Sriramya Gade1, Maheshwari Rajamanikyam1, Varahalarao Vadlapudi1, Krishna Madhav Nukala1, Rajendar Aluvala2, Chandrasekhar Giddigari2, Naga Jyothi Karanam3, Nabin C Barua4, Richa Pandey2, Vijaya Saradhi V Upadhyayula5, Prabhakar Sripadi5, Ramars Amanchy6, Suryanarayana Murty Upadhyayula7. 1. Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India. 2. Natural Products Chemistry, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India. 3. Centre for Semiochemicals, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad -500607, India. 4. Natural Products Chemistry Division, Council for Scientific and Industrial Research -North East Institute of Science and Technology (Ministry of Science and Technology), Jorhat 785006, Assam, India. 5. National Centre for Mass Spectrometry, Council for Scientific and Industrial Research -Indian Institute of Chemical Technology (Ministry of Science and Technology), Tarnaka, Hyderabad, India. 6. Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India. Electronic address: ramars@iict.res.in. 7. Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India; NIPER Guwahati, Institute of Pharmacy, Guwahati Medical College & Hospital, 1st Floor, Guwahati 781 032, Assam, India.
Abstract
BACKGROUND: Chromolaena odorata, has been traditionally known for its insect repellent property. Aim of this study was to determine larvicidal tendency of C. odorata on Culex quinquefasciatus and isolate compounds responsible for this activity and to determine the mechanism of action of these compounds. METHODS: C. odorata plant extract was screened for mosquito larvicidal activity. The extract was fractionated using chromatography and the bioactive fraction showing larvicidal activity was identified. The chemical nature of the compounds in the bioactive fraction was determined using NMR and Mass spectrometry. RESULTS: We identified phytosterols and alkanols to be the compounds regulating larvicidal activity in the bioactive fraction of the plant extract. Stigmasterol and 1-hexacosanol were identified to be the chief orchestrators of larvicidal activity and their mode of action has been observed to be neurotoxicity. At a molecular level both stigmasterol and 1-hexacosanol were found to be inhibiting acetylcholinesterase activity in C. quinquefasciatus & A. aegypti. The acetylcholinesterase inhibitory effect was validated in vitro using recombinant acetylcholinesterase and ex vivo in larval homogenates of Culex and Aedes. Electrophysiological studies using electroantennography have shown enhanced neural response to these compounds. CONCLUSIONS: Neurotoxic effect of C. odorata derived stigmasterol and 1-hexacosanol, exerted through acetylcholinesterase inhibition was responsible for the mortality of C. quinquefasciatus, A. aegypti &Chironomus riparius. EAG studies pointed out hyper-excitability of the olfactory system by these compounds. GENERAL SIGNIFICANCE: These compounds are natural agents for mosquito control that can be used in vector control as larvicidal compounds, pending further investigations.
BACKGROUND:Chromolaena odorata, has been traditionally known for its insect repellent property. Aim of this study was to determine larvicidal tendency of C. odorata on Culex quinquefasciatus and isolate compounds responsible for this activity and to determine the mechanism of action of these compounds. METHODS:C. odorata plant extract was screened for mosquito larvicidal activity. The extract was fractionated using chromatography and the bioactive fraction showing larvicidal activity was identified. The chemical nature of the compounds in the bioactive fraction was determined using NMR and Mass spectrometry. RESULTS: We identified phytosterols and alkanols to be the compounds regulating larvicidal activity in the bioactive fraction of the plant extract. Stigmasterol and 1-hexacosanol were identified to be the chief orchestrators of larvicidal activity and their mode of action has been observed to be neurotoxicity. At a molecular level both stigmasterol and 1-hexacosanol were found to be inhibiting acetylcholinesterase activity in C. quinquefasciatus & A. aegypti. The acetylcholinesterase inhibitory effect was validated in vitro using recombinant acetylcholinesterase and ex vivo in larval homogenates of Culex and Aedes. Electrophysiological studies using electroantennography have shown enhanced neural response to these compounds. CONCLUSIONS:Neurotoxic effect of C. odorata derived stigmasterol and 1-hexacosanol, exerted through acetylcholinesterase inhibition was responsible for the mortality of C. quinquefasciatus, A. aegypti &Chironomus riparius. EAG studies pointed out hyper-excitability of the olfactory system by these compounds. GENERAL SIGNIFICANCE: These compounds are natural agents for mosquito control that can be used in vector control as larvicidal compounds, pending further investigations.
Authors: Kyvia F Alves; Flávio H Caetano; Israel J Pereira Garcia; Hérica L Santos; Denise B Silva; João M Siqueira; Aparecida S Tanaka; Stênio N Alves Journal: Environ Sci Pollut Res Int Date: 2018-09-12 Impact factor: 4.223
Authors: Graziela Holken Lorensi; Raquel Soares Oliveira; Allan P Leal; Ana Paula Zanatta; Carlos Gabriel Moreira de Almeida; Yuri Correia Barreto; Maria Eduarda Rosa; Patrícia de Brum Vieira; Carlos José Brito Ramos; Filipe de Carvalho Victoria; Antônio Batista Pereira; Valéria LaneuvilleTeixeira; Cháriston André Dal Belo Journal: Mar Drugs Date: 2019-10-10 Impact factor: 5.118