Hamdy I. Hussein

Reproductive toxicity and histopathological changes induced by lambda‐cyhalothrin in male mice

Lambda‐cyhalothrin (LCT) is a widely used broad‐spectrum pyrethroid insecticide. Oral LCT administration to adult male mice at 3 doses (0.2, 0.4, and 0.8 mg/kg/day) for 6 weeks caused a significant reduction in the weight of the seminal vesicles. The epididymal sperm count was lower in mice that received at the highest dose than in control mice. However, the proportions of live and motile spermatozoa were reduced at both the medium and the high doses compared with control mice. All doses induced an increase in the number of morphologically abnormal spermatozoa. Histopathological observations of the testes, liver, kidneys, and spleen showed dose‐related degenerative damage in LCT‐treated mice. The results indicate that LCT has reproductive toxicity, hepatotoxicity, nephrotoxicity, and splenotoxicity in male mice at the tested doses.

Molluscicidal activity of methomyl and cardenolide extracts from Calotropis procera and Adenium arabicum against the land snail Monacha cantiana.

In this work, we have evaluated the molluscicidal activity of two cardenolide extracts from Adenium arabicum Balf f. [the benzene (B) and methanol (M) extracts], one cardenolide extract from Calotropis procera (Aiton) W.T. Aiton (extract C), and methomyl against the harmful land snail Monacha cantiana (Montagu). The contact LD50 values for the above mentioned plant extracts were 12.62, 34.63, and 34.35 mg·kg−1 of body weight, respectively, while the LD50 for methomyl was 116.62 mg·kg−1, that is, the plant extracts were 9.24, 3.37, and 3.4 times more toxic than methomyl. In addition, a simple colorimetric method, based on Kedde reagent, was modified to determine cardenolide concentrations in plant extracts. Thin layer chromatography analysis (TLC) showed several cardiac glycosidal compounds in each plant extract. The results proved that cardiac glycosides are promising candidate compounds that could be used to control land snails, or exploited to develop new, effective, and environmentally friendly molluscicides.

Cytotoxic and genotoxic effects of abamectin, chlorfenapyr, and imidacloprid on CHOK1 cells.

The cytotoxicity and genotoxicity of abamectin, chlorfenapyr, and imidacloprid have been evaluated on the Chinese hamster ovary (CHOK1) cells. Neutral red incorporation (NRI), total cellular protein content (TCP), and methyl tetrazolium (MTT) assays were followed to estimate the mid-point cytotoxicity values, NRI50, TCP50, and MTT50, respectively. The effects of the sublethal concentration (NRI25) on glutathione S-transferase (GST), glutathione reductase (GRD), glutathione peroxidase (GPX), and total glutathione content have been evaluated in the presence and absence of reduced glutathione (GSH), vitamin C, and vitamin E. The genotoxicity was evaluated using chromosomal aberrations (CA), micronucleus (MN) formation, and DNA fragmentation techniques in the presence and absence of the metabolic activation system, S9 mix. Abamectin was the most cytotoxic pesticide followed by chlorfenapyr, while imidacloprid was the least cytotoxic one. The glutathione redox cycle components were altered by the tested pesticides in the absence and presence of the tested antioxidants. The results of genotoxicity indicate that abamectin, chlorfenapyr, and imidacloprid have potential genotoxic effects on CHOK1 cells under the experimental conditions.

Fumigant toxicity and antiacetylcholinesterase activity of Saudi Mentha longifolia and Lavandula dentata species against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Summary Mentha longifolia (L.) and Lavandula dentata (L.) (Lamiaceae) are two wild growing folk medicine plants that in Saudi Arabia. This work was conducted to investigate the chemical composition and evaluate the fumigant toxicity of their essential oils against the adults (3-5-day-old) of cowpea beetle, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). The main compounds in M. longifolia oil were pulegone (74.95%), 1,8-cineole (7.35%), l-menthone (6.62%), and eucarvone (2.68%), while the main constituents in L. dentata oil were camphor (61.43%), fenchone (24.3%), d-fenchol (2.15%), and linalool (1.52%). The two oils showed LC50 values of 4.43 and 7.92 µl/L air and exhibited antiacetylcholinesterase activity with IC50 values of 1.01 and 9.74 µl/ml, respectively. The results proved the potential use of these natural materials as effective alternatives to synthetic pesticides.

Cytotoxicity of benalaxyl, metalaxyl, and triadimefon on Chinese hamster ovary cells

The cytotoxicity of the fungicides benalaxyl, metalaxyl, and triadimefon was evaluated in vitro using the Chinese hamster ovary (CHO-K1) cell line. The midpoint cytotoxicity values of neutral red (NR) incorporation (NRI50), total cellular protein content (TCP50), and the methyl tetrazolium assay (MTT50) were estimated. Benalaxyl was the most cytotoxic fungicide, followed by metalaxyl and triadimefon. Fetal calf serum (10%) caused a reduction in benalaxyl, metalaxyl, and triadimefon cytotoxicity by factors of 1.8, 1.3, and 1.3. The effects of sublethal concentrations (NRI25) of the three fungicides on the glutathione redox cycle components glutathione S-transferase, glutathione reductase, glutathione peroxidase, and total glutathione content were studied. The ameliorative effects of extracellular glutathione (1 mmol L−1), vitamin C (70 µmol L−1), and vitamin E (30 µmol L−1) were also investigated. The three antioxidants led to significant effects on the glutathione redox cycle components.

Cytotoxic effects of acephate, ethoprophos, and monocrotophos in CHO-K1 cells

This work evaluates the cytotoxicity of acephate, ethoprophos, and monocrotophos in the Chinese hamster ovary cell line. The neutral red incorporation (NRI), total cellular protein (TCP) content, and methyl tetrazolium (MTT) assays were followed to estimate the midpoint cytotoxicity values, NRI50, TCP50, and MTT50, respectively. The targeted cells were exposed to the tested pesticides in the presence and absence of fetal calf serum. The effects of the sublethal concentration (NRI25) on glutathione S-transferase, glutathione reductase, glutathione peroxidase, and total glutathione content have been evaluated. In addition, the ameliorative effects of extracellular reduced glutathione (GSH, 1 mM), vitamin C (70 µM), and vitamin E (30 µM) were investigated. The exposure period and protein content in the culture medium affected the cytotoxicity of the tested pesticides. Unexpectedly, acephate showed the least MTT50 value, 56.6 µM. The tested antioxidants caused different and significant effects on the components of the glutathione redox cycle.