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.

Slow Pyrolysis of Sugarcane Bagasse for the Production of Char and the Potential of Its By-Product for Wood Protection

Sugarcane bagasse was pyrolyzed using a laboratory fixed bed reactor to produce char and its by-product(pyrolysis liquid).The pyrolysis experiments were carried out using different temperatures(400℃ and 500℃),heating rate(1℃/min and 10℃/min),and holding time(30 min and 60 min).Char was characterized according to its thermal properties,while the pyrolysis liquid was tested for its anti-fungal and anti-termite activities.Pyrolysis temperature and heating rate had a significant influence on the char properties and the yield of char and pyrolysis liquid,where a high-quality char and high yield of pyrolysis liquid can be obtained at a temperature of 500℃ and a heating rate of 10℃/min.The yield of char and pyrolysis liquid was 28.97%and 55.46%,respectively.The principal compounds of pyrolysis liquid were water,acetic acid,glycolaldehyde,1-hydroxy-2-propanone,methanol,formic acid,levoglucosan,furfural,followed by some phenol compounds and guaiacol derivatives.Pyrolysis liquid at a concentration of 0.20%and 0.25%(v/v)caused a 100%inhibition of Coniophora puteana and Trametes versicolor,respectively,when performing inhibition growth tests in Petri dishes.Filter paper treated with 10%of pyrolysis liquid caused 100%of termite mortality,while only 5.65%–7.03%of the treated filter papers consumed by termites at such concentration.Pyrolysis liquid is potentially effective to be used in the formulation of wood protection against fungi and termites.