In vivo Studies on Antidiabetic Plants Used in South African Herbal Medicine

Potential use of the Asteraceae family as a cure for diabetes: A review of ethnopharmacology to modern day drug and nutraceuticals developments

The diabetes-associated mortality rate is increasing annually, along with the severity of its accompanying disorders that impair human health. Worldwide, several medicinal plants are frequently urged for the management of diabetes. Reports are available on the use of medicinal plants by traditional healers for their blood-sugar-lowering effects, along with scientific evidence to support such claims. The Asteraceae family is one of the most diverse flowering plants, with about 1,690 genera and 32,000 species. Since ancient times, people have consumed various herbs of the Asteraceae family as food and employed them as medicine. Despite the wide variety of members within the family, most of them are rich in naturally occurring polysaccharides that possess potent prebiotic effects, which trigger their use as potential nutraceuticals. This review provides detailed information on the reported Asteraceae plants traditionally used as antidiabetic agents, with a major focus on the plants of this family that are known to exert antioxidant, hepatoprotective, vasodilation, and wound healing effects, which further action for the prevention of major diseases like cardiovascular disease (CVD), liver cirrhosis, and diabetes mellitus (DM). Moreover, this review highlights the potential of Asteraceae plants to counteract diabetic conditions when used as food and nutraceuticals. The information documented in this review article can serve as a pioneer for developing research initiatives directed at the exploration of Asteraceae and, at the forefront, the development of a botanical drug for the treatment of DM.

Antidiabetic Medicinal Plants Used in the Eastern Cape Province of South Africa: An Updated Review

Oral antidiabetic drugs are usually costly and are associated with several adverse side effects. This has led to the use of medicinal plants that are considered to have multiple therapeutic targets and are readily accessible. In the Eastern Cape province of South Africa, the number of people using medicinal plants for the management of diabetes has been climbing steadily over the past two decades due to their cultural acceptability, accessibility, affordability, efficacy, and safety claims. In this study, a review of antidiabetic medicinal plants used in the Eastern Cape province of South Africa was conducted. A comprehensive literature survey was thoroughly reviewed using several scientific databases, ethnobotanical books, theses and dissertations. About forty-eight (48) plant species were identified as being used to treat diabetes by the people of Eastern Cape province. Among the plant species, only eight (8) species have not been scientifically evaluated for their antidiabetic activities and twenty antidiabetic compounds were isolated from these medicinal plants. This review has confirmed the use and potential of the antidiabetic medicinal plants in the Eastern Cape province and identified several promising species for further scientific investigation.

Traditionally used polyherbals in a southern African therapeutic context

ETHNOPHARMACOLOGICAL RELEVANCE

In African traditional medicine, there are several plant species that are used in combination with either other plant species or non-plant derived combinations such as sugar and honey, salt and vinegar, milk, fat etc. This review examines the role of these combinations and postulates the scientific and therapeutic validation of such combinations.

AIM OF THE STUDY

This study reviewed the ethnopharmacological literature and documented the use of southern African plant combinations to find a scientific rationale for such combinations, and provide recommendations for future studies.

MATERIALS AND METHODS

Ethnobotanical books and online databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to find ethnobotanical studies within the southern African context that focus on the combinations of plants with other plants or various additional ingredients. The scientific literature was examined to determine if evidence was available to substantiate such combinations.

RESULTS

One hundred and eighty-seven medicinal plant (plant-to-plant) combinations that are used in the southern African traditional healing system were recorded. These plant combinations were used against infections of the gastrointestinal tract, respiratory tract, and skin as well other non-infectious diseases such as reproductive and psychiatric disorders. Respiratory infections were the most documented infections to be treated using plant combinations. The plant that was documented to be most commonly used in combination with other plants was Artemisia afra Jacq. ex Willd. While plant-plant combinations have drawn a marked interest, comparatively, plant-adjuvant (e.g. milk, sugar, honey, salt, vinegar, fats) combinations have attracted less research interest. Milk was reported as the most used additional ingredient in combination with medicinal plants. The combination of animal urine and dung with medicinal plants has been reported as a treatment for treat prostate infections, the human immunodeficiency virus (HIV). Other ingredients such as clay and flour were also documented, and these are often mixed with medicinal plants to treat fever, stomach ailments, sexually transmitted infections (STI) and skin conditions. Although combination therapy has been frequently reported in ethnobotanical records, over 90% of the combinations reviewed still need to be scientifically validated.

CONCLUSION

Scientific reports on the antimicrobial, anti-oxidant, anti-inflammatory and other pharmacological effects of these combinations may offer an understanding of traditional combination therapy. In addition, investigation into the mechanisms of action of these combinations are also recommended to supplement the findings. Nonetheless, the use of plant combinations is still an untapped research area in southern Africa and there is a need to validate the use of those documented combinations to obtain a better understanding of combined traditional medicinal plant use.

Cytotoxicity, Anti-Obesity and Anti-Diabetic Activities of Heteromorpha arborescens (Spreng.) Cham Leaves

This study investigated the cytotoxicity, anti-obesity and anti-diabetic potentials of blanched, aqueous and ethanol extracts of Heteromorpha arborescens (Spreng.) Cham leaves. The results revealed that both ethanol and aqueous extracts exhibited considerable inhibition against α-glucosidase (IC50 of 627.29 ± 4.62 µg/mL and 576.46 ± 3.21 µg/mL respectively), while the blanched extract showed weak α-glucosidase inhibition (IC50; 855.38 ± 4.29 µg/mL) and the aqueous extract showed the best α-amylase inhibition (IC50; 583.74 ± 5.87 µg/mL). However, weak α-amylase inhibition was observed in the ethanol (IC50; 724.60 ± 4.33 µg/mL) and blanched extracts (IC50; 791.63 ± 3.76 µg/mL). The toxicity of the extracts is indicated by LC50 values as 154.75 µg/mL, 125 µg/mL and 90.58 µg/mL for ethanol, aqueous and blanched extracts respectively, indicating the blanched extract to be the most toxic. Moderate glucose utilization in both C3A and L6 cells was also observed for the aqueous and ethanol extracts which may be attributed to the relatively lower toxicity levels present. However, glucose utilization was very weak for the blanched extract, which may be due to higher level of cytotoxicity it possessed. Relatively weaker lipase inhibition was observed for the ethanol (IC50; 699.3 ± 1.33 µg/mL), aqueous (IC50; 811.52 ± 3.52 µg/mL) and blanched extracts (IC50; 1152.7 ± 4.61 µg/mL) compared to orlistat (IC50; 56.88 ± 0.11 µg/mL). However, there was no reasonable reduction in lipid accumulation observed in all the extract treated cells. These observations suggest that ethanol and aqueous extracts of H. arborescens leaf are promising as new agents for the treatment of diabetes and its acclaimed anti-obesity potentials are likely due to its lipase, α-amylase and α-glucosidase inhibition.

