Studies on Phytochemical Screening, Antimicrobial, Antioxidant and Cytotoxic Activities of Caragana Jubata of Nepal

Objective: Phytochemical screening as well as several bioassays was performed on the extracts of aerial parts of Caragana jubata. Methods: Extraction of C. jubata was carried out by solvents of increasing polarity. The Phytochemical screening of extracts was carried out using standard procedures. Furthermore, extracts were also evaluated for (i) antibacterial assay, (ii) brine shrimp lethality bioassay and (iii) antioxidant assay. American Type Culture Collection(ATCC) strains six bacteria, one gram-positive (Staphylococcus aureus ATCC 25525), five gram-negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsella pneumonia ATCC 700603, Serratia marcescens ATCC 13880 and Salmonella Typhimurium ATCC 14028 were used to evaluate its antimicrobial activity. Brine shrimp lethality assay was done on the plants extracts. For the antioxidant test, 2, 2- Diphenyl 1, picrylhydrazyl (DPPH) free radicals scavenging assay was done. Results: The phytochemical analysis indicated the presence of alkaloids, flavonoids, saponins, and terpenoids in aerial parts of C. jubata. In the case of the antibacterial, different extracts showed 9-13 mm and 0-15 mm zone of inhibition in diameter against gram positive bacteria S. aureus and gram negative bacteria (E. coli, P. aeruginosa, K. pneumonia, S. marcescens and S. Typhimurium). This inhibition was found less in comparison to the standard compounds, Chloramphenicol (26±0.5mm to 32±0.5mm) and Gentamicin (26±0.5mm to 30±0.5mm) antibiotics. Similarly, in brine shrimp lethality assay, methanol extracts showed a potent lethal effect against the brine shrimp nauplii with LC50 of 50.93±7.8µg/ml. In the DPPH free radical scavenging assay, the extracts showed strong antioxidant activity in the order: methanol extract> dichloromethane extract> hexane extract, however all the extracts little less active than the standard compound, ascorbic acid. Methanol extract showed the highest DPPH free radical scavenging with IC50 value of 6.1µg/ml. Conclusion: The present study suggests the potentiality of C. jubata to become a natural source of antioxidant for the protective as well as prevention of diseases.