In vitro biological effects of two anti-diabetic medicinal plants used in Benin as folk medicine.

International audienceBACKGROUND: Extracts from Polygonum senegalensis (Polygonaceae) and Pseudocedrela kotschyi (Meliaceae) are two important traditionally used medicinal plants in rural Benin to treat many diseases and notably type 2 diabetes. The aim of the study was to investigate the alpha-glucosidase inhibition, antioxidant and antibacterial activities of those plants extract: Polygonum senegalensis leaves, and Pseudocedrela kotschyi root. METHODS: Hydro-alcoholic (50%) extracts were analyzed for their phytochemical content and tested for their inhibition potency on alpha-glucosidase from Saccharomyces cerevisiae. Antioxidant activities were assessed using the DPPH, ORAC, FRAP and DCFH-DA (cell based) assay. Finally, the antibacterial activity was evaluated using MIC determination on four Gram-positive cocci (Bacillus subtilis, Clostridium difficile, Enterococcus faecalis, Staphylococcus aureus), three Gram-negative bacilli (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae), and the yeast Candida albicans. RESULTS: Each extract presented significant alpha-glucosidase inhibition and antioxidant activities. Polygonum senegalensis leaf extracts were the most active in each in vitro assay with an IC50 = 1.5 mug/ml for alpha-glucosidase inhibition and an IC50 = 6.8 mug/ml for DPPH scavenging, - 4.5 mumol Fe II/g of dry matter - 9366 mumol Trolox / g DW - for FRAP and ORAC values, respectively. IC50 = 2.3 mug GA / ml for DCFH-DA assay. Concerning its antibacterial activity, a growth inhibitory effect was observed only against three Gram negative bacilli: B. subtilis, E. faecalis, S. aureus and the yeast C. albicans at high concentration. CONCLUSION: The results showed that the semi alcoholic extract of the two studied plants possess alpha-glucosidase inhibitory activity, antioxidant potency, and low antibacterial effect

Chemical composition and insecticidal activity of plant essential oils from Benin against Anopheles gambiae (Giles)

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

SYNTHESIS OF gamma -AMINO- beta -ARYL PROPANESULPHONIC ACID DERIVATIVES

The investigation objects are the gamma -aminoalkanesulphonic acids and sulphopyrrolidones. The aim is to investigate the synthesis procedures of the beta -aryl homotaurines including the corresponding alpha -sulpho- beta -aryl pyrrolidones-sulpho analogs of the biologically-active reduced gamma -aminobutyric acids and pyrrolidones. On base of the analysis of the data in IR spectra of the synthesized compounds and also literature data the characteristic stripes have been revealed. These stripes can be proposed as the analytical identifications for the sulphonic acids and their esters. The hydridation reactions of the gamma -nitropropanesulphoesters and acid alkaline hydrolysis of the reduction products - sulpho-pyrrolidones and esters of alpha -carbomethoxy- beta -aryl- gamma -aminopropanesulphoni c acids have been investigated firstly. The new synthesis procedure of the beta -phenylhomotaurine as suotphrananalog of the medicinal preparation phenybut has been developed. Application field: pharmacology and medicineAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Chemical Composition and Evaluation of Anti-tyrosinase and Anti-Oxidative Effects of Topical Cream Formulation from Acacia sieberiana, Vitellaria paradoxa and Beeswax

Skin diseases can get natural therapies from medicinal plant-based products. In this study, a topical cream was formulated from ethanol extract of Acacia sieberiana, beeswax and Vitellaria paradoxa (shea) butter. GC-MS characterization with co-injection of the topical cream revealed Stearic acid (31.43%), Palmitic acid (23.15%), Oleic acid (21.44%) and Linoleic acid (16.20%) as the major components. Seven phenolic conpounds were identified and quantified by HPLC- DAD and Ferulic acid (12.81±0.26 mg/g) was the most abundant. The cream showed good antioxidant properties evaluated through ?-Carotene-linoleic acid assay, DPPH• radical scavenging, ABTS•+ assay, CUPRAC assay, and metal chelating assay. The cream had higher activity in the DPPH• assay (IC50 = 32.10±0.84 µg/mL), ABTS•+ assay (IC50 = 22.49±0.62 µg/mL) and CUPRAC assay (IC50 = 49.27±0.79 µg/mL) than ?-Tocopherol. The antioxidant effects are an indication that the cream can reduce oxidative stress on the skin including aging, carcinogenesis and inflammation. At 100 µg/mL, the topical cream showed tyrosinase inhibition of 48.23±0.87% regarded as relatively good compared to the standard tyrosinase inhibitor kojic acid, which showed 79.50±0.32% inhibition at the same concentration. The cosmetic cream was able to inhibit the melanin production rate-limiting enzyme, tyrosinase, indicating that it can control hyperpigmentation and skin spots

CHEMICAL CHARACTERIZATION AND BIOLOGICAL ACTIVITIES OF EXTRACTS OFTHREE PLANTS USED IN TRADITIONAL MEDICINE IN BENIN: TECTONA GRANDIS, UVARIA CHAMEAE AND JUSTICIA SECUNDA

Objective: The present study was devoted to the chemical analysis of three plants (Tectona grandis, Uvaria chameae and Justicia secunda) usually used by traditional healers in Benin, for their curative properties in the treatment of certain diseases. Methods: After characterization of large chemical groups present in ethanolic extract of these plants, the total polyphenols were measured by the Folin method, the content of condensed tannins, total flavonoids, anthocyanins and anthocyanidins was evaluated by spectrophotometry. Results: The results show the presence of several secondary metabolites such as saponins, alkaloids, tannin, mucilages, anthraquinones, leucoanthocyanins, anthocyanins and triterpene in varying proportions in the three plants. The contents of condensed tannins, of anthocyanidins, total polyphenols and total flavonoids are respectively higher in the leaves (13.409 mg/g, 1.529 mg/g, 3.479 mg/g and 24.640 mg/g) than the bark of T.g (8.612 mg/g, 0 mg/g, 2.694 mg/g and 12.410 mg/g). As against, leaves of U.care richer in condensed tannins, flavonoids and total polyphenols (44.290 mg/g, 9.135 mg/g, 4.779 mg/g) than J.s (0 mg/g, 2.011 mg/g and 1.478 mg/g) unlike anthocyanidins. Of three plants studied, U.c was revealed the richest in polyphenolic compounds (condensed tannins, total polyphenols) and J.s was least rich. This content of polyphenolic compounds explain the antiradical activities observed; an CI50 of 0.700 mg/mL for U.c, 14.340 mg/mL for leaves of T.g, 24.790 mg/mL for bark of T.g and 46.500 mg/mL for leaves of J.s. Conclusion: This study contributes to increase those plants's phytochemical knowledge and allows having a better understanding of their pharmacological properties Keywords: Polyphenols, Antiradical activities, Solid phase micro extraction, Tectona grandis, Uvaria chameae, Justicia secunda