The occurrence of 2-hydroxy-6-methoxybenzoic acid methyl ester in Securidaca longepedunculata Fresen root bark

As part of our ongoing search for natural fumigants from Senegalese plants, we have investigated Securicicidaca longepedunculata root barks and demonstrated that 2-hydroxy-benzoic acid methyl ester (methyl salicylate, I) is responsible of their biocide effect against stored grain insects. A second unknown apparented product, II has been systematically observed in all analyzed samples. The present paper describes the identification of this molecule. The analytical investigations including GCMS, GLC and 1H-NMR. spectrometry led to the conclusion that II corresponds to the 2-hydroxy-6-methoxybenzoic acid methyl ester

Lutte contre les ravageurs des stocks de céréales et de légumineuses au Sénégal et en Afrique occidentale : synthèse bibliographique

Controlling pests of cereals and legumes in Senegal and West Africa: a review. Post-harvest losses of cereals and legumes are a major problem in Senegal and West Africa. The solutions to eliminate insects, major pests of stored products were mainly chemical. However, due to pollution associated with pesticides use, selection of resistant strains, environmental pollution, poisoning, the search for alternatives is needed. It is reported on different methods of protecting stocks performed alternatively or in combination with pesticides. The major pest species encountered, particularly Prostephanus truncatus (Horn), insect emerging in Senegal, could be controlled by alternative methods including specially the use of insecticide plants. Different aspects related to this alternative way to chemical pesticides are reviewed herein

Composition chimique du netetu, condiment alimentaire produit par fermentation des graines de caroubier africain Parkia biglobosa (Jacq.) Benth.

Chemical composition of netetu, a food condiment from fermented Parkia biglobosa seeds. The seed oils and cakes of netetu of different origins available on the Senegalian market have been studied to evaluate the nutritional potentialities of this important food condiment used in many African countries. The total oil content ranged from 141 to 349 g per kg. Careful gas chromatography and GC-MS (Gas Chromatography-Mass Spectrometry) investigations revealed seven major fatty acids among which linoleic (41.9-46.8/ of the total fatty acids), oleic (12.6-14.6/), palmitic (10.2-11.3/), stearic (10.0-13.4/), and behenic (12.6-13.4/) predominate. Significant differences were observed between fermented and non-fermented seeds as well as between netetu of different origins. The tocopherol content was found very low (17.7 to 30.6 mg per 100g fat). The total amino acid patterns showed that beside high level of proteins (331 a 540 g per kg) and interesting levels of essential constituents, there is an important deficiency of tryptophane, cysteine, methionine and threonine

Efficiency of Traditional Maize Storage and Control Methods in Rural Grain Granaries: a Case Study from Senegal

Maize storage and pest control method as practiced in traditional clay granaries in the Kédougou region in eastern Senegal were evaluated under rural conditions during two successive years. Three storage modes, i.e. maize cobs, winnowed and non-winnowed maize grains, were tested in seven granaries where the insecticidal plants Hyptis spicigera or H. suaveolens were either incorporated in the store structure or deposited as layers intermittently with maize. At the beginning of the storage period, all granaries were artificially infested with 7 pairs Tribolium castaneum and Sitophilus zeamais. No damage, losses or live insects were observed during 7 months of storage when maize cobs were placed between layers of H. spicigera. Compared with the control, incorporation of insecticidal plants within the granary bottom had no significant effect on the damage and loss level irrespective of the storage mode. Non-winnowed maize always suffered less damage and losses than the winnowed variant. In all granaries depredation, insect abundance and moisture content were highest toward the end of storage period between June and July

