Gas Chromatography-Mass Spectroscopy and Histopathological Effects of Methanol Leaf Extract of Uvaria chamae on the Midgut of Sitophilus zeamais

Abstract

The present study was carried out to assess the effect of methanol leaf extract of Uvaria chamae using Gas Chromatography-Mass Spectrum (GC-MS) to determine the phytochemicals present and its effect on the histology of midgut of maize weevil, Sitophilus zeamais. Insects were administered with 10 mg/kg of the plant extract using diffusion method where insects were put in a petri dish containing various concentrations and observed to see the stage they begin to die due to toxicity and observed for 5 min. They were collected into foil processing paper and fixed in Bouins fluid for 24 h, repacked after 24 h and folded in fresh foil immersed in buffered formalin for histopathological studies. Result revealed that a severe degeneration de-arrangement of the respiratory tract epithelial lining, secretory lining cells and gastrointestinal layers with the destruction of the muscular layer when compared with the control. The methanol leaf extracts of U. chamae were preliminary screened for the phytochemicals. The extract shows the presence of cardiac glycosides, saponin, steroids/terpenes, flavonoids, alkaloids and phenols. GC-MS analysis of the extract showed the presence of 2-nitrobenzaldehyde (4.00), malic acid (2.04), L-aspartic acid (2.00), 1, 1, dimethylhydrazine (1.86), Cedrandiol (1.75), 2-amino-4-(2-methylpropenyl)-pyrimidin-5-carboxylic acid (1.56), thiirane (1.54), mercaptoethanol (1.11) and some minor compounds. The findings indicated that methanol extract of U. chamae is rich in phyto-compounds having biological activities on the midguts’ histology of S. zeamais. Therefore, it is recommended as an alternative for the synthetic insecticide used by farmers for the preservation of stored grains. © 2021 Friends Science Publishers