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.

Artemisia absinthium-borne compounds as novel larvicides: effectiveness against six mosquito vectors and acute toxicity on non-target aquatic organisms.

Abstract: The eco-friendly control of mosquito vectors is a crucial challenge of public health importance. Here we evaluated the larvicidal potential of Artemisia absinthium essential oil (EO) and its three major chemical constituents against six mosquito vectors: Anopheles stephensi, Anopheles subpictus, Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Culex tritaeniorhynchus. The EO was obtained by leaf hydro-distillation. Its chemical composition was analyzed using gas chromatography-mass spectrometry. Major components were (E)-β-farnesene (31.6 %), (Z)-en-yn-dicycloether (11.12 %), and (Z)-β-ocimene (27.8 %). The EO was toxic effect against larval populations of An. stephensi, An. subpictus, Ae. aegypti, Ae. albopictus, Cx. quinquefasciatus, and Cx. tritaeniorhynchus, with LC50 values of 41.85, 52.02, 46.33, 57.57, 50.57, and 62.16 μg/ml. (E)-β-farnesene, (Z)-en-yn-dicycloether, and (Z)-β-ocimene were highly effective on An. stephensi (LC50 = 8.13, 16.24 and 25.84 μg/ml) followed by An. subpictus (LC50 = 10.18, 20.99, and 30.86 μg/ml), Ae. aegypti (LC50 = 8.83,17.66, and 28.35 μg/ml), Ae. albopictus (LC50 = 11.38,23.47, and 33.72 μg/ml), Cx. quinquefasciatus (LC50 = 9.66, 19.76, and 31.52 μg/ml), and Cx. tritaeniorhynchus (LC50 = 12.51,25.88, and 37.13 μg/ml). Notably, the EO and its major compounds were safer to the non-target organisms Chironomous circumdatus, Anisops bouvieri and Gambusia affinis, with LC50 values ranging from 207.22 to 4385 μg/ml. Overall, our results highlight that (E)-β-farnesene, (Z)-en-yn-dicycloether, and (Z)-β-ocimene from the A. absinthium EO represent promising eco-friendly larvicides against six key mosquito vectors with moderate toxicity against non-target organisms.

Mosquito larvicidal potential of silver nanoparticles synthesized using Chomelia asiatica (Rubiaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae)

Abstract: Mosquitoes transmit serious human diseases, causing millions of deaths every year. Mosquito control is to enhance the health and quality of life of county residents and visitors through the reduction of mosquito populations. Mosquito control is a serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Today, nanotechnology is a promising research domain which has a wide ranging application in vector control programs. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, larvicidal activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using C. asiatica plant leaves against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Cx. quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (40, 80, 120, 160, and 200 μg/mL) were tested against the larvae of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus. The synthesized AgNPs from C. asiatica were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV–Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis (EDX). Considerable mortality was evident after the treatment of C. asiatica for all three important vector mosquitoes. The LC50 and LC90 values of C. asiatica aqueous leaf extract appeared to be effective against An. stephensi (LC50, 90.17 μg/mL; LC90, 165.18 μg/mL) followed by Ae. aegypti (LC50, 96.59 μg/mL; LC90, 173.83 μg/mL) and Cx. quinquefasciatus (LC50, 103.08 μg/mL; LC90, 183.16 μg/mL). Synthesized AgNPs against the vector mosquitoes of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus had the following LC50 and LC90 values: An. stephensi had LC50 and LC90 values of 17.95 and 33.03 μg/mL; Ae. aegypti had LC50 and LC90 values of 19.32 and 34.87 μg/mL; and Cx. quinquefasciatus had LC50 and LC90 values of 20.92 and 37.41 μg/mL. No mortality was observed in the control. These results suggest that the leaf aqueous extracts of C. asiatica and green synthesis of silver nanoparticles have the potential to be used as an ideal eco-friendly approach for the control of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus. This is the first report on the mosquito larvicidal activity of the plant extracts and synthesized AgNPs.

Application of Response Surface Methodolody to Prediction of Dilution in Plasma Transferred Arc Hardfacing of Stainless Steel on Carbon Steel

Abstract: The application of response surface methodology was highlighted to predict and optimize the percentage of dilution of iron-based hardfaced surface produced by the PTA (plasma transferred arc welding) process. The experiments were conducted based on five-factor five-level central composite rotatable design with full replication technique and a mathematical model was developed using response surface methodology. Furthermore, the response surface methodology was also used to optimize the process parameters that yielded the lowest percentage of dilution.