Phytothérapie traditionnelle des conjonctivites en milieu urbain ivoirien : enquête sur les deux marchés aux plantes médicinales d’Abidjan

National audienceA semi-directed ethnobotanic survey of the traditional treatment of ophthalmic diseases was conducted among the medicinal plant retailers in the markets of Adjamé and Abobo, in the District of Abidjan (Côte d’Ivoire). Seventeen female informers from five ethnic groups (mostly Baoulé and Malinké), aged from 20 to 60 years (mean 39.1 years) were interviewed about their knowledge of eye diseases. ‘Conjunctivitis’ and ‘redness of the eye’ were frequently cited, sometimes with a precise traditional definition of the ailment (‘koko’, possibly corresponding to allergic conjunctivitis; ‘apollo’, for viral conjunctivitis). Phytotherapy is largely used to treat these specific ailments and symptoms of conjunctivitis: each informer cited an average of five plant species, with no obvious differences related to ethnic origin. Overall, 44 plant parts from 36 species, belonging to 26 botanical families, among which six were from the Fabaceae, were cited (Table 1). These plants were mostly Fabids and Malvids (Figure 2), in contrast with those used in Europe. Disparate phytotherapeutic uses were found (19 plants, i.e. 54%, were cited only once), but consensus existed for several species, the most cited being Ocimum gratissimum (Lamiaceae; 14 citations, 82% of informers), Dissotis rotundifolia (Melastomataceae; 11 citations), Kalanchoe crenata (Crassulaceae; eight citations), Desmodium adscendens (Fabaceae; five citations), Combretum paniculatum (Combretaceae), Manotes longiflora (Connaraceae), Adenia lobata (Passifloraceae) and Phyllanthus muellerianus (Phyllanthaceae) - all four citations each. Several of these plants had been inventoried in the 1970s, have convergent uses in neighbouring countries [e.g. O. gratissimum, Nauclea latifolia (Rubiaceae)], and/or constitute ‘classical’ plants of the Ivorian popular pharmacopoeia [Spondias mombin (Anacardiaceae), Abrus precatorius (Fabaceae), O. gratissimum, Zanthoxylum zanthoxyloides (Rutaceae)]. Interestingly, their main traditional therapeutic indications, as softeners in sore throats or for antiseptic purposes, can be regarded as evocative of the uses inventoried here. Leaves are used in 64.0% of cases. Roots and flowers are poorly (4.4%) and never cited, respectively. Direct use of latex or of sap was mentioned three times (3.7%). Half of the uses of leaves are performed in a fresh form, as expressed juice. Decoction is, however, the main mode of preparation (56%), the extracts being kept for 3–5 days. These traditional herbal drugs are used as ocular instillations or as an eye bath, and less frequently for face wash (Figure 3). We hypothesized that uses of plants in conjunctivitis could be linked to antiseptic potential, in order to treat the infectious condition, to prevent infection of the injured eye, or to allow conservation of traditional preparations. To test this hypothesis, all plants were harvested in their natural habitats. Aqueous and methanol extracts of dried material were screened for antimicrobial activity, by dilution in solid culture medium, against six bacterial species responsible for ocular infections (Gram-negative bacilli: Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa; Gram-positive cocci: Enterococcus hirae, Staphylococcus aureus, Staphylococcus epidermidis). 52.3% of the extracts and 88.8% of plants inhibited bacterial growth of at least one strain (2 mg/ml, 48 h) (Table 2, Figure 5). Seven extracts were active against all bacteria [methanol extracts of Hibiscus asper (Malvaceae), Hoslundia opposita (Lamiaceae), O. gratissimum, S. mombin, Vitellaria paradoxa (Sapotaceae) and Z. zanthoxyloides (bark); aqueous extracts of Piliostigma thonningii (Fabaceae) and S. mombin]. However, there was no correlation between the displayed spectra and the frequencies of citation, except for O. gratissimum, a readily available species for which the antibacterial potential and safety have been largely studied. In contrast, some poorly cited species are known, or can be suspected, to be toxic, as reported in the literature. From a general point of view, investigation of the benefit/risk ratio of these widespread ocular traditional practices should be pursued for promotion and valorization of safe primary care remedies among the inhabitants of Abidjan.Une enquête ethnobotanique semi-dirigée, focalisée sur le traitement traditionnel des ophtalmies, a été menée auprès de 17 vendeuses de plantes médicinales, issues d’ethnies diverses, installées sur les marchés d’Adjamé et d’Abobo, communes du District d’Abidjan (Côte d’Ivoire). Les pathologies oculaires prises en charge sont notamment les conjonctivites telles que le koko ou l’apollo. Les vendeuses citent chacune, en moyenne, l’emploi de cinq plantes utilisées dans ces affections. 44 drogues végétales issues de 36 plantes appartenant à 26 familles botaniques ont été recensées et identifiées. Leur emploi se fait à l’état sec ou frais, sous forme de décoction ou de jus exprimé, pour instillation ou bain oculaire et parfois lavage du visage. Les espèces les plus citées sont Ocimum gratissimum L. (Lamiaceae), Dissotis rotundifolia (Sm.) Triana (Melastomataceae) et Kalanchoe crenata (Andrews) Haw. (Crassulaceae). Les plantes ont été récoltées et l’activité antibactérienne d’extraits aqueux et méthanoliques préparés à partir des drogues végétales sèches a été évaluée vis-à-vis de six espèces bactériennes couramment responsables d’infections oculaires. Les résultats de ce criblage ne montrent pas de corrélation avec la fréquence de citation des espèces

