Search

La composition chimique de l'huile essentielle extraite des feuilles fraîches de Lantana camara Linn. récoltées sur le campus d'Abomey-Calavi (Bénin) a été étudiée par chromatographie en phase gazeuse couplée avec la spectrométrie de masse (CG et CG/SM). Quarante et un constituants, représentant 94,76 % de l'huile essentielle de Lantana camara, ont été identifiés. Les composés majoritaires sont : β-caryophyllène 18,5 % ; sabinène 13,1 % ; α-humulène 10 % ; 1,8-cinéole 9 % ; δ-guaiene 5,0 %. Cette huile, testée sur des microorganismes (bactéries et champignons) et les tiques (Amblyoma variegatum), s'est révélée très efficace. Pour citer cet article : G. Alitonou et al., C. R. Chimie 7 (2004). [Copyright 2004 Elsevier]

L'huile essentielle des feuilles de Clausena anisata (Rutaceae) collectée à Akassato (Bénin) a été extraite par hydrodistillation et analysée par CG et CG/SM. Les constituants majoritaires sont des méthyl-chavicols : estragole (66,2 %) et (E)-anethole (17,6 %). Les activités antiradicalaires et antioxydantes de l'huile ont été déterminées et comparées à celles trouvées pour les composés de référence. Pour citer cet article : F. Avlessi et al., C. R. Chimie 7 (2004). [Copyright 2004 Elsevier]

La composition chimique de l'huile essentielle extraite des feuilles fraîches d'Eucalyptus tereticornis Sm. récoltées à Sèmè-kpodji (Bénin) a été étudiée par chromatographie en phase gazeuse et chromatographie en phase gazeuse couplée avec la spectrométrie de masse. Vingt-trois composés, représentant 91 % de l'huile, ont été identifiés. Les constituants majoritaires sont le p-cimène (31,4 %), le β-phellandrène (9,77 %), le spathulénol (8,13 %), le γ-terpinène (7,03 %) et le α-phellandrène (6,78 %). Cette essence présente des activités antimicrobiennes et une activité biologique très accentuée contre les tiques. Pour citer cet article : G. Alitonou et al., C. R. Chimie 7 (2004). [Copyright 2004 Elsevier]

The essential oils obtained by hydrodistillation of leaves, bark and roots of Pentadesma butyracea collected in Natitingou (Benin) were investigated by capillary GC and GC/MS. Twenty-eight components, representing 97-99% of oils, were identified. The samples were exclusively sesquiterpenic, dominated in all cases by β-caryophyllene (58.0- 75.0%) and α-humulene (10.1-14.2%); the leaf oil was characterized by a high content of α-copaene (14.2%). Finally, no significant antiradical activity (DPPH method) or inhibitory effect on the soybeen lipoxygenase activity could be observed. [ABSTRACT FROM AUTHOR]

P. suberosa is a multipurpose medicinal plant in West and Central Africa. Fourteen phenolic compounds were identified in the P. suberosa leaves extract using HPLC-DAD and gallic acid (175.10±0.42 μg/g) was the most abundant. The total phenolic content was 112.16 ± 0.33 mg GAE/g DW while the total flavonoid content was 36.10±0.58 mg QE/g DW. Minimal inhibitory concentration (MIC) values for antimicrobial activity were 0.3125 mg/mL and 1.25 mg/mL on S. aureus and E. faecalis respectively and 2.5 mg/mL and 0.3125 mg/mL on E. coli and S. typhi respectively. Biofilm inhibition evaluated at sub-MIC concentrations revealed that gram-negative biofilms were more susceptible to P. suberosa extract than gram-positive ones and E. coli biofilms were the most susceptible. The extract inhibited violacein production and quorum sensing with inhibition zones varying from 17.0±0.5 mm at MIC to 12.0±0.1 mm at MIC/4. The extract showed good antioxidant capacity and was more active in the DPPH• assay than the two standards α-tocopherol and BHA used. In the ABTS•+ and CUPRAC assays, the activity of the extract was greater than that of α-Tocopherol and very close to that of BHA. The extract showed potential to alleviate Alzheimer’s disease by inhibiting acetylcholinesterase and butyrylcholinesterase as well as antidiabetic activity by inhibiting α-amylase and α-glucosidase. [ABSTRACT FROM AUTHOR]

