Dendrobium (Shihu): Anticancer and Health-Promoting Effects
Chinese-medicine shihu is the stem of Dendrobium nobile, Dendrobium loddigesii, Dendrobium candidum, Dendrobium chrysanthum, and Dendrobium fimbriatum of the Orchidaceae family. Dendrobium candidum is also called Tiepi Fengdou, and there are now many health products on the market sold under that name. Clinically one may use fresh dendrobium, dried dendrobium, or dendrobium processed in yellow rice wine. Generally, fresh material is more suitable for heat disease with damaged fluids, dried dendrobium is better for stomach deficiency with heat damaging yin, and wine-processed dendrobium is higher in polysaccharides and dendrobine.
Traditional Chinese medicine classifies dendrobium among the yin-tonifying herbs, holding that it is sweet and slightly cold, entering the lung and kidney meridians, with the effects of benefiting the stomach and generating fluids, and nourishing yin and clearing heat. It is suitable for patients with heat disease damaging fluids, dry mouth and vexed thirst, insufficient stomach yin, poor appetite and retching, and residual deficiency heat after illness. One may use dendrobium alone or combine it with trichosanthes root (Tianhuafen), fresh rehmannia (Sheng Dihuang), rehmannia (Shengdihuang), Ophiopogon (Maidong), white peony (Baishao), bamboo shavings (Zhuru), phellodendron (Huangbai), and lycium bark (Digupi). Paired with different herbs, dendrobium plays different roles: it can treat epigastric dull or burning pain, poor appetite, and retching caused by insufficient stomach yin, and it can also treat yin deficiency with fluid depletion and persistent deficiency heat.
Dendrobium is also a Chinese herb that nourishes kidney yin. Patients with kidney-yin deficiency, dim vision, weak and withered sinews and bones, yin deficiency with effulgent fire, and steaming bone consumptive heat may use dendrobium combined with lycium fruit (Gouqizi), prepared rehmannia (Shudihuang), cuscuta (Tusuzi), ginseng (Renshen), asparagus root (Tiandong), chrysanthemum (Juhua), dioscorea (Shanyao), Ophiopogon (Maidong), tribulus (Jili), and celosia seed (Qingxiangzi). The patent medicine Shihu Yeguang Wan is made according to exactly this kind of composition; it has some effect on improving cataract of the liver-kidney yin deficiency type. Kidney-yin deficiency also causes weak, withered sinews and bones; such patients may combine dendrobium with bone-kidney-tonifying herbs such as prepared rehmannia (Shudihuang), eucommia (Duzhong), teasel (Xuduan), morinda (Bajitian), and achyranthes (Huainiuxi). In addition, for steaming bone tidal heat from yin deficiency with effulgent fire, one may combine dendrobium with lycium fruit (Gouqizi), phellodendron (Huangbai), and picrorhiza (Huhuanglian).
But not everyone is suited to dendrobium. Chinese medicine holds that dendrobium has the side effect of retaining pathogenic evils, so it should not be used too early in warm-heat diseases; moreover, all yin-nourishing herbs have the side effect of promoting dampness, so patients with a dampness-exuberant constitution should not use dendrobium.
Modern pharmacological research shows that dendrobium has good anti-mutagenic and anticancer effects. The water extracts of Dendrobium candidum and fresh Dendrobium candidum show strong anti-mutagenicity against cyclophosphamide (CP) in the mouse micronucleus test. Dendrobium nobile can inhibit expression of the umu gene of the mutagen furylfuramide and suppress the mutagenic activity of various carcinogens such as 4NQO, MNNG, Trp-P-1, aflatoxin, and ultraviolet radiation. Dendrobium nobile is also cytotoxic to human lung cancer A549 cells, human ovarian cancer SK-OV-3 cells, and human leukemia HL-60 cells, and can prolong survival in ICR mice bearing intraperitoneally implanted sarcoma S180.
In addition, dendrobium can raise gastric acid and serum gastrin concentrations, delay aging, boost immunity, act as an anticoagulant, and counter cataract. Dendrobium suits patients with too little gastric acid secretion and too low serum gastrin, but patients with excessive gastric acid will get the opposite effect. So dendrobium is not a health product suitable for all stomach patients; patients with acid reflux and heartburn should avoid it. Whether to use market health products such as Tiepi Fengdou should be discussed with a physician.