Effect of cooking and extraction method on oleaginous cucurbit seed oils quality

In sub-Saharan Africa, Lagenaria siceraria seeds are cooked before consumption. Cooking seed may alter their chemical composition, leading to changes in their health benefits. Thus, this study aimed at determining the effect of cooking of L. siceraria seeds on their edible oil quality. Heat treatments were performed as roasted (100 and 125 \ub0C) and boiled (10, 35, 60 and 90 min). Then oils were extracted with petroleum ether solvent and hot-water flotation process. Peroxide and acid index, and fatty acids composition were evaluated. With the hot-water flotation process, roasting and boiling had no significant effect on acid index and fatty acids composition. However, peroxide values varied from 1.1 to 2.9 meqO2 kg-1 oil. The highest peroxides values were revealed at 90 and 60 min, respectively, in seeds roasted at 100 and 125 \ub0C. With solvent extraction, roasting and boiling affected only peroxide values and fatty acids composition. The highest peroxide values were reached after 10 min of ebullition of roasted seeds, both at 100 and 125\ub0C. Saturated and polyunsaturated fatty acid contents increased after 10 min of boiling of seeds roasted at 100 and 125\ub0C; then decreased to reach the initial content. But, the monounsaturated fatty acids content decreased after 10 min of boiling, and then increased to reach the initial content. The highest values of peroxides and polyunsaturated fatty acids contents were observed with solvent extraction compared to hot-water flotation method. Cooking of L. siceraria seeds does not alter the quality of their oil; solvent extraction makes their oil highly unstable.En Afrique subsaharienne, les graines de Lagenaria siceraria sont consomm\ue9es cuites. La cuisson des graines peut alt\ue9rer leur composition chimique, entra\ueenant des changements quant \ue0 leurs bienfaits pour la sant\ue9. Ainsi, cette \ue9tude visait \ue0 d\ue9terminer l\u2019effet de la cuisson des graines de L. siceraria sur la qualit\ue9 de leurs huiles. Les traitements thermiques ont \ue9t\ue9 effectu\ue9s: torr\ue9faction (100 et 125 \ub0 C) et \ue9bullition (10, 35, 60 et 90 min). Les huiles ont, ensuite, \ue9t\ue9 extraites avec l\u2019\ue9ther de p\ue9trole et par un proc\ue9d\ue9 de flottation \ue0 l\u2019eau chaude. L\u2019indice de peroxyde et d\u2019acide ainsi que la composition en acides gras ont \ue9t\ue9 \ue9valu\ue9s. Avec le proc\ue9d\ue9 de flottation \ue0 l\u2019eau chaude, la torr\ue9faction et l\u2019\ue9bullition n\u2019ont eu aucun effet sur l\u2019indice d\u2019acide et la composition en acides gras. Cependant, les valeurs de peroxyde variaient de 1,1 \ue0 2,9 m\ue9qO2.kg d\u2019huile. Les valeurs les plus \ue9lev\ue9es de peroxydes ont \ue9t\ue9 r\ue9v\ue9l\ue9es \ue0 90 et 60 min respectivement dans les graines torr\ue9fi\ue9es \ue0 100 et 125 \ub0 C. Avec l\u2019extraction par solvant, la torr\ue9faction et l\u2019\ue9bullition n\u2019ont affect\ue9 que les valeurs de peroxyde et la composition en acides gras. Les valeurs de peroxyde les plus \ue9lev\ue9es ont \ue9t\ue9 atteintes apr\ue8s 10 min d\u2019\ue9bullition des graines grill\ue9es \ue0 100 et \ue0 125 \ub0C. Les teneurs en acides gras satur\ue9s et polyinsatur\ue9s ont augment\ue9 apr\ue8s 10 min d\u2019\ue9bullition des graines torr\ue9fi\ue9es \ue0 100 et 125 \ub0C puis ont diminu\ue9 pour atteindre leurs teneurs initiales lorsque le temps d\u2019\ue9bullition a augment\ue9. Mais, la teneur en acides gras monoinsatur\ue9s a diminu\ue9 apr\ue8s 10 minutes d\u2019\ue9bullition, puis a augment\ue9 pour atteindre la teneur initiale. Les valeurs les plus \ue9lev\ue9es des teneurs en peroxydes et en acides gras polyinsatur\ue9s ont \ue9t\ue9 observ\ue9es avec l\u2019extraction par le solvant compar\ue9 \ue0 la m\ue9thode de flottation \ue0 l\u2019eau chaude. Cuire les graines de L. siceraria n\u2019alt\ue8re pas la qualit\ue9 de leur huile\ua0; l\u2019extraction par le solvant rend leur huile hautement instable

Does Tribolium brevicornis Cuticular Chemistry Deter Cannibalism and Predation of Pupae?

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function to prevent pupal cannibalism and predation was evaluated. The cuticular hydrocarbons of T. brevicornis pupae were characterized and flour disk bioassays conducted with individual and combined extract components incorporated into artificial diets on which Tribolium adults fed for six days. Feeding by T. brevicornis and T. castaneum on flour disks containing cuticular extracts of T. brevicornis pupae resulted in reduced consumption and weight loss relative to feeding on control flour disks. In both cases, feeding deterrence indices exceeded 80% suggesting that T. brevicornis cuticular hydrocarbons could function to deter cannibalism and predation of pupae by larvae and adult beetles. Sixteen different cuticular hydrocarbons were identified in T. brevicornis pupal extracts. Eight of the commercially available linear alkanes were tested individually in feeding trials with eight Tribolium species. One compound (C28) significantly reduced the amount of food consumed by three species compared to control disks, whereas the compounds C25, C26, and C27 elicited increased feeding in some species. Four other compounds had no effect on consumption for any species. When four hydrocarbon mixtures were tested for synergistic deterrence on T. brevicornis and T. castaneum, none significantly influenced consumption. Our results indicate that the cuticular chemistry of T. brevicornis pupae could serve to deter predation by conspecific and congeneric beetles