Toxicity of herbal extracts used in ethno-veterinary medicine and green-encapsulated ZnO nanoparticles against Aedes aegypti and microbial pathogens

Abstract

Dengue and chikungunya are arboviral diseases mainly vectored by the mosquito Aedes aegypti. Presently, there is no treatment for these viral diseases and their prevention is still based on vector control measures. Nanopesticides fabricated using herbal extracts as reducing and capping agents currently represent an excellent platform for pest control. In this scenario, the present study assessed the acute toxicity of seven plants employed in ethno-veterinary medicine of southern India, as well as the green synthesis of zinc oxide nanoparticles, on third-instar larvae of A. aegypti. Larvae were exposed to extracts of the seven plants obtained with solvents of different polarity (acetone, ethanol, petroleum ether, and water) for 24 h. Maximum efficacy was observed for Lobelia leschenaultiana leaf extracts prepared using all the four solvent extracts (LC = 22.83, 28.12, 32.61, and 36.85 mg/L, respectively). Therefore, this plant species was used for the synthesis and stabilization of ZnO nanoparticles based on its maximum efficacy against third-instar larvae of A. aegypti. L. leschenaultiana-encapsulated ZnO nanoparticles showed 100% mortality when tested at 10 mg/L, the LC was extremely low, 1.57 mg/L. Zinc acetate achieved only 65.33% when tested at 60 mg/L, with a LC of 51.62 mg/L. Additionally, ZnO nanoparticles inhibited growth of Pseudomonas aeruginosa, Proteus vulgaris, Shigella sonnei, and Vibrio parahaemolyticus and also inhibited biofilm formation on selected microbila pathogens, showing impact on EPS production and hydrophobicity. Overall, our results suggest that L. leschenaultiana-fabricated ZnO nanoparticles have a significant potential to control A. aegypti mosquitoes and Gram-negative bacterial pathogens.

The Cytochrome P450-Mediated Metabolism Alternation of Four Effective Lignans From Schisandra chinensis in Carbon Tetrachloride-Intoxicated Rats and Patients With Advanced Hepatocellular Carcinoma

“…Actually, “all natural” herbal products are mixtures of potentially biologically active ingredients without clear quantities. These ingredients may possess inherent pharmacological activities, cause unexpected herb-drug interactions and even have direct toxicities (Baig et al, 2014 ; Banumathi et al, 2017 ). Meanwhile, it is known that expressions of proteins, activities of enzymes and functions of organs would be altered in pathological conditions.…”

Bactericidal Properties of Plants-Derived Metal and Metal Oxide Nanoparticles (NPs)

“…[ 75 , 136 ], and Vibrio spp. [ 101 , 129 ]. More promisingly, NPs have also been shown to inhibit antibiotic-resistant bacteria such as Methicillin-resistant S. aureus (MRSA) [ 81 , 130 ] and drug-resistant E. coli [ 123 ].…”

Eco-friendly approach to control dengue vector Aedes aegypti larvae with their enzyme modulation by Lumnitzera racemosa fabricated zinc oxide nanorods

“…Green technologies have recently been shown to be a new strategy for reducing the use of chemical pesticides since overuse has often led to massive non-target impacts and widespread resistance [9,18]. Modern study has revealed an increased level of insecticide activity in green nanoparticles (NPs) synthesized by Euphorbia rothiana [19], Cymbopogon citratus [20], Pedalium murex [21] etc. Among different NPs, Zinc Oxide nanoparticles (ZnO NPs), having nanosized morphology, have increased interest among several researchers as a result of their exclusive optical or chemical activities [22].…”