PHYTOCHEMICAL, IN VITRO ANTIMICROBIAL, ANTIOXIDANT PROPERTIES AND POLYPHENOLIC CONTENT OF METHANOL LEAVES EXTRACT OF Piliostigmathonningii SCHUM MILNE-REDHEAD (FABACEAE)

PHYTOCHEMICAL, IN VITRO ANTIMICROBIAL, ANTIOXIDANT PROPERTIES AND POLYPHENOLIC CONTENT OF METHANOL LEAVES EXTRACT OF Piliostigma thonningii SCHUM MILNE-REDHEAD (FABACEAE)

OGBIKO CYRIL1,2*, OKOYE FESTUS BASDEN CHIEDU2 AND EBOKA CHUKWUENWENIWE JONATHAN3

 
  1. Department of Pure and Applied Chemistry, Faculty of Science, UsmanuDanfodiyo University Sokoto, 85004 Sokoto State Nigeria.
  2. Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, 420281 Awka, Anambra State, Nigeria.
  3. Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, University of Benin, Benin City Edo State Nigeria.

Afr. J Pharm Res Dev; Volume 12(3): 299-312 (2020)

ABSTRACT

Piliostigma thonningii leaves are used in Nigeria folk medicine for the treatment and management of diverse ailments. This study evaluated the phytochemical composition, polyphenolic content, antioxidant and antimicrobial activities of the crude extract and fractions with a view to validating its folkloric usage. While the phytochemical screening was performed using standard procedures, the phenolic, flavonoid, antioxidant and antimicrobial screening were performed using the Folin-Ciocalteu, aluminum chloride, DPPH free radical scavenging and agar well diffusion methods respectively. Qualitative phytochemical analysis showed the presence of important metabolites in the crude methanol extract and its fractions. While the ethyl acetate fraction at the highest concentration of 1 mg/mL produced the best (p<0.05) antibacterial activity, the n-hexane fraction had the least. The extract and its fractions showed no sensitivity against the selected fungi. Using gallic acid and quercetin equivalent plots, the crude extract contained a significantly higher concentration of total phenolic and flavonoid contents when compared with other fractions. The standard antioxidant (ascorbic acid) had superior DPPH antioxidant capacity when compared with the extract and its fractions. The ethyl acetate fraction had the least IC50 value when compared to other fractions. However, there was no significant correlation between the DPPH antioxidant activity and the polyphenolic contents in the extract and fractions. Our results provide evidence that the plant extract and fractions exhibited marked antibacterial and antioxidant activities thus justifying the popular use of the plant leaves to treat selected microbial infections and free radical implicated illnesses.

Email of correspondence: cyrilogbiko@gmail.com; 

KEYWORDS: Antioxidant; Antimicrobial; Phytochemical; Piliostigma thonningii; Polyphenol.