Potencial protetor do Extrato de Psidium guajava frente à toxicidade induzida pelo organosfosforado Clorpirifós em Drosophila melanogaster

Abstract

Chlorpyrifos (CP) is an organophosphate insecticide widely used for control agricultural and household pests. The main damage caused by the CP is the neurotoxicity induced by inhibition of the enzyme acetylcholinesterase, which causes an increase in the neurotransmitter acetylcholine and promotes hiperexitação the central nervous system and muscle junctions, leading to disruption of physiologic function. Occupational exposure is a major form of human poisoning by organophosphates and current therapies for these compounds are not fully efficient. In this sense the search for compounds that can reverse this damage has intensified and some studies have focused their efforts on plants protection purposes or natural compounds in various neuropathological conditions. Psidium guajava is a plant widely used in popular medicine and its antioxidant activity was described in Brazil leaves and fruit are used for anorexia, cholera, diarrhea, digestive problems, dysentery, gastric insufficiency, inflammation of mucous membranes, laryngitis, skin problems, neck pain, ulcers, among others. In this study we evaluated the antioxidant and protective potential of the hydroalcoholic extract of P. guajava (HEPG) against CP induced toxicity in the fruit fly Drosophila melanogaster. HEPG in vitro antioxidant activity was confirmed by ABTS, DPPH, Total Phenolics and FRAP assays. The exposure of flies to CP caused increased mortality, locomotor deficits and inhibition of acetylcholinesterase. Flies exposed to CP presented elevated ROS and lipid peroxidation which was accompanied by a significant decrease in mitochondrial viability. As a response to increased oxidative stress, CP exposed flies showed increased in GST activity and GSH levels. The mRNA expression of NRF2 and MPK2 (which encodes D. melanogaster p38MAPK) were also significantly up-regulated. HEPG was able to restore all the damage and biochemical/molecular alterations caused by CP. Our results show for the first time the potential of P. guajava protective effect against the toxicity caused by Chlorpyrifos, suggesting Psidium guajava as an adjunct alternative treatment for poisoning by organophosphorus compounds.