Sutherlandia Frutescens Research Articles

The Induction of Apoptosis in A375 Malignant Melanoma Cells by Sutherlandia frutescens.

Sutherlandia frutescens is a medicinal plant indigenous to Southern Africa and is commonly known as the “cancer bush.” This plant has traditionally been used for the treatment of various ailments, although it is best known for its claims of activity against “internal” cancers. Here we report on its effect on melanoma cells. The aim of this study was to investigate whether an extract of S. frutescens could induce apoptosis in the A375 melanoma cell line and to outline the basic mechanism of action. S. frutescens extract induced apoptosis in A375 cells as evidenced by morphological features of apoptosis, phosphatidylserine exposure, nuclear condensation, caspase activation, and the release of cytochrome c from the mitochondria. Studies in the presence of a pan-caspase inhibitor allude to caspase-independent cell death, which appeared to be mediated by the apoptosis inducing factor. Taken together, the results of this study show that S. frutescens extract is effective in inducing apoptosis in malignant melanoma cells and indicates that further in vivo mechanistic studies may be warranted.

Inhibition of Hedgehog-Signaling Driven Genes in Prostate Cancer Cells by Sutherlandia frutescens Extract.

Sutherlandia frutescens (L) R. Br. (Sutherlandia) is a South African botanical that is traditionally used to treat a variety of health conditions, infections and diseases, including cancer. We hypothesized Sutherlandia might act through Gli/ Hedgehog (Hh)-signaling in prostate cancer cells and used RNA-Seq transcription profiling to profile gene expression in TRAMPC2 murine prostate cancer cells with or without Sutherlandia extracts. We found 50% of Hh-responsive genes can be repressed by Sutherlandia ethanol extract, including the canonical Hh-responsive genes Gli1 and Ptch1 as well as newly distinguished Hh-responsive genes Hsd11b1 and Penk.

Unveiling the anti-inflammatory activity of Sutherlandia frutescens using murine macrophages

Sutherlandia frutescens is a botanical widely used in southern Africa for treatment of inflammatory and other conditions. Previously, an ethanolic extract of S. frutescens (SFE) has been shown to inhibit the production of reactive oxygen species (ROS) and nitric oxide (NO) by murine neurons and a microglia cell line (BV-2 cells). In this study we sought to confirm the anti-inflammatory activities of SFE on a widely used murine macrophage cell line (i.e., RAW 264.7 cells) and primary mouse macrophages. Furthermore, experiments were conducted to investigate the anti-inflammatory activity of the flavonol and cycloartanol glycosides found in high quantities in S. frutescens. While the SFE exhibited anti-inflammatory activities upon murine macrophages similar to that reported with the microglia cell line, this effect does not appear to be mediated by sutherlandiosides or sutherlandins. In contrast, chlorophyll in our extracts appeared to be partly responsible for some of the activity observed in our macrophage-dependent screening assay.

