Free radicals are present in human serum of Catha edulis Forsk (Khat) abusers

Coenzyme Q10 nullified khat-induced hepatotoxicity, nephrotoxicity and inflammation in a mouse model

Ethnopharmacological relevance

The consumption of khat (Catha Edulis, Forsk) is on the rise despite the much publicized associated deleterious health effects. How chemicals present in khat, affect various physiological and biochemical processes requires further scrutiny. A clear understanding of these processes will provide an avenue for countering khat-driven negative effects using appropriate pharmacological and/or nutritional interventions.

Aim of the study

The current study investigated the effect of khat on vital physiological and biochemical processes such as oxidative stress, inflammation and immune responses and the role of Coenzyme-Q₁₀ (CoQ₁₀), a potent antioxidant and anti-inflammatory, in modulating any negative effects due to khat exposure.

Methodology

Three (3) weeks old forty (40) Swiss albino mice were randomly assigned into four treatment groups (n = 10). The first group was the control that was not administered with khat or CoQ₁₀. The second group received 200 mg/kg body weight (b/w) of CoQ₁₀, while the third group received 1500 mg/kg b/w of khat extract and finally the forth group was co-treated with 200 mg/kg b/w of CoQ₁₀ and 1500 mg/kg b/w of khat extract. The experiment was conducted for 90 days after which samples were collected for physiological and biochemical analyses.

Results

The effects of khat and CoQ₁₀ on the weights of brain, liver, kidney and spleen was determined. Administration of khat decreased the levels of RBCs and its subtypes (MCV, MCH, RDW-SD and RDW-CV), a clear indicator of khat-induced normochromic microcytic anemia. White blood cells (lymphocytes, monocytes, neutrophils and eosinophil) which are vital in responding to infections were markedly elevated by khat. Moreover, these results provide evidence for khat-induced liver and kidney injury as shown by increased biomarkers; AST, ALT, GGT and creatinine respectively. Standard histopathological analysis confirmed this finding for khat-driven liver and kidney injury. Further studies showed evidence for khat-induced inflammation and oxidative stress as depicted by increased levels of the pro-inflammatory cytokine TNF-alpha and elevation of GSH in the brain, liver and spleen. Remarkably, this is the first study to demonstrate the potential of CoQ₁₀ in ameliorating khat-induced negative effects as outlined. CoQ₁₀ supplementation restored the khat-induced reduction in RBC subtypes, and was protective against liver and kidney injury as shown by the appropriate biomarkers and standard histopathology analysis. The other significant finding was the CoQ₁₀-driven normalization of GSH and TNF-α levels, indicating a protective effect from khat-driven oxidative stress and inflammation respectively.

Conclusion

From this study, we conclude that CoQ₁₀ may be useful in nullifying khat-driven deleterious events among chronic khat users.

Antioxidant capacity and biomarkers of oxidative stress in saliva of khat-chewing patients: a case-control study

OBJECTIVES

The aim of this study was to investigate the antioxidant levels and biomarkers of oxidative stress in saliva from khat-chewing patients compared with controls.

STUDY DESIGN

Saliva samples were collected from 51 chronic khat chewers and 46 age- and sex-matched controls. Concentrations of oxidative stress biomarkers (malonyl-dialdehyde [MDA], protein carbonyl, and 8-hydroxy-2'-deoxyguanosine) and antioxidant defense (total antioxidant capacity [TAC], superoxide dismutase, glutathione peroxidase, and catalase [CAT) were analyzed.

RESULTS

Salivary MDA level in the khat users group (45 ± 9.2 nmol/mL) was significantly increased in comparison with controls (13 ± 2.1 nmol/mL; P < .001), but there were no significant differences between the 2 groups regarding the levels of salivary protein carbonyl and oxidized guanine species. Salivary TAC was significantly reduced in khat users (0.25 ± 0.028 mmol/L) in comparison with controls (0.34 ± 0.037 mmol/L). Salivary CAT level was significantly reduced in khat users (6.0 ± 0.47 U/mL) in comparison with controls (7.7 ± 0.43 units/mL; P <.05), but no significant differences were observed between the 2 groups with regard to salivary superoxide dismutase or glutathione peroxidase levels.

