Phytochemical and antioxidant studies on the stem bark of Pseudocedrela kotschyi (Meliaceae)

Abstract

Pseudocedrela kotschyi commonly known as Dry-zone cedar and hard cedar-mahogany belongs to the family of Meliaceae. It is widely spread from east Senegal to western Ethiopia, Uganda and Nigeria. The stem bark of the plant has been used for the treatment of numerous diseases among different cultures around the globe. The study aimed at evaluating the phytochemical constituents and the antioxidant effects of P. kotschyi stem bark as claimed traditionally. Qualitative and quantitative Phytochemical screening were done according to standard methods. Antioxidant potentials of the P. kotschyi stem bark crude extracts of (Hexane, Ethyl acetate and Methanol) and isolated compound were estimated using Qualitative and quantitative 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assays. Qualitative preliminary phytochemical screening of the extracts of P. kotschyi revealed the presence of phytochemicals such as carbohydrate, alkaloids, tannins, flavonoids, cardiac glycosides, saponins and steroids/ triterpenes and for qualitative screening, ethyl acetate extract had the highest quantity of phytochemicals tested as represented in table 4 in percentages. The antioxidant activity was observed qualitatively by the change of DPPH colour on TLC plates from purple to yellow. Quantitative antioxidant activity revealed the following IC₅₀ values 324.22, 46.37, 91.77and 34.09 µg/mL for hexane, ethyl acetate, methanol and ascorbic acid, respectively. Ethyl acetate extract had the highest antioxidant effect.  The effects of the extracts is dose dependent and statistically significant(p<0.05). The studies established that P. kotschyi stem bark is rich in phytochemical constituents and was validated to have free radical scavenging effect.