Leonotis Leonurus improves the crosstalk between peripheral tissues both in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Unravelling the anti-diabetic mechanism of action of L. leonurus at adipose, liver, muscle and pancreatic level.

AIMS

To investigate the mechanism of action of an organic extract of L. leonurus and marrubiin at the gene level in adipose, liver and muscle tissues of an obese rat model and in a co-culture model.

MATERIALS AND METHODS

Obese Wistar rats were fed a cafeteria diet for eight weeks, treated with an extract of L. Leonurus, marrubiin, sulfonylurea and aspirin for two weeks and the level of gene expression of selected markers were investigated across different tissues. The effects mediated by the different treatments were investigated in co-culture cell models involving 3T3-L1 (fat), Chang (liver), C2C12 (muscle) and INS-1 (pancreatic) cells under both normal and hyperglycemic conditions.

RESULTS

L. leonurus extract mediated a significant increase in PPAR gamma, glucokinase, FAS and UCP2 gene expression in adipose tissue, whilst the opposite was observed in the liver. At the muscle level, a significant increase in FAS gene expression was observed relative to the obese control rats. Furthermore, the extract as well as marrubiin, modulated improvements in the adipokine profile. The co-culture models showed that the effect mediated by the extract was dependent on, the tissue type as well as the glycemic conditions.

CONCLUSIONS

L. Leonurus extract as well as marrubiin exhibit anti-diabetic properties where the mechanism of action is mainly at the adipose tissue level. The increase in expression of the genes of interest mentioned above potentially play a protective role towards the liver and possibly towards the muscle tissues as well.

Potential Application of Some Lamiaceae Species in the Management of Diabetes

Diabetes is one of the most dangerous metabolic disorders, with high rates of mortality worldwide. Since ancient times, medicinal plants have been used in traditional medicine to treat many diseases, including diabetes and its related complications. Plants are widely accepted, affordable, and perceived to have minimal adverse side effects. The Lamiaceae family is a potential source of therapeutic agents for the management of metabolic disorders, including diabetes. Hence, this review paper summarizes the antidiabetic use of Lamiaceae species in folk medicine globally. Furthermore, we present the antidiabetic activities and phytochemical constituents of twenty-three (23) Lamiaceae species and the antidiabetic activity of some notable chemical constituents isolated from some of these Lamiaceae species.

The use of South African botanical species for the control of blood sugar

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus (DM) is one of the most prevalent diseases globally and is of considerable concern to global health. Approximately 425 million people are estimated to have DM globally and this is predicted to increase to >642 million by 2040. Whilst the prevalence of DM in South Africa is slightly lower than the global average, it is expected to rise rapidly in future years as more South Africans adopt a high calorie "westernised" diet. Traditional medicines offer an alternative for the development of new medicines to treat DM and the usage of South African plants is relatively well documented.

AIM OF THE STUDY

To critically review the literature on the anti-diabetic properties of South African plants and to document plant species used for the treatment of DM. Thereafter, a thorough examination of the related research will highlight where research is lacking in the field.

MATERIALS AND METHODS

A review of published ethnobotanical books, reviews and primary scientific studies was undertaken to identify plants used to treat DM in traditional South African healing systems and to identify gaps in the published research. The study was non-biased, without taxonomic preference and included both native and introduced species. To be included, species must be recorded in the pharmacopeia of at least one South African ethnic group for the treatment of DM.

RESULTS

One hundred and thirty-seven species are recorded as therapies for DM, with leaves and roots most commonly used. The activity of only 43 of these species have been verified by rigorous testing, and relatively few studies have examined the mechanism of action.

CONCLUSION

Despite relatively extensive ethnobotanical records and a diverse flora, the anti-diabetic properties of South African medicinal plants is relatively poorly explored. The efficacy of most plants used traditionally to treat DM are yet to be verified and few mechanistic studies are available. Further research is required in this field.

Reduction of hepatorenal and pancreatic damage by Ferula elaeochytris extract in STZ induced diabetic rats

The therapeutic potential and antioxidant capacity of Ferula elaeochytris extract (FE) in the liver, kidney and pancreas of rats with diabetes induced by streptozotocin (STZ) was assessed using biochemistry, histopathology and immunohistochemistry. Forty adult Wistar albino male rats were divided randomly into five groups of eight rats each. The normal control (NC) group was untreated. The diabetes control (DC) group was treated with STZ to induce diabetes. The diabetes + acarbose group (DAC) was treated with STZ, then with acarbose daily for 28 days. The diabetes + FE (DFE) group was treated with STZ, then FE daily for 28 days. DC rats had inflammatory cell infiltration, hydropic degeneration and necrosis, whereas the DFE rats exhibited nearly normal histology. Insulin immunostaining in the pancreatic beta cells was decreased in the DC group compared to the NC group, whereas the DFE group was similar to the NC group. Many serum biomarkers of damage to liver, kidneys or pancreas were elevated in the DC group compared to the NC group; these biomarkers were decreased in the DFE group. The DC group exhibited increased malondialdehyde levels and decreased levels of the antioxidant defense system constituents compared to the NC group. The level of biomarkers the DFE group was close to the NC group. FE exhibited a protective effect against tissue damage owing to its antioxidant activities and to its ability to effect regeneration of β-cells in STZ induced diabetic rats.

A histopathological, immunohistochemical and biochemical investigation of the antidiabetic effects of the Pistacia terebinthus in diabetic rats

We investigated the antidiabetic activity of Pistacia terebinthus (PT) extracts in streptozotocin (STZ) induced diabetic rats. We used 40 Wistar albino male rats divided into five groups: control (C), diabetes (DM), diabetes + acarbose (DM + AC), diabetes + PT (DM + PT) and PT. DM was established by intraperitoneal injection of STZ. Immunohistochemistry revealed that STZ reduced insulin immunoreactivity in the pancreas of the diabetic rats. To the contrary, insulin immunoreactivity in the pancreatic β cells of PT treated diabetic rats was increased significantly. Decreased levels of blood glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), glucose, total triglyceride (TG), total cholesterol (TC), high density lipoprotein (HDL) and low density lipoprotein (LDL) were found in the PT supplemented diabetic group. Also, malondialdehyde (MDA) and antioxidant defense system enzyme levels were normalized in the DM + PT group. PT exhibited a protective effect on liver, kidney and pancreas that had been damaged by STZ induced DM.

Artemisia afra, a controversial herbal remedy or a treasure trove of new drugs?

