Pharmacognostic Properties and Mosquito Repellent Activity of the Leaf Extract of Vernonia glaberrima (Asteraceae) Welw. Ex O. Hoffm against Aedes aegypti Mosquito
Sabastine Obinna Onugwu 1, Linda Adaeze Onugwu2*, Onyinye Ugwu 1
- Department of Pharmacognosy, Enugu State University of Science and Technology, Agbani, Enugu State.
- Department of Pharmaceutics, University of Nigeria Nsukka
| Key words:
Vernonia glaberrima Dengue, Aedes aegypti, repellent.
*Corresponding author: adaeze.onugwu@unn.edu.ng; Page No: 101-110 |
AbstractThe world’s population is severely burdened by mosquito-transmitted diseases, which claim millions of lives annually. These diseases include malaria, yellow fever, zika virus, dengue fever, and Rift Valley fever. The purpose of this research was to assess the pharmacognostic profile and repellent properties of methanol extract of V. glaberrima leaf and its fractions on Aedes aegypti adult mosquito. The leaf was microscopically examined, and pharmacognostic evaluation was carried out using the standard method to determine the ash values, extractive values, moisture content, microscopy and phytochemical contents. The bioactive constituents of the leaf were extracted by cold maceration using methanol. The extract was further fractionated with n-hexane, ethyl acetate, and n-butanol using column chromatography. The repellent activity was carried out using WHO protocols at concentrations of 10, 50 and 100% for the various fractions of V. glaberrima on adult Aedes aegypti. V. glaberrima leaf exhibited amphistomatic with anomocytic stomata with stomatal index of 3.63% and 11.06% at the adaxial and abaxial leaf surfaces, respectively. The microscopic results show the presence of oil glands, starch, tannins, cellulose, gum, calcium oxalate, fibre and vessel elements. The mean moisture content of Vernonia glaberrima leaf was 9.33±0.57%, while the yield of the methanol extract was 34.60%. The four fractions of V. glaberrima leaf exhibited significant repellency activity against Aedes aegypti mosquitoes, with percentage repellency ranging from 27.8-98.9%. Vernonia glaberrima leaf showed significant repellency against Aedes aegypti mosquitoes and might be an effective and safe repellent for malaria control.
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