To chew or not to chew: that's the question

Phytochemical Screening and Cytotoxic Properties of Ethanolic Extract of Young and Mature Khat Leaves

The khat plant has been culturally used in many parts of Africa and the Arabian Peninsula for many years to induce psycho-stimulating effect. Because of the global wide-spreading nature, khat chewing is being considered as a universally growing problem. Catha abbottii, Catha edulis, and Catha transvaalensis are the three species of khat commonly chewed in Saudi Arabia and nearby regions. Khat users usually prefer to chew young leaves over mature ones due to the diverse effects produced by both. Though many of the constituents of khat leaves have been identified, the complete phytochemical profile of young and mature leaves was not performed or compared; also, no evidence is available to affirm the cytotoxicity of young or mature leaves. Therefore, this study aimed to investigate the phytochemical basis of the differential response of the young and mature leaves and to assess the cytotoxicity of young and mature khat leaves. Ethanolic extracts of young and mature leaves of three khat cultivars were subjected to GC-MS. Hierarchical cluster analysis revealed the existence of two major clusters. The extracts of young leaves were found to contain the maximum content of cathinone; however, methoxyamphetamine was found in only one extract of young leaves. Cytotoxicity investigations were also conducted on both types of leaves using three cancer cell lines, human breast adenocarcinoma, human ovary adenocarcinoma, and human colon adenocarcinoma and also normal human fetal lung fibroblast cell line was used. All extracts showed comparable cytotoxicity, IC50 ranging from 22–59 μg/mL on the cancer cells; however, we observed more cytotoxicity against normal cells (IC50: 6–41 μg/mL). The predominant cytotoxicity on normal cells may pose many health hazards to khat consumers.

High Seroprevalence of Autoantibodies Typical of Autoimmune Liver Disease in Eastern Ethiopia: Is Chewing of Khat (Catha edulis) a Triggering Factor?

BACKGROUND

Recent studies have identified chewing of khat (Catha edulis) as an independent risk factor for liver injury; however, the pathogenetic mechanism remains poorly understood. Case series have found markers of autoimmune hepatitis in patients with khat-related liver disease, suggesting that khat chewing might trigger an autoimmune response. The aims of the present study were (i) to assess the prevalence of autoantibodies typical for autoimmune liver diseases in a healthy population in Ethiopia and (ii) to explore the hypothesis that khat usage triggers autoimmunity.

METHODS

Consenting adults (≥18 years) without known autoimmune disease or manifest liver disease were included. One-hundred-and-sixty-nine individuals with current khat use were compared to 104 individuals who never used khat. Seroprevalence of antinuclear (ANA), antismooth muscle (SMA), and antimitochondrial antibodies (AMA) were determined and compared between the groups using logistic regression models to adjust for age and sex.

RESULTS

Overall, 2.6% of the study subjects were positive for ANA, 15.4% for SMA, and 25.6% for AMA. When comparing khat users to nonusers, ANA was detected in 4.1% vs. 0% (p=0.047), SMA in 16.0% vs. 14.4% (p=0.730), and AMA in 24.9% vs. 26.9% (p=0.704). ANA was excluded from multivariable analysis since there was no seropositive in the reference group. After adjusting for sex and age, no significant association between khat use and SMA or AMA was found.

CONCLUSIONS

No association between khat usage and the seropresence of SMA or AMA was found, weakening the hypothesis that khat-related liver injury is mediated through autoimmune mechanisms. However, the seroprevalences of AMA and SMA were strikingly high in this Ethiopian population compared to global estimates, suggesting that diagnostic algorithms for autoimmune liver diseases developed in Europe and North America might lead to misdiagnosis of patients on the African continent.

