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Dive into the research topics where Vanessa Steenkamp is active.

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Featured researches published by Vanessa Steenkamp.


Journal of Ethnopharmacology | 2003

Traditional herbal remedies used by South African women for gynaecological complaints

Vanessa Steenkamp

Traditional remedies are part of the cultural and religious life of the African people. In this manuscript the nature and range of traditional remedies used for female complaints in relation to gynaecological conditions and disorders is reviewed. A total of 156 medicinal plant species are documented as being used for gynaecological complaints in South Africa. These are presented in a table with the local name, part of the plant used and specific gynaecological treatment. Medicinal plant species which are potentially toxic are noted as are the compounds responsible for the toxicity and the feature(s) of poisoning. Traditional remedies used in South Africa for the treatment of gynaecological problems are compared to those used elsewhere in the world. This manuscript indicates that a wide spectrum of herbal traditional remedies are used to regulate the menstrual cycle, enhance fertility and as either abortifacients or antiabortifacients.


Pharmaceutical Biology | 2007

Medicinal Applications and Toxicological Activities of Aloe. Products

Vanessa Steenkamp; Michael J. Stewart

Abstract Aloe. (Lilliaceae) has long been used as a remedy in many cultures. Aloe. products, which include the latex, gel, and whole leaf, are used, among other reasons, as laxatives, in creams for skin ailments, and as a treatment for a wide range of diseases, respectively. The heterogeneous nature of Aloe. products may contribute to the diverse biological and therapeutic activities that have been observed. Variations in the composition of Aloe. can result in products with different chemical and physical properties, making the comparison of products difficult. In this article, the chemistry, uses, pharmacological activity, and toxicity of Aloe. gel, latex, and isolated compounds are reviewed. This article is confined to literature pertaining to Aloe vera. (L.) Burm.f. (also known as A. barbadensis. Miller) and Aloe ferox. Miller since they are the most widely used species both commercially and for their therapeutic properties.


Therapeutic Drug Monitoring | 2000

The biochemistry and toxicity of atractyloside : A review

Michael J. Stewart; Vanessa Steenkamp

Atractyloside poisoning is an infrequent but often fatal form of herbal poisoning, which occurs worldwide but especially in Africa and the Mediterranean regions. The primary mechanism of atractyloside poisoning is known to be inhibition of the mitochondrial ADP transporter. Poisoning in humans may present with either acute hepatic or renal pathology and it is possible that there is a second, different mechanism of toxicity to the hepatocyte. Atractyloside in large amounts gives rise to massive necrosis, but in vitro studies have shown that at lower doses cells progress to apoptosis. Simple methods for the detection of atractyloside poisoning are at present restricted to thin-layer chromatography in urine and are useful only in the case of severe poisoning. Immunoassays, high-performance liquid chromatography, nuclear magnetic resonance, and a recently developed high-performance liquid chromatogrpahy/mass spectrometry method have yet to be applied to clinical diagnoses. There is at present no treatment, but a fuller understanding of the mechanisms of toxicity may lead to the application of a number of compounds that are effective in vitro.


Therapeutic Drug Monitoring | 2005

Adulteration of South African traditional herbal remedies.

Tracy Snyman; Michael J. Stewart; Alida Grove; Vanessa Steenkamp

Traditional herbal remedies are used as alternative medicine by a large proportion of people worldwide. Herbals are generally perceived as safe, harmless, and free from side effects, but there have been reports of adulteration of Asian herbal remedies with Western pharmaceuticals, a practice that has not hitherto been observed in Africa. The authors present 2 cases from South Africa in which herbal remedies, consumed by patients admitted to hospital, were found to be adulterated with commercially available Western medicines. The adulterants were identified using high-performance liquid chromatography with a photodiode array detector and gas chromatography-mass spectrometry. The authors alert clinicians to the fact that adulteration of herbal remedies may become more common and should be considered, especially in cases where the symptoms are confusing in light of the history.


Therapeutic Drug Monitoring | 2001

Pyrrolizidine poisoning: a neglected area in human toxicology.

Michael J. Stewart; Vanessa Steenkamp

Pyrrolizidine poisoning in humans is regarded by most clinical toxicologists as of little relevance. However, a number of individual case studies in the West and some severe cases of mass poisoning by contaminated grains have led to increased interest in these alkaloids. The increasing use of herbal remedies, some of which contain toxic pyrrolizidines, suggests that the incidence of pyrrolizidine poisoning is likely to increase. In this review the authors describe the chemistry and metabolism of pyrrolizidine alkaloids, the salient features of pyrrolizidine poisoning, and the methods available for detection of these compounds in human fluids.


