Phytochemical composition and antioxidant activity: Comparison of Pentaclethra eetveldeana (De Wild & T. Durand) leaf ethanolic extracts (Congo-Brazzaville)

It is important to know the intraspecific variability of the biological properties and chemical composition of plants in order to promote their better use. Thus, referring to the use of Pentaclethra eetveldeana (De Wild & T. Durand) leaves in a dementia traditional treatment, this study aims to highlight the antioxidant capacity and the chemical composition of the ethanolic extracts of Pentaclethra eetveldeana leaves from four localities of Congo-Brazzaville. The β-carotene bleaching, diphenyl-picryl-hydrazyl (DPPH) radical-scavenging and molybdenum reduction methods were used to determine the antioxidant potency. Subsequently, the yields of the extractions, the phytochemical screening and the quantification of the phenolic compounds were carried out. The results revealed that the extracts of the four localities presented an antiradical and an antilipid peroxidation superior to those of ascorbic acid in DPPH and β-carotene bleaching methods. Moreover, among the extracts, those of the leaves from Boundji and Brazzaville presented the best antilipid peroxidation, antiradical and reducing activities as well as the greatest extraction yields, the greatest quantities of total polyphenols and proanthocyanidins against low levels of flavonoids. Furthermore, saponins, polyphenols, alkaloids, reducing sugars and cardiotonic glycosides were identified in all ethanolic extracts except sterols and triterpenes which were only identified in the extracts of leaves collected in Brazzaville. In addition, flavones were identified in the leaves from Owando and Makoua; flavonols in the leaves from Boundji and Brazzaville. This study showed that Pentaclethra eetveldeana leaf ethanolic extracts exhibit antilipid peroxidation, antiradical properties and phytochemical that varied according to the region.