ETHNOPARMACOLOGICAL RELEVANCE

Artemisia afra is one of the most widely used herbal remedies in South Africa. This highly aromatic shrub is used to treat various disorders including coughs, colds, influenza, and malaria. Due to the long tradition of use and popularity of A. afra, it has been successfully commercialised and can currently be bought from various internet stores and pharmacies. The most notable indication is for the prophylaxis and treatment of Plasmodium falciparum infections. In 2013, the Medicine Control Council (MCC) of South Africa banned the sale of A. afra for the treatment of malaria because it lacks scientific evidence of efficacy. This resulted in a lawsuit being filed in 2017 against the MCC by an herbal company which claimed that artemisinin was responsible for A. afra's antiplasmodial activity. At the time, no scientific literature reported that A. afra contained artemisinin.

MATERIALS AND METHODS

This review aims to collate all available scientific literature regarding the phytochemistry and biological activity, focusing on antimalarial activity, of A. afra published from 2009 to 2019 and follows on our earlier review, which covered all literature until 2009. All scientific literature in English published between 2009 and June 2019 were retrieved from scientific databases (Scifinder scholar, Web of Science, Scopus, PubMed, Google scholar) and a number of books regarding medicinal plants in South Africa were also consulted.

RESULTS

In the last decade very few compounds have been identified in A. afra, none of which were novel compounds. Based on all the tests that have been conducted using extracts and compounds of A. afra in a disparate variety of in vitro and in vivo bioassays, the results indicate only weak biological activity. The activity of extracts, and in some cases pure compounds, exhibited IC₅₀ or MIC values of 1000-10 000 fold less active than the positive controls. In contrast, and quite surprisingly, two randomised controlled trials were recently conducted (Schistosoma mansoni and Plasmodium falciparum infected patients) and although criticised based on design, execution, statistical analysis and ethical concerns, showed remarkably positive results.

CONCLUSIONS

Pre-clinical in vitro and in vivo animal experiments failed to yield any promising drug leads. However, if the recent randomised controlled trials can be independently replicated in well-designed and executed clinical trials it might indicate that A. afra contain powerful 'prodrugs'. Future research on A. afra should therefore focus on reproducing the randomised controlled trials and on artificially metabolising A. afra extracts/compounds in order to identify the presence of any 'prodrugs'.

The traditional Chinese formulae Ling-gui-zhu-gan decoction alleviated non-alcoholic fatty liver disease via inhibiting PPP1R3C mediated molecules

Background

Ling-gui-zhu-gan decoction (LGZG), a classic traditional Chinese medicine formula, has been confirmed to be effective in improving steatosis in non-alcoholic fatty liver disease (NAFLD). However, the mechanism under the efficacy remains unclear. Hence, this study was designed to investigate the mechanisms of LGZG on alleviating steatosis.

Methods

Twenty four rats were randomly divided into three groups: normal group, NAFLD group, fed with high fat diet (HFD) and LGZG group (fed with HFD and supplemented with LGZG). After 4 weeks intervention, blood and liver were collected. Liver steatosis was detected by Oil Red O staining, and blood lipids were biochemically determined. Whole genome genes were detected by RNA-Seq and the significant different genes were verified by RT-qPCR. The protein expression of Protein phosphatase 1 regulatory subunit 3C (PPP1R3C) and key molecules of glycogen and lipid metabolism were measured by western blot. Chromophore substrate methods measured glycogen phosphorylase (GPa) activity and glycogen content.

Results

HFD can markedly induce hepatic steatosis and promote liver triglyceride (TG) and serum cholesterol (CHOL) contents, while liver TG and serum CHOL were both markedly decreased by LGZG treatment for 4 weeks. By RNA sequencing, we found that NAFLD rats showed significantly increase of PPP1R3C expression and LGZG reduced its expression. RT-qPCR and Western blot both verified the alteration of PPP1R3C upon LGZG intervention. LGZG also promoted the activity of glycogen phosphorylase liver type (PYGL) and inhibited the activity of glycogen synthase (GS) in NAFLD rats, resulting in glycogenolysis increase and glycogen synthesis decrease in the liver. By detecting glycogen content, we also found that LGZG reduced hepatic glycogen in NAFLD rats. In addition, we analyzed the key molecules in hepatic de novo lipogenesis and cholesterol synthesis, and indicated that LGZG markedly inhibited the activity of acetyl-CoA carboxylase (ACC), sterol receptor element-binding protein-1c (SREBP-1c) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), resulting in lipid synthesis decrease in the liver.

Conclusion

Our data highlighted the role of PPP1R3C targeting pathways, and found that hepatic glycogen metabolism might be the potential target of LGZG in preventing NAFLD.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2424-1) contains supplementary material, which is available to authorized users.

Ethnobotanical survey of herbs used in the management of diabetes mellitus in Southern Katanga Area/DR Congo

Introduction

Diabetes is becoming a public health burden for sub-Saharan countries due to its prevalence which is growing rapidly. Traditional medicine is more and more used to treat diabetes in RD Congo as well as in other African countries. This study was undertaken in order to list plants used in the management of diabetes by traditional healers in four agglomerations of southern area of Katanga in the Democratic Republic of Congo.

Methods

Forty-nine traditional healers were randomly met and interviewed about diabetes treatment in traditional medicine. The survey concerned the plant identification, their part used, method of preparation and the route of administration. The inquest concerned also traditional medicine users.

Results

Ninety-five plants from 47 families were indicated as antidiabetic. Fabaceae (24.2%), Euphorbiaceae (7.4%), Apocynaceae and Strychnaceae (4.2 each) are the more representative families. This inventory showed that the root is the most used part of the cited plants, the decoction with water as the main preparation method and the oral administration as the principal way to give antidiabetic traditional formulations.

Conclusion

In Lubumbashi region, many plant species are used to treat diabetes either through traditional praticians or by anyone from well-known ancestral knowledge.

Medicinal Plants Used for the Traditional Management of Diabetes in the Eastern Cape, South Africa: Pharmacology and Toxicology

The use of medicinal plants for the management of diabetes mellitus is on the rise in the developing countries, including South Africa. There is increasing scientific evidence that supports the claims by the traditional healers. In this review, we compare the families of previously reported anti-diabetic plants in the Eastern Cape by rating the anti-diabetic activity, mode of action and also highlight their therapeutic potentials based on the available evidence on their pharmacology and toxicity. Forty-five plants mentioned in ethnobotanical surveys were subjected to a comprehensive literature search in the available electronic databases such as PubMed, ScienceDirect, Google Scholar and Elsevier, by using “plant name” and “family” as the keywords for the primary searches to determine the plants that have been scientifically investigated for anti-diabetic activity. The search returned 25 families with Asteraceae highly reported, followed by Asphodelaceae and Alliaceae. Most of the plants have been studied for their anti-diabetic potentials in vivo and/or in vitro, with most of the plants having a higher percentage of insulin release and inhibition against carbohydrate digesting enzymes as compared with insulin mimetic and peripheral glucose uptake. Almost all the investigated plants also inhibit oxidative stress as part of their hypoglycemic activity with less toxicity. However, the isolation of their bioactive molecules is still lacking. This review provides a resource to enable thorough assessments of the therapeutic profiles of available medicinal plants used for the management of diabetes in the Eastern Cape, South Africa. Further studies such as the identification of the active ingredients of potent plants still need to be carried out; this may lead to new molecules in drug discovery and development.

