Substance use and substance use disorders in Africa: An epidemiological approach to the review of existing literature.

The relationship between man and substances that have abuse potentials, and whose use has been associated with the development or progression of substance use disorders has continued to evolve in terms of geography, economic implications, and time. History shows that local plants with psychoactive constituents can get exported worldwide through global travel, commerce, or even conquest. Time and globalization also change people's relationship with substances of abuse; hence, an area that was initially alien to certain substances might evolve to becoming a trafficking hub, and then a destination. A case in point is Africa where a rapidly increasing prevalence of substance use/abuse and substance use disorder among adolescents and young adults is putting enormous strain on the economy, healthcare system, and society at large. However, there appears to be a paucity of scientific literature and data on the epidemiology, risk assessment, and contributing factors to substance use and the development of substance use disorders across Africa. In this narrative review, we examine extant literature (PubMed, Google scholar, Medline) for information on the prevalence, trends, and influencers of substance use and the development of substance use disorders. This is with a view of understanding the determinants of substance use and factors that influence the development of substance use disorders in the region, and how this information can be channeled towards developing a comprehensive intervention and treatment program.

The potential toxicity of food-added sodium benzoate in mice is concentration-dependent.

Sodium benzoate (NaB) is a versatile food preservative that has also found some applications in the treatment of medical disorders. However, till date, its possible widespread effects on the body are not well studied. We examined the likely effect of diet-added NaB on weight/food intake, haematological parameters, neurobehaviour, antioxidant status, lipid profile and anti-inflammatory/apoptotic markers in mice. Animals were assigned randomly into 4 groups of 10 mice each. Groups included normal control (fed rodent chow) and three groups fed NaB at 125 (0.0125%), 250 (0.025% and 500 (0.05%) mg/kg of feed added to diet, respectively, for eight weeks. Body weight and food intake were assessed. At the end of the experimental period animals were euthanized, blood was then taken for the assessment of haematological, biochemical and inflammatory/apoptotic markers. At the lowest concentration, NaB diet increased body weight and food intake. Decrease in haematological cell counts and total antioxidant capacity were observed, whereas serum malondialdehyde levels and superoxide dismutase activity were increased across the three concentrations. Serum tumour necrosis factor-alpha and interleukin-10 decreased, whereas caspase-3 levels showed no significant difference. Lipid profile and biochemical indices of kidney and liver function were also affected by NaB diet. In conclusion, our findings suggest that NaB may be harmful if regulations regarding its limit of consumption are mistakenly or deliberately ignored. Therefore, it is advisable that regulations on quantities to be added to food be enforced.

Hazelnut Modulates Neurobehaviour and Ameliorates Ageing-induced Oxidative Stress, and Caspase-3-Mediated Apoptosis in Mice.

BACKGROUND: Organismal aging has been associated with deleterious effects in different body tissues and organs, including the brain. There have been reports from ancient medicinal scripts of the beneficial effects of nuts like hazelnut in preventing aging induced-brain atrophy and memory loss. OBJECTIVES: This study examined the potential beneficial effects of a diet supplemented with two different (Italian and Turkish) cultivars of hazelnut on the brain of aged mice. METHODS: Aged (24 months old) mice were randomly assigned into 7 groups of ten mice each. Mice were grouped as standard diet (SD) control, three groups of Turkish and three groups of Italian hazelnut incorporated into SD at 2, 4 and 8% respectively. Animals were fed standard or hazelnut diet for 8 weeks. On day 56, behaviours in the elevated plus maze, radial-arm maze, open field, and Y-maze paradigms were monitored and scored, following which animals were euthanized. The brains were removed, weighed and homogenized for the assessment of specific biochemical tests. RESULT: Results showed that hazelnut-supplemented diet was associated with significantly increased weight gain, with the Italian hazelnut being associated with greater weight gain. The hazelnut- supplemented diet also increased behavioural parameters such as horizontal locomotion and grooming, while it decreased rearing activity. Working-memory also improved significantly with both cultivars of hazelnut, while anxiety indices were reduced at lower concentrations of Italian, and higher concentrations of Turkish hazelnut. Both hazelnut varieties were associated with a reduction in acetylcholinesterase activity, superoxide dismutase activity, nitric oxide levels, caspase- 3 level, but increased dopamine level. CONCLUSION: Overall, hazelnut cultivars have beneficial effects on the brain in aged mice; suggesting a possible role in the prevention or management of age-related neurodegenerative changes.