Phytochemical screening and evaluation of antioxidant activity of Picralima nitida (Stapf) T. Durand & H. Durand (Apocynaceae)

Background: Picralima nitida (Stapf) T. Durand & H. Durand (Apocynaceae), a plant species from West Africa is used in traditional Ivorian medicine to treat malaria and diabetes.Objectives: The aim of this study is to perform the phytochemical screening and the antioxidant activity of the fruit of this plant species.Methods: The phytochemical screening of the decoction obtained from the fruit of Picralima nitida was carried out through tube characterization tests. The phenolic compound content in the decoction was evaluated using the Folin-Ciocalteu method. The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical scanning method (DPPH).Results: The phytochemical screening revealed a high content of alkaloids, sterols and polyphenols. On the other hand, we observed a moderate presence of saponosides, flavonoids and the absence of tannins and quinones. The quantification of the total polyphenols gave an estimated value by measuring with a spectrophotometer of 39.19 ± 4.37 mg GAE / g of extract. The extract showed both antioxidant activity against the DPPH radical (IC50 = 104.30 ± 3.17 μg / mL) and the ferric ion Fe3 + (261.4 ± 36.87μmoL Eq Trolox / g ex).Conclusion: Picralima nitida decoction has several secondary metabolites including polyphenols and antioxidant activity. Key words: Picralima nitida, Phytochemical screening, Trolox, DPPH, antioxidant activity French Abstract: Screening phytochimique et évaluation de l’activité antioxydante de Picralima nitida (Stapf) T. Durand & H. Durand (Apocynaceae)Contexte : Picralima nitida (Stapf) T. Durand et H. Durand (Apocynaceae), une espèce végétale d'Afrique de l'Ouest est utilisée en médecine traditionnelle ivoirienne pour traiter le paludisme et le diabète.Objectifs : Le but de cette étude est de réaliser le criblage phytochimique, de doser les polyphénols et d’évaluer l’activité antioxydante du fruit de cette espèce végétale.Méthodes : Le criblage phytochimique de la décoction obtenue à partir des fruits de Picralima nitida a été réalisé par des tests de caractérisation en tube. La teneur en composés phénoliques a été évaluée selon la méthode de Folin- Ciocalteu. L'activité antioxydante réalisée sur l’extrait sec a été évaluée en utilisant la méthode de balayage des radicaux 2,2-diphényl-1-picrylhydrazyle (DPPH).Résultats : Le criblage phytochimique a révélé une teneur élevée en alcaloïdes, stérols et polyphénols. En revanche, nous avons observé une présence modérée de saponosides, de flavonoïdes et l'absence de tanins et de quinones. La quantification des polyphénols totaux a donné une valeur estimée par mesure au spectrophotomètre de 39,19 ± 4,37 mg GAE / g d'extrait. L'extrait a montré à la fois une activité antioxydante contre le radical DPPH (IC50 = 104,30 ± 3,17 μg / mL) et l'ion ferrique Fe3+ (261,4 ± 36,87 μmoLl Eq Trolox / g d’extrait).Conclusion : La décoction des fruits de Picralima nitida possède plusieurs métabolites secondaires, notamment des polyphénols. Le décocté est doué d’une activité antioxydante. Mots clés : Picralima nitida, criblage phytochimique, Trolox, DPPH, activité antioxydant