Medicinal plants with anti-inflammatory activities from selected countries and regions of Africa

Various nonsteroidal anti-inflammatory drugs have been shown to reduce pain and inflammation by blocking the metabolism of arachidonic acid by isoform of cyclooxygenase enzyme, thereby reducing the production of prostaglandin. Sadly, there are many side effects associated with the administration of nonsteroidal anti-inflammatory drugs. However, there are medicinal plants with anti-inflammatory therapeutic effects with low or no side effects. The Afri-can continent is richly endowed with diverse medicinal plants with anti-inflammatory activities that have been shown to be effective in the treatment of inflammatory conditions in traditional medicine. Interestingly, scientists have examined some of these African medicinal plants and documented their biological and therapeutic activities. Unfortunately, medicinal plants from different countries in Africa with anti-inflammatory properties have not been documented in a single review paper. It is important to document the ethnobotanical knowledge and applications of anti-inflammatory medicinal plants from selected countries representing different regions of the African continent. This paper therefore documents anti-inflammatory activities of various medicinal plants from different geographical regions of Africa with the aim of presenting the diversity of medicinal plants that are of traditional or therapeutic use in Africa.

The role of pollutants in type 2 diabetes mellitus (T2DM) and their prospective impact on phytomedicinal treatment strategies

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes and it is characterized by high blood sugar and abnormal sera lipid levels. Although the specific reasons for the development of these abnormalities are still not well understood, traditionally, genetic and lifestyle behavior have been reported as the leading causes of this disease. In the last three decades, the number of diabetic patients has drastically increased worldwide, with current statistics suggesting the number is to double in the next two decades. To combat this incurable ailment, orthodox medicines, to which economically disadvantaged patients have minimal access to, have been used. Thus, a considerable amalgamation of medicinal plants has recently been proven to possess therapeutic capabilities to manage T2DM, and this has prompted studies primarily focusing on the healing aspect of these plants, and ultimately, their commercialization. Hence, this review aims to highlight the potential threat of pollutants, i.e., polyfluoroalkyl compounds (PFCs), endocrine disrupting chemicals (EDCs) and heavy metals, to medicinal plants, and their prospective impact on the phytomedicinal therapy strategies for T2DM. It is further suggested that auxiliary research be undertaken to better comprehend the factors that influence the uptake of these compounds by these plants. This should include a comprehensive risk assessment of phytomedicinal products destined for the treatment of T2DM. Regulations that control the use of PFC-precursors in certain developing countries are also long overdue.

Diversity of use and local knowledge of wild and cultivated plants in the Eastern Cape province, South Africa

BACKGROUND

Traditional ecological knowledge among indigenous communities plays an important role in retaining cultural identity and achieving sustainable natural resource management. Hundreds of millions of people mostly in developing countries derive a substantial part of their subsistence and income from plant resources. The aim of this study was to assess useful plant species diversity, plant use categories and local knowledge of both wild and cultivated useful species in the Eastern Cape province, South Africa.

METHODS

The study was conducted in six villages in the Eastern Cape province, South Africa between June 2014 and March 2017. Data on socio-economic characteristics of the participants, useful plants harvested from the wild, managed in home gardens were documented by means of questionnaires, observation and guided field walks with 138 participants.

RESULTS

A total of 125 plant species belonging to 54 genera were recorded from the study area. More than half of the species (59.2%) are from 13 families, Apiaceae, Apocynaceae, Araliaceae, Asparagaceae, Asphodelaceae, Asteraceae, Fabaceae, Lamiaceae, Malvaceae, Myrtaceae, Poaceae, Rosaceae and Solanaceae. More than a third of the useful plants (37.6%) documented in this study are exotic to South Africa. About three quarters of the documented species (74.4%) were collected from the wild, while 20.8% were cultivated and 4.8% were spontaneous. Majority of the species (62.4%) were used as herbal medicines, followed by food plants (30.4%), ethnoveterinary medicine (18.4%), construction timber and thatching (11.2%). Other minor plant use categories (1-5%) included firewood, browse, live fence, ornamentals, brooms and crafts.

CONCLUSION

This study demonstrated that local people in the Eastern Cape province harbour important information on local vegetation that provides people with food, fuel and medicines, as well as materials for construction and the manufacturing of crafts and many other products. This study also demonstrated the dynamism of traditional ecological knowledge, practices and beliefs of local people demonstrated by the incorporation of exotic plants in their diets and indigenous pharmacopoeia.

Abnormalities in alternative splicing in diabetes: therapeutic targets

Diabetes mellitus (DM) is a non-communicable, metabolic disorder that affects 416 million individuals worldwide. Type 2 diabetes contributes to a vast 85-90% of the diabetes incidences while 10-15% of patients suffer from type 1 diabetes. These two predominant forms of DM cause a significant loss of functional pancreatic β-cell mass causing different degrees of insulin deficiency, most likely, due to increased β-cell apoptosis. Treatment options involve the use of insulin sensitisers, α-glucosidase inhibitors, and β-cell secretagogues which are often expensive, limited in efficacy and carry detrimental adverse effects. Cost-effective options for treatment exists in the form of herbal drugs, however, scientific validations of these widely used medicinal plants are still underway. Alternative splicing (AS) is a co-ordinated post-transcriptional process in which a single gene generates multiple mRNA transcripts which results in increased amounts of functionally different protein isoforms and in some cases aberrant splicing leads to metabolic disease. In this review, we explore the association of AS with metabolic alterations in DM and the biological significance of the abnormal splicing of some pathogenic diabetes-related genes. An understanding of the molecular mechanism behind abnormally spliced transcripts will aid in the development of new diagnostic, prognostic and therapeutic tools.

