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.

Bioactivity of flavonoid compounds from Poncirus trifoliata L. (Family: Rutaceae) against the dengue vector, Aedes aegypti L. (Diptera: Culicidae)

Abstract: The bioactivity of four flavonoid compounds, namely poncirin, rhoifolin, naringin and marmesin, from Poncirus trifoliata was studied against the Aedes aegypti. Larvicidal assays were conducted to evaluate the 24 h LC50 and LC90 values of the flavonoid compounds. The lethal concentration (LC50 and LC90) values ranged from 0.082 to 0.122 mg/l and 0.152 to 0.223 mg/l, respectively. The result of ovicidal test suggests that the ovicidal activity of the flavonoid compounds was influenced by the concentration of flavonoid compounds and age of the eggs. The result of oviposition test showed that the four flavonoid compounds exhibited oviposition-deterrent activity against gravid female mosquitoes. Oviposition decreased with an increase in concentration of flavonoid compounds. A laboratory test was carried out to evaluate protection period and percentage of repellency of four compounds diluted in ethanol (10 mg/l). The compound rhoifolin provided maximum 365.0 ± 12.0 min protection and also 100.0% ± 0.0 repellency against mosquito bite followed by poncirin, marmesin and naringin. None of the 25 volunteers of either sex exposed to 10% (w/v) flavonoid compounds (4-h patch test) showed a positive skin irritant reaction. All of the tested compounds proved to have various activities against different life stages of A. aegypti. Therefore, flavonoid compounds from P. trifoliata can be a potential candidate for use in the development of commercial mosquitocidal products that may be an alternative to conventional synthetic chemicals, particularly in integrated vector control applications.

Protective effect of rutin on lipids, lipoproteins, lipid metabolizing enzymes and glycoproteins in streptozotocin‐induced diabetic rats

Abstract: The protective role of rutin on lipids, lipoproteins, lipid metabolizing enzymes and glycoproteins in streptozotocin-induced diabetic rats has been studied. A single intraperitoneal injection of streptozotocin (50 mg kg(-1)) to rats led to a significant (P < 0.05) increase in the levels of lipids (cholesterol, triglycerides, free fatty acids and phospholipids) in plasma and tissues (liver, kidney, heart and brain). The levels of low density and very low density lipoprotein (LDL and VLDL, respectively) cholesterol were increased, whereas the levels of high density lipoprotein (HDL) cholesterol were decreased significantly (P < 0.05) in plasma. The activity of 3-hydroxy 3-methylglutaryl coenzyme A (HMG CoA) reductase increased significantly (P < 0.05) in liver, kidney and heart, and the activity of lipoprotein lipase (LPL) and lecithin cholesterol acyltransferase (LCAT) decreased significantly (P < 0.05) in the plasma of diabetic rats. Streptozotocin injection also increased the levels of glycoproteins such as hexose, hexosamine, fucose and sialic acid in plasma, liver and kidney. Oral administration of rutin to streptozotocin-induced diabetic rats significantly (P < 0.05) decreased the levels of lipids in plasma and tissues. The levels of plasma HDL-cholesterol increased and the levels of LDL- and VLDL-cholesterol decreased significantly (P < 0.05). The activity of HMG CoA reductase decreased in the tissues and the activity of plasma LPL and LCAT increased significantly (P < 0.05). The levels of glycoproteins were found to be significantly (P < 0.05) decreased in plasma, liver and kidney of rutin-treated diabetic rats. Rutin administration to normal rats did not exhibit any significant (P < 0.05) changes in any of the parameters studied. In conclusion, the beneficial effect of rutin on lipids, lipoproteins, lipid metabolizing enzymes and glycoproteins could be due to its antioxidant property.

One-pot green synthesis of silver nanocrystals using Hymenodictyon orixense: a cheap and effective tool against malaria, chikungunya and Japanese encephalitis mosquito vectors?

Abstract: Mosquitoes are important vectors of malaria, dengue, Zika virus and many other parasites and pathogens of public health relevance. Recently, the green nanosynthesis of mosquitocides relying on plant compounds as reducing and stabilizing agents has received growing interest, due to the absence of toxic chemicals and high-energy input. In this research, Hymenodictyon orixense-mediated synthesis of silver nanoparticles (AgNPs) was conducted to control larval populations of the malaria vector Anopheles subpictus, the chikungunya vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. AgNPs were characterized using UV-visible spectrophotometry, FTIR spectroscopy, EDX and XRD analyses, AFM, SEM and TEM. AgNPs were toxic towards all the mosquito vectors, LC50 values ranged from 17.10 μg ml−1 to 20.08 μg ml−1. Notably, AgNPs were safer to the non-target mosquito predator Diplonychus indicus (LC50 = 833 μg ml−1). Overall, H. orixense-fabricated AgNPs can be considered for the development of novel and safer control tools against mosquito vectors of medical and veterinary importance.

Screening dietary flavonoids for the reversal of P-glycoprotein-mediated multidrug resistance in cancer.

Abstract: P-Glycoprotein (P-gp) serves as a therapeutic target for the development of inhibitors to overcome multidrug resistance in cancer cells. Although various screening procedures have been practiced so far to develop first three generations of P-gp inhibitors, their toxicity and drug interaction profiles are still a matter of concern. To address the above important problem of developing safe and effective P-gp inhibitors, we have made systematic computational and experimental studies on the interaction of natural phytochemicals with human P-gp. Molecular docking and QSAR studies were carried out for 40 dietary phytochemicals in the drug-binding site of the transmembrane domains (TMDs) of P-gp. Dietary flavonoids exhibit better interactions with homology modeled human P-gp. Based on the computational analysis, selected flavonoids were tested for their inhibitory potential against P-gp transport function in drug resistant cell lines using calcein-AM and rhodamine 123 efflux assays. It has been found that quercetin and rutin were the highly desirable flavonoids for the inhibition of P-gp transport function and they significantly reduced resistance in cytotoxicity assays to paclitaxel in P-gp overexpressing MDR cell lines. Hence, quercetin and rutin may be considered as potential chemosensitizing agents to overcome multidrug resistance in cancer.