Department of Biochemistry, Osun State University, Osogbo, Nigeria.
Trans-Saharan Disease Research Centre, Ibrahim Badamasi Babangida University, Nigeria.
PLoS One. 2024 May 2;19(5):e0302677. doi: 10.1371/journal.pone.0302677. eCollection 2024.
The incorporation of phytoactive compounds in the management of malarial vectors holds promise for the development of innovative and efficient alternatives. Nevertheless, the molecular and physiological responses that these bioactive substances induce remain underexplored. This present study investigated the toxicity of different concentrations of aqueous and methanol extracts of Ocimum tenuiflorum against larvae of Anopheles gambiae (sensu stricto) and unraveled the possible underlying molecular pathways responsible for the observed physiological effects. FTIR and GCMS analyses of phytoactive compounds in aqueous and methanol crude extracts of O. tenuiflorum showed the presence of OH stretching vibration, C = C stretching modes of aromatics and methylene rocking vibration; ring deformation mode with high levels of trans-β-ocimene, 3,7-dimethyl-1,3,6-octatriene in aqueous extract and 4-methoxy-benzaldehyde, 1,3,5-trimethyl-cyclohexane and o-cymene in methanol extract. The percentage mortality upon exposure to methanol and aqueous extracts of O. tenuiflorum were 21.1% and 26.1% at 24 h, 27.8% and 36.1% at 48 h and 36.1% and 45% at 72 h respectively. Using reverse transcription quantitative polymerase chain reaction (RT-qPCR), down-regulation of ABC transporter, overexpression of CYP6M2, Hsp70, and α-esterase, coupled with significantly increased levels of SOD, CAT, and GSH, were observed in An. gambiae (s.s.) exposed to aqueous and methanol extracts of O. tenuiflorum as compared to the control. Findings from this study have significant implications for our understanding of how An. gambiae (s.s.) larvae detoxify phytoactive compounds.
植物活性化合物在疟疾病媒管理中的应用具有开发创新和高效替代品的潜力。然而，这些生物活性物质诱导的分子和生理反应仍未得到充分探索。本研究调查了不同浓度的水提和甲醇提丁香罗勒（Ocimum tenuiflorum）提取物对冈比亚按蚊（Anopheles gambiae （sensu stricto））幼虫的毒性，并揭示了观察到的生理效应可能的潜在分子途径。水提和甲醇粗提取物中植物活性化合物的傅里叶变换红外光谱（FTIR）和气相色谱质谱联用（GCMS）分析显示，存在 OH 伸缩振动、芳烃的 C = C 伸缩模式和亚甲基摇摆振动；环变形模式，水提物中存在高浓度的反式-β-罗勒烯、3,7-二甲基-1,3,6-辛三烯，甲醇提物中存在 4-甲氧基苯甲醛、1,3,5-三甲基环己烷和对伞花烃。24 h 时，暴露于丁香罗勒甲醇和水提物中的死亡率分别为 21.1%和 26.1%，48 h 时分别为 27.8%和 36.1%，72 h 时分别为 36.1%和 45%。使用反转录定量聚合酶链反应（RT-qPCR），与对照组相比，暴露于丁香罗勒水和甲醇提取物中的冈比亚按蚊（s.s.）中 ABC 转运蛋白下调，CYP6M2、Hsp70 和 α-酯酶过表达，同时 SOD、CAT 和 GSH 水平显著升高。本研究的结果对我们理解冈比亚按蚊（s.s.）幼虫如何解毒植物活性化合物具有重要意义。
