南非传统草药Sutherlandia 抗糖尿病作用的研究

目的：观察南非传统草药Sutherlandia水提物对糖脂代谢的影响。方法：腹腔注射链脲佐菌素（STZ）并高脂饲料喂养诱导2型糖尿病大鼠模型。随机分为正常组、模型组、吡格列酮组、Sutherlandia组。观察体质量、口服糖耐量试验（OGTT）、血甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白-胆固醇（LDL-C）、高密度脂蛋白-胆固醇（HDL-C）指标的改变,Western Blot法检测各组大鼠骨骼肌胰岛素受体底物（IRS-1）表达情况。结果：与正常组比较,模型组大鼠体质量降低,OGTT、TG、TC、LDL-C指标明显升高（P<0.05）,多饮、多食、多尿症状明显,IRS-1 蛋白表达明显降低（P<0.05）;治疗后,与模型组比较,Sutherlandia组及吡格列酮组的体质量未见明显增长,Sutherlandia组及吡格列酮组血糖、TG、TC均明显降低（P<0.05或P<0.01）,二者之间无统计学差异,Sutherlandia组及吡格列酮组骨骼肌中IRS-1蛋白表达明显升高（P<0.05）,二者之间无统计学差异。结论：腹腔注射STZ并高糖高脂饲料喂养诱导2 型糖尿病大鼠模型存在糖脂代谢紊乱;南非传统草药Sutherlandia可明显降低其血糖水平,改善血脂代谢,提高胰岛素水平;Sutherlandia可提高IRS-1骨骼肌中的表达水平,进而改善胰岛素抵抗,降低血糖,其确切的作用途径有待进一步深入研究。     

A review of the taxonomy, ethnobotany, chemistry and pharmacology of Sutherlandia frutescens (Fabaceae)

Sutherlandia frutescens (tribe Galegeae, Fabaceae), a popular plant in traditional medicine, is indigenous to South Africa, Lesotho, southern Namibia and southeastern Botswana. It is chemically, genetically and geographically extremely variable and has been divided into three subspecies and several regional forms. A second species, Sutherlandia tomentosa, is localized along the Cape coast. Sutherlandia is sometimes treated as part of the genus Lessertia. There are numerous vernacular names and a wide diversity of uses, including poor appetite, indigestion, stomach complaints, dysentery, colds, influenza, kidney conditions, fever, diabetes, internal cancers, uterine troubles, liver conditions, backache, rheumatoid arthritis, urinary tract infections, stress and anxiety, dropsy and heart failure. Notable is the use as a bitter tonic ("blood purifier"), anti-stress medication ('musa-pelo) and, at least since 1895, specifically as a cancer tonic (both as treatment and as prophylaxis). Externally it is applied to haemorrhoids, inflamed wounds and eye infections. Recent in vitro and in vivo studies have shown antiproliferative, anti-HIV, anti-diabetic, anti-inflammatory, analgesic, antibacterial, anti-stress, anticonvulsant and antithrombotic activities. Aqueous extracts often differ in activity from organic solvent extracts. The presence of high levels of free amino acids, non-protein amino acids such as canavanine and GABA, the cyclitol pinitol, flavonols and triterpenes (including SU1, a cycloartane-type triterpene saponin) provide plausible hypotheses on how these compounds, individually or collectively, may be responsible for the reputed efficacy in a wide range of ailments. Results of animal studies, as well as a phase I clinical study, have shown no indications of toxicity. Sufficient preclinical data are now available to justify controlled clinical studies.     

Impact of traditional medicinal plant extracts on antiretroviral drug absorption

Ethopharmacological relevance

Traditional herbal medicines are often used for the treatment of different diseases in developing countries, especially in the rural areas where a lack of an efficient primary health care system is usually experienced. Many patients infected with the human immunodeficiency virus are taking traditional herbal medicines in conjunction with their modern antiretroviral medication and drug–herb interactions can occur in these cases.

Aim of the study

To investigate the effect of water extracts of two traditional medicinal plants, Hypoxis hemerocallidea and Sutherlandia frutescens as well as l-canavanine (a constituent of Sutherlandia frutescens) on the transport of nevirapine across human intestinal epithelial cells.

Materials and methods

Nevirapine transport in the apical to basolateral and basolateral to apical directions across Caco-2 cell monolayers was determined alone (normal control) and in the presence of verapamil (positive control), water extracts of Hypoxis hemerocallidea and Sutherlandia frutescens and an aqueous solution of l-canavanine. The cumulative transport and apparent permeability coefficient (P_app) values were calculated and compared.Results: Nevirapine alone was substantially effluxed in the basolateral to apical direction across the intestinal epithelial cell monolayers, which was statistically significantly (p ≤ 0.05) decreased by addition of verapamil, Hypoxis hemerocallidea extract and the l-canavinine solution. The effect of Sutherlandia frutescens on nevirapine transport was not statistically significantly different from the control.

Conclusions

Hypoxis hemerocallidea and l-canavanine interact with the efflux of nevirapine across intestinal epithelial cells and therefore can potentially increase the bioavailability of this antiretroviral drug when taken concomitantly.     