A review of commercially important African medicinal plants

Ethnopharmacological relevanceData on the relative importance and research status of commercially relevant African medicinal plants are needed for developing new research strategies in order to stimulate much-needed ethnopharmacological research and to promote the commercialization of African plants. Aim of the studyTo present an illustrated bird’s eye view and comparative analysis of the relative popularity and importance of commercialized African medicinal plants. A comparison is made between the general popularity and commercial importance of the species (as indicated by their footprint on the World Wide Web) and their scientific popularity and importance (as indicated by the number of research publications). The inventory and review is strongly focussed to cover all or most of the medicinal plant raw materials in the international trade that are exported from African countries, with less emphasis on those that are regularly traded on local and regional markets within Africa. Materials and methodsThe review is based on literature data, Scopus and Google searches, commercial information and the author’s own experience and observations. ResultsMore than 5400 plant species are used in traditional medicine in Africa, of which less than 10% have been commercially developed to some extent. Africa is home to more than 80 valuable commercial species that are regularly traded on international markets, including phytomedicines (e.g. Harpagophytum procumbens and Pelargonium sidoides), functional foods (e.g. Adansonia digitata and Hibiscus sabdariffa) and sources of pure chemical entities (e.g. caffeine from Coffea arabica and yohimbine from Pausinystalia johimbe). According to the Scopus results, about 60% of all recent publications on African medicinal plants appeared in the last decade, with an average of 280 papers (28 per year) for 85 prominent species of international trade. The most popular African species for research (number of publications in brackets) were: Ricinus communis (5187), Aloe vera (2832), Catharanthus roseus (2653), Sesamum indicum (2534), Strophanthus gratus (2514), Coffea arabica (2431), Citrullus lanatus (2215), Momordica charantia (2047), Withania somnifera (1767), Trigonella foenum-graecum (1687), Acacia senegal (1373), Centella asiatica (1355), Griffonia simplicifolia (1010), Hibiscus sabdariffa (987), Tamarindus indica (973) and Catha edulis (947). The top species in terms of recent research interest (% of publications in last decade) were: Hoodia gordonii (95%), Cyclopia genistoides (93%), Sceletium tortuosum (90%), Agathosma betulina (89%), Pelargonium sidoides (86%), Boswellia papyrifera (85%), Lessertia (Sutherlandia) frutescens (84%), Boswellia sacra (83%), Mondia whitei (81%), Hibiscus sabdariffa (80%), Hypoxis hemerocallidea (80%) and Tylosema esculentum (80%). Both lists reflect the recent interest in functional foods and dietary supplements. ConclusionDespite a marked recent increase in the number of publications on indigenous medicinal plants and dietary supplements, Africa lags behind Europe and Asia in terms of the number of products that have been commercialised and the percentage of the flora that is utilized for international trade. There is a tremendous potential for developing new crops and new products but much work remains to be done to generate more focussed and relevant pre-clinical data and convincing proof of concept through clinical studies.

Inhibition of Gli/hedgehog signaling in prostate cancer cells by "cancer bush" Sutherlandia frutescens extract.

Sutherlandia frutescens is a medicinal plant, traditionally used to treat various types of human diseases, including cancer. Previous studies of several botanicals link suppression of prostate cancer growth with inhibition of the Gli/hedgehog (Gli/Hh) signaling pathway. Here we hypothesized the anti-cancer effect of S. frutescens was linked to its inhibition of the Gli/Hh signaling in prostate cancer. We found a dose- and time-dependent growth inhibition in human prostate cancer cells, PC3 and LNCaP, and mouse prostate cancer cell, TRAMP-C2, treated with S. frutescens methanol extract (SLE). We also observed a dose-dependent inhibition of the Gli-reporter activity in Shh Light II and TRAMP-C2QGli cells treated with SLE. In addition, SLE can inhibit Gli/Hh signaling by blocking Gli1 and Ptched1 gene expression in the presence of a Gli/Hh signaling agonist (SAG). A diet supplemented with S. frutescens suppressed the formation of poorly differentiated carcinoma in prostates of TRAMP mice. Finally, we found Sutherlandioside D was the most potent compound in the crude extract that could suppress Gli-reporter in Shh Light II cells. Together, this suggests that the S. frutescens extract may exert anti-cancer effect by targeting Gli/Hh signaling, and Sutherlandioside D is one of the active compounds.

Testing of Eight Medicinal Plant Extracts in Combination with Kresoxim-Methyl for Integrated Control of Botrytis cinerea in Apples

Botrytis cinerea is a fungus that causes gray mold on many fruit crops. Despite the availability of a large number of botryticides, the chemical control of gray mold has been hindered by the emergence of resistant strains. In this paper, tests were done to determine the botryticidal efficacy of selected plant extracts alone or combined with kresoxim-methyl. In total, eight South African medicinal plants viz Artemisia afra, Elyptropappus rhinocerotis, Galenia africana, Hypoxis hemerocallidea, Siphonochilus aetheopicus, Sutherlandia frutescens, Tulbaghia violacea and Tulbaghia alliacea were screened. Allium sativum, a plant species known to have antifungal activity, was included in the in vivo studies. For the in vitro studies, synergistic interactions between the plant extracts and the kresoxim-methyl fungicide were tested with radial growth assays. Data indicated synergistic inhibitory effects between the fungicide and the plant extracts. Next, different doses of plant extracts combined with kresoxim-methyl were used for decay inhibition studies on Granny Smith apples. Synergistic and additive effects were observed for many of the combinations. Even though this study was done using only one strain of B. cinerea, results showed that the tested indigenous South African plant species possess natural compounds that potentiate the activity of kresoxim-methyl.

