In vitro anti-infective and antioxidant activity of plumbago zeylanica linn

Abstract

Plumbago zeylanica (Plumbaginaceae) is a perennial shrub with semi-woody stems and numerous branches. It is used in Africa and Asia for the treatments of common ailments such as hemorrhoids, diarrhoea, leprosy, acute inflammation, and cuts. This study aims at evaluating the antimicrobial, anthelmintic, and antioxidant activities of P. zeylanica methanol and ethyl acetate leaf extracts. The antimicrobial activity was evaluated by determination of the minimum inhibitory concentration using the micro-broth dilution method against selected microorganisms. Anthelminthic activity was evaluated by determining the in vitro paralysis and death times of the extracts on Pheretima posthuma at concentrations of 300, 100 and 30 mg/mL. Antioxidant activity was conducted by 2, 2- diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. Results revealed that both extracts had antimicrobial activity. Significant anthelminthic activity was observed at 30, 100 (p<0.001) and 300 mg/mL (p<0.05) with ethyl acetate extract being a more potent anthelminthic agent. The ethyl acetate extract showed better antioxidant activity with inhibitory concentration (IC50) of 0.29 μg/mL as compared to that of the methanol extract (2.33 μg/mL). The ethyl acetate extract showed better anti-infective and antioxidant activity than that of methanol. Phytochemical screening of the plant revealed the presence of alkaloids, glycosides (saponins, anthraquinones), tannins, and flavonoids.