CONCLUSIONS

Chronic khat chewing is associated with increased levels of salivary MDA and reduced levels of TAC and CAT among a population of adult men in comparison with non-khat-chewing controls. These findings suggest that the pro-oxidative effect of khat chewing may be a contributing mechanism for various oral diseases associated with khat use, including cancer, periodontitis, and caries.

Characterization of the Antinociceptive Mechanisms of Khat Extract (Catha edulis) in Mice

This study investigated the antinociceptive mechanisms of khat extract (100, 200, and 400 mg/kg, i.p.) in four pain models: two thermic (hot plate, tail-flick) and two chemical (acetic acid, formalin) models. Male mice were pretreated intraperitoneally (i.p.) with the opioid receptor blocker naloxone (5 mg/kg), the cholinergic antagonist atropine (2 mg/kg), the selective α₁ blocker prazosin (1 mg/kg), the dopamine D₂ antagonist haloperidol (1.5 mg/kg), or the GABA_A receptor antagonist, bicuculline (1 mg/kg) 15 minutes prior to i.p. injection of khat extract (400 mg/kg). Khat extract reduced the nociceptive response of mice in the four pain tests. Naloxone significantly inhibited the antinociceptive effect of khat extract in the hot plate, tail-flick, and the first phase of formalin tests. Bicuculline significantly antagonized the antinociceptive effect of khat extract on the hot plate and tail-flick tests. Haloperidol significantly reversed the antinociceptive effect of khat extract on the tail-flick test and the first phase of formalin test. These results provide strong evidence that the antinociceptive activity of khat extract is mediated via opioidergic, GABAergic, and dopaminergic pathways. The mechanism of the antinociceptive action of khat may be linked to the different types of pain generated in animal models.

Conflicting reports on the role of the glycemic effect of Catha edulis (Khat): A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Traditionally, the leaves of Catha edulis Forsskal (Khat) are consumed by the people of Yemen primarily for its recreational effect, and secondarily, for achieving certain tasks. Additionally, Yemeni diabetics chew such leaves in the belief that this can control their elevated blood glucose level.

AIMS

This review focuses on outlining the findings of studies that have been conducted to display the glycemic effect of Catha edulis, while trying to balance it with findings of the association of its chewing with the development of type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

The search strategy adopted was based on a comprehensive research in Medline, PubMed, Web of Science, JSTOR, Scopus and Cochrane for articles, proceeding abstracts and theses to identify complete reports written in the English language about the glycemic effect of Catha edulis in humans and animals from 1976 to 2016. In addition, bibliographies were also reviewed to find additional reports not otherwise published. Thirty seven records were identified of which, 25 eligible studies were included in the meta-analysis using blood glucose as an outcome measurement. Studies were divided into four subgroups according to the experimental model, namely; non-diabetic animals, diabetic animals, non-diabetic humans and diabetic humans. The pooled mean difference (MD) of blood glucose between experimental and control were calculated using random effects model of the weighted mean difference of blood glucose with 95% confidence interval (CI). Heterogeneity between studies was tested using I(2) statistic and a value of P<0.05 was considered to indicate statistical significance.

RESULTS

The scientific reports in the literature prevailed that the glycemic effect of Catha edulis were greatly conflicting with the majority of studies indicating that Catha edulis has a mild hypoglycemic effect. However, the meta-analysis indicted that the overall result showed an insignificant reduction in blood glucose (MD=-9.70, 95% CI: -22.17 to 2.76, P=0.13, with high heterogeneity between subgroups, I(2)=88.2%, P<0.0001). In addition, pooled mean difference of blood glucose of non-diabetic animals, diabetic animals and non-diabetic humans showed an insignificant reduction in blood glucose (MD=-18.55, 95% CI: -39.55 to 2.50, P<0.08, MD=-52.13%, 95% CI: -108.24 to 3.99, P=0.07 and MD=-2.71%, 95% CI: -19.19 to -13.77, P=0.75) respectively. Conversely, a significant elevation in the pooled mean difference of blood glucose in diabetic humans was indicated (MD=67.18, 95% CI: 36.93-97.43, P<0.0001). The conflict shown in the glycemic effect of Catha edulis is thought to be cultivar-related, while demographic and epidemiological reports suggested that chewing Catha edulis might be a predisposing factor contributing to the development of type 2 DM.