Sutherlandia frutescens treatment induces apoptosis and modulates the PI3-kinase pathway in colon cancer cells

Sutherlandia frutescens is a plant that is endemic to South Africa and is traditionally used for the treatment of cancer and many other ailments. Although previous studies have shown S. frutescens to exert anti-proliferative and apoptotic effects in human mammary adenocarcinoma- and leukemia cell lines, its potential cytotoxic effects on colon cancer cells have not yet been established. Moreover, limited information is available elucidating the major signaling pathways involved upon exposure to the herbal extract. The aim of this study was therefore to assess the cytotoxic effect of S. frutescens on the colon cancer cell line CaCo2, to investigate molecular role players of apoptosis and to assess the involvement of the PI3-K survival pathway. CaCo2 cells exposed to ethanolic extracts of S. frutescens showed significant decreased cell viability, indicated by reduced MTT reductive capacity, increased pyknosis as well as loss in cellular membrane integrity. Western blot analysis revealed a down-regulation in the PI3-K and Akt phosphorylation, a decrease in forkhead transcription factor (FKHR) phosphorylation as well as a concomitant induction of apoptosis. This study demonstrates that Sutherlandia treatment attenuates proliferation of colon cancer cells in vitro by the disruption of the key molecules in the PI-3K pathway thereby inducing apoptosis.

An ethnobotanical survey of medicinal plants used by traditional health practitioners to manage HIV and its related opportunistic infections in Mpoza, Eastern Cape Province, South Africa

Ethnopharmacological relevanceThe aim of the study was to identify and document plants traditionally used to manage HIV and treat its opportunistic infections (OIs) in Mpoza, a rural village located in the Mount Frere Alfred Nzo District, Eastern Cape Province, South Africa.Materials and methods: Semi-structured interviews and focus group discussions (FGDs) were conducted with 18 traditional health practitioners from January 2012 to August 2012 to obtain information about medicinal plants used in the management of HIV and treatment of OIs. ResultsSeventeen plant species belonging to 12 families were identified for the management of HIV and treatment of OIs in Mpoza. The identified plant species belonged mostly to the families Asparagaceae (12%), Araliaceae (12%), Apiaceae (12%), Xanthorrhoeaceae (12%) and Lamiaceae (12%). The remaining 40% of identified plant species was evenly split over seven families - Urticaceae, Hypoxidaceae, Leguminosae, Verbenaceae, Rosaceae, Compositae and Rutaceae. The most frequently used medicinal plants were Hypoxis hemerocallidea (85%), Asparagus densiflorus (68%) and Lessertia frutescens (68%). The leaves (43.5%) and roots (21.7%) were the most frequently used plant parts, usually prepared as infusions and decoctions for oral administration. ConclusionThis study provides documentation of medicinal plants used in the management of HIV and treatment of commonly associated OIs, which might provide a potential lead that will significantly contribute in reducing the burden of HIV infections in South Africa. We envisage that this paper will provide some background for further studies in developing new, effective, safe and affordable plant-derived medicines.

Immunomodulation of innate immune cells by Sutherlandia frutescens: A transcriptomic analyses

Sutherlandia frutescens (SF) is a plant found in southern portions of Africa with a rich history of traditional use as a beverage to ameliorate some of the symptoms associated with cancer and HIV‐AIDS. To date no research has reported the impact of SF on global gene regulation. Therefore, we designed an experiment to evaluate the effects of SF treatment on gene expression in a murine macrophage cell line (RAW 264.7). Cells were exposed to SF extract or a vehicle control for 1 hr prior to activation with LPS and IFNγ. Gene expression at 8 & 24 hr post‐stimulation were analyzed using RNA sequencing. Immune‐stimulation caused ~2600 genes to be up‐regulated and another 2600 genes to be down‐regulated at 8 hr and at 24 hr post‐stimulation up‐ and down‐regulated genes expanded to ~4100 and >4500, respectively. SF treatment resulted in 547 differentially expressed genes (DEGs) at 8 hr post‐stimulation and for most of these genes (~64%) SF altered the direction of their expression. While the total number of genes modulated at 24 hr post‐stimulation was much greater than at 8 hr, the portion that were differentially regulated by SF treatment was lower (1369 out of 3625, ~38%). Pathway analysis identified that many of these DEGs participate in inflammatory signaling pathways, such as NF‐kB and MAPK. These findings were consistent with previously reported anti‐inflammatory activity for SF and should help us better understand the immune‐modulating properties of this botanical.

