In vitro study of the effects of khat (Catha edulis Forsk) extract on isolated mouse interstitial cells

Khat, a Cultural Chewing Drug: A Toxicokinetic and Toxicodynamic Summary

Khat (Catha edulis) is a recreational, chewed herbal drug that has been used as a psychostimulant for centuries in East Africa and the Arabian Peninsula, namely in Somalia, Ethiopia, and Yemen. However, the growing worldwide availability of khat has produced widespread concern. The plant comprises a large number of active substances, among which cathinone, cathine, and norephedrine are the main constituents, which can be included in the group of sympathomimetics of natural origin. In fact, these compounds are amphetamine analogues, and, as such, they have amphetamine-like nervous system stimulant effects. Chewing the leaves gives people a sensation of well-being and increases energy, alertness, and self-confidence. The chronic use of khat is, however, associated with severe cardiac, neurological, psychological, and gastrointestinal complications. The psychological dependence and withdrawal symptoms of khat are the reasons for its prolonged use. The aim of this paper is to review current knowledge on the khat plant with toxicokinetic and toxicodynamic perspectives. Namely, this review paper addresses in vitro, in vivo, and human studies. The models used, as well as the concentrations and doses with the respective biological effects, are discussed. Additionally, the main drug interactions involved with khat are described.

Khat (Catha Edulis Forsk) induced apoptosis and cytotoxicity in cultured cells: A scoping review

Background

Khat (Catha edulis Forsk) leaves are chewed by people in certain regions of East Africa and the Middle East for their stimulating amphetamine-like effects. The purpose of this scoping review is to systematically map the current in vitro publications that investigated the toxicological potential effects of khat on cultured human or animal cells in terms of cellular viability and activity.

Methods

A comprehensive electronic database search was undertaken up to December 2020 without starting date or language restrictions in accordance with the PRISMA extension for scoping review guideline and methodological quality evaluation based on the guidelines for reporting pre-clinical in vitro studies on dental materials. All in vitro studies that investigated the effect of khat plant extract (Catha Edulis) on the cultured human or animal cells were included.

Results

The initial search yielded 599 articles and 16 articles were finally selected to be included. The treatment of cells with khat produced different degrees of cellular changes, including decreased cellular survival, induction of apoptosis, increased ROS production, alteration of cell phenotype, and of arrest cell cycle. In this contest, khat-exposed cells expressed higher levels of pro-apoptotic protein Bax and lower levels of anti-apoptotic Bcl-2, up-regulated p38, p53, p16, and p21 proteins, as well as premature expression of differentiation markers.

Conclusion

Based on the current scoping review, khat induced apoptosis and cytotoxicity in cultured human cells, including oral cells.

Gonadal and Cortisol Hormone Profile among Male Chronic Khat, Marijuana, and Heroin Abuses

BACKGROUND

Drugs of abuse could interfere with the hypothalamic-pituitary-gonadal axis, causing impaired functions of the gland and associated functions of target organs. Drugs of abuse tend to cause changes in the endocrine system, and these changes could be physiological, molecular, biochemical, genetic, and cellular.

METHOD

A case-control study design was conducted from a total of 171 male consented study participants (148 drug abusers and 23 controls). The serum gonadal and cortisol hormone levels were assayed using the electrochemiluminescence immunoassay method. Socio-demographic variables were collected using a semi-structured questionnaire by the interview method. Nonparametric statistical tools (Mann-Whitney test and median) were used to compare the groups. In all cases, P < 0.05 was considered statistically significant.

RESULT

The median age for drug abusers and control groups was 27, and the age difference between drug abusers and control group was not statistically important. The median estradiol levels among chronic khat chewers (39.4 pg/ml), marijuana (44 pg/mL), and users of heroin (40.2 pg/mL) were significantly higher than control groups (23 pg/mL), P < 0.003. However, the median luteinizing hormone levels among chronic khat chewers (5 IU/L), marijuana users (5 IU/L), and heroin users (5.6 IU/L) were significantly lower than those of control groups (6.2 IU/L), P < 0.02. The median testosterone levels among chronic khat chewers (6.1 ng/mL), marijuana users (6.3 ng/mL), and heroin users (6.6 ng/mL) were significantly lower than control groups (8.0 ng/mL), P < 0.003. However, cortisol and follicle stimulating hormone did not show statistically significant difference between users of khat, marijuana, and heroin compared with the control group.

