The Lipid-Lowering, Wind-Damp-Dispelling, Anti-Leukemia, and Urinary-Frequency-Treating Effects of Bixie (Dioscoreae Hypoglaucae Rhizoma)
The Chinese medicine Bixie is the rhizome of Dioscorea hypoglauca, a plant of the yam family. The yam family plant we are most familiar with is Shanyao (Chinese yam), a widely popular food; Bixie belongs to the same plant family as Chinese yam. The stems, leaves, and rhizomes of Bixie are very similar to those of Chinese yam, and the slices of the medicinal Bixie resemble those of Chinese yam. Their effects also have similarities: both secure the kidney and can treat diarrhea, leukorrhea, and frequent urination.
But the two also differ. Chinese yam is a typical tonifying medicinal, sweet in flavor and warm in nature, whereas Bixie is bitter in flavor and neutral in nature, with its main effect on draining damp turbidity and dispelling wind-dampness. It principally treats cloudy strangury (gao lin), white turbidity (bai zhuo), leukorrhea, eczema, sores and ulcers, frequent urination, and wind-damp bi pain.
Modern pharmacological research shows that dioscin and the prosapogenin B of gracillin in Bixie have antifungal effects (against Trichophyton and Pityrosporum) but are ineffective against bacteria. The total gracillin saponins in Bixie lower blood sugar and blood lipids and have a certain improving effect on cardiovascular disease. The lipid-lowering effect of Bixie is a discovery of modern TCM. Studies show that taking Bixie alone, ground into powder, 3 times a day, 5 g each time, infused in warm water and persisted in for more than 3 months, can significantly improve blood lipids in patients with hypercholesterolemia and hypertriglyceridemia, without easy recurrence.
In addition, the dioscin in Bixie can also inhibit the leukemia L1210 tumor cell line, but clinical research in this area is still scarce, and further research is needed to reveal its anti-leukemia mechanism.
In ancient China, Bixie's best-known effect was treating frequent urination. In the Ji Sheng Fang there is a "Bixie Wan," using only the single herb Bixie, made into wutong-seed-sized pills (soybean-sized, about 6-10 mm in diameter); 70 pills are taken each time to treat frequent urination day and night without regularity. The Bixie Fenqing San in the Yangshi Jia Cang Fang is made of equal parts Bixie, Yizhiren (Alpiniae Oxyphyllae Fructus), Wuyao (Linderae Radix), and Shichangpu (Acori Tatarinowii Rhizoma) as a powder; each time 3 qian (9 g) is decocted and taken to treat white turbid urine with frequent, uncontrolled urination, white as rice water and congealing like paste. These symptoms treated by Bixie resemble the clinical symptoms of modern medicine's chyluria, urethritis, prostatitis, and nephrotic syndrome, so such formulas are now mostly used to treat the above diseases.
Another major effect of Bixie is dispelling wind-dampness. The Shennong Bencao Jing records that Bixie "mainly treats lower-back pain, strengthens the bones and joints, and wind-cold-damp generalized bi." The Yaoxing Lun records that Bixie "treats cold-wind bi, inability of the lower back and feet, and twitching of the hands and feet." From ancient formula books one can find many formulas using Bixie to treat paralysis, numbness of the legs and feet, and lower-back pain; in such formulas Bixie is often used together with herbs that likewise treat wind-damp bi pain and paralysis, such as Duzhong (Eucommiae Cortex), Xuduan (Dipsaci Radix), Qianghuo (Notopterygii Rhizoma), Duhuo (Angelicae Pubescentis Radix), Mugua (Chaenomelis Fructus), Niuxi (Achyranthis Bidentatae Radix), Huangbai (Phellodendri Cortex), and Cangzhu (Atractylodis Rhizoma).