Mosquitocidal Effect of Glycosmis pentaphylla Leaf Extracts against Three Mosquito Species (Diptera: Culicidae)

Background

The resistance status of malaria vectors to different classes of insecticides used for public health has raised concern for vector control programmes. Alternative compounds to supplement the existing tools are important to be searched to overcome the existing resistance and persistence of pesticides in vectors and the environment respectively. The mosquitocidal effects of Glycosmis pentaphylla using different solvents of acetone, methanol, chloroform and ethyl acetate extracts against three medically important mosquito vectors was conducted.

Methods

Glycosmis pentaphylla plant leaves were collected from Kolli Hills, India. The WHO test procedures for larval and adult bioassays were used to evaluate extracts against mosquito vectors, and the chemical composition of extracts identified using GC-MS analysis.

Results

The larvicidal and adulticidal activity of G. pentaphylla plant extracts clearly impacted the three species of major mosquitoes vectors. Acetone extracts had the highest larvicidal effect against An. stephensi, Cx. quinquefasciatus and Ae. aegypti with the LC₅₀ and LC₉₀ values of 0.0004, 138.54; 0.2669, 73.7413 and 0.0585, 303.746 mg/ml, respectively. The LC₅₀ and LC₉₀ adulticide values of G. pentaphylla leaf extracts in acetone, methanol, chloroform and ethyl acetate, solvents were as follows for Cx. quinquefasciatus, An. stephensi and Ae. Aegypti: 2.957, 5.458, 2.708, and 4.777, 3.449, 6.676 mg/ml respectively. The chemical composition of G. pentaphylla leaf extract has been found in 20 active compounds.

Conclusions

The plant leaf extracts of G. pentaphylla bioactive molecules which are effective and can be developed as an eco-friendly approach for larvicides and adulticidal mosquitoes vector control. Detailed identification and characterization of mosquitocidal effect of individual bioactive molecules ingredient may result into biodegradable effective tools for the control of mosquito vectors.

Fucoidan--a α-D-glucosidase inhibitor from Sargassum wightii with relevance to type 2 diabetes mellitus therapy

The present study was conducted to screen the α-d-glucosidase inhibitory activity of fucoidan extracted from Sargassum wightii collected at Mandapam coastal area, Tamil Nadu, India. Fucoidan was extracted from the sporophyll of S. wightii using ethanol, acetone and CaCl2 precipitation. The average yield was 1.8 ± 0.16% and the extracted fucoidan was found to contain 53 ± 0.52% of fucose and 36 ± 0.60% of sulphate. FT-IR, NMR and in vitro α-d-glucosidase activity of purified fucoidan were performed. Fucoidan at the concentration of 31.25, 62.5, 125 and 250 μg exhibited 19, 31, 38 and 71% inhibition against α-d-glucosidase respectively in a dose dependent manner. The IC50 value against α-D-glucosidase of fucoidan is found to be 132.9 μg which is more effective than that of acarbose (1mg). The diverse biological activities of Fucoidan include anticancer, anti inflammatory and antimicrobial but the α-d-glucosidase inhibitory activity of native fucoidan from S. wightii for type 2 diabetes therapy is first of its kind.