CONCLUSION

The drug abuser group had significantly lower testosterone and luteinizing hormone levels compared with control groups. Drug abuse has been shown to affect gonadal hormones in an unusual physiological phenomenon. These findings reveal the need for intervention programs to solve these problems.

Immunohistochemical localization of anterior pituitary cell types of vervet monkey (Chlorocebus aethiops) following sub-chronic cathinone exposure

ETHNOPHARMACOLOGICAL RELEVANCE

Khat (Catha edulis) contains cathinone, an active principal that is customarily used as a psychostimulant that wards off fatigue and to some extent used as an aphrodisiac.

AIM OF STUDY

To investigate effects of escalating doses of cathinone on hormone expression by different anterior pituitary cell types using specific antibodies.

MATERIAL AND METHODS

Eleven vervet monkeys (6 males and 5 females) divided into tests (n=9) and controls (n=2) were used. Animals were allocated as group I (saline controls), group II (0.8 mg/kg), group III (3.2 mg/kg) and group IV (6.4 mg/kg) of cathinone. All treatments were via oral route at alternate days of each week. At the end of 4-month treatment phase, GnRH agonist (ZOLADEX) was administered to group II (low dose) and group IV (high dose) alongside cathinone for 2 additional weeks.

RESULTS

High cathinone dose at long-term exposure caused proliferation of gonadotrophs but decrease in lactotrophs and corticotrophs in anterior pituitary sections of animals while effect of low dose on these cells was insignificant. Subsequent GnRH agonist co-treatment with low and high cathinone doses enhanced gonadotroph proliferation but no change on decline of lactotrophs and corticotrophs.

CONCLUSION

We believe that there was a possible potentiation of cathinone on pituitary hormone synthesis thereby influencing reproductive function. Suppression of corticotrophic and lactotrophic functions suggest lowering of stress levels and modulation of reproductive function based on dose level and chronicity of exposure. The findings are consistent with the hypothesis that cathinone interferes with pituitary cell integrity and consequently target organs, but further studies are required to address the precise mechanism underlying this phenomenon.

Short-term effects of high-dose khat on sperm parameters and reproductive hormonal levels in olive baboons (Papio anubis)

The biological effects of khat (Catha edulis) on reproduction and fertility are inadequately investigated and controversial, hence we determined the effects of oral administration of high-dose khat on sperm parameters and male hormonal levels in olive baboons. In this study, 6 male baboons received a high dose of khat (500 g/week) during 1 month. Electroejaculation for sperm studies (concentration, motility and chromatin integrity) and plasma collection for hormonal analysis (testosterone, prolactin and cortisol) were done weekly during 1 month before and 1 month during khat administration as well as 2 weeks after the last dose of khat administration. Administration of khat extract induced a significant reduction in sperm motility (p = 0.008), sperm count (p = 0.041), sperm chromatin integrity (p = 0.0003), testosterone levels (p = 0.035) and prolactin levels (p = 0.0115), but not in cortisol levels and sperm volume (p > 0.05). The results suggest that high-dose khat decreases sperm quality and testosterone and hence may contribute to male infertility.

Khat (Catha edulis) alters the phenotype and anti-microbial activity of peripheral blood mononuclear cells

AIMS OF STUDY

The habit of khat chewing has been associated with increased risk of systemic and oral disease. Although research has been conducted on the affects of khat on oral epithelial cells, little is known about its influence on immune cells. This study examined the biological effects of khat on the phenotype and function of peripheral blood mononuclear cells (PBMCs).

MATERIAL AND METHODS

Khat-stimulated PBMCs were examined for signs of cytotoxicity, apoptosis and changes in cell surface receptor and cytokine expression. Khat-induced regulation of transcription factors and stress-related factors were examined, as was PBMC phagocytic activity against oral bacteria.

RESULTS

Khat was cytotoxic to PBMC in a dose- and time-dependent manner and cell death was mediated by apoptosis. Khat-treated PBMC showed increased expression of co-stimulatory molecules (CD80, CD86 and MHC II) and pattern recognition receptors (TLR-2, TLR-4 and TREM-1) but secretion of inflammatory cytokines (TNFα, IL-6, CCL5, CXCL8) was inhibited. In contrast, khat induced an increase in the anti-inflammatory cytokine IL-10 as well as IL-2, IFN-γ, FasL and HSP70. These khat-induced alterations were accompanied by increased expression of transcription factors p38 MAPK and HIF-1α, whilst expression of NFκB p65 was inhibited. Although the ability of PBMC to phagocytose dextran and oral bacteria was inhibited, production of reactive oxygen species was increased.

