Avaliação da composição fitoquímica e actividade antioxidante das sementes, polpa e casca da fruta de Strychnos spinosa

Abstract

Strychnos spinosa is a plant belonging to the Loganiaceae family, and is known in Mozambique, specifically in the south as NSALA. It grows in places with a tropical climate and various parts of the tree are used by the rural population, from root to fruit, to treat diseases and the fruit is traditionally used as food in Africa. The pulp of the fruit is the edible part and is used for the production of liqueurs. The present work aims to carry out a comparative study of the phytochemical composition and antioxidant activity of the extracts of the seeds, pulp and skin of the fruit. The crude extracts of the seeds, husk and pulp were obtained by extraction with sohxlet, using 70% MeOH, ethyl acetate and petroleum ether as solvents. The obtained extracts were submitted to phytochemical tests to identify alkaloids, steroids, tannins, saponins, coumarins, anthraquinones and resins. Selective steroid extraction and chromatographic characterization were performed using specific solvents and identification reagents. The evaluation of antioxidant activity was performed using the DPPH method and the reducing power. The determination of the total phenol content was performed using the Folin-Ciocalteu method. The determination of flavonoids was performed by complexation with AlCl3 followed by analysis by UV-Vis spectrophotometry. Phytochemical tests showed the presence of alkaloids, flavonoids, tannins, steroids / triterpenoids, anthraquinones and resins in the seeds, pulp and bark. Cardenolides are the steroids identified in all parts of the fruit and withanolides were not identified in any of the 3 parts. The antioxidant activity of the pulp and seeds is superior to that of the peel. As for the content of total phenolic compounds, the pulp and seeds show values ​​close to and higher than that of the peel. The content of flavonoids in the pulp and peel was similar but relatively higher than that of the seeds. The phytochemical composition, the antioxidant activity, the content of total alkaloids, total phenols and flavonoids in the extracts of the seeds, pulp and peel of the Strychnos spinosa fruit show that the 3 parts can be used for medicinal purposes.