Phytonanotherapy for management of diabetes using green synthesis nanoparticles

The world has a rich diversity of indigenous medicinal plants. The World Health Organization (WHO) gives high priority to eco-friendly, non-hazardous and cost effective healthcare such as the use of medicinal plants to treat various illnesses, including Human immunodeficiency virus (HIV) infection and Acquired immune deficiency syndrome (AIDS), tuberculosis (TB), diabetes mellitus (DM), malaria, and cancer. In developing countries, a high proportion of the population tends to use complementary and alternative medicines (CAM) together with conventional prescription drugs. Globally, CAM has been used in both developed and developing countries. In China, 30-50% of medicinal use is based on traditional alternative medicine. In Africa, it is estimated that 80% of primary health care is CAM, whilst in the USA, about 158 million people us CAM. This increase is due to three main influences: improve their eminence of life, relieve symptoms and preclude long-term complications. Despite the advances and advantages of conventional pharmaceutical medication, these are associated with long-term side effects and pose risks of inefficacy for treatment of chronic diseases such as cancer and DM. The biosynthesis of metal nanoparticles (NPs) using medicinal plants has received considerable attention as a proper alternative to using hazardous chemical and physical synthetic techniques. Plants are being exploited for their unique metal tolerance and effective production of gold metal NPs. A single medicinal plant contains an orchestra of chemical elements (e.g. proteins, vitamins, enzymes, amino acids, polysaccharides and organic compounds) that are "environmentally benign, yet chemically complex" and therefore serve as ideal tools for enhanced medicinal applications. It is reported that phytocompounds such as terpenoids, polysaccharides, polyols and flavones take part in the bio-reduction, stabilization and bio-capping mechanisms to form stable gold and silver NPs. Also the inhibitory potential of plant compounds against diabetic targets followed by a study of enzyme inhibitor kinetics, ligand binding dynamics supported by in silico docking studies that reveal the mode of bioactive compounds and their inhibitory activities. The present review focuses on the potential anticancer, antidiabetic and antimicrobial activity of phyto-synthesized gold and silver NPs. In phytonanotherapy, synergistic features of plant and metal NPs are unique as they offer healing properties that may be the clinical bioequivalent to many synthetic drugs, with minimal side effects. This could provide alternative treatment for chronic diseases that is efficient to overcome the disadvantages of synthetic monotherapy and allows medicinal plant therapy to co-exist with current synthetic treatments. This creates a much needed paradigm shift for further clinical studies in non-communicable and communicable diseases.

Ethnobotanical survey of medicinal plants used to manage High Blood Pressure and Type 2 Diabetes Mellitus in Bitterfontein, Western Cape Province, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

The aim of this study was to identify and document medicinal plants used to manage High Blood Pressure and Type 2 Diabetes Mellitus in Bitterfontein, Western Cape Province, South Africa.

METHODS

One hundred and twelve (112) respondents were interviewed between August 2014 and September 2015 through semi-structured surveys to gather data on the percentage of people who had been diagnosed with High Blood Pressure and/or Type 2 Diabetes Mellitus and to determine the frequency of medicinal plant and allopathic medicine use. Twelve (12) key respondents were subsequently selected, using a non-probability snowball sampling method. They were interviewed in-depth concerning their plant practices and assisted with plant collection.

RESULTS

Twenty-four plant (24) species belonging to 15 families were identified for the management of High Blood Pressure and Type 2 Diabetes Mellitus. The most frequently reported families were Asteraceae (20.8%), Lamiaceae (16.67%), Crassulaceae (8.33%) and Aizoaceae (8.33%). The remaining (45.54%) were evenly split over eleven families- Fabaceae, Amaryllidaceae, Anacardiaceae, Capparaceae, Geraniaceae, Apiaceae, Convolvulaceae, Apocynaceae, Rutaceae, Asphodelaceae and Thymelaeaceae. The most commonly used plant species overall was Lessertia frutescens (96.55%). The most frequently used plant parts included leaves (57.63%) roots/bulbs (15.25%) and stems (11.86%), mostly prepared as infusions or decoctions for oral administration.

CONCLUSIONS

Medicinal plants are widely used by High Blood Pressure and Type 2 Diabetes Mellitus sufferers. They employ diverse plant species to manage both conditions. In addition, some sufferers often use prescribed allopathic medication, as well as medicinal plants, but at different intervals. Despite high usage the plants identified are not currently threatened (Red Data list status: least concern).

Antidiabetic Medicinal Plants Used by the Basotho Tribe of Eastern Free State: A Review

Diabetes mellitus (DM) belongs to the group of five leading important diseases causing death globally and remains a major health problem in Africa. A number of factors such as poverty, poor eating habit, and hormonal imbalance are responsible for the occurrence of the disease. It poses a major health challenge in Africa continent today and the prevalence continues to increase at an alarming rate. Various treatment options particularly the usage of herbs have been effective against diabetes because they have no adverse effects. Interestingly, South Africa, especially the Basotho tribe, is blessed with numerous medicinal plants whose usage in the treatment of DM has been effective since the conventional drugs are expensive and often unaffordable. The present study attempted to update the various scientific evidence on the twenty-three (23) plants originating from different parts of the world but widely used by the Sotho people in the management of DM. Asteraceae topped the list of sixteen (16) plant families and remained the most investigated according to this review. Although limited information was obtained on the antidiabetic activities of these plants, it is however anticipated that government parastatals and scientific communities will pay more attention to these plants in future research.

Hypoxis hemerocallidea Significantly Reduced Hyperglycaemia and Hyperglycaemic-Induced Oxidative Stress in the Liver and Kidney Tissues of Streptozotocin-Induced Diabetic Male Wistar Rats

Background. Hypoxis hemerocallidea is a native plant that grows in the Southern African regions and is well known for its beneficial medicinal effects in the treatment of diabetes, cancer, and high blood pressure. Aim. This study evaluated the effects of Hypoxis hemerocallidea on oxidative stress biomarkers, hepatic injury, and other selected biomarkers in the liver and kidneys of healthy nondiabetic and streptozotocin- (STZ-) induced diabetic male Wistar rats. Materials and Methods. Rats were injected intraperitoneally with 50 mg/kg of STZ to induce diabetes. The plant extract-Hypoxis hemerocallidea (200 mg/kg or 800 mg/kg) aqueous solution was administered (daily) orally for 6 weeks. Antioxidant activities were analysed using a Multiskan Spectrum plate reader while other serum biomarkers were measured using the RANDOX chemistry analyser. Results. Both dosages (200 mg/kg and 800 mg/kg) of Hypoxis hemerocallidea significantly reduced the blood glucose levels in STZ-induced diabetic groups. Activities of liver enzymes were increased in the diabetic control and in the diabetic group treated with 800 mg/kg, whereas the 200 mg/kg dosage ameliorated hepatic injury. In the hepatic tissue, the oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP), catalase, and total glutathione were reduced in the diabetic control group. However treatment with both doses improved the antioxidant status. The FRAP and the catalase activities in the kidney were elevated in the STZ-induced diabetic group treated with 800 mg/kg of the extract possibly due to compensatory responses. Conclusion. Hypoxis hemerocallidea demonstrated antihyperglycemic and antioxidant effects especially in the liver tissue.

