Catha edulis Forsk (khat) reduces spontaneous and rewarded alternation in female mice.

Around 10 million people chew the fresh leaves and twigs of Catha edulis Forsk (khat), which synthesize cathinone, for its psychostimulatory effect. Several studies have reported that regular khat users show executive and cognitive dysfunction, such as impaired inhibitory control and poor performance on memory tests. In this study, the effect of fresh khat extract (100 and 250 mg/kg) on spatial working memory and short-term memory in mice was assessed using spontaneous and rewarded alternation T-maze tests. In the spontaneous alternation test, mice treated with fresh khat extract decreased their spontaneous alternation level to around chance level, and it remained at this level over the 7 days of khat administration and testing. On testing after a 7-day khat free period, the previously khat treated mice showed alternation level above chance but below their pre-khat alternation level. In the rewarded alternation test, acute treatment with khat caused the mice to alternate well below chance level, and then over the next 3 days of khat treatment, the alternation level increased. After a 2 and 9-day khat-free period, the previously khat treated mice alternated above chance level but below their pre-khat level. In both these tests, the mice did not show any position preference before khat treatment; however, during the khat treatment, the mice showed a right side tendency. The results show that khat treatment causes persistent changes in alternation behavior and promotes perseverative behavior, presumably due to its effect on the neural circuits activity and the neurotransmitters and promotion of position preference.

Khat (Catha edulis Forsk) - And now there are three.

For centuries, a large number of people living in the southwestern part of the Arabian Peninsula and eastern Africa have chewed the fresh leaves and twigs of the plant Catha edulis Forsk, more commonly known as khat, for its psychostimulatory effect. The main active compound in khat is cathinone, whose synthetic derivatives form a part of the new psychoactive substances list. This review summaries the prevalence of khat use, its harvesting and consumption, the biosynthetic pathway in khat, the mechanism of action, the results from animal and human studies, and its dependence potential. It is unlikely that khat use will be prohibited in countries where it is traditionally consumed and socially acceptable unlike in other countries of the world where both the importation and the consumption of khat and cathinone is banned. Khat users being mainly Muslims prohibited from using alcohol or other drugs probably represent the largest global number of mono-drug users of an amphetamine-like stimulant. Thus, khat use represents a unique situation and a neglected area of research in Africa.

Effect of moderate-intensity exercise bouts lasting <10 minutes on body composition in sedentary Kenyan adults aged ≥50 years.

BACKGROUND: Sedentary lifestyles and related morbidities are rising among adults despite existing exercise recommendations. Appealing exercise regimes yielding similar/better body composition should be sought. OBJECTIVE: We investigated the effect of moderate-intensity exercise bouts of <10 min on body composition in previously sedentary adults. METHODS: This unblinded study enrolled 53 healthy sedentary volunteers aged ≥50 years, randomised into one of two gender-balanced exercise interventions: (1) male and (2) female short-duration bouts (MS, n=14; FS, n = 13), and (3) male and (4) female long-duration bouts (ML, n=13; FL, n=13). Short-duration bouts entailed 5-10 min of jogging thrice daily; long-duration bouts, 30-60 min 3-5 days weekly. Body composition was determined at recruitment and 8-weekly thereafter, for 24 weeks. RESULTS: At baseline, 14.3% of MS, 38.5% of ML, 92.3% of FS and 69.2% of FL were obese, dropping to 7.1%, 15.4%, 61.5% and 30.8%, respectively. For waist:height ratio, 64.3 % of MS, 76.9% of ML, 100% of FS and 84.6.3% of FL had ratios >0.5, dropping to 42.9%, 30.8%, 92.9% and 26.2%, respectively. While baseline MS and ML waist:hip ratio (WHR) ≥0.9 were 64.3% and 69.2%, respectively, they correspondingly dropped to 23.1% and 21.4%. The FS and FL with WHR ≥0.85 dropped from 46.2% to 15.4% and from 30.8% to 7.7%, respectively. Body composition variables improved for both sexes (all p <0.05) and mean change between exercise regimes was comparable for both sexes. CONCLUSION: In equal cumulative times, moderate-intensity exercise bouts lasting <10 min are comparable with current 30-60 min bouts in body composition modification for adults of ≥50 years.

Effect of short and long moderate-intensity exercises in modifying cardiometabolic markers in sedentary Kenyans aged 50 years and above.

OBJECTIVES: We compared effects of shorter moderate-intensity exercise time (<10 min bouts) on cardiometabolic parameters with the current recommendations among elderly adults. METHODS: Fifty-three sedentary individuals aged ≥50 years were divided into exercise groups1: male and2 female short-duration bouts (MS and FS, respectively), and3 male and4 female long-duration bouts (ML and FL, respectively). Short-duration bouts consisted three 5-10 min moderate-intensity jogging sessions daily, and long-duration bouts consisted 30-60 min sessions 3-5 days weekly. Cumulative exercise times were equivalent. Physical activity (PA) was measured by log and activity monitors. Fasting venous blood at baseline and 8 weekly intervals was used for blood chemistry. RESULTS: After 24 weeks, MS and FS with total cholesterol (TC) of >5.2 mmol/L and >5.3 mmol/L decreased from 22.2% to 14.8% and from 30.9% to 11.5%, respectively. For ML, this decreased from 25.9% to 3.7%, while FL had 0% change. In MS and ML, TC/high-density lipoproteins (HDLs) of >5.0 mmol/L dropped from 22.2% to 7.4% and from 22.2% to 15.4%, respectively. In FS and FL, TC/HDL of >4.5 mmol/L declined from 19.2% to 7.7% and from 19.2% to 3.8%, respectively. MS and ML with fasting blood glucose of ≥5.5 mmol/L declined from 40.7% to 11.1% and from 33.3% to 3.7%, respectively. Similarly, it declined from 46.2% to 0% and 42.3% to 11.5% for FS and FL, respectively. There were no differences in the changes between regimes throughout the study. CONCLUSION: Bouts lasting <10 min per session are as good as those lasting;≥30 min in improving cardiometabolic profiles of sedentary adults aged ≥50 years.