CONCLUSION

It was difficult to draw a meaningful conclusion from both the systematic and the meta-analysis with respect to the glycemic effect of Catha edulis since the meta-analysis results were insignificant with high heterogeneity among subgroups and are greatly conflicting. The variation is most likely due to unadjusted experimental factors or is related to Catha edulis itself, such as the differences in the phytochemical composition. Therefore, it is highly recommended that further studies of the glycemic effect of the cultivar of Catha edulis being studied should come with the identification and quantification of phytochemical content so that a meaningful assessment can be made with regard to its hypoglycemic properties. In addition, well-controlled clinical studies should be conducted to confirm whether or not chewing Catha edulis is associated with the development of type 2 DM, since this would be a source of concern seeing that the plant is widely consumed in certain populations.

Qat Chewing and Risk of Potentially Malignant and Malignant Oral Disorders: A Systematic Review

BACKGROUND

Qat (also known as Khat, Kat and Miraa) is a green-leaved plant (Catha edulis). It is a shrub indigenous to Yemen and certain parts of eastern Africa. Chewing the leaves, which have sympathomimetic and euphoric effects, has been documented in many countries and increased with worldwide migration. The effect of long-term chewing Qat on the oral cavity is unknown.

OBJECTIVE

A systematic review was performed to identify any associations between Qat chewing and the occurrence of potentially malignant and malignant oral disorders.

METHODS

Medline and the Web of Science were searched for articles published before May 2014 without limits with regard to publication date and language.

RESULTS

From a total of 890 papers identified, 17 English papers reported potentially malignant or malignant oral disorders and Qat chewing. One additional paper in Arabic language was identified from reviewing the list of references of eligible papers. It was found that exposure to Qat may be associated with potentially malignant and malignant oral disorders, but methodological issues, such as inadequate study design, sample size, selection of study subjects, clinical evaluations of outcome and limited adjustment for confounders, limit the strength of the evidence base in this area.

CONCLUSION

The association between Qat chewing and potentially malignant and malignant oral disorders remains debatable and requires further investigations.

Before the ban--an exploratory study of a local khat market in East London, U.K

BACKGROUND

Khat is a green leaf with amphetamine-like effects. It is primarily used among people in Africa, the Middle East and in the diaspora communities from these countries. Prior to the prohibition of khat in the UK on 24 June 2014, there was almost no information available on key aspects of the local khat market.

METHODS

A cross-sectional study was conducted in 2012 using snowball sampling, Privileged Access Interviewing and area mapping in order to identify khat sale establishments. Data was collected via face-to-face interviews using mixed methods for data collection. This included information about the establishments selling khat, khat pricing and its use among different ethnic minority groups, in addition to the potential sale of khat to children and risk assessment (e.g., use of pesticides on khat).

RESULTS

Five out of seven sellers identified agreed to participate. Sellers described their khat sale establishments as 'community centres' which included, for example, a restaurant basement. The sellers' history of selling khat ranged between 1-15 years and khat's sale took place between 2pm-10pm. Miraa (e.g., Lara) from Kenya was the most popularly used khat variety, sold in pre-wrapped bundles of approximately 250 g costing £3 each and delivered four days a week. Harari (e.g., Owdi) from Ethiopia was sold in 200 g, 400 g and 1 kg bundles, priced between £5 and £20 and delivered two days a week. The primary benefit of khat use was reported to be social interaction. The customers were predominantly adult males of Somali origin. Most sellers claimed a self-imposed ban on sales to children under 18 years old. Khat bundles had no labelling describing variety or weight and sellers had no knowledge of the use of pesticides on khat and did not advertise the risks associated with khat use.

