SIMPLE TRADITIONAL FORMULAS FOR PAIN
Shixiao San, Jin Lingzi San, Liang Fu Wan, and Baishao Gancao Tang
Treatment of pain is a primary function of all medical systems. Throughout history, analgesic substances have been intensively sought out; among the earliest materials found to be effective were alcohol, cannabis, and datura. In China, Hua Tuo (110-207 A.D.) is credited with having developed the first anesthetic used in performing surgery. His formulation may have been comprised primarily of an alcoholic infusion of cannabis and datura. One of the greatest achievements in drug development was the isolation of morphine from the opium poppy during the early years of the 19th century. It was named after the Greek god Morpheus, god of sleep, because of its profound sleep-inducing properties, but it soon became the preferred drug for severe pain, a role it retains to the present. Anti-inflammatory drugs, starting with aspirin, were developed during the latter half of the 19th century, and evolved into large group of important analgesics that are described today as non-steroidal anti-inflammatories; these are given for treatment of pain with or without evident inflammation (1, 2).
The use of crude herbs for alleviating pain still has a role in medical practice, particularly in Chinese herbalism. The primary application is in the treatment of chronic or recurrent pain in patients who experience unacceptable side effects or are concerned about adverse effects that might arise from prolonged use of the drug therapies. In addition, there is a hope that proper herb therapy may eventually resolve the cause of the pain syndrome, rather than just alleviating the pain only at the time when the herbs or drugs are consumed.
While numerous herbs are believed to be helpful in the treatment of pain (see Appendix 1), in most cases, Chinese herbalists simply incorporate two or three herbs that are considered especially effective into a prescription that addresses the patient's general syndrome. Four small analgesic formulations that might be added to complex prescriptions are outlined here; these are probably the most commonly used herb combinations for pain that involve non-toxic herbs.
Shixiao San is a formula of the Taiping Huimin Hejiju Fang (ca. 1110), a famous medical dictionary of the Song Dynasty. It is comprised of just two ingredients-trogopterus and typha-in equal amounts, ground to powder, to be swallowed down with water containing a little vinegar, which is said to enhance the ability of herbs to break down static blood. The combination, usually taken 6 grams each time, is indicated for blood stasis that causes pain, particularly in cases that are persistent or recurrent. The formula name literally means the powder for the lost smile, but has been translated also to describe the effect of taking the formula, namely as the "sudden smile powder." In the book Chinese Herbal Medicine: Formulas and Strategies (3) its name is depicted this way:
Before taking this formula, the patient for whom it is indicated has pain so severe that it is difficult to tolerate. After taking the formula, the pain disappears so fast that it brings a sudden smile to the face.
As relayed further in Formulas and Strategies, the Hejiju Fang indicates that the formula is for post-partum pain that is so severe that the patient wants to die; and that other herbal medicines are ineffective, but this one is rapidly effective. Later generations of traditional doctors have extended its use to other painful conditions related to blood stasis, most recently for treatment of angina pectoris and its causes: vascular blockage and arterial spasm.
One of the ingredients of Shixiao San is puhuang, the pollen from the well-known plant called cattail, so-named because of its long, round shoot that is about the width of a cat's tail. This plant (see Figure 1) grows in marshes and has a hollow stem, similar to a rush, and is often referred to as the bulrush. The Chinese name for rush type plants is pu; the pollen is bright yellow (huang), yielding the Chinese name puhuang. The botanical names of the main plant sources are Typha latifolia and Typha angustifolia, so the common names given for this herb include typha, bulrush, or cattail pollen. Little is known about it chemical constituents and pharmacology, other than the fact that it is rich in flavonoids, a group of compounds that have been associated with improving blood circulation.