Isolation of the Predominant Cycloartane Glycoside, Sutherlandioside B, from Sutherlandia frutescens (L.) R.Br. by Spiral Countercurrent Chromatography

The introduction to high-speed countercurrent chromatography of a spiral tubing support rotor has enabled the application of more polar volatile solvent systems for natural products separation, especially water soluble compounds and their metabolites. Here is reported the use of spiral countercurrent chromatography with the spiral tubing support rotor to fractionate extracts of the African medicinal plant Sutherlandia frutescens (L.) R.Br. A two-phase solvent system of ethyl acetate, methanol, water, and n-butanol, with the lower aqueous phase mobile, separated sutherlandioside B efficiently from other compounds. The purity of sutherlandioside B was determined by high-performance liquid chromatography and mass spectrometry analysis. Sufficient quantities of sutherlandioside B can be purified by this method for use in cell culture assays and the development of a sensitive antibody by which to detect the consumption and metabolism in vivo of this novel botanical.

An integrated multi-target in vitro screening platform to prioritise medicinal plant extracts with antidiabetic activity

Medicinal plants have attracted much interest as a potentially inexpensive and culturally acceptable therapy for the treatment of diabetes, however most have not been scientifically evaluated for safety and efficacy. Unfortunately the high cost of clinical studies reside beyond the reach of most academic and research institutions and subsequently do not represent a viable option for exploring the many medicinal plants reported to treat this disease. While animal models afford an accepted alternative, the multifactor nature of diabetes poses a significant challenge as it is not possible to accurately select appropriate animal models without some knowledge of the mechanism through which complex plant extracts elicit their therapeutic effect. To address this problem a multi-target in vitro antidiabetic screening platform was established and used to prioritise plant extracts according to therapeutic target. The selectivity of our screening platform was confirmed through a comparison of known antidiabetic drugs relative to a set of drugs not associated with the treatment of diabetes. Furthermore a selection of natural compounds with previously established in vivo antidiabetic activity highlighted the increased propensity of natural compounds to target multiple molecular mechanisms. Screening of 40 South African medicinal plant extracts identified Sutherlandia frutescens as a promising antidiabetic therapy with a strong lipocentric mechanism. Using a high fat diet induced insulin resistant animal model, we confirmed these antidiabetic properties [1]. Together these findings support an integral role for in vitro assays as a strategy to characterise the antidiabetic potential of natural products prior to confirmation in animal models.

Dietary Sutherlandia and elderberry mitigate cerebral ischemia-induced neuronal damage and attenuate p47phox and phospho-ERK1/2 expression in microglial cells.

Sutherlandia (Sutherlandia frutescens) and elderberry (Sambucus spp.) are used to promote health and for treatment of a number of ailments. Although studies with cultured cells have demonstrated antioxidative and anti-inflammatory properties of these botanicals, little is known about their ability to mitigate brain injury. In this study, C57BL/6 J male mice were fed AIN93G diets without or with Sutherlandia or American elderberry for 2 months prior to a 30-min global cerebral ischemia induced by occlusion of the bilateral common carotid arteries (BCCAs), followed by reperfusion for 3 days. Accelerating rotarod assessment at 24 h after BCCA occlusion showed amelioration of sensorimotor impairment in the mice fed the supplemented diets as compared with the ischemic mice fed the control diet. Quantitative digital pathology assessment of brain slides stained with cresyl violet at 3 days after ischemia/reperfusion (I/R) revealed significant reduction in neuronal cell death in both dietary groups. Immunohistochemical staining for ionized calcium-binding adapter molecule-1 demonstrated pronounced activation of microglia in the hippocampus and striatum in the ischemic brains 3 days after I/R, and microglial activation was significantly reduced in animals fed supplemented diets. Mitigation of microglial activation by the supplements was further supported by the decrease in expression of p47phox, a cytosolic subunit of NADPH oxidase, and phospho-ERK1/2, a mitogen-activated protein kinase known to mediate a number of cytoplasmic processes including oxidative stress and neuroinflammatory responses. These results demonstrate neuroprotective effect of Sutherlandia and American elderberry botanicals against oxidative and inflammatory responses to cerebral I/R.

