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

Progress and Research Trends on Catha edulis (Vahl) Endl. (Catha edulis): A Review and Bibliometric Analysis

Catha edulis (Vahl) Endl., known as Catha edulis or Khat is a traditional and regional plant for chewing, smoking and drinking, that has posed a worldwide public health problem due to its recent emerging abused consumption. In the face of the massive use of Catha edulis, we reviewed related publications to analyze the progress and research trends through bibliometric methods. After screening, a total of 514 scientific publications published from 1997 to 2020 were included by systematic retrieval from the Web of Science (WoS) database. According to further scientometric analysis, the annual number of publications output kept rising in most of the years. Ethiopia and the United States of America (USA) have been devoting significant contributions to the field. Though the research emphasis had been the chemical composition and pharmacological and toxicological effects for several years, the hot spots were transferred; the mechanism investigations of Catha edulis have been the focus in recent years, which might be continued in the future. Furthermore, co-operations of multi-disciplinary researchers are needed to minimize abuse harms and maximize the medicinal benefits of Catha edulis to human beings.

Qualitative ultrastructural analysis of the submandibular salivary glands after administration of khat: in vivo study

Objective

Khat (Catha edulis Forssk) plant has been widely chewed for its psychostimulatory effects in the African and Arabian Peninsula, particularly in Yemen. Considering the khat leaves are gradually chewed without swallowing, while its active constituents are extracted into saliva, studying the effect of khat on salivary glands is necessary. This work is an extension of the previously published work that studied the effect of khat extract on the rats' submandibular salivary glands in terms of histological and immunohistochemical evaluations. The current research note aimed to better understand this effect on the ultrastructure of submandibular salivary gland cells by using transmission electron microscope.

Results

Oral administration of khat extract produced degenerative changes in the secretory and ductal cells of rats' submandibular salivary glands. These changes involved irregular boundaries of variable sized-nuclei, dilated RER, cytoplasmic vacuoles as well as swollen and degenerated mitochondria.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05595-8.

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.

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.

Dose-response inhibitory effects of purified cathinone from khat (Catha edulis) on cortisol and prolactin release in vervet monkeys (Chlorocebus aethiops)

This study reports acute and sub-chronic effects of cathinone on hormonal alterations in single-caged vervet monkeys. Fourteen adult vervet monkeys were used, 12 of which were treated and 2 controls. Pre-treatment phase of 1 month aimed at establishing baseline levels of hormones while treatment phase of 4 months considered the dose- and time-response effects of cathinone on serum cortisol and prolactin levels. Test animals were allocated four groups of three animals each and administered 0.8, 1.6, 3.2 and 6.4 mg/kg body weight of cathinone orally while controls were administered normal saline. Treatment was done at alternate days of each week. Serum prolactin and cortisol immunoassays were done. Hormonal data was analysed by repeated measures ANCOVA. Results indicate a dose [F (4, 8) = 218, P < 0.001] and time [F (18, 142) = 21.7, P < 0.001] dependent effect of cathinone on cortisol levels with a significant dose by week interaction [F (71, 142) = 4.86, P < 0.001]. Similarly, there was a decrease in serum prolactin [F (4, 8) = 267, P < 0.001] with escalating doses of cathinone with a significant dose x week interaction [F (59, 118) = 13.03, P < 0.001]. The findings demonstrate that at high doses and long-term exposure, cathinone causes hormonal alterations probably via changes in hypothalamo-hypophyseo-adrenocortical and gonadal axes integrity.

Khat use among HIV voluntary counselling and testing centre clients in Ethiopia

Khat (Catha edulis, a natural stimulant), has been used in Ethiopia for centuries. Over the past few decades, however, its use has dramatically increased, with recent research linking khat use to HIV status. Using qualitative methods, we explored the individual and micro-environmental characteristics of khat use and the social and physical contexts influencing type, acceptability and consequences of khat use. Among khat chewers attending an HIV voluntary counselling and testing centre in Addis Ababa, Ethiopia, we found that chewing typically starts at an early age (15-18 years). The majority of users are young (aged 18-35) and chew for pleasure, primarily in social settings. Over 25 types of khat, with varying effects were reported. Approximately half of the participants perceived khat to enhance sexual desire, while the rest claimed the effect on sexual desire to be the opposite. Alcohol use among chewers was high. Our findings suggest the need for culturally appropriate interventions that highlight the factors associated with khat use and the potential interplay between khat, alcohol and risky sexual behaviour.

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.

Khat chewing, cardiovascular diseases and other internal medical problems: the current situation and directions for future research

The leaves of khat (Catha edulis Forsk.) are chewed as a social habit for the central stimulant action of their cathinone content. This review summarizes the prevalence of the habit worldwide, the actions, uses, constituents and adverse health effects of khat chewing. There is growing concern about the health hazards of chronic khat chewing and this review concentrates on the adverse effects on health in the peripheral systems of the body, including the cardiovascular system and gastrointestinal tract. Comparisons are made with amphetamine and ecstasy in particular on the detrimental effects on the cardiovascular system. The underlying mechanisms of action of khat and its main constituent, cathinone, on the cardiovascular system are discussed. Links have been proposed between khat chewing and the incidence of myocardial infarction, dilated cardiomyopathy, vascular disease such as hypertension, cerebrovascular ischaemia and thromboembolism, diabetes, sexual dysfunction, duodenal ulcer and hepatitis. The evidence, however, is often based on limited numbers of case reports and only few prospective controlled studies have been undertaken. There is therefore an urgent need for more thorough case-control studies to be performed. This review outlines the current knowledge on the adverse health effects of khat chewing on the cardiovascular system and other internal medical problems, it assesses the evidence and the limitations of the studies and identifies the questions that future studies should address.