 | ||
Huáng bǎi (黄栢 or 黃栢, literally "yellow fir") or huáng bò (黄檗) is one of the fifty fundamental herbs of traditional Chinese medicine. Known also as Cortex Phellodendri, it is the bark of one of two species of Phellodendron tree: Phellodendron amurense or Phellodendron chinense.
Contents
Cultivation
For Phellodendron amurense (关黄柏, i.e. "highland Phellodendron") one of the major producing areas is Taoshan District of Heilongjiang province, though other regions of Heilongjiang, Jilin, Liaoning and Inner Mongolia may also be suitable. These provinces are in the far northeast of China, near the Heilong Jiang river, known in Russian as the Аму́р (Amur River), and Phellodendron amurense is commonly known as the Amur cork tree.
Phellodendron chinense (川黄柏, i.e. "lowland Phellodendron") producing areas include Sichuan, Hubei, Guizhou, Yunnan, and Guangxi.
Preparation
Bark is collected during Qingming (Pure Brightness), the fifth solar term (April 4–20). It is sun-dried and cut into slices. The bark may be used raw or fried with salt. Typical dosage is 3-10 grams. A variety of methods of water and ethanol extraction may have differing activities (see below) and methods such as "semi-bionic extraction" have been investigated to improve yields. Some pharmacological activities of the bark can be standardized by analyzing the level of berberine using a monoclonal antibody, thin-layer chromatography, HPLC, potentiometry, or acidic potassium permanganate chemiluminescence. There are quantitative differences between the two species of Cortex Phellodendri (P. amurense and chinense) and it has been suggested that they should be used as separate resources in the clinic. An analysis of 31 commercial samples in 1993 found that the total level of five alkaloids in samples of P. wilsonii and P. amurense var. sachalinense was 4.1% (mostly berberine), while the level in P. amurense and Ph. chinense was 1.5%.
The levels of four harmful trace heavy metals (arsenic, cadmium, mercury, and thallium) in P. chinense for export are limited by the Pharmacopoeia of the People's Republic of China and the Green Trade Standard for Importing and Exporting Medicinal Plant and Preparation.
History
The earliest known report of this medicine is in the Shen nong ben cao jing
Traditional attributes
The bark is categorized in a traditional Chinese medicine counterpart of humorism, Wu Xing, as bitter and cold, affecting the kidney, urinary bladder and large intestine meridians. Is said "to clear heat and dry dampness", and "to reduce fire and release toxins".
Physiological effects
A wide range of primary scientific publications have been made about the activities of extracts of Phellodendron bark, primarily from the People's Republic of China. These should be evaluated cautiously, as many of them represent small studies, with little confirmation, and occasionally are subject to conflict of interest, but they are what is available.
In mice with hyperuricemia, Phellodendron amurense (whether raw or processed with salt) reduced blood uric acid levels by inhibiting xanthine oxidase activity.
In vitro studies found that the extract reduced neuronal cell death (apoptosis) in a tissue culture line treated with a strong toxin (MPTP). By contrast, it was identified as a possible inducer of apoptosis in HL-60 cells.
Various preparations of the bark showed antioxidant activities, with an 80% ethanol extract of the bark stir-fried with yellow alcohol having the largest effect.
Phellodendron amurense and Coptis chinensis were identified from among 297 Chinese medicines as herbs that reduce activation of NF-κB by a liver cell line in response to acetaldehyde, a breakdown product of ethanol associated with cirrhosis. NF-κB is part of an inflammatory process, and it is believed that berberine, a component of the two herbs, is responsible for the effect. Phellodendron amurense also inhibited proinflammatory iNOS and TNF-alpha activity in a glial cell line and has topical anti-inflammatory activity. Phellodendron wilsonii was found to have a hepatoprotective activity in carbon tetrachloride treated rats.
Ethanol extracts, but not water extracts, of huáng bǎi appeared to exert antidiarrheal activity by attenuating ion transport by intestinal epithelium.
Medicinal extracts of the bark reduced the rate of growth of Candida, which has been ascribed to berberine and palmatine content. They have also been investigated for use against Mycoplasma hominis, Propionibacterium acnes, and Helicobacter pylori. A bark extract was reported to reduce formation of stomach ulcers in mice under several stresses, due to cytoprotection and reduced secretion of stomach acid. The cytoprotective effect against ulcers is abolished by pretreatment with N-ethylmaleimide, suggesting that sulfhydryl compounds are involved.
A methanol extract (100–400 mg/kg) was found to protect against airway inflammation in response to lipopolysaccharide treatment of mice.
The extract (379 mg/kg) was found to reduce blood glucose levels and slow the development of diabetic nephropathy in mice treated with streptozocin to induce diabetes. Similar effects have been attributed to berberine.
Extracts of the bark have been reported to reduce contractions of smooth muscle of isolated rat prostate glands. Certain polysaccharide fractions from Phellodendron chinense were reported to increase T cell activity and reduce cell replication of tumors in mice. A group studying Nexrutine, a brand of fractionated extract, found that it reduced the rate of replication of prostate tumor cells. Tests of Nexrutine (300–600 mg/kg) in a mouse strain designed to develop prostate cancer found a dramatic reduction in palpable tumors. Another brand, Prostant, has been used for chronic prostatitis
Phellodendrine and magnoflorine from the bark showed an immunosuppressive effect on local graft-versus-host reactions in mice, but phellodendrine does not affect antibody production in mice to SRBC.
Combination therapies
In combination with Citrus sinensis extract, it reduced pain and inflammatory markers in arthritis patients, with apparent benefits on weight loss and cardiovascular health.
Traditional Chinese medicines containing Huáng bǎi include:
Korean medicines include:
Cortex Phellodendri, known in Japanese as Ōbaku (黄檗) is also among the Kampo herb list of traditional Japanese medicine. The 1249 treatise Pí Wèi Lùn, known in Japanese as the Hi-i-ron, notably recommended it in combination with sweet Qi-tonics (Hoki-yaku) such as Ginseng and Atractylodis Macrocephalae Rhizome, but these formulations are less prominent in the Nei Wai Shang Bian Huo Lun. Use of the root (Radix Phellodendri) was described in the 1735 Sambutsu-cho.
Use of the herb has been unknown in European medicine.
Biochemical analysis
Small molecules found in the bark include: