Antimalarial efficacy of Albizia lebbeck (Leguminosae) against Plasmodium falciparum in vitro & P. berghei in vivo

BACKGROUND & OBJECTIVES: Albizia lebbeck Benth. (Leguminosae) has long been used in Indian traditional medicine. The current study was designed to test antimalarial activity of ethanolic bark extract of A. lebbeck (EBEAL). METHODS: EBEAL was prepared by soxhlet extraction and subjected to phytochemical analysis. The extract was evaluated for its in vitro antimalarial activity against Plasmodium falciparum chloroquine (CQ) sensitive (MRC2) and CQ resistant (RKL9) strains. Cytotoxicity (CC(50)) of extract against HeLa cells was evaluated. Median lethal dose (LD(50)) was determined to assess safety of EBEAL in BALB/c mice. Schizonticidal (100-1000 mg/kg) and preventive (100-750 mg/kg) activities of EBEAL were evaluated against P. berghei. Curative activity (100-750 mg/kg) of extract was also evaluated. RESULTS: Phytochemical screening revealed presence of alkaloids, flavonoids, phenols, saponins, terpenes and phytosterols. The extract exhibited IC(50) of 8.2 μg/ml (MRC2) and 5.1 μg/ml (RKL9). CC(50) of extract on HeLa cell line was calculated to be >1000 μg/ml. EBEAL showed selectivity indices (SI) of >121.9 and >196.07 against MRC2 and RKL9 strains of P. falciparum, respectively. LD(50) of EBEAL was observed to be >5 g/kg. Dose-dependent chemosuppression was observed with significant (P<0.001) schizonticidal activity at 1000 mg/kg with ED(50) >100 mg/kg. Significant (P<0.001) curative and repository activities were exhibited by 750 mg/kg concentration of extract on D7. INTERPRETATION & CONCLUSIONS: The present investigation reports antiplasmodial efficacy of EBEAL in vitro against P. falciparum as evident by high SI values. ED(50) of <100 mg/kg against P. berghei categorizes EBEAL as active antimalarial. Further studies need to be done to exploit its antiplasmodial activity further.