Abstract

IN VITRO ANTIOXIDANT ACTIVITY OF EXTRACTS, FRACTIONS AND POLYSACCHARIDES, AND IN VIVO SUB-CHRONIC AND SUB-ACUTE TOXICITY OF LYOPHILIZED AQUEOUS EXTRACT FROM BRUCEA SUMATRANA ROXB. (SIMAROUBACEAE) LEAVES

Cimanga Kanyanga R.*, Tshodi Ehata M., Nsaka Lumpu S., Lami Nzunzu J., Vlietinck A. J. and Pieters L.

ABSTRACT

The present work reported for the first time the antioxidant properties of extracts, fractions and polysaccharides, and sub-chronic and sub-acute toxicity of lyophilized aqueous extract of Brucea sumatrana leaves collected in Mai-Ndombe in Democratic Republic of Congo (DR-Congo). In the antioxidant test, results indicated that lyophilized aqueous extract and its soluble fractions, 80% methanol and polysaccharide extracts and pure polysaccharide fractions from B. sumatrana leaves exhibited good and interesting antioxidant activity against some selected reactive oxygen species (ROS) like DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS (2,2-azino-bis-3-ethylbenzthiazoline-6-sulphonate or 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)), superoxide anions, hydrogen peroxide and hydroxyl with IC50 values ranging from 2.05±0.01 to 17.±0.03 μ/ml for extracts and fractions, and from 20 to 370 µg/ml for polysaccharides The most active samples were the lyophilized aqueous and 80% methanol extracts, ethylacetate and residual aqueous soluble fractions exerting this activity with IC50 < 10 μg/ml while polysaccharides also showed appreciable antioxidant activity with 20 < IC50 < 130 µg/ml against all selected ROS cited above. In sub-chronic and sub-acute toxicity tests, the lyophilized aqueous extract was devoid of toxic effects at all administered oral doses from 500,1000, 3000 and 5000 mg/kg bodyweight on treated animals according to the case. It did not induce mortality at all oral administered doses in treated Wistar rats compared to untreated group. Its LD50 was estimated to be greater than 5000 mg/kg bodyweight and was considered practically non-toxic by oral route, safe and placed in class 5 of toxic products. In histologic study, the extract did not affect the architecture of selected vital organs of treated Wistar rats at all oral administered doses and no abnormality was observed in treated group compared to untreated in both toxicity tests.

Keywords: Brucea sumatrana, leaves, extracts, fractions, polysaccharides, antioxidant activity, sub-chronic and sub-acute toxicity, histology.