Dioscorea villosa (wild yam) induces chronic kidney injury via pro-fibrotic pathways

School of Medicine, University of Queensland, Brisbane, Queensland, Australia.
Food and Chemical Toxicology (Impact Factor: 2.9). 10/2008; 46(9):3122-31. DOI: 10.1016/j.fct.2008.06.090
Source: PubMed


Dioscorea villosa (wild yam) rhizome extract is a medicinal herb that is commonly used to treat symptoms of menopause and rheumatoid arthritis. We had evidence from previous in vitro experiments that this extract is toxic and pro-fibrotic in renal cells and aimed to test whether this occurs in vivo. Sprague-Dawley rats received 0.79g/kg/d D. villosa extract in their food or no treatment over 7, 14 and 28d (n=4 per group). Kidney and liver tissues were collected for protein extraction and Western immunoblots or fixed for special histologic stains, immunohistochemistry (IHC) and microscopy. Collagen deposition was assessed using Masson's trichrome staining and morphometry. Macrophage infiltration (ED-1), epithelial-to-mesenchymal transdifferentiation or activation of fibroblasts (vimentin, alpha-SMA), and pro-fibrotic growth factors (TGFss1, CTGF) were assessed using IHC. Protein expression levels of the pro-inflammatory cytokine, TNF-alpha, the pro-fibrotic transcription factor, NFkappaB, a measure of oxidative stress (heme oxygenase-1), alpha-SMA, vimentin and TGFss1 were determined. Results showed that kidneys of the treated animals had significantly increased collagen, vimentin, TGFbeta1, NFkappaB, EDI, CTGF and alpha-SMA by 28d. In the liver, there was increased ED-1 and TGFbeta1 in the centrilobular zone at 28d in treated animals. In conclusion, there was no acute reno- or hepato-toxicity associated with administration of D. villosa. However, there was an increase in fibrosis in the kidneys and in inflammation in livers of rats consuming D. villosa for 28 days. Long term supplementation with D. villosa may be best avoided, especially in people with compromised renal function and in those who need to take other drugs which may alter kidney function.

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    • "Tubers from the Dioscorea genus were widely used in CM to relieve the menopausal syndrome [89]. A tuber storage protein from Dioscorea batatas, dioscorin, was isolated and purified by ammonium sulfate fractionation, DE-52 ion-exchange chromatography, and Sephadex G-75 column chromatography [90]. "
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    ABSTRACT: Some protein pharmaceuticals from Chinese medicine have been developed to treat cardiovascular diseases, genetic diseases, and cancer. Bioactive proteins with various pharmacological properties have been successfully isolated from animals such as Hirudo medicinalis (medicinal leech), Eisenia fetida (earthworm), and Mesobuthus martensii (Chinese scorpion), and from herbal medicines derived from species such as Cordyceps militaris, Ganoderma, Momordica cochinchinensis, Viscum album, Poria cocos, Senna obtusifolia, Panax notoginseng, Smilax glabra, Ginkgo biloba, Dioscorea batatas, and Trichosanthes kirilowii. This article reviews the isolation methods, molecular characteristics, bioactivities, pharmacological properties, and potential uses of bioactive proteins originating from these Chinese medicines.
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    • "The chemical composition of DV includes protodioscin, methylprotodioscin, dioscine, prosapogenin, epiafzelechin glucopyranoside, saponin glycosides, steroidal saponin, diosgenin, alkaloids, tannins and phytoestrogen [8-12]. In addition, the rhizomes and roots of DV have been popularly used as a non-conventional treatment of the symptoms of menopause [13,14], rheumatoid arthritis and hypoprogesteronaemia [8,11]. "
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    • "They are characterized by the possession of edible tubers that are rich in starch, some ions and vitamins. However, most of the yam tubers have to be cooked before consumption, in order to remove the toxic compounds present [19], [20]. "
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