Hoodia gordonii extract targets both adipose and muscle tissue to achieve weight loss in rats

The Potential Therapeutic Value of Medicinal Plants in the Management of Metabolic Disorders

Metabolic syndrome (MetS) is a prevalent, multifactorial and complex disease that is associated with an increased risk of developing diabetes and other major cardiovascular complications. The rise in the global prevalence of MetS has been attributed to genetic, epigenetic, and environmental factors. The adoption of sedentary lifestyles that are characterized by low physical activity and the consumption of high-energy diets contributes to MetS development. Current management criteria for MetS risk factors involve changes in lifestyle and the use of pharmacological agents that target specific biochemical pathways involved in the metabolism of nutrients. Pharmaceutical drugs are usually expensive and are associated with several undesirable side effects. Alternative management strategies of MetS risk factors involve the use of medicinal plants that are considered to have multiple therapeutic targets and are easily accessible. Medicinal plants contain several different biologically active compounds that provide health benefits. The impact of phytochemicals present in local medicinal plants on sustainable health and well-being of individuals has been studied for many years and found to involve a plethora of complex biochemical, metabolic, and physiological mechanisms. While some of these phytochemicals are the basis of mainstream prescribed drugs (e.g., metformin, reserpine, quinine, and salicin), there is a need to identify more medicinal plants that can be used for the management of components of MetS and to describe their possible mechanisms of action. In this review, we assess the potential health benefits of South African ethnomedicinal plants in protecting against the development of health outcomes associated with MetS. We aim to provide the state of the current knowledge on the use of medicinal plants and their therapeutically important phytochemicals by discussing the current trends, with critical examples from recent primary references of how medicinal plants are being used in South African rural and urban communities.

Review: Southern African medicinal plants used as blood purifiers

ETHNOPHARMALOGICAL RELEVANCE

Blood purification practices, also referred to as blood cleansing or detoxification, is an ancient concept which is widespread amongst African traditional medicine, but for which no modern scientific basis exists. There prevails considerable ambiguity in defining what a blood purifier is.

AIM OF THE STUDY

The purpose of this review is to firstly define what a blood purifier is in the context of African traditional medicine and compare to other cultural and westernized interpretations. Thereafter, this study identifies traditionally used medicinal plants used as blood purifiers in southern Africa and correlates these species to scientific studies, which may support evidence for these "blood purifying plant species".

MATERIALS AND METHODS

Ethnobotanical books and review articles were used to identify medicinal plants used for blood purification. Databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to source scientific articles. An evaluation was made to try correlate traditional use to scientific value of the plant species.

RESULTS

One hundred and fifty nine plant species have been documented as traditional remedies for blood purification. Most of the plant species have some pharmacological activity, however, very little link to the traditional use for blood purification. There has been some justification of the link between blood purification and the use as an antimicrobial and this has been explored in many of the plant species identified as blood purifiers. Other pharmacological studies specifically pertaining to the blood require further attention.

CONCLUSION

Irrespective of the ambiguity of interpretation, medicinal plants used to "cleanse the blood", play an important holistic role in traditional medicine and this review with recommendations for further study provides some value of exploring this theme in the future.

Natural antioxidants in prevention of accelerated ageing: a departure from conventional paradigms required

The modern lifestyle is characterised by various factors that cause accelerating ageing by the upregulation of oxidative stress and inflammation-two processes that are inextricably linked in an endless circle of self-propagation. Inflammation in particular is commonly accepted as aetiological factor in many chronic disease states, such as obesity, diabetes and depression. In terms of disease prevention or treatment, interventions aimed at changing dietary and/or exercise habits have had limited success in practise, mostly due to poor long-term compliance. Furthermore, other primary stimuli responsible for eliciting an oxidative stress or inflammatory response-e.g. psychological stress and anxiety-cannot always be easily addressed. Thus, preventive medicine aimed at countering the oxidative stress and/or inflammatory responses has become of interest. Especially in developing countries, such as South Africa, the option of development of effective strategies from plants warrants further investigation. A brief overview of the most relevant and promising South African plants which have been identified in the context of inflammation, oxidative stress and chronic disease is provided here. In addition, and more specifically, our group and others have shown considerable beneficial effects across many models, after treatment with products derived from grapes. Of particular interest, specific cellular mechanisms have been identified as therapeutic targets of grape-derived polyphenols in the context of inflammation and oxidative stress. The depth of these studies afforded some additional insights, related to methodological considerations pertaining to animal vs. human models in natural product research, which may address the current tendency for generally poor translation of positive animal model results into human in vivo models. The importance of considering individual data vs. group averages in this context is highlighted.

