Annamalai University

About: Annamalai University is a education organization based out in Chidambaram, Tamil Nadu, India. It is known for research contribution in the topics: Lipid peroxidation & Antioxidant. The organization has 8098 authors who have published 10758 publications receiving 203872 citations.

Mosquito larvicidal activity of thymol from essential oil of Coleus aromaticus Benth. against Culex tritaeniorhynchus, Aedes albopictus, and Anopheles subpictus (Diptera: Culicidae)

Abstract: Diseases transmitted by blood-feeding mosquitoes, such as dengue fever, dengue hemorrhagic fever, Japanese encephalitis, malaria, and filariasis, are increasing in prevalence, particularly in tropical and subtropical zones. To control mosquitoes and mosquito-borne diseases, which have a worldwide health and economic impacts, synthetic insecticide-based interventions are still necessary, particularly in situations of epidemic outbreak and sudden increases of adult mosquitoes. However, the indiscriminate use of conventional insecticides is fostering multifarious problems like widespread development of insecticide resistance, toxic hazards to mammals, undesirable effects on nontarget organisms, and environmental pollution. The aim of this research was to evaluate the toxicity of mosquito larvicidal activity of essential oil from Coleus aromaticus and its pure isolated constituent thymol against larvae of Culex tritaeniorhynchus, Aedes albopictus, and Anopheles subpictus. The chemical composition of the essential oil was analyzed using gas chromatography-mass spectroscopy. A total of 14 components of the essential oil of C. aromaticus were identified. The major chemical components identified were thymol (82.68%), terpinen-4-ol (3.2%), and trans-Caryophyllene (3.18%). Twenty-five early third instar larvae of C. tritaeniorhynchus, A. albopictus, and A. subpictus were exposed and assayed in the laboratory. Thymol and essential oil were tested in concentrations of 10, 20, 30, 40, and 50 and 30, 60, 90, 120, and 150 ppm, respectively. The larval mortality was observed after 24 h of treatment. The thymol had a significant toxic effect against early third-stage larvae of C. tritaeniorhynchus, A. albopictus, and A. subpictus with an LC50 values of 28.19, 24.83, and 22.06 μg/mL respectively, whereas the essential oil of C. aromaticus had an LC50 values of 72.70, 67.98, and 60.31 μg/mL, respectively. No mortality was observed in controls. The Chi-square values were significant at p < 0.05 level. The result indicated that the essential oil of C. aromaticus and the isolated constituent have a potential for use in control of C. tritaeniorhynchus, A. albopictus, and A. subpictus larvae and could be useful in search of newer, safer, and more effective natural compounds as larvicides.

Extraction, characterization and in vitro antioxidative potential of chitosan and sulfated chitosan from Cuttlebone of Sepia aculeata Orbigny, 1848

Abstract: Objective To investigate antioxidant potency of chitosan and sulfated chitosan in various established in vitro systems, such as superoxide (O 2- )/hydroxyl (-OH) radicals scavenging, reducing power, metal ion chelating. Methods Chitosan was prepared from deacetylation of chitin from cuttlefish. FTIR, degree of acetylation and mineral studies was carried out from the chitosan. Chitosan was converted into sulfated chitosan using DMF/HClSO 3 and their antioxidant activity was tested. Results Mineral content of chitosan was Ca – 30 ppm, Na- 0.092 ppm, Cu-0.172 ppm, Mg- 3.601, Mn- 0.264 and Zn- 0.924 ppm, DA was 49.9% (IR spectroscopy) and 40.56% (UV spectrophotometer) recorded. Cuttlefish chitosan showed high level of superoxide radical scavenging activity (88.6%) and hydroxyl radical scavenging activity (72.1%), moderate activity was noted in chelating activity (62.6% at 100 μgm/mL). At the same time low level of reducing power was observed (0.300 Absorbance at 0.75 mg/mL) when compared to standard BHA and Ascorbic acid (2.305 and 2.05 Absorbance). Conclusions Finally, the scavenging rate, reducing power, chelating and reducing power of sulfated chitosan increased with their increasing concentration.

Development of new formulations of Bacillus subtilis for management of tomato damping-off caused by Pythium aphanidermatum

Abstract: Formulations of a strain of Bacillus subtilis AUBS-1 inhibitory to the growth of the damping-off pathogen, Pythium aphanidermatum, were developed for seed treatment. The formulations included a talc-based powder, lignite-based powder, lignite+fly ash-based powder, wettable powder, bentonite-paste, polyethylene glycol (PEG) paste and a water-dispersible tablet. Formulations were stored at room temperature for 2 years and frequently sampled to test their shelf life. Populations of bacteria in the formulations were stable for up to 2 years storage at room temperature (28°C). Viability of propagules in lignite, lignite+fly ash, bentonite paste, wettable powder and water dispersible tablet formulations was 100% for up to 1 year. However, the viability of propagules was significantly reduced in talc, wettable powder, PEG paste and tablet formulations beyond 1 year of storage. Seed treatment of tomato with these formulations resulted in effective control of damping-off caused by P. aphanidermatum, and also enhan...