Insecticidal and biochemical activity of essential oil from Citrus sinensis peel and constituents on Callosobrunchus maculatus and Sitophilus zeamais.

Essential oils are promising substitute for chemical pesticides with the inherent resistance by pests, environmental and health effects on humans. In this study, the chemical composition of essential oil extracted from Citrus sinensis peel was characterized, the insecticidal activities of the oil and its constituents against Callosobrunchus maculatus (Cowpea weevil) and Sitophilus zeamais (maize weevil) were investigated and the underlying insecticidal mechanism were elucidated. The essential oil was extracted by hydro-distillation and characterized using gas chromatography-mass spectrometry (GC-MS). Insecticidal activity was determined by contact and fumigant toxicity assay. The inhibitory effect of the oil and its constituents on acetylcholinesterase (AChE), Na+/K+-ATPase and glutathione-S- transferase (GST) activity were assayed using standard protocols. The total number of volatile compounds detected in C. sinensis essential oil was eighteen (18). d-limonene (59.3%), terpineol (8.31%) and linalool (6.88%) were the major compounds present in the essential oil. Among the tested essential oil compounds, terpineol showed highest contact toxicity against C. maculatus (LD50 =17.05 µg/adult) while 3-carene showed highest contact toxicity against S. zeamais (LD50 =26.01 µg/adult) at 24 h exposure time. Citral exhibited the highest fumigant toxicity against C. maculatus and S. zeamais with LC50 value 0.19 and 2.02 µL/L air at 24 h respectively. Acetylcholinesterase and Na+/K+-ATPase activities were significantly inhibited by C. sinensis oil and its constituents in both C. maculatus and S. zeamais as compared to control. This study indicates that C. sinensis essential oil and its constituents have potential to be developed into botanical pesticides.

Investigations into the Risk of Reproductive Toxicity Following Exposure to Highly Active Anti-Retroviral Drugs in Rodents.

With the introduction of Highly Active Antiretroviral Therapy (HAART), there has been drastic decline in morbidity and mortality associated with HIV/AIDS. However, many patients experience adverse drug reactions perhaps due to the inherent toxic nature of HAART. The possible toxic effect of HAART (combination ARVs) on reproduction and sexual dysfunction in seropositive HIV patients remains a subject of intense research. This study was designed to investigate the toxic effects of HAART on the reproductive hormones and organs of male and female rats. Sexually mature adult male and female rats were administered therapeutic doses of single and combination antiretroviral drugs for 48 days and thereafter sacrificed under anaesthesia. Morphological and histopathological examination of the testes and ovaries were carried out. Serum biochemical assay, semen quality analysis and hormonal assays were also conducted using standard methods. Results show significant (p < 0.05) reductions in the weight of testes and epididymis across all groups versus control; sperm count and motility were also significantly reduced in the test groups while hormonal analysis in males revealed significant reductions in LH, FSH and Testosterone. In the females, there was a significant (p < 0.05) reduction in the number of ovarian follicles, prolactin, estrogen and progesterone. We thus conclude that the administration of single and combined antiretroviral drugs have potential reproductive toxic effects.

The combined fixed-dose antituberculous drugs alter some reproductive functions with oxidative stress involvement in wistar rats.

The reproductive toxicity of combined fixed-dose first-line antituberculosis (CFDAT) regimen was assessed in rats. Thirty-two (32) Wistar rats weighing 168.1 ± 8.0 g were divided into four groups of eight rats per group. Two groups of male and female rats were administered oral distilled water (1.6 ml) and CFDAT drugs containing rifampicin, isoniazid, pyrazinamide and ethambutol (RIPE, 92.5 mg/m2 per body surface area) respectively for forty-five days. Serum follicle stimulating hormone, luteinizing and testosterone were reduced significantly (p < 0.05) in the treated male rats. Similarly, sperm count levels were decreased by 27.3% when compared with control. RIPE elevated serum oestrogen (p < 0.05), progesterone (p < 0.05) as well as prolactin (p > 0.05) levels in the treated females. In addition, RIPE reduced (p < 0.05) total proteins levels and increased (p < 0.05, 53%) catalase levels in male but not female animals. Superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, reduced glutathione levels as well as lipid peroxidation were unaltered in all rats respectively. Histopathological studies revealed congested peritesticular vessels and no changes in the ovary when compared with control. Overall, our results demonstrate reproductive toxicity potentials of RIPE in the rat, thus, suggesting that these reproductive parameters be monitored during antituberculous chemotherapy.