Euclasta condylotricha flowers essential oils: A new source of juvenile hormones and its larvicidal activity against Anopheles gambiae s.s. (Diptera: Culicidae).

The essential oil (EO) of plants of the Poaceae family has diverse chemical constituents with several biological properties. But, data on the chemical constituents and toxicity are still unavailable for some species belonging to this family, such as Euclasta condylotricha Steud (Eu. condylotricha). In this study, the chemical composition of the EOs of Eu. condylotricha flowers was evaluated by gas chromatography coupled with mass spectrometry (GC-MS). The EOs larvicidal property was assessed against third instar larvae of three Anopheles gambiae laboratory strains (Kisumu, Acerkis and Kiskdr) according to the WHO standard protocol. The percentage yields of the EOs obtained from hydro distillation of Eu. condylotricha flowers varied 0.070 to 0.097%. Gas Chromatography-Mass Spectrometry (GC-MS) applied to the EOs revealed fifty-five (55) chemical constituents, representing 94.95% to 97.78% of the total essential oils. Although different chemical profiles of the dominant terpenes were observed for each sample, EOs were generally dominated by sesquiterpenoids with juvenile hormones as the major compounds. The primary compounds were juvenile hormone C16 (JH III) (35.97-48.72%), Methyl farnesoate 10,11-diol (18.56-28.73%), tau-Cadinol (18.54%), and ß-Eudesmene (12.75-13.46%). Eu. condylotricha EOs showed a strong larvicidal activity with LC50 values ranging from 35.21 to 52.34 ppm after 24 hours of exposition. This study showed that Eu. Condylotricha flowers essential oils are potent sources of juvenile hormones that could be a promising tool for developing an eco-friendly malaria vector control strategy.

Physicochemical Characterization of Detarium microcarpum Seeds from Northern Benin.

The objective of this work is to determine the physicochemical characteristics of the Detarium microcarpum seeds from North Benin, specially the proximate composition, colour, minerals, and antinutritional factors using standard analytical methods. The results show that the contents of moisture, protein, total sugars, lipid, crude fiber, and ash ranged, respectively, from 10.85 to 14.69%, from 13.54 to 17.82%, from 19.69 to 32.04%, from 8.68 to 11.90%, from 19.78 to 34.24%, and from 1.5 to 3.49%. The luminance (l∗), red saturation (a∗), and yellow saturation (b∗) have, respectively, ranged from 60.45 to 67.64, from 5.44 to 8.86, and from 8.24 to 9.28. Seeds contain interesting contents of potassium, calcium, magnesium, manganese, sodium, and iron; they have, respectively, varied from 6141.88 to 12305.16 mg/kg, from 1254.47 to 2168.62 mg/kg, from 1298.87 to 2533.06 mg/kg, from 75.18 to 307.23 mg/kg, from 53.52 to 136.19 mg/kg, and from 28.46 to 181.42 mg/kg. The investigation of antinutritional factors indicates the presence of oxalates, phytates, total phenolic compounds, and saponins with contents that have varied, respectively, from 1.01 to 2.36%, from 0.37 to 0.87%, from 3.13 to 7.61%, and from 1.35 to 4.59%. On average, the physicochemical characteristics of the Sudanian and Sudano-Guinean zones are similar, except for total sugar content.

Chemical composition and the insecticidal activity of Aeollanthus pubescens leaf essential oil against Anopheles gambiae sensu stricto.

BACKGROUND: The excessive use of synthetic insecticides is responsible for many cases of resistance in insects. Therefore, the use of natural molecules of ecological interest with insecticidal properties is an alternative approach to the use of synthetic insecticides. The aim of this study is to investigating the larvicidal and adulticidal activity and the chemical composition of the essential oil of Aeollanthus pubescens on the major malaria vector, Anopheles gambiae. METHODS: Three reference strains of Anopheles gambiae sensu stricto (Kisumu, Kiskdr and Acerkis) were used in this study. The leaves of A. pubescens were collected in southern Benin. The standard World Health Organisation (WHO) guidelines for larvicide evaluation were used, and the chemical composition of the essential oil was analysed by gas chromatography coupled to mass spectrometry. Adult mosquitoes of each strain were exposed to pieces of net coated with the essential oil for 3 min using the WHO cone bioassay method. Probit regression analysis was used to determine the concentrations that would kill 50 and 95% of each test population (LC50, LC95) and the knockdown time for 50 and 95% of each test population (KDT50, and KDT95). The difference between the mortality-dose regressions for the different strains was analysed using the likelihood ratio test (LRT). The log-rank test was performed to evaluate the difference in survival between the strains. RESULTS: A total of 14 components were identified, accounting for 98.3% of total oil content. The major components were carvacrol (51.1%), thymyle acetate (14.0%) and É£-terpinene (10.6%). The essential oil showed larvicidal properties on the Kisumu, Acerkis and Kiskdr strains, with LC50 of 29.6, 22.9 and 28.4 ppm, respectively. With pieces of netting treated at 165 µg/cm2, the KDT50 of both Acerkis (1.71 s; Z = 3.34, P < 0.001) and Kiskdr (2.67 s; Z = 3.49, P < 0.001) individuals were significantly lower than that of Kisumu (3.8 s). The lifespan of the three mosquito strains decreased to 1 day for Kisumu (χ2 = 99, df = 1, P < 0.001), 2 days for Acerkis (χ2 = 117, df = 1, P < 0.001) and 3 days for Kiskdr (χ2 = 96.9, df = 1, P < 0.001). CONCLUSION: Our findings show that A. pubescens essential oil has larvicide and adulticide properties against the malaria vector An. gambiae sensu stricto, suggesting that this essential oil may be a potential candidate for the control of the resistant malaria-transmitting vectors.

