PHYTOCHEMICAL SCREENING, ANTIMICROBIAL AND TOXICOLOGICAL ACTIVITIES OF CRUDE EXTRACTS OF LEAVES AND STEM BARKS OF Osyris quadripartita Decn. AND Toddalia asiatica (L.) Lam.

Abstract

Plants have been used for generations as source of medicine in the treatment of human and livestock ailments. Ethiopia is also well recognized for higher diversity and uses of medicinal plants in the treatments of diversified human and livestock diseases. Osyris quadripartita and Toddalia asiatica were reported to possess different phenolic compounds claimed to have potential antimicrobial inhibitory effects. Therefore, the objectives of this study were to assess the phytochemical screening, antimicrobial and toxicological activities of crude extracts of leaves and stem barks of Osyris quadripartita and Toddalia asiatica. Extractions were done by maceration using methanol and chloroform solvents. Qualitative analysis of phytochemical was carried out using standard protocols. Furthermore, antimicrobial activities of the leaves and stem bark extracts were determined by the disc diffusion and broth dilution methods. Toxicity study was carried out following the method of the Organization for Economic Cooperation and Development (OECD) guidelines. Data were analyzed using SPSS version 20 software. In this regard, six experimental mice, in each were grouped into four groups; three experimental groups and one negative control. The qualitative chemical test indicated that methanol and chloroform extract of leaves and stem barks of both plants showed the presence of alkaloids, tannins, saponins, flavonoids, and terpenoids whereas absence of phlobatannins in both plant extracts. The TLC profiles indicated two spots in each of the methanolic extract of leaves and stem barks of both plant species. The methanol stem bark crude extracts of Osyris quadripartita Decn. had highest zone of inhibition (15.23±0.25 mm) at 175 mg/ml against S.aureus with a MIC and MBC of 83.33±28 mg/ml. It was concluded that acute toxicity in both plant extracts did not show any sign of toxicity up to 2000 mg/kg and further showed that there were no obvious toxicity to the mice. These results indicated the safety of oral administration of these plant species extract as it has been used in the traditional system, which need to give attention for oral dose.