title: Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae.
abstract: OBJECTIVE
  To identify the larvicidal activity of the seagrass extracts.
  
  
  METHODS
  Seagrass extracts, Syringodium isoetifolium (S. isoetifolium), Cymodocea serrulata and Halophila beccarii, were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg - 0.1 mg). After 24 h the mortality rate was identified with the formulae [(% of test mortality - % of control mortality)/(100 - % of control mortality)] × 100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only.
  
  
  RESULTS
  : The root extract of S. isoetifolium showed maximum larvicidal activity with minimum concentration of extract of LC50= 0.0 604 ± 0.0 040)µg/mL with lower confidence limit (LCL) - upper confidence limit (UCL) = (0.051-0.071) and LC90=0.0 972µg/mL followed by leaf extract of S. isoetifolium showed LC50= (0.062 ± 0.005)µg/mL. The regression equation of root and leaf extract of S. isoetifolium for 4th instar larvae were Y= 4.909 + 1.32x (R(2)= 0.909) and Y= 2.066 + 1.21x (R(2) =0.897) respectively. The results of the preliminary phytochemical constituents shows the presence of saponin, steroids, terpenoid, phenols, protein and sugars.
  
  
  CONCLUSIONS
  From the present study the ethanolic extracts of seagrass of S. isoetifolium possesses lead compound for development of larvicidal activity.
authors.affiliation: School of Marine Sciences, Division of Marine Microbiology and Medicine, Department of Oceanography and Costal Area Studies, Alagappa University, Thondi Campus, Thondi-623409, Tamil Nadu, India.
authors.forename: M Syed
authors.initials: MS
authors.lastname: Ali
authors.forename: S
authors.initials: S
authors.lastname: Ravikumar
authors.forename: J Margaret
authors.initials: JM
authors.lastname: Beula
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000502:physiology; D035961:Alismatales / Q000737:chemistry*; D000818:Animals; D005260:Female; D007303:Insect Vectors; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000502:physiology; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology; D016019:Survival Analysis
chemical_list: D007306:Insecticides; D010936:Plant Extracts
keywords: Aedes aegypti; Bioinsecticides; Cymodocea serrulata; Dengue fever; Extract; Halophila beccarii; Larvicides; Mosquito; Seagrass; Syringodium isoetifolium