Toxicological Characterization of Ten Medicinal Plants of the Beninese Flora Used in the Traditional Treatment of Diarrheal Diseases.

The use of medicinal plants in traditional medicine is a common practice in developing countries. However, this unregulated or poorly rational use may present a dose-dependent risk of toxicity to humans. This study aimed to explore the phytochemical and toxicological characteristics of ten (10) plant species used in the traditional treatment of infectious diarrhea in Benin. The acute toxicity of aqueous and hydroethanolic extracts of Khaya senegalensis, Daniellia oliveri, Rauvolfia vomitoria, Vernonia amygdalina, Manihot esculenta, Ocimum gratissimum, Senna italica, Diospyros mespiliformis, Pterocarpus erinaceus, and Anacardium occidentale was evaluated following the OECD 423 protocol at a single dose of 2000 mg/kg. This safety test was complemented by a larval cytotoxicity test. Hematological and biochemical examinations, as well as a histological study of the liver and kidneys, were performed. Larval cytotoxicity was assessed by the sensitivity of Artemia salina larvae to different concentrations of the plant extracts studied. Testing for chemical compounds was performed on the basis of differential staining and precipitation reactions. The mean lethal concentration (LC50) was determined by the probit method. The qualitative phytochemical screening of the plants studied revealed the presence of catechic tannins, gallic tannins, flavonoids, anthocyanins and sterol-terpenes, alkaloids, saponosides, and reducing compounds. This composition varied according to the plants studied. Acute toxicity data indicated that there was no mortality and no structural and functional alterations of the liver and kidneys of treated animals. Larval cytotoxicity data suggest that the plants studied are not cytotoxic (LC50 ≥ 0.1 mg/mL). These observations reflect the safety of these plants and justify their use in traditional medicine in the treatment of many diseases including diarrheal diseases.

Physicochemical Characterization and Polyphenolic Content of Beninese Honeys.

The physicochemical and phytochemical analyses of honeys (n = 50) from Sudanese, Sudano-Guinean, and Guinean areas of Benin were investigated. Results showed that dark amber is the dominant color. Moisture content ranged from 15.50% to 23.50%, and 72% of honeys respected the Codex Alimentarius recommendation. pH varied between 2.87 and 6.15, and free acidity ranged from 9.00 to 39.00 meq/kg. Electrical conductivity varied from 0.37 to 1.43 mS/cm. The content in fructose varied from 21.67% to 94.21%, and proline content ranged between 306.31 and 1187.93 mg/kg. All physicochemical characteristics varied with the areas. A negative correlation was found between pH and moisture content (r = -0.55; p < 0.01). A positive correlation was established between pH and conductivity (r = 0.79; p < 0.01) and between proline and color (r = 0.44; p < 0.01). Total phenolic content varied between 55.97 and 224.99 mg GAE/100 g, and flavonoid content ranged between 1.43 and 29.81 mg CAE/100 g. Flavonoid was positively correlated with color (r = 0.78; p < 0.01) and proline (r = 0.47; p < 0.01). Tukey's test revealed differences between total phenolic and flavonoid contents of honeys from five areas (p < 0.01). In general, Sudanese and Sudano-Guinean honeys showed potential toward therapeutic applications because of their high phenolic contents.

Profiling the quality characteristics of the butter of Pentadesma butyracea with reference to shea butter.

BACKGROUND: Pentadesma butyracea is a tropical plant species. Its kernels are rich in edible butter similar to shea butter. This study evaluated the quality characteristics of the Pentadesma butter produced by cottage enterprises in Benin, using a quantitative survey approach and physicochemical and sensorial analysis methods. RESULTS: The butter of Pentadesma is mostly used for food preparation, cosmetic and therapeutic applications. It is characterized by a yellow colour, a hard texture, a relatively sweet taste and a bright appearance. Consumers preferred Pentadesma butter to shea butter for colour, taste, texture and appearance. Instrumental analysis showed that the average water content (6.5 g kg(-1) ) and peroxide value (0.74 mEq O2 kg(-1) ) of Pentadesma butter were lower than those of shea butter, for which average water content and peroxide values were 20.7g kg(-1) and 2.09 mEq O2 kg(-1) respectively. The fatty acid profile of Pentadesma butter is similar to that of shea butter. CONCLUSION: This study showed that the Pentadesma butyracea butter produced by cottage enterprises in Benin exhibited quality characteristics which are better than that of shea butter. The data generated can be used for a better exploitation of the butter in food and cosmetic industries.