Pharmacological and toxicological studies on CATHA EDULLIS

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Research type: Research Paper

Authors: Al Adhal, Adnan Abdo Hussien

Abstract: An experiment was planned on nine male healthy Yemeni volunteers, using the cross-over technique, to study the effect of chewing Khat on gastric emptying, Urine Flow Rate during 24 hours (UFR), respiratory rate and onthe blood pressure and pulse rate. These volunteers are weekly Khat chewers. Khat caused a decrease in gastric emptying, this is reflected (PDE) of ciprofloxacin by 38 percent, and delaying the time to reach the maximum peak of excretion rate (TTP) by 40 percent. Urine flow rate was decreased by Khat by 44 percent, while the respiratory rate measured after four hours of starting chewing was increased by 28 percent. The peak systolic, and diastolic blood pressure and pulse rate were increased by 11 percent, 7 percent and 7.5 percent respectively during the Khat session. Other clinical trials were also performed to investigate the interactions of some durgs with Khat. The interaction parameters include the blood pressure, the pulse rate, the 24 hour urinary flow rate, in addition on the subjective symptoms: Khat-induced euphoria and the post-Khat depressive and anorectic effects. The subjective symptoms were graded from zero to three degrees, degree three being the highest. Isradpine the calcium-channel blocker, and the putative central inhibitor of dopamine the release, abolished the blood pressure elevating effect of Khat, and improved the 24 hour urinary flow rate by 12 percent, while it further increased the pulse rate by 17 percent. Concerning the subjective symptoms, isradipine lowered both the Khat-induced euphoria, and the post-Khat depression. Pizotifen a 5HT2-receptor anagonist, also abolished the blood pressure elevating effect of Khat, and increased the pulse rate by 22 percent, while it further reduced the 24 hour urinary flow rate by 30 percent. Concerning the subjective symptoms, pizotifen did not significantly affect the Khat-induced euphoria, and the post-Khat depression. Moreover, it did not improve the Khat-induced anorexia. In another aspect, the dopamine agonist bromocriptine decreased craving to Khat in weekly Khat chewers, while the dopamine antagonist chlorpromazine increased that craving concerning the animal studies, fresh Khat in adose of 20 grams/Kilogram (20 times the normal dose), was given to three group was left as a control, and in another trial fresh Khat was given in three doses 20, 30 and 40 gram/kilogram to three groups of rabbits (six each), for six months, and a fourth group was left as a control. The result were as follows: Fasting Blood Sugar (FBS), Triglyceride (TG), GOT, and GPT were increased in both trials. The CBC which was measured only in the second trial showed that Khat lowerd hemoglobin, WBCs, and Lymphocytes while it increased neutrophils. The Khat-treated groups showed lowerd body weights in the second (six months) trial. The heart weight relative to the body weight was increased in the first trial, while this result was not seen in the second trial. In the study of the effect of Khat on blood pressure and pulse rate in the normal population, results showed that systolic and diastolic blood pressure and pulse rate of the daily khat consumers are elevated by 5 percent, 10 percent, 14 percent respectively comparing to these parameters in occasional or non khat consumers. Moreover, mild to moderat hypertensive patients Khat daily, who used nifedipine 20 mg/d showed normal blood pressure. Finally, concerning the retrospective studies, patients with a long history of Khat consumption, showed statistically significant increase in the incidence of cerebral strokes, myocardial infarctions, congestive heart failur, and schizophrenia.