Pharmacognostic studies and antioxidant activity of the stem-bark of Entandrophragma utile Dawe & Sprague (Meliaceae)

Usman, S.O. ; Agunu, A. ; Njinga, N.S. ; Oladipupo, A.F. ; Olutayo, A.O. (2018-03)


The stem-bark of Entandrophragma utile (Meliaceae) is used traditionally for treatment of rheumatism, eye inflammation, sickle cell disease, gastric and duodenal ulcers in Nigeria. The aim of this study is to evaluate the pharmacognostic and antioxidant properties of the stem-bark of E. utile. Macroscopic and microscopic examinations, physicochemical parameters as well as phytochemical analyses of the powdered stem bark are performed. The antioxidant activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effects. The macroscopic studies indicated that the stem-bark is brown, bitter, rough, channeled or squilled and has a smooth fracture type. The microscopy showed the presence of bundles of fibres, single fibres, cork cells, and sclereids. Chemo-microscopy showed the presence of lignified cell walls, suberized/cuticular cell walls, tannins and starch. Physicochemical constants are: moisture-content 8.3 ± 0.03 %, alcohol-soluble extractive 0.8 ± 0.07 % and 0.4 ± 0.03 % water-soluble extractive values. The phytochemical screening showed the presence of tannin, saponin and flavonoid. The total phenolic and flavonoid contents of the extract was found to be 452.8±39.4 (GAE/g of dried extract mg/g) and 15,673±261.7 (QE mg/g) respectively. The IC50 was found to be 0.75 mg/mL. The study showed that the stem bark extract is a good source of polyphenols that could be responsible for the observed antioxidant activity of the plant.