Pattern of anti-diabetic drugs prescribed in a tertiary care hospital of Bangladesh

Background

Globally, diabetes mellitus is a common endocrine disorder. This study was conducted for collecting the demographic details of diabetic patients and determining the pattern of drugs prescribed among them in outpatient department of a tertiary healthcare center.

Methods

A descriptive type of cross-sectional study was carried out at the outpatient department of Endocrinology, Dhaka Medical College Hospital, Bangladesh from 1 May to 31 July, 2015. Diabetic patients receiving the management for at least 6 months were enrolled and interviewed by the researchers after getting informed written consent. Structured case record form was used for demographic data & prescription details. Data were analysed using computer in SPSS 22 and Microsoft Excel 2010.

Results

Altogether 105 patients, 40 males (38.1%) and 65 females (61.9%) were enrolled with urban predominance (69.5%) where 51 (48.6%) were in the age group 47-61 years with a mean of 53.4 (SD±10.6) years. 70 (66.7%) had diabetic history of less than 5 years and 66 (62.9%) had at least one concurrent illness. Hypertension accounted for majority (34.3%) of complications. On an average, 5.62 (SD±3.16) drugs were advised per prescription for diabetes as well as associated co-morbidities and majority (23.8%) had 4 drugs. The majority of drugs (74.3%) were from local manufacturers. Most patients (62.9%) were prescribed with oral drugs singly. Metformin alone predominated in 41% prescriptions followed by the combination of Metformin and Sitagliptin (31.4%).

Conclusions

The findings can serve as a guide to choose the formulation and combination of anti-diabetic drugs in this part of the world before developing & marketing any new drug.

Herbal therapy: A review of emerging pharmacological tools in the management of diabetes mellitus in Africa

BACKGROUND

Diabetes mellitus is a chronic physiological glucose metabolic disorder. It has affected millions of people all over the world thereby having a significant impact on quality of life. The management of diabetes includes both nonpharmacological and conventional interventions. Drawbacks in conventional therapy have led to seeking alternative therapy in herbal medicine. Therefore, the need to review, elucidate and classify their mode of action in therapy for diabetes disease arises.

MATERIALS AND METHODS

Comprehensive literature reports were used to review all conventional agents and herbal therapy used in the management of diabetes. An online database search was conducted for medicinal plants of African origin that have been investigated for their antidiabetic therapeutic potentials.

RESULTS

The results showed that of the documented sixty five plants used, fourteen inhibit intestinal absorption of glucose, three exhibit insulin-mimetic properties, seventeen stimulate insulin secretion from pancreatic beta cells, twelve enhance peripheral glucose uptake, one promotes regeneration of beta-cell of islets of Langerhans, thirteen ameliorate oxidative stress and twenty induces hypoglycemic effect (mode of action is still obscure). Thirteen of these plants have a duplicate mode of actions while one of them has three modes of actions. These agents have a similar mechanism of action as the conventional drugs.

CONCLUSION

In conclusion, antidiabetic activities of these plants are well established; however, the molecular modulation remains unknown. It is envisaged that the use of herbal therapy will promote good health and improve the status of diabetic patients.

Hypoglycemic effect of Brassica juncea (seeds) on streptozotocin induced diabetic male albino rat

OBJECTIVE

To evaluate the hypoglycemic effect of Brassica juncea (seeds) on streptozotocin induced diabetic male albino rats.

METHODS

Hypoglycemic activity of Brassica juncea (seeds) aqueous extract at a dose of 250, 350 and 450 mg/kg body weight was evaluated. Adult male Swiss albino rats of six numbers in each group was undertaken for study and evaluated.

RESULTS

The serum insulin levels were recorded a significant depletion in all groups, short term as well as long term diabetic animals, when compared to that of normal animals. A significant dosage dependent augmenting effect of the seed extract on the serum insulin was recorded in both short term as well as long term groups.

CONCLUSIONS

The aqueous seed extract of Brassica juncea has potent hypoglycemic activity in male albino rat.

Quercetin in anti-diabetic research and strategies for improved quercetin bioavailability using polymer-based carriers – a review

With numerous pharmacological and biological functions bio-flavonoids gain appreciable attention in diabetes and other therapeutic research.

Antihyperglycemic, hypolipidemic, hepatoprotective and antioxidative effects of dietary clove (Szyzgium aromaticum) bud powder in a high-fat diet/streptozotocin-induced diabetes rat model

BACKGROUND

Syzygium aromaticum (L.) Merr. & Perry (clove) bud is an important spice used in the preparation of several delicacies and in folklore for diabetes management. The present study was convened to assess the effects of dietary clove bud powder (CBP) on biochemical parameters in a type 2 diabetes rat model, induced by a combination of high-fat diet and low-dose streptozotocin (35 mg kg⁻¹) for 30 days.

RESULTS

Diabetic rats were placed on dietary regimen containing 20-40 g kg⁻¹ clove bud powder. The results revealed that there was no significant (P > 0.05) difference in the average feed intake and weight changes between the rat groups. Furthermore, supplementation with CBP gradually reduced blood glucose level in diabetic rat compared to control diabetic rats without CBP supplementation (DBC). Moreover, reduced activity of α-glucosidase was observed in CBP and metformin-treated rat groups when compared to that of the DBC rat group. In addition, the DBC group had significantly (P < 0.05) higher lipid concentrations (except for high-density lipoprotein cholesterol) when compared to all other groups. Furthermore, CBP had significantly (P < 0.05) reduced activity of liver enzymes (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) and showed elevated levels of antioxidant status (glutathione, ascorbic acid, superoxide dismutase and catalase).

CONCLUSION

The results suggest that the clove bud diet may attenuate hyperglycemia, hyperlipidemia, hepatotoxicity and oxidative stress in the type 2 diabetic condition.

From arrow poison to herbal medicine--the ethnobotanical, phytochemical and pharmacological significance of Cissampelos (Menispermaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Cissampelos species have a rich history of traditional use, being used for both therapeutic and toxic properties. It is traditionally applied therapeutically in a diverse range of conditions and diseases including asthma, cough, fever, arthritis, obesity, dysentery, snakebite, jaundice and heart, blood pressure and skin-related problems. Conversely, it was traditionally included in preparations of curare applied as arrow poison during hunting to cause death of animals by asphyxiation. This review unites the ethnobotanical knowledge on Cissampelos with the phytochemistry and pharmacological activity which has been explored thus far. In addition, it identifies knowledge gaps and suggests further research opportunities.