The chemical composition of the essential oils obtained by hydrodistillation from leaves of three samples of Aeollanthus pubescens Benth. (Lamiaceae) growing wild in Benin were analyzed by GC and GC-MS. To date the biological functions of A. pubescens essential oils have not been demonstrated scientifically even if this plant is traditionally used by local population in alimentary and medicine. We investigated the chemical composition of A. pubescens essential oils and their antiradical and anti-inflammatory activities. Twenty four compounds were identified and quantified in the essential oils, the major compounds being thymol (63.6%; 9.5%; 63.4%), carvacrol (3.1%; 51.1%; 2.1%), thymyl acetate (9.8%; 0.8%; 10.2%), carvacryl acetate (0.8%; 6.1%; 0.7%), p-cymene (5.6%; 9.0%; 5.5%) and -terpinene (6.4%; 11.2%; 6.6%). The antiradical activity of these oils was found to be high and a low anti-inflammatory activity was observed. Fractionation of a thymol rich sample allowed the identification of the bioactive fractions and their contribution to the efficiency of the whole extract. This study suggests that A. pubescens essential oils may be useful in the food industry where the antioxidants are used to retard the degradation of fatty substances, but also in cosmetics or in the field of herbal medicine, where the radical species are associated with the concept of antiaging. [ABSTRACT FROM AUTHOR]

Abstract: Samples of Azadirachta indica and Carapa procera seeds collected in Benin have been analyzed and the results are compared to scarce literature data. The extracted lipids (44.0 and 61.5%, respectively) were examined for fatty acid composition by gas chromatography. The most interesting feature is the very high oil content and the prominent concentration of oleic acid (59.1%) of C. procera seed oil. Oleic (43.5%), linoleic (18.7%), palmitic (17.8%) and stearic (17.4%) acids were the predominant fatty acids in A. indica seed oil, while palmitic (21.1%) and oleic acids (59.1%) were the major acids in C. procera seed oil, this leading to saponification values of 167 and 188 and iodine values of 75 and 69, respectively. Among the unsaponifiable fraction (1.2 and 1.6%, respectively), whose composition has never been reported to date – except the sterol fraction of A. indica – the major sterol is β-sitosterol (77.7 and 61.2%). Tocols (298 and 92ppm respectively) show α-tocopherol and γ-tocopherol as major components (30.8 and 67.3%; 32.5 and 12.2%, respectively). Regarding the cake, results show the interesting content of proteins (31.4 and 20.2%) comprising 17 amino acids with the prominent concentration of arginine, leucine, aspartic and glutamic acids and a noticeable amount of sugars (9.6 and 12.4%). Total ash in cake amounts 5.3 and 8.3%, primarily N and K, but C. procera shows a noticeable amount of Na (1574ppm). Possible uses of oils and cakes are discussed. [Copyright &y& Elsevier]

The chemical volatile profiles of four plant species from Benin were established via SDE/GC–MS and SPME/GC–MS, and were compared to chemical profiles obtained by hydrodistillation/GC–MS. Essential oils and selected identified compounds were used to perform fumigant tests and contact “no choice” tests against adults of the red flour beetle Tribolium castaneum , an important pest insect in stored products worldwide. The chemical profiles and the concentrations of the main compounds varied with the method used. Geranial (hydrodistillation, SPME) and geraniol (SDE) for Cymbopogon citratus , piperitone for Cymbopogon schoenanthus (hydrodistillation, SPME, SDE), E-p -mentha-1(7), 8-dien-2-ol for Cymbopogon giganteus (hydrodistillation, SPME, SDE), neo-isopulegol (SDE) and citronellal (hydrodistillation and SPME) for Eucalyptus citriodora, were identified as main volatile compounds. By fumigation, the LC 50 values obtained after 24 h for essential oils of C. citratus , C. giganteus , C. schoenanthus , E. citriodora, and for piperitone and citronellal were 4.2 mL/L air, 2.3 mL/L air, 2.1 mL/L air, 2.0 mL/L air, 0.5 mL/L air and 1.2 mL/L air, respectively. Furthermore, mortalities of 100%, 82%, 75%, 72%, 68% and 42%, respectively, were found for piperitone at 2.4 mL/L air, citronellal at 2.1 mL/L air, and essential oil extracted from E. citriodora, C. schoenanthus, C. giganteus and C. citratus , at 4 mL/L air. By contact “no choice” test, the LC 50 values for the crude oils after 72 h were: 15% (w/v), 6% (w/v), 6% (w/v) and 5% (w/v) for C. citratus, C. giganteus, C . schoenanthus and E. citriodora , respectively. After 72hours, mortalities of 18%, 67%, 73%, 82%, 87% and 40% for essentials oils (8% w/v) of C. citratus, C. giganteus, C. schoenanthus, E. citriodora , piperitone at 4.7% w/v, and citronellal at 4.2% w/v, respectively, were obtained. The essential oil from C. schoenanthus and E. citriodora as well as piperitone and citronellal represent potential valuable alternative pesticides to conquer the resistance of T. castaneum to synthetic insecticides. [ABSTRACT FROM AUTHOR]