Antioxidant potential of Sutherlandia frutescens and its protective effects against oxidative stress in various cell cultures.

BackgroundSutherlandia frutescens (L.) R.Br. (SF) is a South African plant that is widely used to treat stress, infections, cancer, and chronic diseases, many of which involve oxidative stress. The aim of the study was to quantitatively assess the antioxidant potential of SF extracts in cell-free system as well as in cell lines.MethodsDried SF vegetative parts were extracted using six different solvents, and the extracts were assessed for total phenolic and flavonoid contents, total reducing power, iron chelating capacity, and free radical scavenging power, including, scavenging of hydroxyl radicals, superoxide anions, nitric oxide, and hydrogen peroxide. We further investigated the freeze-dried hot water extract of SF (SFE) to assess its effect against oxidative stress induced by tert-butyl hydroperoxide (t-BHP), an organic peroxide. Three different cell lines: Chinese hamster ovary (CHO), human hepatoma (HepaRG), and human pulmonary alveolar carcinoma (A549) cells, were employed to determine cell viability, intracellular reactive oxygen species (ROS) levels, and reduced to oxidized glutathione levels (GSH/GSSG).ResultsThe results indicated that: (1) SF extracts have significant antioxidant potential that is dependent upon the nature of the extraction solvent and (2) SFE protects against tBHP-induced oxidative stress in cells by scavenging ROS and preserving intracellular GSH/GSSG.ConclusionOxidative stress is implicated in a number of disorders, and due to the public’s concerns about synthetic antioxidants, various natural antioxidants are being explored for their therapeutic potential. Our findings support claims for S. frutescens being a promising adjunctive therapeutic for oxidative stress-related health problems.

The immunostimulatory and antimicrobial property of two herbal decoctions used in the management of HIV/AIDS in Ghana.

HIV/AIDS is a pandemic retarding economic growth and destroying human capital globally. This study therefore investigated the perceived efficacy of Betula alba (BA) and Sutherlandia frutescens (SF) decoctions used in the management of HIV/AIDS in Ghana. A study on the records of HIV/AIDS patients attending Habibi Herbal Clinic, Kumasi, Ghana, was conducted to obtain information on the initial viral load presented during their maiden visit and results after treatment with the herbal decoctions. The decoctions were assessed for immunostimulatory property in cyclophosphamide-induced immunosuppressed ICR mice. Total white blood cell count, as well as lymphocyte and neutrophil counts were determined and their effects compared with Levamisole. The decoctions were also screened for antimicrobial activity by the micro dilution method. The two herbal decoctions used significantly reduced (P ≤ 0.001) the patients' viral loads (47.42 ± 17.28 % to 13.69 ± 12.42 %; n=16). BA (1, 2, and 4 mg/kg) and SF (0.4, 0.8, and 1.6 mg/kg) caused significant increment (P ≤ 0.001) in total WBC and lymphocyte count in mice comparable to that produced by 2.5 mg/kg Levamisole. The decoctions also exhibited antimicrobial activity against gram negative and gram positive bacteria as well as Candida albicans (MIC 0.607 to 3.062 mg/ml). Phytochemicals present in both plants include saponins, terpenoids and coumarins. The Betula alba and Sutherlandia frutescens decoctions have interesting immunostimulatory and antimicrobial properties and hence could be useful in the management of HIV/AIDS and associated opportunistic infections.

A chemometric approach to the quality control of Sutherlandia (cancer bush)

Sutherlandia frutescens (Fabaceae) commonly known as cancer-bush, is a well-known traditional phytomedicine in South Africa used to treat a range of ailments. There is limited information available on the phytochemistry and chemical variation within and between the S. frutescens and Sutherlandia microphylla species complex. This paper aims to elucidate the chemical variation of phytoconstituents (other than the non-protein amino acids) between the two species S. frutescens and S. microphylla and also between the wild and cultivated varieties of S. frutescens. An UPLC–MS analysis in tandem with chemometric analysis has been performed to assess the metabolite content of aerial plant parts obtained from different populations. Principal component analysis (PCA) was performed to observe groupings and trends in the data matrix. An orthogonal partial least square discriminant analysis (OPLS-DA) was performed which resulted in clear groups between the two taxa. Several flavonoid and triterpenoid glycoside derivatives contribute to the quantitative chemotypic variation within and between the species as observed. The identification of these compounds using advanced chromatographic techniques (UPLC–MS) and chemometric analysis leads to a better understanding of the phytochemical variation of Sutherlandia which can aid in quality control of raw material, phytomedicines and commercial herbal products.

