title: Acetylcholinesterase inhibitory activity of stigmasterol & hexacosanol is responsible for larvicidal and repellent properties of Chromolaena odorata.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  These compounds are natural agents for mosquito control that can be used in vector control as larvicidal compounds, pending further investigations.
authors.affiliation: Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India.
authors.forename: Sriramya
authors.initials: S
authors.lastname: Gade
authors.affiliation: Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India.
authors.forename: Maheshwari
authors.initials: M
authors.lastname: Rajamanikyam
authors.affiliation: Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India.
authors.forename: Varahalarao
authors.initials: V
authors.lastname: Vadlapudi
authors.affiliation: Biology Division, Council for Scientific and Industrial Research - Indian Institute of Chemical Technology (Ministry of Science and Technology), Uppal Road, Tarnaka, Hyderabad 500607, India.
authors.forename: Krishna Madhav
authors.initials: KM
authors.lastname: Nukala
authors.affiliation: 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.
authors.forename: Rajendar
authors.initials: R
authors.lastname: Aluvala
authors.affiliation: 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.
authors.forename: Chandrasekhar
authors.initials: C
authors.lastname: Giddigari
authors.affiliation: 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.
authors.forename: Naga Jyothi
authors.initials: NJ
authors.lastname: Karanam
authors.affiliation: 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.
authors.forename: Nabin C
authors.initials: NC
authors.lastname: Barua
authors.affiliation: 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.
authors.forename: Richa
authors.initials: R
authors.lastname: Pandey
authors.affiliation: National Centre for Mass Spectrometry, Council for Scientific and Industrial Research -Indian Institute of Chemical Technology (Ministry of Science and Technology), Tarnaka, Hyderabad, India.
authors.forename: Vijaya Saradhi V
authors.initials: VSV
authors.lastname: Upadhyayula
authors.affiliation: National Centre for Mass Spectrometry, Council for Scientific and Industrial Research -Indian Institute of Chemical Technology (Ministry of Science and Technology), Tarnaka, Hyderabad, India.
authors.forename: Prabhakar
authors.initials: P
authors.lastname: Sripadi
authors.affiliation: 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.
authors.forename: Ramars
authors.initials: R
authors.lastname: Amanchy
authors.affiliation: 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.
authors.forename: Suryanarayana Murty
authors.initials: SM
authors.lastname: Upadhyayula
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000330:Aedes / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D036604:Chromolaena / Q000737:chemistry*; D005233:Fatty Alcohols / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects*; D009498:Neurotoxins / Q000494:pharmacology; D010840:Phytosterols / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D013265:Stigmasterol / Q000494:pharmacology*
chemical_list: D002800:Cholinesterase Inhibitors; D005233:Fatty Alcohols; D007306:Insecticides; D009498:Neurotoxins; D010840:Phytosterols; D010936:Plant Extracts; D013265:Stigmasterol; D000110:Acetylcholinesterase; C051942:1-hexacosanol
keywords: 1-Hexacosanol; 1-Hexacosanol (PubChem CID: 68171); Acetylcholinesterase; EAG; Larvicide; Phytosterol; Stigmasterol; Stigmasterol (PubChem CID: 5280794)