Effect of Sutherlandia frutescens on the Lipid Metabolism in an Insulin Resistant Rat Model and 3T3‐L1 Adipocytes

High fat diet induced insulin resistance correlates with dyslipidaemia and ectopic fat deposits in skeletal muscle and liver. The effects of Sutherlandia frutescens, an antidiabetic medicinal plant, on lipid metabolism were evaluated in an insulin resistant (IR) rat model and in 3 T3‐preadipocytes. Wistar rats received normal diet (ND) or high fat diet (HFD). After the onset of IR in the HFD group, the rats were subdivided into two subgroups, which either continued with HFD or were treated with 50 mg S. frutescens/kg BW/day and HFD (HFD + SF). After 4 weeks, the HFD + SF rats had a significantly lower body weight than the HFD rats (p < 0.05). Blood plasma analysis showed a decrease in insulin, free fatty acids and triglycerides. Related changes in lipid parameters were observed in the liver, skeletal muscle and adipose tissue. To investigate the effects of S. frutescens on adipose tissue, 3 T3‐L1 cells were used as a model. Treatment with S. frutescens led to a decrease in triglyceride accumulation, whilst glucose consumption and lactate production were increased (p < 0.05). These results indicate that S. frutescens directly affects mitochondrial activity and lipid biosynthesis in adipose tissue and provide a mechanism by which S. frutescens can restore insulin sensitivity by modulating fatty acid biosynthesis. Copyright © 2012 John Wiley & Sons, Ltd.     

Differential signaling involved in Sutherlandia frutescens-induced cell death in MCF-7 and MCF-12A cells

Ethnopharmacological relevance

The scientific study of natural products traditionally used in anticancer preparations has yielded several therapeutically relevant compounds. One of these traditional preparations with potentially beneficial properties is aqueous extracts of Sutherlandia frutescens, a shrub indigenous to the Western Cape region of South Africa. The aims of this study were to evaluate in vitro efficacy of these preparations on the MCF-7 breast adenocarcinoma and MCF-12A non-tumorigenic cell lines in terms of cell proliferation, cell morphology and possible induction of cell death.

Materials and methods

Crystal violet staining was used to evaluate cell proliferation, light-and fluorescence microscopy were used to investigate both intracellular and extracellular morphological features of apoptosis and autophagy (e.g. membrane blebbing, condensed chromatin and intracellular lysosomes), while flow cytometry quantified cell cycle changes and induction of apoptosis through analysis of the flip-flop translocation of phosphatidylserine.

Results

Crystal violet staining showed a time- and dose specific response to aqueous Sutherlandia frutescens extracts, revealing exposure to 1 mg/ml aqueous extract for 48 h to be ideal for comparing the differential effects of Sutherlandia frutescens in the MCF-7 and MCF-12A cell lines. Microscopy showed distinct morphological changes with hallmarks of apoptosis being observed in both cell lines. Flow cytometry revealed a decrease in actively cycling cells in both cell lines, and a 4.36% increase in phosphatidylserine translocation in the MCF-7 cell line, indicative of apoptosis induction, while fluorescence microscopy showed evidence of the induction of autophagy.

Conclusions

Analyses revealed the carcinogenic MCF-7 cell line to be more susceptible to the cytostatic and cytotoxic effects of aqueous extracts of Sutherlandia frutescens when compared to the non-tumorigenic MCF-12A cell line, thus warranting further research into the exact cellular mechanisms involved and the possible synergistic activities of Sutherlandia frutescens ingredients.     

Quantitative determination of flavonoids and cycloartanol glycosides from aerial parts of Sutherlandia frutescens (L.) R. BR. by using LC-UV/ELSD methods and confirmation by using LC–MS method

This paper describes the first analytical method for the determination of four flavonoids (sutherlandins A–D) and four cycloartanol glycosides (sutherlandiosides A–D) from the aerial parts of Sutherlandia frutescens (L.) R. Br. A separation by HPLC was achieved by using a reversed phase (RP-18) column, PDA with ELS detection, and a water/acetonitrile gradient as the mobile phase. The wavelength used for quantification of four flavonoids with the diode array detector was 260 nm. Owing to their low UV absorption, the cycloartanol glycosides were detected by evaporative light scattering. The method was validated for linearity, repeatability, limits of detection (LOD) and limits of quantification (LOQ). The limits of detection and limits of quantification of eight compounds were found to be in the range from 0.1 to 7.5 μg/mL and 0.5 to 25 μg/mL, respectively. The analysis of products showed considerable variation of 1.099–5.224 mg/average weight for the major compound, sutherlandioside B. The eight compounds in plant sample and products of S. frutescens were further confirmed by LC–ESI-TOF. This method involved the use of the [M+H]⁺ and [M+Na]⁺ ions in the positive ion mode with extractive ion monitoring (EIM).     

