Phytochemical screening, assessment of biological activity and nutritional value of Sudanese Hibiscus sabdariffa L. seeds

Abstract

Medicinal plants are widely used in traditional cultures all over the world and they are becoming increasingly popular in modern society as natural alternatives. This research aimed to conduct phytochemical screening; assess of antimicrobial and antioxidant activities; evaluate toxicity and detect the nutritional value of Hibiscus sabdariffa L. seeds. The Phytochemical screening was carried out using standard procedures. The samples were extracted using hexane and absolute ethanol respectively. The extracts were evaluated for their effectiveness against microorganisms using the disc diffusion method and the antioxidant potential was measured by the DPPH assay. The proximate analysis of seed powder and mineral composition was determined using standard procedures. Toxicity was evaluated by the brine shrimp lethality test and the LD50 was calculated. Phytochemical screening revealed the presence of alkaloids, saponins and flavonoids, while tannins and anthraquinones were not detected. Generally, the hexane extract showed higher antibacterial activity than the ethanolic extract against 4 bacteria. Both extracts exhibited antifungal activity against Candida albicans ranging from 12-17 mm. The hexane extract showed higher antioxidant activity than the ethanolic extract (60 % and 47 % respectively). Both extracts were non-toxic against brine shrimps, suggesting that they are safe for medicinal use. The results of the proximate analysis showed that the seeds contain high amounts of fat (34.19 %) and protein (33.25 %). The seeds of H. sabdariffa contained considerable amounts of some important elements, while lead was not detected. The findings of this study revealed that H. sabdariffa seeds are a rich source of secondary metabolites and nutritional value and could be used for pharmaceutical preparation and drug development.