Background Insecticide resistance in sub-Saharan Africa and especially in Benin is a major public health issue hindering the control of the malaria vectors. Each Anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. Therefore, it is urgent to find alternative compounds to conquer the vector. In this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in Benin, were investigated. Methods Essential oils of nine plant species were extracted by hydrodistillation, and their chemical compositions were identified by GC-MS. These oils were tested on susceptible "kisumu" and resistant "ladji-Cotonou" strains of Anopheles gambiae, following WHO test procedures for insecticide resistance monitoring in malaria vector mosquitoes. Results Different chemical compositions were obtained from the essential oils of the plant species. The major constituents identified were as follows: neral and geranial for Cymbopogon citratus, Z-carveol, E-p-mentha-1(7),8-dien-2-ol and E-p-mentha-2,8-dienol for Cymbopogon giganteus, piperitone for Cymbopogon schoenanthus, citronellal and citronellol for Eucalyptus citriodora, p-cymene, caryophyllene oxide and spathulenol for Eucalyptus tereticornis, 3-tetradecanone for Cochlospermum tinctorium and Cochlospermum planchonii, methyl salicylate for Securidaca longepedunculata and ascaridole for Chenopodium ambrosioides. The diagnostic dose was 0.77% for C. citratus, 2.80% for E. tereticornis, 3.37% for E. citriodora, 4.26% for C. ambrosioides, 5.48% for C. schoenanthus and 7.36% for C. giganteus. The highest diagnostic doses were obtained with S. longepedunculata (9.84%), C. tinctorium (11.56%) and C. planchonii (15.22%), compared to permethrin 0.75%. A. gambiae cotonou, which is resistant to pyrethroids, showed significant tolerance to essential oils from C. tinctorium and S. longepedunculata as expected but was highly susceptible to all the other essential oils at the diagnostic dose. Conclusions C. citratus, E. tereticornis, E. citriodora, C. ambrosioides and C. schoenanthus are potential promising plant sources for alternative compounds to pyrethroids, for the control of the Anopheles malaria vector in Benin. The efficacy of their essential oils is possibly based on their chemical compositions in which major and/or minor compounds have reported insecticidal activities on various pests and disease vectors such as Anopheles. [ABSTRACT FROM AUTHOR]

The chemical composition of the essential oils obtained by hydrodistillation from fresh leaves of four Annonaceae: Annona muricata, Annona squamosa, Monodora myristica and Xylopia aethiopica growing wild in Benin were analyzed by GC and GC/MS. Twenty four compounds were identified and quantified in the essential oil of Annona muricata with isocaryophyllene (20.2%); β-caryophyllene (16.1%); δ-cadinene (11.4%), β-elemene (8.9%); muurolene (6.9%) as major components. Twenty nine compounds were identified and quantified in the essential oil of Annona squamosa which contained isocaryophyllene (24.9%), camphene (10.2%), β-caryophyllene (2.6%), epi-α-cadinol + epi-α-muurolol (9.2%) as prominent components. Essential oil of Monodora myristica screened contained twenty four components identified and quantified with α-phellandrene (65.5%), α-pinene (6.2%) as main compounds. Thirty three compounds were identified and quantified in the essential oils of Xylopia aethiopica, the major compounds being p-cymène (16.0%), sabinene (12.6%), terpinen-4-ol (11.3%), β-elemene (10.6%) and β-pinene (7.1%). The antiradical and anti-inflammatory activities of these oils were found to be low. [ABSTRACT FROM AUTHOR]