Phytochemical Study and Evaluation of the Antiradical Activity of Extracts of Oleaginous Seeds of <i>Panda oleosa</i> and <i>Isolona hexaloba</i> from Gabon

Abstract

Our study focused on phytochemical tests and evaluation of the anti-free radical activity of seed extracts of two oleaginous plants from Gabon used in traditional medicine or as condiments: Panda oleosa and Isolona hexaloba. The extraction was carried out by maceration with solvents of increasing polarity: cyclohexane, trichloroethylene, acetone, ethanol and finally distilled water. The total yields of the extracts are about 69.50% for Panda oleosa and 34.28% for Isolona hexaloba. The phytochemical tests carried out on the extracts of the seeds of Panda and Isolona highlight in both seeds the presence of alkaloids, polyphenols, triterpenes, carotenoids, reducing compounds, flavonoids, total sugars, coumarins, anthraquinones, free quinones, free anthracene derivatives, and terpenoids. Isolona seeds also contain leucoanthocyanins, sterols, cardiac glycosides and saponins. Phytochemical tests revealed the absence of tannins and mucilage in both seeds. The free radical scavenging activity was measured by scavenging the free radical cation of 2,2’-azino-bis[3-ethylbenzothiazoline-6-sulfonic acid] (ABTS-+) with gallic acid as the reference antioxidant. The results of the free radical scavenging activity of the aqueous and ethanolic extracts of both seeds showed that the aqueous extracts were more active than the ethanolic extracts. The IC50s of the aqueous and ethanolic extracts of Panda seeds are 40 and 60 μg·mL-1 respectively, and those of the aqueous and ethanolic extracts of Isolona are 37.5 and 95 μg·mL-1 respectively. Gallic acid, the reference antioxidant (IC50 = 0.37 μg·mL-1) is about 10 times more active than the aqueous extracts of both seeds, 16 times more active than the ethanolic extract of Panda and 25 times more active than the ethanolic extract of Isolena.