Journal of Ethnopharmacology | 2012

Cytotoxicity and acetylcholinesterase inhibitory activity of an isolated crinine alkaloid from Boophane disticha (Amaryllidaceae)

Emmanuel Adekanmi Adewusi; Gerda Fouche; Vanessa Steenkamp

ETHNOPHARMACOLOGICAL RELEVANCE Boophane disticha of the family Amaryllidaceae is used traditionally in southern Africa in the treatment of several neurological disorders. AIM OF THE STUDY Although acetylcholinesterase (AChE) inhibitory activity has been reported for this plant, the aim of the study was to identify and characterise the compound responsible for this activity using bioassay guided fractionation. Toxicity of the isolated compound was also assessed. MATERIALS AND METHODS Bioassay guided isolation of the active compound from the methanol extract was carried out using column chromatography, TLC and preparative thin layer chromatography. Structural elucidation was carried out using high field 1D and 2D NMR and mass spectroscopy. AChE inhibitory activity was determined using the Ellmans colorimetric method. Cytotoxicity assessment was determined in human neuroblastoma (SH-SY5Y) cells using the MTT and neutral red uptake assays. RESULTS The data obtained from the integration of the (1)H spectra confirmed the compound to be a 3:1 mixture of two epimers, with epimer A, 6α-hydroxycrinamine as the major epimer. The IC(50) value for AChE inhibitory activity of the compound was 445 μM. The compound was observed to be cytotoxic in both the MTT and neutral red assays with IC(50) values of 54.5 and 61.7 μM, respectively. CONCLUSION The present study describes for the first time, the isolation of 6-hydroxycrinamine, a crinine alkaloid, from the methanol extract of the bulbs of B. disticha. Although this compound possessed AChE inhibitory activity, it was found to be toxic to the neuroblastoma cells. Quantitative structure-activity relationship studies could be carried out to modify the structure in order to make it less toxic and improve its activity.


Fitoterapia | 2003

Phytomedicines for the prostate.

Vanessa Steenkamp

Phytomedicines are becoming more popular all over the world. Prostate cancer patients and those with benign prostatic hyperplasia are increasingly exploring the use of complementary alternative medicine especially due to the risk of mortality and long-term morbidity associated with surgical procedures. The incidences of prostate diseases are continually rising and the effect of phytomedicines already tested do provide relief, are well comparable with that of traditional forms of treatment. This paper reviews the phytomedicines used in Africa, Western countries and China as a treatment of benign prostatic hyperplasia, prostatitis and prostate cancer. Herbals which hold potential promise are mentioned, although much research is still required.


Pharmaceutical Biology | 2012

Herbal remedies affecting coagulation: A review

Werner Cordier; Vanessa Steenkamp

Context: Herbal remedies are used to treat a large variety of diseases, including blood-related disorders. However, a number of herbal preparations have been reported to cause variations in clotting time, this is mainly by disruption of the coagulation cascade. Objective: The compiling of plants investigated for effects on the coagulation cascade. Methods: Information was withdrawn from Google Scholar and the journal databases Scopus and PubMed. Results: Sixty-five herbal remedies were identified with antiplatelet, anticoagulant, or coagulating ability. Bioactive compounds included polyphenols, taxanes, coumarins, saponins, fucoidans, and polysaccharides. Conclusion: Although research has been conducted on the effect of herbal remedies on coagulation, most information relies on in vitro assays. Contradictory evidence is present on bleeding risks with herbal uses, though herb–drug interactions pose a threat. As the safety of many herbals has not been proven, nor their effect on blood parameters determined, the use of herbal preparations before undergoing any surgical procedure should discontinued.


Human & Experimental Toxicology | 2008

In-vitro bioactivity of Venda medicinal plants used in the treatment of respiratory conditions

Ca Pallant; Vanessa Steenkamp

Infectious diseases, especially those affecting the respiratory tract, represent a critical problem to health. Crude methanol and water extracts of 10 Venda plants reported to be used ethnomedically in the treatment of respiratory conditions were assessed for their antimicrobial activity against standard strains and clinical isolates of Candida albicans, Haemophilis influenzae, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium smegmatis using the disc diffusion assay. Four of the 10 plants tested possessed antimicrobial activity, but no activity against K. pneumoniae was observed. Minimum inhibitory concentrations, as determined by the broth microdilution assay, showed three plants, Securidaca longepedunculata, Syzygium cordatum, and Tabernaemontana elegans, to possess MICs ≤ 1 mg/mL. Phytochemical screening, performed by separation on thin layer chromatography using a variety of mobile phases and visualization with spray reagents as well as UV light showed various classes of compounds in the active extracts. Some of these have been associated with antioxidant activity, as confirmed in this study. Moreover, these extracts showed toxicity in vitro to lymphocytes. Although three plant species with significant antimicrobial activity were identified, there is a need for further scientific evaluation regarding identification of the bioactive constituents, as well as their toxicity.


Therapeutic Drug Monitoring | 2005

Nephrotoxicity associated with exposure to plant toxins, with particular reference to Africa.

Vanessa Steenkamp; Michael J. Stewart

Acute renal failure is a frequent cause of morbidity and mortality in the hospitalized population worldwide. In Africa, apart from hemodynamic causes and infections, herbal remedies contribute to both morbidity and mortality, although these causes often go unrecognized. This paper reviews reports of herbal remedies that have been shown to result in nephrotoxicity. The indications for use of the remedies, signs and symptoms in poisoned patients, and the methods used to detect toxic compounds in plant specimens or in biological fluids are covered.

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Michael J. Stewart

University of the Witwatersrand

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Gerda Fouche

Council for Scientific and Industrial Research

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Mary Gulumian

University of the Witwatersrand

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Paul A. Steenkamp

University of Johannesburg

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