Interactive antimicrobial and toxicity profiles of conventional antimicrobials with Southern African medicinal plants

Medicinal plant use plays an important role in the healthcare of many South Africans. Furthermore, in orthodox medicine, conventional antimicrobial agents are amongst the most commonly prescribed groups of drugs. Therefore, due to the prevalence of use of these two forms of healthcare, there is a high probability for their concurrent use. Thus, the aim of this study was to evaluate the interactive antimicrobial and toxicity profiles of six Southern African medicinal plants (Agathosma betulina, Aloe ferox, Artemisia afra, Lippia javanica, Pelargonium sidoides and Sutherlandia frutescens) when combined with seven conventional antimicrobials (ciprofloxacin, erythromycin, gentamicin, penicillin G, tetracycline, amphotericin B and nystatin). Antimicrobial activity was assessed using the minimum inhibitory concentration (MIC) assay against a range of pathogens and interactions were further classified using the sum of the fractional inhibitory concentration (∑FIC). Notable synergistic or antagonistic interactions were studied at various ratios (isobolograms). The toxicity of the individual samples, as well as the notable combinations, was assessed using the brine-shrimp lethality assay (BSLA) and the 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on the HEK-293 human cell line. Of the 420 antimicrobial:plant combinations studied, 14.29% showed synergistic interactions, 7.56% antagonistic, 35.71% additive and 42.44% indifferent interactions. Some notable synergistic interactions (ciprofloxacin with A. betulina and S. frutescens against Escherichia coli) and antagonistic interactions (ciprofloxacin with A. afra organic extract against Escherichia coli) were identified. None of the notable combinations were found to show toxicity in the BSLA or MTT assay. In conclusion, the majority of combinations were found to have no notable interaction, alleviating some concern related to the concurrent use of these two forms of healthcare.

Lessertia frutescens (Sutherlandia) suppresses multiple intracellular signaling pathways associated with inflammatory responses in murine macrophages (830.12)

Sutherlandia is an herb native to southern Africa and traditionally used in various inflammatory conditions. Previously, we reported that an ethanolic extract of Sutherlandia (SE) had anti‐inflammatory activity in murine macrophages. This study was designed to investigate the impact of SE on inflammation‐related intracellular signaling pathways, and to identify the bioactive component(s) in this herb. RAW 264.7 cells were exposed to various concentrations of SE for 1 hr, then an inflammatory response was triggered by co‐treatment with LPS and IFNγ. The phosphorylated and total STAT1, ERK1/2, p38, and JNKs in cell lysates were determined by Western blot. Exposure to SE significantly decreased the phosphorylation of STAT1 and ERK1/2 by up to 80% and 70%, respectively. Meanwhile, SE had only a limited effect on the phosphorylation of p38 and JNK. We used nitric oxide (NO) production as a screening tool to evaluate the anti‐inflammatory activities of Sutherlandia‐specific constituents: sutherlandiosides A‐D, sutherlandins A‐D. None of these compounds were able to reduce LPS/IFNγ‐induced NO production. In summary, our crude Sutherlandia extract suppressed several key signaling pathways related to inflammatory responses in macrophages, and we continue to search for the constituent(s) responsible.Grant Funding Source: Supported by NIH P50AT006273

Sutherlandia frutescens Ethanol Extracts Inhibit Oxidative Stress and Inflammatory Responses in Neurons and Microglial Cells

