Phytochemical Study and Evaluation of the Antioxidant Activity of Aqueous and Ethanolic Extracts of Hua gabonii

Abstract

Objective: The aim of this study was to identify major phytoconstituents and evaluate the antioxidant activity of extracts from different organs of Hua gabonii. Methods: Phytochemical screening was carried out in order to highlight the major groups of secondary metabolites contained in the various extracts through TLC. To assess the antioxidant activity, three methods were used namely DPPH, ABTS and FRAP. The IC50 values for the various samples were determined using GraphPad Prism 9.0 software, while ANOVA and LSD multiple comparison test, were carried out using Statistix 10 software. Results: The findings showed that the ethanolic extracts of stem bark exhibited a higher activity with DPPH (IC50: 0.84±0.03 µg/mL) compared to the standards (0.81±0.15 µg/mL, 0.42±0.10 µg/mL and 0.33±0.05 µg/mL for gallic acid, catchin and quercetin respectively). In addition, the analysis by the ABTS test showed that leaf extracts also showed interesting activity (IC50: 13.86±0.29 µg/mL and 12.76 ±0.42 µg/mL for aqueous and ethanolic extracts respectively). The FRAP test revealed interesting activity for the aqueous extracts of leaves, stem bark and branch bark with IC50s of 0.006±0.00 µg/mL; 0.02±0.00 µg/mL and 0.02±0.01 µg/mL respectively, compared with 2,41±0.00 µg/mL for ascorbic acid. In addition, the TLC showed the presence of total polyphenols, phenolic acids, coumarins, flavonoids, anthocyanins, leuco-anthocyanins, tannins, quinones, alkaloids and terpenoids. Conclusion: While assay analyses revealed that the total polyphenol content was high in the ethanolic extracts and in particular in the stem extracts. In conclusion, H. gabonii can be considered as good sources of natural antioxidants.