Introduction: CHLORPYRIFOS (CPF) is a broad-spectrum organophosphorus insecticide that has been used abundantly over the globe during the past 40 years. Chemical pesticides may induce oxidative stress via generating free radicals and altering antioxidant levels of the free radical scavenging enzyme activity. Therefore, this study aimed to evaluate the toxicity of CHLORPYRIFOS-induced oxidative stress in the plasma samples of Wistar rat.Methods: Twenty-four male Wistar rats were selected randomly which were assigned to 2 equal groups, e.g. control and test. The control group received corn oil as the solvent, and the experimental group received 16.5mg/kg/day of CPF (4mg/ml) orally via a stomach tube for four weeks. Plasma samples were taken on 1st, 7th, 14th, 21st, and 28th days, at a specific time. Catalase (CAT), superoxide dismutase (SOD) activities and also levels of malondialdehyde (MDA) and glutathione (GSH) were determined.Results: The oral administration of CPF could induce symptoms such as tremors, hair erection, weakness, diarrhea and asthma on Day 7 and onward. The data analysis of plasma samples showed significant (P<0.001) decrease in the levels of glutathione and CAT enzymatic activity and a significant increase in SOD enzymatic activity and the MDA level.Conclusion: CPF could induce oxidative stress probably via production of free radicals as was evident by reduction of GSH level and CAT activity accompanied by increase in the activity of SOD and enhancement in the level of MDA in plasma samples. This necessitates the application of antioxidants when having exposure with OP pesticides.

CHLORPYRIFOS (CPF) is a widely used organophosphate pesticide that has been shown to cause a range of toxic effects, including oxidative stress and endocrine disruption. This review aims to summarize the most recent findings regarding CPF’s toxicological impacts on human health, with a focus on its mechanisms of action, particularly in relation to oxidative stress and endocrine disruption. The review also addresses the environmental persistence of CPF and the potential cumulative effects of chronic exposure. Recent studies (2018–2023) are integrated to present novel insights into CPF-induced cellular damage, as well as its broader implications for public health and the environment. Furthermore, the paper discusses potential strategies for mitigating CPF’s harmful effects, including bioremediation and antioxidant therapies.

Nowadays use of pesticides are common in agriculture and yearly so many investigations are carried out for determination of pesticidal residue in crops with gas and liquid chromatography. But these methods are expensive and time consuming. Developing of new methods of immunoassays like ELISA are interesting for many researchers. In this research, evaluation of production of antibody against chlropyrifos has been done. Pesticide is broken, then conjucation was made with protein BSA and rabbit got immunized by injection. Then after different intervals the blood was collected and titer was determined with ELISA reader and showed great difference with reference. This method is cheap, easy and more sensitive as compare as chromatography.

Tomato is a very common agricultural commodity in our country and The producers use pesticides frequentely for its pest control. This vegetable is usually presented to market a short time after the last insecticide spraying, it is more probable to be contaminated in the time of consumption. This study was conducted to measure the safety interval of the two common insecticides used in greenhouses of Iran, CHLORPYRIFOS and deltamethrin. Tomato samples cultivated in 2 greenhouses with the design pattern of randomized complete block with 3 replicates. For deltametherin within one hour and 1, 2, 3, 4, 5, 7, 10, 15 days after spraying and for CHLORPYRIFOS within one hour and 1, 3, 5, 7, 10, 15, 20, 30 days after spraying sampling was performed. Samples in laboratory were extracted by using SPE (Solid Phase Extraction) and with the help of Nitrogen were concentrated and extracts were injected for measurement into HPLC (High Performance Liquid Chromatograph), GC (Gas Chromatograph), GC/MS (GC/Mass Spectrometer) devices. Data were compared with WHO/FAO and Recovery results were 101% and 94% for CHLORPYRIFOS and deltametherin as respectively also results showed that deltametherin has the php about 3 days and CHLORPYRIFOS has the php near 15 days in greenhouse condition has been studied. However, to get the post harvest period under farm condition more studies are needed.

Microcerotermes diversus Silvestri, is an important termite in Khuzestan province with a broad range of foraging. In recent years, control of underground termites has been more based on the application of chemicals which has increased pest insecticide resistance. In this study, the resistance of different populations of termites to CHLORPYRIFOS was investigated using estimated LC50 and measuring the activity of two acetylcholinesterase (AChE) and glutathione-s-transferase enzymes. Four populations of M. diversus with different histories of organophosphorus insecticide spraying were studied. Populations A (Am Altamir1), B (Am Altamir2), and C (Mollasani) were collected from date palm groves with 30 and 10-year histories of organophosphorus insecticide spraying, as well as without spraying history, respectively. Population D (Ramin University) was collected from orange trees, three weeks after spraying with CHLORPYRIFOS. The bioassay results showed that the highest and lowest LC50 values were observed in populations A and C, respectively. Moreover, the activity of AChE using acetylthiocholine iodide, propionylthiocholine iodide, and butyrylthiocholine iodide substrates was higher in the populations with CHLORPYRIFOS spraying history, with the highest activity in population A. It was also demonstrated that the AChE activity with acetylthiocholine iodide substrate was higher than the activity of this enzyme with butyrylthiocholine iodide and the propionyl choline substrates in the populations with 30 and 10-year history of spraying. The Michaelis constant (Km) and maximum velocity (Vmax) values of AChE as two important kinetic factors, indicated the highest affinity of this enzyme to the substrate in population A.

Introduction: Paraoxonase 1 (PON1) is a high-density lipoprotein-associated enzyme with both aryl esterase and lactonase activity, and it possesses significant antioxidant and anti-inflammatory properties. PON1 hydrolyzes the active metabolites of several organophosphorus (OP) insecticides, including parathion, diazinon, and CHLORPYRIFOS. This widely studied enzyme is recognized for its protective role against organophosphate poisoning and vascular diseases, as well as its potential as a biomarker for conditions related to oxidative stress, inflammation, and liver disease. However, limited knowledge exists regarding PON1 activity status following acute organophosphate intoxication. The aim of the present study was to investigate changes in serum PON1 activity after acute CHLORPYRIFOS poisoning and its relationship with acetylcholinesterase (AChE) activity. Method: Rats were orally given a single dose of CHLORPYRIFOS (160 mg/kg), and blood samples were collected before treatment, as well as at 6 and 96 hours post-treatment. We measured serum cholinesterase, paraoxonase, and arylesterase activity of PON1. Results: Signs of OP poisoning, including miosis, salivation, tremors, fasciculation, and paralysis, were observed following intoxication, accompanied by a significant inhibition of AChE activity. All symptoms resolved after 48 hours, and AChE activity returned to baseline levels at 96 hours. In contrast, paraoxonase and arylesterase activities progressively increased after 6h and 96h treatment respectively. Conclusion: The results of our study indicated that serum cholinesterase activity and paraoxonase activity negatively associated in OP poisoning. Based on these findings, monitoring paraoxonase activity after OP intoxication may serve as a valuable biomarker for assessing intoxication.