CONCLUSION

These data suggest that khat may severely influence the effectiveness of immune surveillance and anti-microbial capacity of PBMCs.

Reproductive parameters are differentially altered following subchronic administration of Catha edulis F. (Khat) extract and cathinone in male rats

AIMS OF THE STUDY

Controversy surrounds on the effect of khat, a widely chewed herb for its stimulant effect on sexuality. This study investigated the effect of fresh Catha edulis F. (Khat) extract, synthetic cathinone and vehicle on reproductive parameters, including sexual motivation and performance, serum testosterone and cortisol levels, epididymal sperm count, and histoarchitecture of testis in male rats.

OBJECTIVE

This study investigated the effect of fresh Catha edulis Forsk (Khat, Celastraceae) extract, synthetic cathinone and vehicle on reproductive parameters, including sexual motivation and performance, serum testosterone and cortisol levels, epididymal sperm count, and histoarchitecture of testis in male rats.

MATERIALS AND METHODS

Rats were treated with either Tween 80 (3%, v/v) in water, khat extract (100mg/kg, K100; 200mg/kg, K200; and 300mg/kg, K300 doses) or cathinone (5mg/kg, CAT5) intragastrically for four weeks and subjected to a battery of behavioral tests. Three days following the last administration, blood was drawn for hormonal analysis and the animals were sacrificed for sperm count and morphologic-pathology studies.

RESULTS

K100 significantly decreased mount latency (ML) (p<0.05) and intromission latency (IL) (p<0.01) compared to controls. K200 whilst significantly reduced IL (p<0.01) and intromission frequency (IF) (p<0.01), increased postejaculatory latency (PEL) (p<0.01). K300 significantly reduced IF (p<0.01) and ejaculatory latency (EL) (p<0.01), but increased mount frequency (MF), IL, PEL, and ML (p<0.01, in all cases). With CAT5, MF (p<0.05) and IL (p<0.01) were significantly greater but EL and IF were lower (p<0.05, in both cases) than controls. Serum levels of testosterone were doubled in K100 (p<0.01), but a significant decrease was recorded in both K200 (18%, p<0.01) and K300 (50%, p<0.01) rats. Whereas K100 did not have any effect on cortisol levels, K200 and K300 significantly increased by 83% (p<0.05) and 164.5% (p<0.01), respectively. CAT5 affected neither serum testosterone nor cortisol levels. Khat extract demonstrated a dose-dependent decline in epididymal sperm count: 50% with K100 (p<0.05), 78% with K200 (p<0.01) and 89% with K300 (p<0.01). CAT5 did not, however, produce any significant change in sperm count. Khat extract and cathinone did not produce any discernible damage on testis.

CONCLUSION

Mild dose of khat improves sexual motivation, without much effect on performance. With increasing dose, however, both motivation and performance are reduced. Although testosterone levels correlated well with motivation, there was dissociation with sperm count, indicating optimum level might be required for normal spermatogenesis.

East African discourses on khat and sex

AIM OF THE STUDY

The study aims to review and analyse the varied East African discourses on the effects of khat use on libido, fertility, transmission of HIV, prostitution and rape.

MATERIALS AND METHODS

The data were gathered between 2004 and 2009 in Kenya and Uganda. Between 2004 and 2005 across Kenya and Uganda a broad survey approach was adopted, involving identification of and travel to production areas, interviews with producers and consumers in rural and urban settings. In addition, a survey of 300 Ugandan consumers was carried out in late 2004. Between 2007 and 2009, an in-depth study of khat production, trade and consumption was conducted in Uganda. This study also employed a mixture of methods, including key informant interviews participant-observation and a questionnaire survey administered to 210 khat consumers.

RESULTS

Khat is associated, by consumers and its detractors alike, with changes in libido and sexual performance. Although there is no evidence to support their claims, detractors of khat use argue that khat causes sexual violence, causes women to enter sex work, and that chewing causes the spread of sexually transmitted diseases, including the HIV virus.

CONCLUSIONS

In East Africa the discourse on khat and sex has led to consumption of the substances being associated by many people with uncontrolled sexual behaviour. There is no evidence that khat use fuels promiscuity, commercial sex, sexually transmitted diseases or rape. The current discourse on khat and sex touches on all these topics. Local religious and political leaders invoke khat use as a cause of what they argue is a breakdown of morals and social order. In Kenya and Uganda it is women khat consumers who are seen as sexually uncontrolled. In Uganda, the argument is extended even to men: with male khat chewers labelled as prone to commit rape.