"Natural Amphetamine" Khat: A Cultural Tradition or a Drug of Abuse?

Khat, Catha edulis Forsk, is among the most widely used plant-based psychoactive substance in the world. Grown in Eastern Africa, Horn of Africa, and southwestern part of the Arabian Peninsula, its fresh young leaves and twigs are used daily by over 20 million people for the psychostimulatory effects it produces in the user, a practice deeply rooted in the history, tradition, and culture of the indigenous population. Once hardly known outside the regions where it is grown and used, khat use has now spread to other countries. This review will cover the, phytochemistry, pharmacokinetics of the active ingredients-cathinone, cathine, norephedrine, neurochemistry, effects on cognitive and executive functions as well as its ability to produce dependency in the user. Whether it is an innocuous cultural practice or a drug of abuse is debatable as the preclinical and clinical data needed to arrive at an authoritative conclusion is lacking.

Role of Grooming in Reducing Tick Load in Wild Baboons (Papio cynocephalus).

Nonhuman primate species spend a conspicuous amount of time grooming during social interactions, a behavior that probably serves both social and health-related functions. While the social implications of grooming have been relatively well studied, less attention has been paid to the health benefits, especially the removal of ectoparasites, which may act as vectors in disease transmission. In this study, we examined the relationship between grooming behavior, tick load (number of ticks), and haemoprotozoan infection status in a population of wild free-ranging baboons (Papio cynocephalus). We found that the amount of grooming received was influenced by an individual's age, sex and dominance rank. The amount of grooming received, in turn, affected the tick load of an individual. Baboons with higher tick loads had lower packed red cell volume (PCV or haematocrit), one general measure of health status. We detected a tick-borne haemoprotozoan, Babesia microti, but its low prevalence in the population precluded identifying sources of variance in infection.

A comparative study to screen dementia and APOE genotypes in an ageing East African population.

Previous studies have established cross-cultural methods to screen for ageing- related dementia and susceptibility genes, in particular Alzheimer's disease (AD) among the Canadian Cree, African Americans and Yoruba in Nigeria. We determined whether the Community Screening Interview for Dementia (CSID), translated into Kikuyu, a major language of Kenya, could be used to evaluate dementia of the Alzheimer type. Using two sets of coefficients of cognitive and informant scores, two discriminant function (DF) scores were calculated for each of 100 elderly (>65 years) Nyeri Kenyans. When the cut-off points were selected for 100% sensitivities, the specificities of the DF scores were remarkably similar (93.75%) in the Kenyan sample. We propose the adapted CSID can be utilised to detect dementia among East Africans. We also show that apolipoprotein E epsilon 4 allele frequencies were high (approximately 30%) and not different between normal subjects and those with probable AD. There was no evidence to suggest years of education or vascular factors were associated with dementia status.

Proconvulsant effect of khat (Catha edulis) in Sprague dawley rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Catha edulis (khat) is a plant whose fresh young leaves are used by an estimated five million people in eastern Africa and the Arabian Peninsula as a drug of recreation. The fresh leaves and shoots are rich in cathinone, a psychostimulant with effects similar to those of amphetamines. Psychostimulants produce a dose-related excitation of the central nervous system which can lead to seizures and convulsions. However there are no reports on studies of the effect of this herb on brain excitability and seizures. This knowledge is useful for doctors who may prescribe drugs whose side effects include lowering seizure threshold because there could be additive proconvulsant effect among khat users. AIM OF THE STUDY: to determined whether khat lowers pentylenetetrazole (PTZ) seizure threshold. METHODOLOGY: Male Sprague dawley rats were given fresh aqueous khat extract, old aqueous khat extract (3 g/kg bw), methylphenidate or saline and the timed intravenous (PTZ) seizure threshold test was used to study its effect on seizure threshold. RESULTS: Fresh khat (3 g/kg) and methylphenidate (4 mg/kg) lowered PTZ seizure threshold. CONCLUSION: Khat lowers seizure threshold.

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

Isolated mouse interstitial cells were incubated with different concentrations of khat (Catha edulis) extract (0.06 mg/ml, 0.6 mg/ml, 6 mg/ml, 30 mg/ml and 60 mg/ml) and cell viability as well as testosterone concentration measured at 30 min intervals over a 3h incubation period. High concentrations of khat extract (30 mg/ml and 60 mg/ml) significantly inhibited testosterone production while low concentrations (0.06 mg/ml, 0.6 mg/ml and 6 mg/ml) significantly stimulated (P<0.05) testosterone production by mouse interstitial cells. Similarly, at concentrations of 30 mg/ml and 60 mg/ml, there was a significant decrease in interstitial cell viability, whereas at 0.06 mg/ml, 0.6 mg/ml and 6 mg/ml there was no significant decrease. There was only a weak correlation (r=0.39) between testosterone production and viable interstitial cells. We postulate that khat extract at high concentrations may cause reproductive function impairment in the user but at low concentrations, may enhance testosterone production with accompanying effects on reproductive functions in male mice.