Khat chewing increases the risk for developing chronic liver disease: A hospital-based case-control study

The chewing of the leaves of Catha edulis (khat) has been implicated in the development of liver disease, but no controlled observations have been undertaken. The objective of the present study was to determine whether khat chewing is associated with development of chronic liver disease (CLD). A case-control study was conducted at two public hospitals in Harar, Ethiopia, between April 2015 and April 2016. A consecutive sample of 150 adult hospital attendees with CLD were included as cases, and 300 adult hospital attendees without clinical or laboratory evidence of CLD were included as controls. Khat consumption was quantified in "khat years"; 1 khat year was defined as daily use of 200 g of fresh khat for 1 year. A logistic regression model was used to control for confounders. There was a significant association between chewing khat and the risk for developing CLD (crude odds ratio, 2.64; 95% confidence interval [CI], 1.56-4.58). In men, this risk, following adjustment for age, alcohol use, and chronic hepatitis B/C infection, increased with increasing khat exposure; thus, compared to never users the adjusted odds ratios were for low khat exposure 3.58 (95% CI 1.05-12.21), moderate khat exposure 5.90 (95% CI 1.79-19.44), and high khat exposure 13.03 (95% CI 3.61-47.02). The findings were robust in a post hoc sensitivity analysis in which individuals with identifiable risk factors for CLD were excluded.

CONCLUSION

A significant association was observed between chewing khat and the risk for developing CLD, and in men the association was strong and dose-dependent, suggesting a causal relationship; as the prevalence of khat chewing is increasing worldwide, these findings have major public health implications. (Hepatology 2018;68:248-257).

Pharmacological and Toxicological Effects of Catha edulis F. (Khat)

Khat chewing is deeply rooted in the culture and tradition of communities in khat belt countries, and its consumption is spread to other countries through the suitcase trade. The aim of this article is to review current knowledge on the chemistry, social, pharmacology and toxicology of khat and its use. Khat produces effect invariably in every system, which is harmful or beneficial in some instances. Harmful effects are observed in heavy users, although firm evidence is lacking. Chewing khat acutely elicits states of euphoria, which is followed by low mood. Khat contains alkaloids with psychostimulant properties, but the effect cannot be totally explained by these alkaloids. It is also not clear whether the effect produced in some organs like liver could be attributed to khat or pesticides sprayed during farming. Although the evidence indicates that khat has adverse effects in most organs, our understanding of the complex interaction between use and effect is incomplete, and causal relationships have not yet been described. Moreover, khat has positioned itself well in the social, economic and political arena. Thus, a multidisciplinary research is required to understand the different dimensions and come up with ways that maximize the benefit while minimizing the risk. Copyright © 2017 John Wiley & Sons, Ltd.

Khat chewing and cirrhosis in Somaliland: Case series

BACKGROUND

Khat chewing is common especially among men in East Africa and Yemen. It is generally viewed by the populace as a benign social custom. Several studies of ethnic Somali immigrants to Western countries suggest an association between khat chewing and hepatotoxicity, but the risk of hepatotoxicity related to khat chewing within African settings is not documented.

AIM

To identify and describe liver disease without evidence of alcohol exposure or infectious etiology in khat chewers.

SETTINGS

A university-affiliated teaching hospital in Somaliland.

METHODS

Cases of cirrhosis of unknown cause were identified from the clinical practice of Al Hayatt Hospital in Borama, Somaliland, during 14 months beginning December 2012.

RESULTS

Eight Somali men aged 27-70 years living in Somaliland were identified with cirrhosis of otherwise unknown cause. All chewed khat habitually for many years (15-128 bundles per day times years of use). A liver biopsy of one man was consistent with khat hepatotoxicity. Four of the eight men died during the study period.

CONCLUSION

Khat chewing may be associated with health consequences including severe hepatotoxicity with cirrhosis.

Hepatotoxicity Induced by "the 3Ks": Kava, Kratom and Khat

The 3Ks (kava, kratom and khat) are herbals that can potentially induce liver injuries. On the one hand, growing controversial data have been reported about the hepatotoxicity of kratom, while, on the other hand, even though kava and khat hepatotoxicity has been investigated, the hepatotoxic effects are still not clear. Chronic recreational use of kratom has been associated with rare instances of acute liver injury. Several studies and case reports have suggested that khat is hepatotoxic, leading to deranged liver enzymes and also histopathological evidence of acute hepatocellular degeneration. Numerous reports of severe hepatotoxicity potentially induced by kava have also been highlighted, both in the USA and Europe. The aim of this review is to focus on the different patterns and the mechanisms of hepatotoxicity induced by “the 3Ks”, while trying to clarify the numerous aspects that still need to be addressed.