Sutherlandia frutescens (L.) R.Br. (SF) is a medicinal plant indigenous to southern Africa and used in folk and contemporary remedies for stress, chronic diseases, cancer, and HIV/AIDS. While previous studies have focused on physiological effects of SF on cellular and systemic abnormalities associated with these diseases, little is known about its effects in the brain and immune cells in the central nervous system. Results of this study indicate that ethanol extracts of SF (SF-E) suppress NMDA-induced reactive oxygen species (ROS) production in neurons, and LPS- and IFNγ-induced ROS and nitric oxide (NO) production in microglial cells. SF-E’s action on microglial cells appears to be mediated through inhibition of the IFNγ-induced p-ERK1/2 signaling pathway which is central to regulating a number of intracellular metabolic processes including enhancing STAT1α phosphorylation and filopodia formation. The involvement of SF in these pathways suggests the potential for novel therapeutics for stress and prevention, and/or treatment of HIV/AIDS as well as other inflammatory diseases in the brain.

Effect of strigolactones and auxins on growth and metabolite content of Sutherlandia frutescens (L.) R. Br. microplants in vitro

The influence of strigolactones as hormones in plants is not fully characterised even though they are known to affect plant architecture, both above ground and in the roots. Using an in vitro system, the effects of the synthetic auxins 1-naphthalene acetic acid and indole-3-butyric acid (NAA and IBA) and synthetic strigolactones (GR24 and Nijmegen-1) were tested on microplant development of Sutherlandia frutescens, a leguminous medicinal plant native to South Africa. Considerable phytochemical variation in wild populations has led to the proposal of using micropropagation for this species. This will assist with domestication and provide plants with a more predictable chemistry for the phytopharmaceuticals industry. Nodal explants with an axillary bud were grown on Murashige and Skoog (Plant Physiol 15:473–497, 1962) medium [0.8 % (m/v) agar (pH 5.8), 3 % (m/v) sucrose and 0.1 g/L myo-inositol] supplemented with NAA, IBA, GR24 and Nijmegen-1, either singly or in combination. The amino acid profile and secondary metabolite pool was monitored using LC–MS-profiling. Treatment with NAA promoted mass shoot production, whilst a combination of NAA and Nijmegen-1 also positively influenced the accumulation of amino acids, flavonoids (sutherlandins) and terpenoids (sutherlandiosides) that S. frutescens produces. Since these compounds represent the presumed active compounds in this species and the biomarkers used in quality control assessment of S. frutescens tissues harvested for the pharmaceutical industry, this treatment holds promise for the commercial production of Sutherlandia extracts and herbal medications.

Immunomodulating polysaccharides from Lessertia frutescens leaves: Isolation, characterization and structure activity relationship

Ethnopharmacological relevanceSutherlandia frutescens (syn. Lessertia frutescens) is an indigenous plant in Southern Africa and has been extensively studied from the ethnobotanical point of view. Amongst the various traditional uses, several illnesses involving the immune system have been reported. Due to some of the therapeutic effects observed, in relation to the traditional uses reported by the “khoi san” and “nama” people on cancer related illnesses, the plant has been given the local name kankerbos (cancerbush). Recently the plant has also been used amongst HIV/AIDS patients to stimulate the immune system. Materials and methodsLeaves of Sutherlandia frutescens were extracted sequentially with ethanol, 50% ethanol/water, and water at 50 and 100°C. The polysaccharides were extracted with water and fractionated by ion exchange chromatography and gel filtration to obtain enriched polysaccharide fractions. The bioactivities of the fractions were tested in the complement assay. Some of the fractions were treated with the enzyme pectinase, and the fragments thus produced were separated by gel filtration and their activities tested. Monosaccharide compositions and linkage analyses were determined for the relevant fractions. ResultsThe leaves of Sutherlandia frutescens contain polysaccharides of the pectin type. Fractions from both the water extracts of 50 and 100°C were bioactive. Fractions chosen for further studies showed that the fragment with the highest MW after the pectinase treatment had a substantially higher biological effect than the parent molecules. Based on a comparison of the different fractions it was concluded that galactose-rich regions were important for the bioactivity, these being of the AGII and AGI type, with the latter probably being more important than the former. Fragments rich in xylose also gave higher activity than those without it. ConclusionsOur theory that the polysaccharides present in the leaves of Sutherlandia frutescens could be of importance as immunomodulating agents was confirmed. It was also shown that certain types of polysaccharides had a higher effect in the complement system than others. Thus both the water extracts obtained at 50 and 100°C contain interesting biologically active polysaccharides.