Compounds in yam have vasodilating and antioxidant properties
12/09/2019 / By Melissa Smith
Wild yam joins the roster of heart-healthy foods, as a study published in the Journal of Medicinal Food reveals that a compound called diosgenin in the Dioscorea species of yam has vasodilating effects that may boost cardiovascular health.
Researchers from Brazil looked at the effects of diosgenin on the cardiovascular health of rats. They examined both the vasorelaxant and antioxidant mechanisms of diosgenin in isolated rat aortic rings.
The research team randomly subjected female rats to sham operation or ovariectomy – the removal of ovary or ovaries – at eight weeks of age. The operation was performed to induce menopause after anesthesia. The researchers then treated the rats with diosgenin for 28 days.
The results showed that diosgenin produced a concentration-dependent relaxation in aortic rings precontracted with phenylephrine, an active ingredient in many over-the-counter medicines. In the endothelium-intact rings, the vasorelaxant effect of diosgenin was reduced.
The researchers also found that diosgenin inhibited the contractions induced by cumulative addition of phenylephrine. Furthermore, the 28-day treatment with diosgenin significantly increased the levels of the antioxidant enzymes glutathione, superoxide dismutase, and nitric oxide, as well as decreased the concentration of malondialdehyde, a marker for oxidative stress related to lipid peroxidation.
Based on these results, the researchers concluded that diosgenin has vasodilating effects through an endothelium-dependent pathway, which involves the endothelium-derived relaxing factor (EDRF), the opening of potassium channels, and antioxidant action. (Related: Eat your medicine: 5 Herbs in your pantry that have amazing health benefits.)
Other health benefits of diosgenin and yams
Diosgenin may also protect against cancer. A study published in PLOS One journal suggests that diosgenin may help protect against prostate cancer. In this study, researchers from Taiwan used diosgenin from fenugreek to examine the compound’s cancer-fighting properties. Specifically, they examined the effects of diosgenin on migration and invasion of human prostate cancer PC-3 cells.
Treating prostate cancer cells with diosgenin prevented the migration and invasion of the cancer cells. It also significantly reduced the level of nuclear factor kappa B (NF-kB), a protein complex that controls DNA transcription, cytokine production, and cancer cell survival. The researchers concluded that diosgenin may potentially be used in anti-metastatic therapy.
The diosgenin in yams also boosts brain health. Animal and human studies found that this compound promotes neuron growth and improves memory, learning abilities, and overall brain function.
Yams also have powerful antioxidants, which help fight inflammation and inflammation-related diseases like diabetes, obesity, and heart disease. Several animal studies have shown that yam powder reduced inflammation related to several diseases, such as colon cancer, stomach ulcers, and irritable bowel syndrome (IBS).
Yams are also a great source of fiber, vitamins, and minerals. They are especially rich in copper, manganese, potassium, and vitamin C.
Extracting diosgenin from yam species
Researchers from China conducted a comparative analysis to screen potential resource from yam species and related medicinal plants for diosgenin extraction. They developed an ultra-performance liquid chromatography (UPLC) coupled with diode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS) method to identify the presence of diosgenin in different plants.
They used 24 batches of plant samples from four yam species, one Smilax species and two Heterosmilax species. The method presented good sensitivity, precision, and accuracy. Out of the samples examined, the researchers found diosgenin in three yam species and one Heterosmilax species – D. zingiberensis, D. septemloba, D. collettii, and H. yunnanensis. By comparing the plants’ diosgenin content, the researchers determined that D. zingiberensis is an important plant resource for diosgenin harvesting.
Overall, the researchers concluded that the method is suitable for screening diosgenin resources from plants. These findings contribute to the research and development of medicinal plants, especially for the screening of plant-derived diosgenin sources.
To learn more about plant compounds that have beneficial effects on your health, visit Phytonutrients.news.
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