CONCLUSIONS

Khat selling establishments were businesses that did not adhere to trade standards regulations (e.g., labelling khat bundles). They claimed to provide a community service (facilitating social interaction) to their predominately Somali customers. Without a better understanding of the dynamics of the khat market there is a risk that both health and social needs of the vulnerable populations involved in the market continue to go unaddressed. Future research should track changes in the now illicit khat market in order to evaluate the social and public health implications following the recent changes to the current U.K. regulatory environment regarding khat.

Khat use: history and heart failure

Recent reports suggest that 20 million people worldwide are regularly using khat as a stimulant, even though the habit of chewing khat is known to cause serious health issues. Historical evidence suggests khat use has existed since the 13th century in Ethiopia and the southwestern Arabian regions even before the cultivation and use of coffee. In the past three decades, its availability and use spread all over the world including the United States and Europe. Most of the consumers in the Western world are immigrant groups from Eastern Africa or the Middle East. The global transport and availability of khat has been enhanced by the development of synthetic forms of its active component. The World Health Organization considers khat a drug of abuse since it causes a range of health problems. However, it remains lawful in some countries. Khat use has long been a part of Yemeni culture and is used in virtually every social occasion. The main component of khat is cathinone, which is structurally and functionally similar to amphetamine and cocaine. Several studies have demonstrated that khat chewing has unfavorable cardiovascular effects. The effect on the myocardium could be explained by its effect on the heart rate, blood pressure, its vasomotor effect on the coronary vessels, and its amphetamine-like effects. However, its direct effect on the myocardium needs further elaboration. To date, there are few articles that contribute death among khat chewers to khat-induced heart failure. Further studies are needed to address the risk factors in khat chewers that may explain khat-induced cardiotoxicity, cardiomyopathy, and heart failure.

Why would khat chewers quit? An in-depth, qualitative study on Saudi Khat quitters

Background: Khat chewing, which has many adverse health and social consequences, is highly prevalent and socially accepted in the Jazan region of the Kingdom of Saudi Arabia. Methods: A qualitative study was conducted with 47 adult male former khat users regarding their khat initiation, continuance, and cessation, the amounts of khat they had used, and the health and social consequences of their use and cessation of use. Results: Participants noted a desire to show maturity, ease of availability of khat, and peer pressure as reasons for initiating khat chewing. Many noted long leisure times with little to do as a reason for continuing use. Negative consequences of khat use were seen in economic, health, familial, and sexual areas of their lives. After quitting khat use, participants saw improvements in all of these areas. Conclusions: A comprehensive community development program (CCDP) tackling, among other issues, the normalization of khat use, substantial leisure times with few positive activities, and misinformation about the “benefits” of khat use, as well as developing peer and family training programs to help prevent or stop khat use, would be useful to reduce khat chewing in this community.

Khat chewing and health related quality of life: cross-sectional study in Jazan region, Kingdom of Saudi Arabia

Background

The chewing of Khat leaves, a natural psychoactive substance is widely chewed in countries of East Africa and the southern Arabian Peninsula, and is reported to be associated with a range of unfavorable health outcomes including khat dependence. The impact of Khat chewing on Health Related Quality of Life is yet to be explored. Aims: to measure and compare the quality of life of the khat chewers and non-khat chewers using a short form health survey (SF36), and to assess factors associated with Khat chewing using SF36 in a sample of adult population in Jazan region, Kingdom of Saudi Arabia.

Methods

A total of 630 participants from two independent male populations of khat chewers and non-khat chewers were recruited into a cross-sectional survey study. A self administrative survey based on the SF-36 questionnaire was used to collect data on measures of health-related quality of life (HRQoL). Socioeconomic data of the respondents were also collected for detailed analysis. Data analysis include: descriptive statistics, reliability tests (Cronbach’s alpha and intraclass correlation coefficient), and bivariate analysis (Chi square and Mann–Whitney U-test) to compare HRQoL of Khat chewers and non-Khat chewers.

