title: Larvicidal activity, inhibition effect on development, histopathological alteration and morphological aberration induced by seaweed extracts in Aedes aegypti (Diptera: Culicidae).
abstract: OBJECTIVE
  To investigate the larvicidal activity, inhibition effect on development, histopathological alteration and morphological aberration induced by the extracts derived from seaweeds Bryopsis pennata (B. pennata), Sargassum binderi (S. binderi) and Padina australis in Aedes aegypti (Ae. aegypti) larvae and to characterize the phytochemical components of the three seaweeds.
  
  
  METHODS
  Larvicidal activity of the seaweeds towards the larvae of Ae. aegypti was determined according to WHO. The inhibition effect of seaweeds was assessed by determining the mortality, adult emergence rate, larval and pupa duration of the treated larvae. Histopathological effect on midgut epithelium of larvae and morphological aberration induced by the methanol extracts were examined. Phytochemical analysis was done to determine the presence of alkaloids, saponins, steroids and terpenoids in the seaweeds.
  
  
  RESULTS
  Chloroform partition of B. pennata extract exhibited the strongest larvicidal activity (LC50 = 82.55 μg/mL), followed by methanol extract of B. pennata (LC50 = 160.07 μg/mL) and chloroform partition of S. binderi extract (LC50 = 192.43 μg/mL). The methanol extract of S. binderi exhibited the strongest effect on prolongation of larval period (1.5-fold longer as compared to control) and resulted in strongest inhibition effect in adult emergence (98.67%). The histopathological study showed that larvae treated with seaweed extracts had cytopathological alteration of the midgut epithelium. The morphological observation revealed that the anal papillae and terminal spiracles of larvae were the common sites of aberrations.
  
  
  CONCLUSIONS
  The study provided information on various effects of seaweed extracts on Ae. aegypti. Further investigation on identifying the active compounds and their mechanisms of action is recommended.
authors.affiliation: Drug and Herbal Research Centre, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia.
authors.forename: Ke-Xin
authors.initials: KX
authors.lastname: Yu
authors.affiliation: School of Biosciences, Taylor's University, Taylor's Lakeside Campus, 47500 Subang Jaya, Selangor, Malaysia.
authors.forename: Ching-Lee
authors.initials: CL
authors.lastname: Wong
authors.affiliation: Medical Entomology Unit, Infectious Disease Research Centre, Institute for Medical Research, 50588 Kuala Lumpur, Malaysia.
authors.forename: Rohani
authors.initials: R
authors.lastname: Ahmad
authors.affiliation: Drug and Herbal Research Centre, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia. Electronic address: profibj@gmail.com.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Jantan
keywords: Aedes aegypti; Bryopsis pennata; Dengue vector; Mosquito larvicidal activity; Padina australi; Sargassum binderi