectively as wellas on Saccharomyces cerevisae. In our investigation, the extracts that were obtaineddemonstrated very nominal cytotoxic effect on the macrophage cells at a givenconcentration of 0-300µg/ml using MTT assay signifying that plant extract render no risk tothe normal cell lines but provide platform to study cytotoxicity againstHelacell lines.Thecrude extract of T.cordifolia exhibited the pronounced effect on Hela cells in dosedependent manner especially the methanolic extract. Methanolic extract of T. cordifoliademonstrated the significant cytotoxicity (89.79±2.908) and lowest ICLower the IC 50 5o 50value(50.754±5.776).value higher the cytotoxicity effect.These findings suggest that medicinalplants taken under studyshowantibacterial and cytotoxic activity and show promisingfuture for further researches. Key words: Medicinal plants, Phytochemical screening, Antioxidant, DPPH, Flavonoid,Phenol,Cytotoxicity.