Exploring the Efficacy and Synergistic Potential of Ficus sycomorus Leaves against Anopheles coluzzii Mosquitoes: A Preliminary Study on Toxicity and Impact on Metabolic Resistance Gene Expression
NJE Vol. 41: 90-107, 2025
DOI.10.36108/NJE/5202/14.0170
Abba Babandi1,,5*, Abdullahi Muhammad3, Chioma A. Anosike2, Muhammad M. Mukhtar1, Ahmad S. Muhammad4, Parker, J. Elijah2. Lawrence L. U. Ezeanyika2 and Sulaiman S. Ibrahim 1.
1Department of Biochemistry, Bayero University, P.M.B. 3011, Kano, Nigeria.
2Department of Biochemistry, University of Nigeria, Nsukka, 410001, Enugu, Nigeria
3Centre for Biotechnology Research, Bayero University, P.M.B. 3011, Kano, Nigeria
4Department of Plant Biology and Biotechnology, Bayero University, P.M.B. 3011, Kano, Nigeria. Medical Biochemistry Unit, Federal University, P.M.B 7156, Dutse, Jigawa State-Nigeria
Abstract
Preliminary study on the efficacy and synergistic potentials of active fraction of Ficus sycomorus leaves (AFFS) and its impact on expression profiles of some metabolic resistance genes were investigated in adult Anopheles coluzzii mosquitoes, from Kano, northern Nigeria. Female An. coluzzii (F0, 3-4 days old) were exposed to various concentrations of AFFS to establish the lethal and sub-lethal concentrations (LC50 and LC25). The sub-lethal concentration of AFFS and standard diagnostic dose of pyrethroid (0.05% deltamethrin) were used for adult bioassay using WHO protocol. Synergist bioassays were also conducted using P450 inhibitor, piperonylbutoxide (4% PBO) and the additive effect of AFFS and synthetic pyrethroid was also evaluated (AFFS+DM exposure). Females alive after 48 h were used for transcriptional analyses of four metabolic resistance genes, CYP6P3, CYP6Z2, CYP6M3 and GSTe2 using qRT-PCR. Preliminary toxicity study revealed an LD50 of 1.04 mg/ml for AFFS. The average percentage mortality of AFFS exposure is higher, at 42.0% ± 4.02 compared to 31.0% ± 3.01 obtained from deltamethrin exposure alone (p<0.05), while no mortality observed in unexposed control. Pre-exposure to PBO significantly increased mortality with deltamethrin (47.04% ± 3.03, χ2 = 9.977, df = 1, p < 0.05) compared to deltamethrin alone, and also AFFS + DM (73.00% ± 14.20, χ2 14.865, df = 1, p<0.05 compared to AFFS alone, partly implicating P450s in the resistance. The qRT-PCR analysis revealed CYP6M3 significantly over-expressed (fold changed = 6.35x, p<0.05) in mosquitoes that survived exposure to AFFS+DM compared to AFFS alone (FC = 2.55) and unexposed control (FC = 1.22). In contrast, CYP6P3 and CYP6Z2 were significantly down-regulated upon exposure to AFFS alone (FC = 43.70 and 16.16, respectively) compared to unexposed control (FC= 328.04 and 46.94 respectively; p<0.05). All the P450s analyzed in this study were over-expressed compared to Ngousso colony. The GSTe2, was not over-expressed in AFFS and AFFS+ DM exposed mosquitoes (FC = 0.35 and 0.79, respectively) compared to Ngousso colony (p<0.05), but significantly reduced compared to unexposed control (FC = 6.06). This study preliminarily indicated toxicity of AFFS in control of An. coluzzii, and identified a potential gene, CYP6M3 which could be involved in the detoxification of the active components in the extract.
Keywords: Anopheles coluzzii, deltamethrin, Ficus sycomorus, CYP450s, CYP6M3, qRT-PCR