title: Linalool, derived from Cinnamomum camphora (L.) Presl leaf extracts, possesses molluscicidal activity against Oncomelania hupensis and inhibits infection of Schistosoma japonicum.
abstract: BACKGROUND
  Schistosomiasis japonicum remains a considerable economic and public health concern in China, the Philippines and Indonesia. Currently available measures to control the unique intermediate host Oncomelania hupensis are frequently associated with severe side effects. Previous studies have demonstrated that linalool-rich extracts from various plants exhibited promising biological activities including cytotoxic, anti-microbial and anti-parasitic properties.
  
  
  METHODS
  We identified the components of leaf extracts from Cinnamomum camphora by gas chromatography coupled to mass spectrometry (GC-MS) and investigated molluscicidal and larvicidal effects of linalool against O. hupensis and Schistosoma japonicium. The ultrastructural alterations in gills, salivary gland, stomach and hepatopancreas of snails were observed under the light microscope and transmission electron microscope, and lesions to tegument of cercaria were examined under a light microscope and fluorescence microscope. We then evaluated the effects of linalool on skin penetration and migration of schistosomula and adult survival by measurement of worm burden and egg counts in Balb/C mice infected with linalool-treated cercariae.
  
  
  RESULTS
  In the present work, 44 components were identified from the leaf extracts of C. camphora, of which linalool was the most abundant constituent. Linalool exhibited the striking molluscicidal and larvicidal effects with LC50 = 0.25 mg/L for O. hupensis and LC50 = 0.07 mg/L for cercaria of S. japonicium. After exposure to linalool, damage to the gills and hepatopancreas of the snails, and to the tegument and body-tail joint of cercariae was apparent. In addition, linalool markedly reduced the recovered schistosomulum from mouse skin after challenge infection, and therefore decreased the worm burden in infected animals, but not fecundity of female adults of the parasite.
  
  
  CONCLUSIONS
  Our findings indicated that linalool might be a novel chemotherapeutic agent against S. japonicium and the snail intermediate host.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Erping
authors.initials: E
authors.lastname: Long
authors.forename: Juhua
authors.initials: J
authors.lastname: Wen
authors.forename: Lei
authors.initials: L
authors.lastname: Cao
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhu
authors.forename: Huanxin
authors.initials: H
authors.lastname: Hu
authors.forename: Ying
authors.initials: Y
authors.lastname: Ruan
authors.forename: Kamolnetr
authors.initials: K
authors.lastname: Okanurak
authors.forename: Huiling
authors.initials: H
authors.lastname: Hu
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Wei
authors.forename: Xiangyun
authors.initials: X
authors.lastname: Yang
authors.forename: Chaofan
authors.initials: C
authors.lastname: Wang
authors.forename: Limei
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.forename: Pengyu
authors.initials: P
authors.lastname: Ji
authors.forename: Huanqin
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou 510080, China. wuzhd@mail.sysu.edu.cn.
authors.forename: Zhongdao
authors.initials: Z
authors.lastname: Wu
authors.forename: Zhiyue
authors.initials: Z
authors.lastname: Lv
mesh_terms: D000080462:Acyclic Monoterpenes; D000818:Animals; D027423:Cinnamomum camphora / Q000737:chemistry*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008975:Molluscacides / Q000737:chemistry / Q000494:pharmacology; D039821:Monoterpenes / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D011897:Random Allocation; D012549:Schistosoma japonicum / Q000187:drug effects*; D012908:Snails / Q000187:drug effects* / Q000469:parasitology
chemical_list: D000080462:Acyclic Monoterpenes; D008975:Molluscacides; D039821:Monoterpenes; C018584:linalool