METHODS

The available electronic literature on the genus Cissampelos was collected using database searches including Scopus, Google Scholar, Pubmed, Web of Science, etc. The searches were limited to peer-reviewed English journals with the exception of books and a few articles in foreign languages which were included.

RESULTS

The literature revealed that pharmacological activity including analgesic and antipyretic, anti-inflammatory, anti-allergic, bronchodilator, immunomodulatory, memory-enhancing, antidepressant, neuroprotective, antimicrobial, antimalarial, antiparasitic, anti-ulcer, anticancer, anti-oxidant, cardiovascular, muscle-relaxant, hepatoprotective, antidiabetic, antidiarrhoeal, antifertility, and antivenom activity have been confirmed in vitro and/or in vivo for various Cissampelos species. Cissampelos pareira L. and Cissampelos sympodialis Eichl. are the most explored species of this genus and the smallest number of studies have been conducted on Cissampelos laxiflora Moldenke and Cissampelos tenuipes Engl. Many alkaloids isolated from Cissampelos such as warifteine, methylwarifteine, berberine, hayatin and hayatidin showed promising anti-allergic, immunosuppressive, antidepressant, anticancer, vasodilatory and muscle-relaxant activities.

CONCLUSION

The plants of this genus are used in traditional medicine for the treatment of various ailments. These plants are a rich source of bioactive bisbenzylisoquinoline and aporphine alkaloids together with other minor constituents. Although these plants are reputable and revered in various traditional medicine systems, many have not yet been screened chemically or pharmacologically and so there is a vast amount of research still to be conducted to validate their traditional use.

Anti-biofilm activity of Marula - a study with the standardized bark extract

ETHNOPHARMACOLOGICAL RELEVANCE

Marula (Sclerocarya birrea; family - Anacardiaceae) is an African plant, which enjoys wide socio-economic importance particularly in southern part of Africa. The fruits are consumed as food and also as alcoholic beverage (cream liquor). In different parts of Africa, the decoction of the bark is traditionally used for the treatment of dysentery, diarrhoea, and various other infectious conditions. The aim of the study was to investigate the anti-biofilm properties of the methanol extract of Marula bark (stem bark of Sclerocarya birrea), with a view towards combating the emergence of antimicrobial resistance often associated with bacterial biofilms.

MATERIALS AND METHODS

The standardized methanol extract was initially tested for its antimicrobial property. The crystal violet assay was used for evaluating anti-biofilm (biofilm formation by Pseudomonas aeuginosa) activity. Further in order to study the mechanism of anti-biofilm activity, the same was evaluated for understanding its role on various quorums sensing mediated phenomenon (swarming motility assay, protease and pyoverdin assay) that are known to be associated with the formation of biofilms and pathogenicity.

RESULTS

The methanol extract showed no inhibition of bacterial growth up to a concentration of 200 µg/ml. Interestingly, the sample produced anti-biofilm activity (around 75% decrease; 100 µg/ml) at sub-lethal concentration. Further it also significantly reduced the QS mediated swarming motility. The release of various virulent factors (protease and pyoverdin) was found to be lowered when pre-treated with the extract.

CONCLUSION

The present study illustrates the anti-biofilm property Sclerocarya birrea. The standardized extract significantly disrupted the quorum sensing mediated production of biofilm formation and also inhibited swarming ability of the cells. The extract displayed a regulatory role on the secretion of protease and pyoverdin, two QS dependent pathogenic factors found in Pseudomonas aeruginosa. This study also validates the ethnobotanical use of Marula.

Dietary supplements in the management of hypertension and diabetes - a review

BACKGROUND

The use of alternative therapies like herbs and dietary supplements is very common among hypertensive and diabetic patients all over the globe. Hypertension is a silent disease that causes increase in cardiovascular, cerebrovascular, renal morbidity and mortality whereas diabetic complications cause heart attack, stroke, blindness and kidney disease. These are serious and chronic metabolic disorders that have a significant impact on the health, quality of life, and life expectancy of patients, as well as on the health care systems. Orthodox drugs used for the treatment of hypertension and diabetes produce side effects such as headache, nausea, vomiting, stomach pain, constipation, diarrhea, weakness, fatigue and erectile dysfunction. The need for considering alternate therapies in the form of dietary supplements known to promote good health, having little or no side effects therefore arises.

MATERIALS AND METHODS

This review was carried out using comprehensive and systematic literature reports on the concurrent use of dietary supplements in the management of diabetes and hypertension. Empirical searches were conducted using Google scholar (http://scholar.google.com), and Science Direct (http://www.sciencedirect.com). In addition to these databases, the University database was also used. Searches were also undertaken using keyword combinations such as dietary supplements and the names of the diseases in question.

RESULT AND DISCUSSION

This review chronicled the therapeutic values of vitamins, minerals, amino acids, fruits, vegetables, herbs and other botanicals used as dietary supplements. Results show that these supplements provided better and safe substitutes to toxic and expensive conventional drugs. Generally dietary supplements are free from major side effects, readily available and affordable. It is envisaged that the use of dietary supplement will promote good health and improve the status of hypertensive and diabetic patients.

CONCLUSION

Medical doctors are therefore encouraged to incorporate dietary supplements into the regimen employed for hypertension and diabetes management.

Rhinacanthus nasutus Improves the Levels of Liver Carbohydrate, Protein, Glycogen, and Liver Markers in Streptozotocin-Induced Diabetic Rats

The present study was designed to investigate the total carbohydrate, total protein, and glycogen levels in the liver and to measure functional liver markers such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in streptozotocin-(STZ-) induced diabetic rats after treatment with methanolic extract of Rhinacanthus nasutus (R. nasutus). The methanolic extract of R. nasutus was orally administered at 200 mg/kg/day while glibenclamide was administered at 50 mg/kg/day. All animals were treated for 30 days before being sacrificed. The amounts of carbohydrate, glycogen, proteins, and liver markers (AST and ALT) were measured in the liver tissue of the experimental animals. The levels of carbohydrate, glycogen, and proteins were significantly reduced in the diabetic rats but were augmented considerably after 30 days of R. nasutus treatment. The elevated AST and ALT levels in diabetic rats showed a significant decline after treatment with R. nasutus for 30 days. These results show that the administration of R. nasutus ameliorates the altered levels of carbohydrate, glycogen, proteins, and AST and ALT observed in diabetic rats and indicate that R. nasutus restores overall metabolism and liver function in experimental diabetic rats. In conclusion, the outcomes of the present study support the traditional belief that R. nasutus could ameliorate the diabetic state.