Results

The odds of being a khat chewer were higher in respondents with a lower socioeconomic status. The SF-36 scores were significantly lower in all domains for respondents with khat chewing, indicating that non-khat chewers had higher health perceptions compared with those chewing khat. The overall mean score of HRQoL for non-khat chewers was 92.7% (SD 5.53) compared with 63.5% (SD 21.73) for the khat chewing group. The study had shown good internal consistency and reproducibility across the eight subscales of SF-36 questionnaire (α 0.74-0.95). The Mann–Whitney U-test showed a significant difference between khat chewers and non-khat chewers (P < 0.001).

Conclusions

This study measured and compared the quality of life of khat chewers and non-khat chewers using a generic health survey (SF36). The study had shown that khat chewing is associated with lower quality of life (HRQoL) and lower socioeconomic status. However in future a more refined SF36 developed especially for Khat chewers can provide more useful information.

Khat (Catha edulis): A systematic review of evidence and literature pertaining to its harms to UK users and society

The use of khat ( Catha edulis) has been associated with a large number of physiological and societal harms, leading to calls for it to be controlled in the UK. The evidence of these harms is often equivocal, limited by confounding factors, or entirely anecdotal: high-powered, quality-controlled studies are lacking. Regardless, the body of relevant literature indicates that the once socially-regulated use of khat has been eroded. Some individuals have developed excessive consumption patterns, either using khat daily or in binge-sessions, though daily consumption is not necessarily problematic per se. The majority of users seem to use khat in moderation, where the associated harms appear low. For excessive users, harms associated with khat are greater, particularly relating to mental health. Social harms also seem to be largely related to excessive khat use rather than khat use itself. Even in cases of excessive khat use, however, causal relationships between chewing and harms have not been described. More research is required to establish the role of khat in liver disease, coronary problems, cancers of the digestive tract and incidents of domestic violence. Studies should consider the likeliness that certain users are more vulnerable to developing patterns of excessive khat use due to an interwoven set of factors such as social health determinants and pre- and post-migration experiences.

Cardiovascular complications of Khat

This article reviews current knowledge in khat (cathinone) research and its health impacts and toxicity in the cardiac system of khat chewers based on current evidence. The authors describe the process by which khat is postulated to induce multiple cardiac abnormalities by illustrating multiple case reports as described from around the world. The role of free radicals in inducing cardiac disease is also discussed. Future research areas are proposed to enhance our understanding of the mode of action of this toxicological drug.

Toxicological Features of Catha edulis (Khat) on Livers and Kidneys of Male and Female Sprague-Dawley Rats: A Subchronic Study

Hepato- and nephrotoxicity of Khat consumption (Catha edulis Forskal) have been evoked. Therefore, this study was conducted to evaluate such possible hepatorenal toxicity in female and male Sprague-Dawley rats (SD rats) focusing primarily on liver and kidney. In addition, female and male rats were investigated separately. Accordingly, forty-eight SD-rats (100–120 g) were distributed randomly into four groups of males and female (n = 12). Normal controls (NCs) received distilled water, whereas test groups received 500 mg/kg (low dose (LD)), 1000 mg/kg (medium dose (MD)), or 2000 mg/kg (high dose (HD)) of crude extract of Catha edulis orally for 4 weeks. Then, physical, biochemical, hematological, and histological parameters were analyzed. Results in Khat-fed rats showed hepatic enlargement, abnormal findings in serum aspartate aminotransferase (AST), and alkaline phosphatase (ALP) of male and female SD-rats and serum albumin (A) and serum creatinine (Cr) of female as compared to controls. In addition, histopathological abnormalities confirmed hepatic and renal toxicities of Khat that were related to heavy Khat consumption. In summary, Khat could be associated with hepatic hypertrophy and hepatotoxicity in male and female SD-rats and nephrotoxicity only in female SD-rats.

Khat a drug of abuse: roles of free radicals and antioxidants

Many articles have reviewed the health impact of Khat consumption; however the role of free radicals in the pathogenesis associated with short- and long-term consumption of Khat is absent in the literature. As free radicals and antioxidants converge across various mechanisms in normal physiological function and in disease, this review attempts to uncover the role of endogenous free radicals and the mechanism of cellular injury associated with Khat consumption.