Biocontrol effect of entomopathogenic fungi Metarhizium anisopliae ethyl acetate-derived chemical molecules: an eco-friendly anti-malarial drug and insecticide

Authors: ERUMAL, VIVEKANANDHAN - SAVEETHA INSTITUTE OF MEDICAL AND TECHNICAL SCIENCES; KANNAN, SWATHY - CHIANG MAI UNIVERSITY; ALFORD, LUCY - UNIVERSITY OF BRISTOL; PITTARATE, SARAYUT - CHIANG MAI UNIVERSITY; MEKCHAY, SUPAMIT - CHIANG MAI UNIVERSITY; Reddy, Gadi V.P.; ELANGOVAN, DILIPAN - SAVEETHA INSTITUTE OF MEDICAL AND TECHNICAL SCIENCES; MARIMUTHU, RAMACHANDRAN - PERIYAR UNIVERSITY; KRUTMUANG, KRUTMUANG - CHIANG MAI UNIVERSITY

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2023
Publication Date: 7/27/2023
Citation: Erumal, V., Kannan, S., Alford, L., Pittarate, S., Mekchay, S., Reddy, G.V., Elangovan, D., Marimuthu, R., Krutmuang, K. 2023. Biocontrol effect of entomopathogenic fungi Metarhizium anisopliae ethyl acetate-derived chemical molecules: an eco-friendly anti-malarial drug and insecticide. Archives of Insect Biochemistry and Physiology. https://doi.org/10.1002/arch.22037.
DOI: https://doi.org/10.1002/arch.22037

Interpretive Summary: The study results, in conjunction with previous research, highlight the potential for entomopathogenic fungus spores and their chemical constituents as target-specific, effective, and eco-friendly alternatives to the chemical control of insect pests. Isolation of the entomopathogenic fungus was confirmed through morphological and molecular characterization. Fungi ethyl acetate crude extract caused toxicity to the protozoan malaria parasite and larvae of mosquitoes, armyworms, and mealworms, offering support for the use of the extract in the control of medical and crop insect pest larvae and Plasmodium protozoan parasite. The non-target bioassay results revealed no toxic or histopathological effects on the non-target species earthworm. These findings provide the first steps in developing a new larvicidal and anti-plasmodial agent. Further investigations are in progress to isolate the active molecule from the mosquito ethyl acetate crude extract responsible for the anti-plasmodial and insect larvicidal activity.

Technical Abstract: Insect pests represent a major threat to human health and agricultural production. With a current over-dependence on chemical insecticides in the control of insect pests, leading to increased chemical resistance in target organisms, as well as side effects on non-target organisms, the wider environment, and human health, finding alternative solutions is paramount. The employment of entomopathogenic fungi is one such potential avenue in the pursuit of greener, more target-specific methods of insect pest control. To this end, the present study tested the chemical constituents of Metarhizium anisopliae fungi against the unicellular protozoan malaria parasite Plasmodium falciparum, the insect pests Anopheles stephensi Listen, Spodoptera litura Fabricius, and Tenebrio molitor Linnaeus, as well as the non-target bioindicator species, Eudrilus eugeniae Kinberg. Fungal crude chemical molecules caused a noticeable anti-plasmodial effect against P. falciparum, with IC50 and IC90 values of 11.53 and 7.65 µg/mL respectively. The crude chemical molecules caused significant larvicidal activity against insect pests, with LC50 and LC90 values of 49.228-71.846 µg/mL in A. stephensi, 32.542-76.510 µg/mL in S. litura, and 38.503-88.826 µg/mL in T. molitor at 24 h post treatment. Based on the results of the non-target bioassay, it was revealed that the fungal-derived crude extract exhibited no histopathological sub-lethal effects on the earthworm E. eugeniae. LC-MS analysis of M. anisopliae-derived crude metabolites revealed the presence of 10 chemical constituents. Of these chemicals, three major chemical constituents, namely, camphor (15.91 %), caprolactam (13.27%), and monobutyl phthalate (19.65%), were highlighted for potential insecticidal and anti-malarial activity. The entomopathogenic fungal-derived crude extracts thus represent promising tools in the control of insect pests and malarial parasites.