ETHNOTOXIC POTENTIAL OF Eugenia aromatica AGAINST COCOA MOTH Ephestia cautella (Lepidoptera: Pyralidae) AND ITS SAFETY ON ALBINO RAT

Abstract

Eugenia aromatica is a popular spice with diverse medicinal uses and exhibit insecticidal effectiveness against stored insect pest. This study investigated contact and fumigant efficacy of the powder and oil extract of E. aromatica on the developmental stages of Ephestia cautella and also tested their toxicity effect on albino rat. Powders of E aromatica were administered as contact insecticide at different concentrations (0.5g, 1.0g, 1.5g, 2.0g, and 2.5g). The oil from E. aromatica was extracted with ethanol using soxhlet extractor, redistilled using rotary evaporator and tested for fumigant insecticidal activity against development stages of E. cautella at 0.5ml, 1.0ml, 1.5ml, 2.0ml, and 2.5ml. Egg hatchability, adult emergence, larvae and adult mortality of E. cautella were used as indices of insecticidal activities at 24hrs, 48hrs, 72hrs, and 96hrs post-treatment period. This experiment was laid out in completely randomized design with three replications. Essential oil obtained from the clove of the plant was purified and analysed by Gas Chromatography Mass Spectrometer (GC-MS). The toxic effect of the plant extract after a single dose study for 24 hours (Acute toxicity) and 21 days (Sub-chronic) toxicity were carried out on male albino rat. Data obtained were subjected to analysis of variance (ANOVA) and means were separated using Tukey HSD at 5% level of significance. Result obtained showed that 0% hatchability was recorded at all concentrations of the treatments. Asides the 0.5g and 1.0g of E. aromatica that recorded 50.00% and 76.67% larva mortality at 24hrs, other treatment concentrations recorded 100% larva mortality. Also, 2.5ml of E. aromatica oil tested as contact and fumigant larvicides after 96hrs recorded 91.33% and 98.33% mortality respectively. The main chemical components were Eugenol, Caryophyllene and Humulene while plant extract contains antioxidants which significantly (p<0.05) cause decrease in the activity of ALT and AST in the serum of composite feed with E. aromatica administered rats compared with E. aromatica (only) administered rats. LD50 of Eugenia aromatica was 1833 mg/kg. The histopathology results of the liver revealed that groups of rats administered with E. aromatica extract alone exhibited a mild to moderate vacuolar degeneration and congestion in their liver cells with respect to increase in the concentration of the extract while feed and extract administered rats livers’ histology revealed that there was a mild congestion at lower concentrations. The histopathological results of the kidney of the composite feed and E. aromatica administered rats revealed that visible lesion on the kidney cells at 2500 mg/Kg of composite feed and E. aromatica groups. However, mild congestion and fibroplasia was observed in the portal area of the kidney at lower concentrations below 2000 mg/Kg of composite feed and E. aromatica compared to the control group that exhibited no visible lesion on the interstitial vessels of the kidney. These findings suggested that E. aromatica extract has potential natural pesticidal properties and at low concentration could be a potential source of insecticide which in future may serve for the production of synthetic biopesticide