Dioscorea sp. is a wild yam of the Gabonese forests. It is poorly studied because of its toxic and inedible tubers. The stems of this plant are however heavily consumed by several ethnic groups of Gabonese populations. The present work has been done to study some nutritional characteristics of these organs. The plant material was bought at the market from vendors in Moanda, and analyzed in the laboratory. The physicochemical and biochemical characters were studied using standard food analysis techniques. The results showed that the stems of this plant were rich in water (87.52%), ash (13.22%), and fiber (14.30%). From the biochemical point of view, the results revealed high levels of proteins (24.43%), carbohydrates (44.30%), vitamins C (2.38%) and polyphenols (0.78%). These different physicochemical and biochemical characteristics suggest that wild yam contains many nutritional and medicinal potentialities. It is therefore possible to foresee the domestication of this plant for a wider diet.

Introduction: Roselle is a wet rot in Gabon caused by Phoma sabdariffae Sacc., a deuteromycete fungus of the family Phomaceae. The chemical control used for its eradication has had many limitations, including the appearance of fungal resistance and the persistence of chemoactive substances. Objective: The present study was initiated to test an alternative control solution, by the use of a toxic plant, Tephrosia vogelii. Methods: For this purpose, this plant was macerated, and the solutions transferred to PDA solid culture media, to constitute 4 treatments: T5 (5%), T10 (10%), T15 (15%) and T20 (20%). Fungal spores were cultured in the center of petri dishes, and mycelial growths measured every 2 days for 10 days. Results: The results revealed that all the modified treatments in solution of Tephrosia vogelii reduced the mycelial growth of Phoma sabdariffae. The most pronounced reductions were produced by the T15 and T20 treatments, with the respective inhibition rates of 81% and 100% at the 10th day of incubation. Conclusion: The use of concentrated extracts of Tephrosia vogelii is therefore possible in the biological control of roselle rot in Gabon.

Gabon contains the richest and most diverse forest block in the Congo Basin. More than 50 non-timber forest products are listed. Despite this natural advantage, Gabon continues to import many forest products, including spices. The present work was initiated to study some morphometric, physicochemical and biochemical characteristics of a species of local wild pepper (Piper guineense), in order to domesticate and commercialize it. The results obtained showed that the leaves of this pepper had average leaf area of 106.71 cm2. These organs contained 87.57% moisture content, 17.13% dry matter and 3.4% crude ash. At the biochemical level, the wild pepper leaves of Gabon contain 26.04 g/ 100 g of protein DM, 21.48 g/ 100 g of total sugar DM and 244 g/ 100 g of chlorophyll Pigment FM. This plant is also rich in polyphenols (0.6 g/ 100 g DM) and ascorbic acid (3.58 g/ 100 g DM). It is not very pungent and contains only one (1) digital unit of Scoville. All these physicochemical and biochemical characteristics bring this morphotype closer to other types of pepper imported from Central America or Asia. Gabon's wild pepper can therefore be domesticated and marketed to reduce the country's food dependency.