Phytochemical Screening and Antioxidant Activities of Water Lilies Seeds, Neglected and Underused Species in the Delta and Lower Valley of the Senegal River

Abstract

Studies carried out in the delta and the lower valley have demonstrated, through ethnobotanical surveys, the importance of the species Nymphaea lotus L. and Nymphaea micrantha Guill. et Perr in the diet. The seeds are used in food and pharmacopoeia with a good appreciation by the indigenous population, especially in the diet of diabetics. However, studies on their biochemical aspects are still very rare in the literature. It is for this reason that this study was conducted to gather useful scientific information to allow a better appreciation of the pharmacological potentialities of these seeds. To do so, seeds were collected in ponds, tributaries of the Senegal River, dried in the shade, and divided into three different batches: a batch of red seeds of N. lotus, a batch of black seeds of N. lotus, and a batch of seeds of N. micrantha. Chemical screening, tannin, flavonoid, and polyphenol assays as well as antioxidant power of the seeds were carried out according to official standard methods. The results obtained in the qualitative analysis showed the presence of a high quantity of tannins, total phenols, flavonoids, and alkaloids, as well as a lower quantity of cardiac glycosides and the absence of anthracene compounds and saponosides in the seeds. The assay showed that Tannins are the highest (38.118 ± 0.021 to 118.132 ± 0.034 mg EAT/g DM) followed by flavonoids (24.057 ± 0.113 to 31.970 ± 0.087 mg EC/g DM) and polyphenols which are the lowest (0.544 ± 0.054 to 1.955 ± 0.120 mg EAG/g DM). In addition, these seeds have a high antioxidant power with high inhibition percentages, ranging from 83.92% ± 1.40% to 87.67% ± 0.16%. The promotion of their consumption could thus have a positive impact on the health of the populations of the Senegal River valley.