Decoctions of Hibiscus sabdariffa L. (Family Malvaceae) are very popular for the preparation of homemade refreshing drinks and are also used medicinally for a variety of ailments. Particularly remarkable are the various scientific reports supporting diuretic and antihypertensive potentials. It is therefore not unusual for patients who are on orthodox antihypertensive medications to use medicinal H. sabdariffa drinks concomitantly without regard to the possibility of herb-drug interactions. This possibility necessitated this study in which the pharmacokinetic and pharmacodynamic interactions of H. sabdariffa extract (HSE) and hydrochlorothiazide (HCT), a commonly prescribed diuretic drug, were examined. The effects of concomitant administration of HSE on urine volume, urine pH, and urinary concentrations of sodium, bicarbonate, and chloride ions, as well as on the pharmacokinetic parameters of HCT, were determined in experimental rats and rabbits. Co-administration of HSE with HCT caused a significant increase in the volume of urine excreted and resulted in a decrease in the pH of urine and the concentrations of sodium, bicarbonate, and chloride ions. Co-administration of HSE (20-40 mg/kg) with HCT (10 mg/kg) increased and prolonged the plasma concentration, the mean area under the concentration-time curve, and the volume of distribution of HCT achieved over the 24-hour sampling period. The plasma clearance and the elimination rate constant of HCT decreased with increasing dose of HSE co-administered with the HCT. The results of this study reveal a possible herb-drug interaction involving HCT and HSE, used as an ingredient in medicinal or refreshing drinks in many countries.

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This study investigated the effects of administration of monosodium Lglutamate (MSG) on serum gonadotrophin-releasing hormone (GnRH), luteinising hormone (LH), testosterone and total cholesterol (TC), cauda epididymal sperm reserves (CESR) and testicular histomorphology of adult male albino rats. Eighty-four rats, randomly assigned to 7 groups of 12 rats each, were used for the study. Varying low doses (0.25, 0.50 or 1.00 g/kg body weight) of MSG were administered orally or subcutaneously at 48-h intervals for six weeks. Serum GnRH, LH, testosterone and TC, and CESR were evaluated on days 14, 28 and 42 of MSG administration. Testicular histomorphology was evaluated on day 42. The results showed that the mean serum GnRH, LH and testosterone levels, and the CESR of all the treated groups were significantly (P < 0.05) lower than those of the untreated control on days 14, 28 and 42 of MSG administration. The mean serum TC levels of all the treated groups were also significantly (P < 0.05) lower than those of the control group on days 14 and 28. No lesions were observed on sections of the testes. It was concluded that MSG administration for 14, 28 and 42 days led to significantly lower serum levels of GnRH, LH, testosterone and TC, and significantly lower CESR.

A new and simple method o detecting mated female albino rats was developed and tested for precision and accuracy. The method involved the gross observation of grey to yellow sh protein coagulates (remnants of the copulatory plug) on vaginal smears of mated females made on clean glass slides. Results o test of the new method showed that the mean length of time between observation of the protein coagulates on vaginal smears and delivery o the mated pregnant emales was 21.39 ± 0.11 days (range = 20-23 days, n = 58), wh ch concurred with the normal 21-day gestation length o rats. The coefficient o variation (CV) of imprecision of the new method was found to be 3.74 %. This new method is simple, easy to apply and does not interfere with fertilization and pregnancy, and also does not involve either the use of specially designed rat cages or microscopy of vaginal smears, which were the constraints of the former methods of confirming mating in rats. f i f f f i f f

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