Crotalaria medicaginea Lamk.: An unexplored source of anticancer, antimicrobial and antioxidant agents

Introduction: Crotalaria medicaginea is an ethnomedicinally acclaimed species of the genus Crotalaria which has not been extensively researched. The current study reports the anticancer, antimicrobial and antioxidant ac-tivities of the plant. Methods: Aerial parts of C. medicaginea were extracted in organic solvents. The cytotoxicity of the extracts was determined against MDA-MB-231, SW-620 and HEK-293 cell lines using MTT assay. The antimicrobial activity was carried out against clinical isolates of Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA), Salmonella typhi and Shigella flexnari and for antioxidant activity DPPH and FRAP assays were used. Results: The extracts produced a strong cytotoxic effect against cancer cells. Dichloromethane fraction was the most prominent inhibitor of cancer cells with IC50 values of 0.001 +/- 0.00 and 0.007 +/- 0.00 mu g/mL for MDA-MB-231 and SW-620 respectively. The extracts also produced strong inhibitory effects against selected bacterial strains with MIC values ranging between 0.42 +/- 0.14 - 5 +/- 0 mg/mL and MBC values between 0.25 -1 mg/mL. Ethyl acetate, acetone and methanol fractions possessed strong antioxidant activity in DPPH radical scavenging (IC50 values 0.785 +/- 0.07, 0.986 +/- 0.01 and 0.61 +/- 0.12 mg/mL respectively) and FRAP assays. Phytochemical analysis indicated the highest phenolic and tannin contents in methanol fraction and the highest flavonoid and saponin contents in dichloromethane fraction. All the extracts were found to be nontoxic in brine shrimp lethality assay. Conclusion: C. medicaginea possesses strong anticancer and antibacterial potential and can be an excellent source of plant-based anticancer drugs with antimicrobial and antioxidant activities.