Mindédé Assih

Some victims die, others survive with disabilities following the ophidian envenomations. Among the clinical signs of snake bites is hypotension. Most of snake bites victims live in countryside use medicinal plants to treat themselves in case of snakes bite. This study is part of research on antivenom effects of Annona senegalensis and Securidaca longepedunculata, specifically, the mechanisms by which both plants control blood pressure variation caused by Echis ocellatus venom. Venom toxicity tests determined LD50 of E. ocellatus venom in Sprague-Dawley rats, which is equal to 0.235 mg/kg. E. ocellatus venom decreases mean arterial blood pressure in rats to 27.16 ± 3.04 % and decreased heart rate to 49.51 ± 3.16 beats/min. Hydroethanolic extracts of A. senegalensis and S. longepedunculata slow down the decrease in blood pressure caused by E. ocellatus venom significantly (p > 0.05) the mean arterial pressure at doses of 20 mg/kg. These results show that hydroethanolic extract of A. senegalensis roots and hydroethanolic extract of S. longepedunculata roots have antivenom properties against E. ocellatus venom.

Background : The increase in agricultural production has been accompanied by intensive pesticide use, leading to chronic environmental contamination. In Togo, residues exceeding regulatory limits have been detected in vegetable crops, particularly abamectin (ABM) and cypermethrin (CYP). ABM, derived from Streptomyces avermitilis, acts on GABA-gated chloride channels and crosses the blood–brain barrier, inducing oxidative stress and neurotoxic damage. CYP, a synthetic pyrethroid, targets voltage-gated sodium channels, resulting in abnormal neuronal discharges and excessive production of reactive oxygen species. While their acute effects are well known, the subchronic impacts of low-dose exposure, especially in combination, remain poorly understood. In this context, the present study aims to evaluate the subchronic neurotoxic effects of combined exposure to abamectin and cypermethrin, administered at realistic doses, in rats. Methods : This study evaluated the subchronic neurotoxicity of ABM and CYP, administered individually or in combination for 90 days to 40 Wistar rats divided into five groups: control, ABM (0.3 mg/kg/day), CYP (0.7 mg/kg/day), mixture M1 (ABM 0.3 + CYP 0.7 mg/kg/day), and mixture M2 (ABM 0.6 + CYP 1.4 mg/kg/day). Results : The results revealed that exposure, particularly to mixtures, decreased brain protein levels, significantly reduced glutathione, superoxide dismutase, and catalase, and markedly increased malondialdehyde levels compared to groups exposed to a single pesticide.. Glutathione S-transferase activity was less affected, but caspase-3 was activated in M1 and M2 groups, indicating apoptosis induction. Histological analyses in M1 and M2 groups showed pronounced hypocellularity associated with cellular hypertrophy and necrotic foci compared with controls. Conclusions : The observed synergistic effect highlights an increased toxicological risk, underscoring the need for further mechanistic studies and appropriate regulatory measures. Under environmental conditions where combined exposures are frequent, these results highlight the importance of considering the impact of mixtures rather than isolated compounds. Keywords: Abamectin, Cypermethrin, Oxidative stress, Pesticide mixture, low-dose

Objective: This study aims to evaluate the acute and subacute toxicity, as well as the cytotoxicity of the hydroethanolic extract of D. guineense willd fruit pulp. Methodology: Three different tests were performed. The cytotoxicity test was performed using Artemia salina larvae. The acute toxicity test was conducted by single oral administration of Dialium guineense at 5000 mg/kg. When subacute toxicity tests were performed by repeated oral administration of Dialium guineense at 250, 500, and 1000 mg/kg/day for 28 days. Results: The fruit pulp of Dialium guineense presented a CL ₅₀ equal to 1.40 mg/mL and an LD ₅₀ greater than 5000 mg/kg. This pulp at the dose of 1000 mg/kg significantly reduced blood glucose as well as the overall white blood cell counts, particularly neutrophils and eosinophil polymorphonuclear cells, at low doses after 28 days of treatment. Conclusion: The hydroethanolic extract of the Dialium guineense willd fruit pulp does not show signs of cytotoxicity, major acute or subacute toxicity.

Objective. This study is aimed at evaluating the effects of Dialium guineense Willd fruit pulp powder on diarrhea induced by castor oil in Wistar rats. Materials and Methods. Three different tests were carried out. A preventive test by administration of a single dose of 250, 500, 1000, 2000, and 4000 mg/kg before the induction of diarrhea by castor oil. Another preventive test after repeated administration of Dialium guineense at 250, 500, and 1000 mg/kg/day for 8 days, before the induction of diarrhea, was done. The third test was a curative test with a single dose of 250, 500, 1000, and 2000 mg/kg after the induction of diarrhea by castor oil. Results. D. guineense fruit pulp at 1000, 2000, and 4000 mg/kg administered before the induction of diarrhea, has significantly delayed diarrhea; reduced the frequency of defecation, reduced the amount of diarrheal stools, and also reduced the purging index, with a degree of inhibition comparable to that of loperamide. But the water content of the stools of the group treated with D. guineense does not change significantly compared to the controls. D. guineense has reduced significantly from 500 mg/kg the diarrhea induced by castor oil after 8 days of treatment. It appears that the doses of 250 and 500 mg/kg, which were not effective with the single‐dose preventive test, significantly delayed diarrhea; reduces the frequency of diarrheal stools and also reduces the purging index. D. guineense administered, after the induction of diarrhea, by castor oil has significantly reduced the diarrhea from 250 mg/kg. Conclusion. The fruit pulp of D. guineense has showed antidiarrheal activities in Wistar rats by reducing the frequency of defecation, the amount of diarrheal fecal matter emitted as well as the water content. It also delayed the onset of diarrhea and significantly reduced the purging index like loperamide.

Hydrocotyle bonariensis is one of the medicinal plants used in traditional medicine for the management of hypertension in Africa, Asia, and Latin America. However, the real impact of the traditional use of this plant on arterial hypertension has not yet been the subject of conclusive scientific information in the literature. This study aimed essentially to evaluate the potential cardiomodulatory effect of the hydroethanolic extract of Hydrocotyle bonariensis. In other to do so, the hydroethanolic extract of H. bonariensis was studied in vivo on the Wistar rat ECG and then in vitro on the isolated perfused Wistar rat heart using the Langendorff system. The extract was also tested on isolated guinea pig atria kept alive in the organ-specific vessel under physiological conditions similar to those of a living organism. At the cellular level, the effects of the extract were evaluated on the human cardiac sodium current INav1.5 and on the human cardiac pacemaker current If. We noted that the extract caused a decrease in P wave and T wave amplitudes and heart rate and an increase in the duration of the RR interval on the in vivo rat ECG. On the isolated perfused Langendorff heart as well as on the isolated atria, a decrease in the RR interval and in the heart rate was noted. The extract had no effect on human cardiac sodium current, but it did reduce human cardiac pacemaker current. In conclusion, the present study demonstrated that Hydrocotyle bonariensis, a medicinal plant traditionally used to prevent and treat hypertension, has an overall cardiomoderating effect. This effect would contribute to the reduction of blood pressure.