Effect of khatamines and their enantiomers on plasma triiodothyronine and thyroxine levels in normal Wistar rats

Khat use and appetite: an overview and comparison of amphetamine, khat and cathinone

ETHNOPHARMACOLOGICAL RELEVANCE

To understand the role of khat (Catha edulis) use on the aberrations in appetite and weight which are common comorbidities for khat and other amphetamine users.

MATERIALS AND METHODS

We provide a comprehensive overview and conceptual summary of the historical cultural use of khat as a natural stimulant and describe the similarities and differences between cathinone (the main psychoactive constituent of khat) and amphetamine highlighting the limited literature on the neurophysiology of appetite and subsequent weight effects of khat.

RESULTS

Animal and some human studies indicate that khat produces appetite suppression, although little is known about mechanisms of this effect. Both direct and indirect effects of khat stem from multiple factors including behavioral, chemical and neurophysiological effects on appetite and metabolism. Classic and newly identified appetite hormones have not been explored sufficiently in the study of appetite and khat use. Unique methodological challenges and opportunities are encountered when examining effects of khat and cathinone including khat-specific medical comorbidities, unique route of administration, differential patterns of behavioral effects relative to amphetamines and the nascent state of our understanding of the neurobiology of this drug.

CONCLUSION

A considerable amount of work remains in the study of the appetite effects of khat chewing and outline a program of research that could inform our understanding of this natural amphetamine׳s appetite effects and help prepare health care workers for the unique health effects of this drug.

Khat (Catha edulis)-an updated review

The habit of chewing fresh leaves and twigs of khat (Catha edulis) for their stimulating amphetamine-like effects is highly prevalent in East Africa and southwest on the Arabic peninsula. There is an extensive literature on khat providing information about its history, botany, production, geographical distribution, chemistry and pharmacology, and exploring the social, economic, medical, psychological and oral aspects related to its use. Some of this literature dates as early as the 11th century; however, most of it appeared after the first scientific description of khat by Peter Forskal in 1775. This review provides a panorama of khat and the various aspects of its use. A non-technical description of the plant chemistry and pharmacology is included. The medical, psychological and oral aspects are emphasized, and the current knowledge about the microbiological effects of khat is also presented.

Effect of Catha edulis (khat) chewing on plasma lipid peroxidation

The effect of regular khat (Catha edulis) chewing and the combination of khat chewing and smoking on plasma lipid peroxidation as a biomarker of oxidative stress and free radical activity (measured as plasma malondialdehyde, MDA), as well as on the lipid profiles were investigated. The fasting plasma levels of MDA were non-significantly higher in both groups (4% in khat chewers and 9.2% in khat chewers and smokers), whereas these levels were observed to be significantly increased at post meal and 2h through the khat session. Post meal increase of plasma MDA could be attributed partially to the meal-induced oxidative stress and the possible decrease in the overall antioxidant capacity. This increase in plasma levels of MDA in both tested groups were found to be higher in the control group suggesting the presence of other contributing factors beside the meal-induced oxidative stress. Plasma levels of MDA were observed to fall slightly 2h through the khat session over the post meal levels, suggesting a lack of additive effect of khat consumption. Plasma triglycerides, total cholesterol, and LDL-cholesterol were shown to be non-significantly affected in this study by khat chewing or by the combination of khat chewing and smoking.

Achyranthes aspera elevates thyroid hormone levels and decreases hepatic lipid peroxidation in male rats

A study was made to evaluate the role of Achyranthes aspera on the changes in serum thyroid hormone concentrations and glucose levels in male rats. An attempt was also made to establish the relationship between hepatic lipid peroxidation and extract induced changes in thyroid hormone concentration, if any. Adult male Wistar rats were orally administered with the aqueous leaf extract of Achyranthes aspera at a dose of 200 mg/kg b. wt./day for 7 days. The effects of the extract on body weight, hepatic protein content, lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activities and on serum triiodothyronine (T3), thyroxine (T4) and glucose levels were evaluated. The extract exhibited significant prothyroidic activity as it enhanced the levels of both the thyroid hormones along with an increase in serum glucose concentration, body weight and hepatic protein content. On the other hand, it decreased hepatic LPO without altering the activities of the two antioxidant enzymes, SOD and CAT significantly, suggesting a direct free radical scavenging activity of the extract. It appears that the Achyranthes aspera leaf extract is both prothyroidic and antiperoxidative in nature.

Role of Moringa oleifera leaf extract in the regulation of thyroid hormone status in adult male and female rats

The role of Moringa oleifera aqueous leaf extract in the regulation of thyroid hormone status, was studied in adult Swiss rats. Other than the thyroid hormone concentrations, hepatic lipid peroxidation (LPO) and the activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were evaluated. In the first experiment, effects of the leaf extract (175 mg kg(-1)body wt. day(-1)for 10 days) were studied both in male and female animals. Following the administration of the extract, serum triiodothyronine (T(3)) concentration and hepatic LPO decreased with a concomitant increase in the serum thyroxine (T(4)) concentration, in female rats, while in males no significant changes were observed, suggesting that Moringa oleifera leaf extract is more effective in females than in the males. To evaluate the impact of a higher dose, in the second experiment, the study was repeated in female rats, with 350 mg kg(-1)body wt. day(-1)for the same duration. Almost similar reduction in the serum T(3)concentration (approx. 30%) and an increase in the T(4)concentration were observed suggesting the inhibiting nature of Moringa oleifera leaf extract in the peripheral conversion of T(4)to T(3), the principal source of the generation of latter hormone. As the antiperoxidative effects were exhibited only by the lower dose and percent decrease in T(3)concentration was nearly the same by both the doses, it is suggested that the lower concentration of this plant extract may be used for the regulation of hyperthyriodism. 2000 Academic Press@p$hr

Withania somnifera and Bauhinia purpurea in the regulation of circulating thyroid hormone concentrations in female mice

The effects of daily administration of Withania somnifera root extract (1.4 g/kg body wt.) and Bauhinia purpurea bark extract (2.5 mg/kg body wt.) for 20 days on thyroid function in female mice were investigated. While serum triiodothyronine (T3) and thyroxine (T4) concentrations were increased significantly by Bauhinia, Withania could enhance only serum T4 concentration. Both the plant extracts showed an increase in hepatic glucose-6-phosphatase (G-6-Pase) activity and antiperoxidative effects as indicated either by a decrease in hepatic lipid peroxidation (LPO) and/or by an increase in the activity of antioxidant enzyme(s). It appears that these plant extracts are capable of stimulating thyroid function in female mice.