Lessertia (Sutherlandia frutescens) et la fatigue en cancérologie*

Résumé: Lessertia frutescens est un arbuste du désert du Kalahari de la famille des Fabacées, connu des Bushmen San sous le nom de «Pethora», «celle qui change» le développement de la maladie, des Sothola sous le nom de «Motlepelo», «celle qui ramène le cœur à la vie», et des Zoulous sous le nom d’«Insiswa», «celle qui disperse l’obscurité». La plante a été employée comme adaptogène par les colons blancs qui l’ont surnommée le buisson pour le cancer «cancer bush».Elle est peu connue en Occident. Ses principes actifs sont la L. canavanine, le pinitol, le Gaba, et surtout un glucoside triterpénoïde dénommé SU1. Des études non contrôlées en signalent l’utilisation chez plus de 1 000 patients affectés du sida dans une étude de trois à quatre ans.Après une évaluation préliminaire sur des patients séropositifs européens qui en faisaient l’usage en automédication, nous avons vu un bénéfice évident sur l’asthénie; nous avons donc utilisé une préparation orale à base de lessertia en poudre à la posologie de 600 mg par jour sur 16 patients atteints de cancer (11 femmes et 5 hommes) entre 35 et 76 ans, en cours de chimiothérapie pour le contrôle de la «fatigue».* Allocution présentée lors de la 11^e journée universitaire de phytothérapie de l’AMPP, juin 2003: Cancer et autres pathologies graves,nutrition, phytothérapie.     

The apoptosis inducing effects of Sutherlandia spp. extracts on an oesophageal cancer cell line

Aim of study

Oesophageal cancer is the ninth most common cancer in the world and the second most common cancer among South African men. It also has one of the lowest possibilities of cure, with the 5-year survival rate estimated to be only 10% overall. Sutherlandia frutescens, or the “cancer bush”, is a medicinal plant indigenous to southern Africa that is believed to have anti-cancer and anti-proliferative properties. The aim of this study was to investigate the potential apoptosis-inducing effects of two S. frutescens extracts and one Sutherlandia tomentosa extract on the SNO oesophageal cancer cell line.

Materials and methods

Cell viability and morphology of SNO cells were evaluated following exposure to the extracts. Apoptotic markers including cytochrome c translocation and phosphatidylserine externalisation were quantified by flow cytometry. The activity of caspases 3 and 7 was evaluated with spectrofluorometry. Apoptosis was evaluated in the presence of the pan-caspase inhibitor, Z-VAD-fmk. The effect of the extracts was compared to non-cancerous peripheral blood mononuclear cells (PBMCs).

Results

Time- and dose-response studies were conducted to establish treatment conditions of 2.5 and 5 mg/ml of crude plant extracts. Microscopy studies revealed that S. frutescens- and S. tomentosa-treated SNO cells had morphological features characteristic of apoptosis. Annexin V/propidium iodide flow cytometry confirmed that the extracts do, in fact, induce apoptosis in the SNO cells. Caspase inhibition studies seem to indicate that extracts A (S. frutescens (L.) R. Br. subsp. microphylla from Colesberg), B (S. frutescens (L.) R. Br. subsp. microphylla from Platvlei) and C (S. tomentosa Eckl. & Zeyh from Stil Bay) are able to induce caspase-dependent as well as -independent cell death. The S. frutescens and S. tomentosa extracts were found to be more cytotoxic to cancerous SNO cells when compared to the PBMCs.

Conclusions

S. frutescens and S. tomentosa extracts show promise as apoptosis-inducing anti-cancer agents.     

Effects of Sutherlandia Frutescens Extracts on Normal T-Lymphocytes In Vitro

Sutherlandia frutescens (SF), a popular traditional medicinal plant found in various parts of southern Africa, is used for treatment or management of HIV/AIDS and other diseases including cancer. However, its toxicity profile has not been fully established. The aims of this study were to examine the effects of 70% ethanol (SFE) and deionised water (SFW) extracts on normal isolated human T cells. An experimental study on normal human lymphocytes treated with doses SF extract doses ranging from 0.25 to 2.5 mg/ml. Untreated, vehicle-treated (Ethanol) and camptothecin (CPT) treated normal T cells were used as controls. Induction of cell death, changes in intracellular ATP, caspase-3/-7 activity and nuclear changes were analysed using flow cytometry, luminometry and nuclear staining (Hoechst) respectively. The highest concentration (2.5 mg/ml) of SFE extract induced significant necrosis (95%), depletion of ATP (76%), and inhibition of caspase-3/-7 activity (11%) following a 24 hour incubation period (p< 0.001). The 2.5 mg/ml concentration of SFW showed the same trend but were less effective (necrosis- 26%, ATP- 91%, & caspase-3/-7- 15%). These effects showed a time-dependence over 48 hours of incubation, with high doses of SFE extracts eliminating viable cells by necrosis, depleting ATP levels and decreasing caspase-3/-7 activity (p< 0.001). The activity of SFE extract was independent of ethanol. The SFW extract dilutions were less toxic than the SFE extracts. Significant DNA fragmentation as demonstrated by Hoechst staining was also seen over 48-hour incubation for high doses of both types of SF extracts. These results showed that although high concentrations of SF extracts can be toxic to normal T cells in vitro, SFW fractions were relatively safe for use.