Colloidal particles for the delivery of steroid glycosides

Food grade colloidal particles comprising steroid glycosides with excellent stability are prepared using a liquid antisolvent precipitation method.

High-mesembrine Sceletium extract (Trimesemine™) is a monoamine releasing agent, rather than only a selective serotonin reuptake inhibitor

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts from and alkaloids contained in plants in the genus Sceletium have been reported to inhibit ligand binding to serotonin transporter. From this, the conclusion was made that Sceletium products act as selective serotonin-reuptake inhibitors. However, other mechanisms which may similarly result in the anxiolytic or anti-depressant effect ascribed to Sceletium, such as monoamine release, have not been investigated.

AIMS OF THE STUDY

The current study investigated simultaneously and at two consecutive time points, the effect of high-mesembrine Sceletium extract on both monoamine release and serotonin reuptake into both human astrocytes and mouse hippocampal neurons, as well as potential inhibitory effects on relevant enzyme activities.

MATERIALS AND METHODS

Human astrocytes and mouse hippocampal cells were treated with citalopram or Sceletium extract for 15 and 30min, after which protein expression levels of serotonin transporter (SERT) and vesicular monoamine transporter-2 (VAMT-2) was assessed using fluorescent immunocytochemistry and digital image analysis. Efficacy of inhibition of acetylcholinesterase (AChE) and monoamine oxidate-A (MAO-A) activity were assessed using the Ellman and Olsen methods (and appropriate controls) respectively.

RESULTS

We report the first investigation of mechanism of action of Sceletium extract in the context of serotonin transport, release and reuptake in a cellular model. Cell viability was not affected by Sceletium treatment. High-mesembrine Sceletium extract down-regulated SERT expression similarly to citalopram. In addition, VMAT-2 was upregulated significantly in response to Sceletium treatment. The extract showed only relatively mild inhibition of AChE and MAO-A.

CONCLUSIONS

We conclude that the serotonin reuptake inhibition activity ascribed to the Sceletium plant, is a secondary function to the monoamine-releasing activity of high-mesembrine Sceletium extract (Trimesemine(TM)).

Modulation of glucocorticoid, mineralocorticoid and androgen production in H295 cells by Trimesemine™, a mesembrine-rich Sceletium extract

ETHNOPHARMACOLOGICAL RELEVANCE

Stress-related illnesses rate among the most prevalent non-fatal diseases globally. With the global trend for consumer bias towards natural medicine, the Sceletium plant has become more prominent in the field of natural products. Although potentially useful effects of Sceletium tortuosum on the central nervous system have been reported, limited data is available on effects of the plant in the peripheral compartment.

AIM OF THE STUDY

The current study aimed to elucidate the effect(s) of a Sceletium extract (TRI) rich in mesembrine (1% of plant extract w/w), on adrenal steroid biosynthesis.

MATERIALS AND METHODS

Steroidogenesis was assessed basally and in response to stimuli (forskolin, angiotensin II, KCl), in human adrenocortical carcinoma cells (H295R). Steroid hormone levels were assessed using UPLC-MS/MS. UPLC-MS analyses of TRI identified major alkaloids Δ7-mesembrenone, mesembrenone and mesembrine.

RESULTS

Highest dose TRI treatment (1 mg/ml, 34.5 μM mesembrine) increased pregnenolone and decreased 16-hydroxyprogesterone levels (both P<0.00001) in forskolin-stimulated conditions only, suggesting CYP17 enzyme inhibition. This led to significant inhibition of forskolin-associated increases in cortisol levels at the highest dose (P<0.001) and basal cortisol levels across all doses (P<0.0001). Independently of forskolin, TRI inhibited androstenedione and testosterone production across all doses (both P<0.00001), suggesting inhibition of 3βHSD and 17βHSD respectively. TRI decreased both the angiotensin II- (P<0.05) and forskolin-induced (P<0.0001) increases in aldosterone production.

CONCLUSIONS

Our data suggest potentially beneficial effects of TRI in the context of stress and hypertension. These should be further investigated in a whole organism model, while the effects on the androgenic pathway should also be further elucidated.