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

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.

Characterization of Extracts from the Bark of the Gabon Hazel Tree (Coula edulis baill) for Antioxidant,Antifungal and Anti-termite Products

Chemical composition of the bark extracts of Coula edulis was investigated to find potential antioxidant,anti-termite and antifungal compounds which can find useful applications in the fields of food,nutraceuticals,cosmetics or agrochemical.Phytochemical screening revealed the presence of several groups of active molecules such as alkaloids,polyphenols,flavonoids,saponins and sterols and/or terpenes in the different extracts.Total phenols,condensed tannins and flavonoids contents corroborated phytochemical screening.Gas chromatographymass spectrometry(GC-MS)analysis revealed compounds in dichloromethane extract different from those obtained with all the other solvents.Hexadecanoic and trans-9-octadecenoic acids,as well as stigmasterol andβ-sitosterol have been identified as the major compounds in the dichloromethane extract.Extracts obtained with acetone and toluene/ethanol mixture(2/1,v/v)indicated the presence of few amounts of fatty acids and sugars,catechin in small amount and huge amounts of phenolic acids like gallic and ellagic acids.The radical 2,2-diphenyl-1-picrylhydrazyle(DPPH)and the cationic radical 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS+)were used for evaluation of antioxidant properties of the different extracts.The dichloromethane extracts had a very low antioxidant activity,while acetone and toluene/ethanol extracts presented EC50 values similar to those of catechin and BHT used as reference antioxidant compounds.Effect of the different extracts of the bark of C.edulis on fungal growth inhibition indicated better inhibition of the mycelium growth of brown rot fungi compared to white rot fungi.Low anti-termite activities were recorded with the aqueous extracts,while stronger activities were recorded with dichloromethane,acetone and toluene/ethanol extracts.