Herbal medicine: a survey of use in Nigerian presurgical patients booked for ambulatory anaesthesia

BACKGROUND

Utilization of herbal medicines in the preoperative period by Nigerian patients booked for day case surgery has not been explored.

METHODS

Cross-sectional survey of 60 patients presenting for day-case surgery at a tertiary healthcare institution over a 3-week period in August 2011 was conducted. Using a structured questionnaire, inquiries were made concerning use of herbal medicines in the immediate preoperative period. Socio-demographic characteristics, information on use of concurrent medical prescriptions, types of herbs used, reasons for use, perceived side effects and perceived efficacy were obtained. Data were evaluated using descriptive statistics and Chi-square.

RESULTS

Fifty-two (86.7%) were American Society of Anesthesiologists (ASA) class 1 while 8 (13%) were ASA 2. Most patients (86.7%) had their procedures done under local infiltration with monitored anaesthesia care (MAC), while 5.0% and 8.3% had their procedures done under regional and general anaesthesia, respectively. About 48.3% of respondents were on concurrent medical prescriptions while 51.7% were not. Forty percent (40%) of patients admitted to use of herbal medicine, all by the oral route, in the immediate perioperative period; 87.5% did not inform their doctor of their herbal use. Types of herbs used included 'dogonyaro', 'agbo', 'nchanwu', and Tahitian noni. Treatment of malaria was commonest reason for use in 29.2% of patients, while cough and concurrent surgical condition were reasons given by 12.5% of patients, respectively. Seventy-nine percent (79.2%) of patients considered their herbal medications effective. Perceived side effects of herbal medication (16.6%) included fever, waist pain and intoxication. There were no variations in use between ASA 1 and ASA 2 patients and none between respondents on conventional medication against those that were not. Variables such as age less than 35 years, female gender, being married and being an urban dweller did not show any significant difference in use.

CONCLUSION

This survey revealed many patients were on one or more herbal preparations in the immediate preoperative period. In consideration of possible untoward drug interactions between conventional medication, herbal preparations and anaesthesia, doctors (especially anaesthetists) should routinely assess all patients booked to be anaesthetized, especially those for day case surgery. The authors recommend surveys with larger respondent numbers to determine prevalence of use and possible interactions between indigenous Nigerian herbs and anaesthesia.

Volatile compounds in the stem bark of Sclerocarya birrea (Anacardiaceae) possess antimicrobial activity against drug-resistant strains of Helicobacter pylori

The aim of this study was to isolate and identify phytochemicals with anti-Helicobacter pylori activity from the stem bark of Sclerocarya birrea. The plant crude extract was fractionated by silica gel column and thin layer chromatography techniques, initially with ethyl acetate (EA) and subsequently with a combination of ethyl acetate/methanol/water (EMW). Further fractionation and identification of the phytoconstituents was achieved by gas chromatography and mass spectrometry (GC/MS) analysis. The antimicrobial activity of the fractions and compounds was evaluated against five metronidazole- and clarithromycin-resistant strains of H. pylori as well as a reference strain ATCC 43526 using the microbroth dilution technique. Amoxicillin was included in the experiments as a positive control antibiotic. Of the 18 fractions collected, 16 demonstrated anti-H. pylori activity with 50% minimum inhibitory concentration (MIC(50)) values ranging from 310 μg/mL to 2500 μg/mL. Two of the fractions (EMW fraction 6 and EA fraction 1) revealed the presence of 5 and 24 compounds, respectively, representing 40.5% and 86.57% of the total composition. Most of the compounds were essential oils, with terpinen-4-ol being the most abundant agent (35.83%), followed by pyrrolidine (32.15%), aromadendrene (13.63%) and α-gurjunene (8.77%). MIC(50) ranges for amoxicillin, terpinen-4-ol and pyrrolidine were 0.0003-0.06 μg/mL, 0.004-0.06 μg/mL and 0.005-6.3 μg/mL, respectively. The inhibitory activities of terpinen-4-ol and pyrrolidine were similar to amoxicillin (P>0.05). Most of these compounds are being reported in this plant for the first time and may represent new sources of therapeutically useful compounds against H. pylori.

Hypoglycemic effect of resveratrol in type 2 diabetic model db/db mice and its actions in cultured L6 myotubes and RIN-5F pancreatic β-cells

Resveratrol, a phytoalexin present in the skin of grapes and red wine, has been demonstrated to possess a wide range of health promoting activities including anti-diabetic properties. In the present study, we investigated the effect of resveratrol in both type 2 diabetic mice and cell culture systems. In cultured L6 myotubes, we studied the effect of resveratrol on glucose uptake and translocation of glucose transporter 4 to plasma membrane from the aspects of insulin signaling and AMP-activated protein kinase signaling. In cultured RIN-5F cells, we examined whether resveratrol would protect the pancreas-derived β-cells from oxidative stress. Resveratrol significantly suppressed the elevation in the fasting blood glucose level and the serum triglyceride and lipid peroxide levels in db/db mice. Resveratrol stimulated glucose uptake and glucose transporter 4 translocation by activating both insulin signaling and AMP-activated protein kinase signaling. Moreover, resveratrol could protect pancreatic β-cells from advanced glycation end products-induced oxidative stress and apoptosis. From these results, resveratrol is suggested to show anti-diabetic effect by stimulating both insulin-dependent and -independent glucose uptake in muscles and by protecting pancreatic β-cells from advanced glycation end products-induced oxidative stress and apoptosis.

Hypoglycemic effect of resveratrol in type 2 diabetic model db/db mice and its actions in cultured L6 myotubes and RIN-5F pancreatic β-cells

Resveratrol, a phytoalexin present in the skin of grapes and red wine, has been demonstrated to possess a wide range of health promoting activities including anti-diabetic properties. In the present study, we investigated the effect of resveratrol in both type 2 diabetic mice and cell culture systems. In cultured L6 myotubes, we studied the effect of resveratrol on glucose uptake and translocation of glucose transporter 4 to plasma membrane from the aspects of insulin signaling and AMP-activated protein kinase signaling. In cultured RIN-5F cells, we examined whether resveratrol would protect the pancreas-derived β-cells from oxidative stress. Resveratrol significantly suppressed the elevation in the fasting blood glucose level and the serum triglyceride and lipid peroxide levels in db/db mice. Resveratrol stimulated glucose uptake and glucose transporter 4 translocation by activating both insulin signaling and AMP-activated protein kinase signaling. Moreover, resveratrol could protect pancreatic β-cells from advanced glycation end products-induced oxidative stress and apoptosis. From these results, resveratrol is suggested to show anti-diabetic effect by stimulating both insulin-dependent and -independent glucose uptake in muscles and by protecting pancreatic β-cells from advanced glycation end products-induced oxidative stress and apoptosis.