Extraction and microencapsulation of khat: effects on sexual motivation and estradiol level in female rats

INTRODUCTION

Khat (Catha edulis) is an evergreen tree/shrub that is thought to affect sexual motivation or libido. Its positive effect on sexual desire is more frequently observed in females than in males and occurs when khat is chewed. Thus, khat's effects on sexual behavior may depend on the release mode of its active constituent.

AIM

This study aimed to investigate the effect of dried khat alkaloids on the sexual motivation and estradiol levels of female rats, with special emphasis on the importance of the sustained release effect.

METHODS

Dried khat leaves were extracted and isolated. The alkaloids in khat extract were identified and calculated using thin layer chromatography and high-performance liquid chromatography. The isolated khat extract was microencapsulated using a phase separation coacervation method. The morphology, particle size, yield, drug loading, and entrapment efficiency were evaluated. The in vitro release and stability of alkaloids in khat extract and in khat extract microcapsules were determined. The effect of khat extract microcapsules and varying doses of khat extract on sexual motivation in female rats were investigated. Additionally, estradiol levels, vaginal secretions and vaginal pH were determined.

MAIN OUTCOME MEASURES

The differences in the effect of khat extract and khat extract microcapsules on sexual motivation, vaginal secretion and estradiol levels in female rats were compared. Results. Cathine and norephedrine were identified in the isolated khat extract at composition of 81.3% and 17.2%, respectively. Among the formulations studied, khat extract microcapsules of formulation 2:3:5 (containing a ratio of khat extract to ovalbumin to gelatin of 2:3:5) were found to exhibit higher yield, loading, and entrapment efficiency. Khat extract microcapsules showed sustained in vitro release and were more stable than khat extract. In addition, khat extract microcapsules enhanced sexual motivation, increased vaginal secretions, and upregulated estradiol level in female rats.

CONCLUSION

The sustained release of alkaloids from dried khat has significantly enhanced the sexual motivation and increased the estradiol level of female rats. Thus the release of dried khat alkaloids from microcapsules might be an effective means of enhancing the libido in females.

Effect of finasteride treatment on suburethral prostatic microvessel density in patients with hematuria related to benign prostate hyperplasia

INTRODUCTION

In the present study we evaluated the effect of short-term finasteride treatment on microvessel density (MVD) which is an indicator of prostatic angiogenesis in patients with hematuria secondary to benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

30 patients who were candidates for BPH surgery were prospectively included in the study. All patients had history of gross hematuria and evaluated by ultrasonography and cystoscopy. The patients were randomized two groups before surgery. The treatment group consisted of 13 patients who were given 5 mg finasteride daily for 4 weeks before surgery. The control group consisted of 17 patients who did not receive finasteride before surgery. During surgery, resected suburethral and hyperplastic prostate specimens were sent for histopathologic MVD determination separately.

RESULTS

Mean MVD in the suburethral portion of prostate was significantly lower in patients treated with finasteride when compared with controls (9.08 +/- 5.6 and 13.94 +/- 5.90, respectively, p < 0.05). Mean MVD for the hyperplastic portion of prostate was similar for the finasteride and control groups (14.21 +/- 7.10 and 19.75 +/- 9.73, respectively, p > 0.05).

CONCLUSION

The potential role of finasteride on hematuria related to BPH may be the suppressive effect on MVD in the suburethral tissue of prostate.

Khat (Catha edulis) lowers plasma luteinizing hormone (LH) and testosterone secretion, but increases cortisol levels in male rabbits

AIM

This study investigated the effects of fresh khat extract on specific circulating hormones in male rabbits.

MATERIALS AND METHODS

A total of 25 male New Zealand White rabbits were divided into five groups each comprising five animals. The first four groups were fed four doses (1.5 g/kg, 4.5 g/kg, 13.5 g/kg and 40.5 g/kg body weight) of khat extract twice a week for 5 weeks while the last group, serving as control, was fed only normal saline via intragastric tube. Blood samples were collected at 15 min interval for up to 3 h after khat extract administration and plasma assayed for luteinizing hormone (LH), testosterone and cortisol levels using radioimmunoassay technique.

RESULTS

Khat extract at all doses significantly lowered (P<0.05) LH pulse frequency, area under LH curve, mean plasma LH and mean plasma testosterone levels. Plasma cortisol levels were significantly elevated (P<0.05) in khat-treated rabbits in a dose-dependent manner.

CONCLUSION

This study demonstrates that khat may impair reproductive function in male rabbits by interfering with sex hormone profiles.