Cucumeropsis mannii reverses high-fat diet induced metabolic derangement and oxidative stress.

Cucumeropsis mannii (CM) belongs to the melon family and is native to West Africa. There is a paucity of information on its medicinal or nutraceutical potential. Here, we examined the impact of CM in mice that were treated with a normal or a high fat diet (HFD). The CM extracts had a high levels of phenols, flavonoids, ascorbic acid and significant antioxidant activity. Treatment of mice with a HFD diet, led to the memory impairment. However, mice on HFD and received CM, despite increased food intake, showed a decrease in the body weight, locomotion, rearing, grooming, acetylcholinesterase activity and ?-amino butyric acid levels and anxiolysis. Also CM induced a reversal of HFD-induced changes in glucose levels, lipid peroxidation and super-oxide dismutase activity. These data show that CM leads to variable behavioural, biochemical and metabolic effects depending on the diet of animals.

Corylus avellana L. modulates neurobehaviour and brain chemistry following high-fat diet.

Consumption of a high-fat diet has adverse impacts on metabolism, neurobehavioral, and neurochemical homeostasis in both humans and experimental animals. Here, we examined the effects of two different cultivars of Corylus avellana L. in a mouse model of metabolic syndrome. Corylus avellana L. reduced weight gain in mice that were treated with a high-fat diet, improved their behavioral parameters as exemplified by locomotion and rearing, working-memory, and reduced grooming and anxiety indices. Both Corylus avellana L. varieties reduced blood glucose levels and lipid peroxidation, improved lipid profile, and antioxidant status in mice placed on a high fat diet. Finally, brain acetylcholinesterase activity was also reduced, dopamine level was increased, while caspase-3 level in the brain was reduced. Thus, the Corylus avellana L. cultivars improve metabolic, behavioral, and neurochemical homeostasis in a diet with a high-fat content.

Dietary Melatonin Protects Against Behavioural, Metabolic, Oxidative, and Organ Morphological Changes in Mice that are Fed High-Fat, High- Sugar Diet.

BACKGROUND: Metabolic syndrome is a complex pattern of disorders that occur jointly and is associated with an increased risk of cardiovascular and cerebrovascular disease. Therefore the need for more-efficient options of treatment has become imperative. OBJECTIVE: This study examined the effect of dietary-melatonin in the management of behavioural, metabolic, antioxidant, and organ changes due to high-fat/high-sugar (HFHS) diet-induced metabolic syndrome in mice. METHODS: Mice were randomly assigned into five groups of ten animals each. Groups were normal control [fed standard diet (SD)], HFHS control, and 3 groups of melatonin incorporated into HFHS at 2.5, 5, and 10 mg/kg of feed. Mice were fed for seven weeks, and body weight was assessed weekly. Open-field behaviours, radial-arm, and Y-maze spatial memory were scored at the end of the experimental period. Twenty-four hours after the last behavioural test, blood was taken for estimation of blood glucose levels after an overnight fast. Animals were then euthanised, and blood was taken for estimation of plasma insulin, leptin, and adiponectin levels, and serum lipid profile. The liver, kidneys, and brain were excised and processed for general histology, while homogenates of the liver and whole brain were used to assess oxidative stress parameters. RESULTS: Results showed that dietary melatonin (compared to HFHS diet) was associated with a decrease in body weight, food intake, and novelty-induced behaviours; and an increase in spatial-working memory scores. A decrease in glucose, insulin, leptin, and malondialdehyde levels; and an increase in adiponectin levels and superoxide dismutase activity were also observed. Histomorphological/ histomorphometric examination revealed evidence of organ injury with HFHS diet, and varying degrees of amelioration with melatonin-supplemented diet. CONCLUSION: In conclusion, dietary melatonin supplementation may have beneficial effects in the management of the metabolic syndrome.