The other ingredient of Shixiao San is wulingzhi, which is the dung collected mainly from Trogopterus xanthipes (flying squirrels), but also from Pteropus pselaphon (known as flying foxes, which are, actually, fruit bats). These are rare species of cave dwelling rodents. Little is known about the active constituents of this material or how they might act to aid blood circulation or relieve pain. The Chinese name refers to "the grease of the spirit of the five elements." This mysterious reference to grease may be to its use as a topical application, perhaps in ointment form, for treatment of skin diseases; the dung has antibacterial properties that would explain its utility in this application. According to Li Shizhen (who wrote the Bencao Gangmu and described this substance in his book), wulingzhi is affected by the spirit of the five elements (4). To improve its blood vitalizing properties, it is usually prepared by frying with vinegar.
Wulingzhi has been included in a number of anticancer formulas, because of its implied ability to resolve blood-stasis masses. According to Jia Kun, in his book Treatment and Prevention of Carcinoma in Traditional Chinese Medicine (5), wulingzhi is bitter, sour, pungent, and sweet, with moderate nature, and no toxicity. It is indicated for amenorrhea, menorrhagia, dysmenorrhea, and pain caused by stagnation and obstruction. It relaxes spasms of the smooth muscles, as indicated by laboratory animal studies.
It has become a common practice to combine one or both of the herbs from this traditional formula with corydalis (yanhusuo) and/or salvia (danshen) to improve the blood vitalizing and pain relieving effects. For example, in Wang Qingren's formula for lower abdominal pain, Shaofu Zhuyu Tang, trogopterus, typha, and corydalis are key ingredients. In the English-Chinese Encyclopedia of Practical Traditional Chinese Medicine (6), a formula for dysmenorrhea is presented, in which 9 grams each of trogopterus and typha are combined with 30 grams of salvia for a one day dose (decocted and taken all at once). The recommended use is for five days administration prior to each menstrual period. In the treatment of stabbing stomach pain that is worsened when pressure is applied, the combination of Shixiao San with Danshen Yin (salvia drink) is recommended (15). Danshen Yin is made up mainly of salvia, with a small amount of cardamon and sandalwood.
A simple formula for treating abdominal pain due to blood stasis is relayed in Danxi Xinfa: combine equal amounts of trogopterum, corydalis, myrrh, and caoguo, a type of cardamon (7). The cardamons are a source of borneol and related compounds that have analgesic and dispersing qualities. In the book Modern Clinical Necessities for Traditional Chinese Medicine (8) two highly effective prescriptions used in clinical trials for treatment of dysmenorrhea are described: the dysmenorrhea powder, comprised of trogopterus, salvia, corydalis, sparganium, zedoaria, carthamus, cinnamon, saussurea, and tang-kuei; and the notoginseng (sanqi) powder for dysmenorrhea, comprised of typha, trogopterus, corydalis, notoginseng, cnidium, fennel, saussurea, and borneol. For severe abdominal pain in women with endometriosis (relapsing after surgery), the following recipe was recommended: 15 grams each of typha and trogopterus, 12 grams each of corydalis and salvia; plus persica, red peony, moutan, and other herbs that vitalize blood (16).
It should be noted that when puhuang is fried and carbonized, it helps stop bleeding, a property commonly found with carbonized herb materials; trogopterus may be prepared similarly to stop bleeding. In these formulas for pain, the cattail pollen and the trogopterus dung are not carbonized.
Jin Lingzi San is comprised of equal parts of two herbs: melia and corydalis, a relative of the opium poppy (see Figure 2). The formula name refers to the golden (jin) little bell (lingzi) powder (san), which has a golden color; the melia fruit may be reminiscent of a small golden bell. The herbs are ground to powder and preferably taken with a small amount of wine to aid its blood circulating properties. A typical dose is 9 grams each time.
Melia (chuanlianzi) is classified as a qi regulating herb, while corydalis (yanhusuo) is a qi regulating and blood vitalizing herb; both are deemed specific for alleviating pain. Melia is one of the few qi regulating herbs that has a cold property (chih-shih and chih-ko are slightly cold; akebia seed is cold, the rest of the herbs in this category are warm). Melia is utilized in abdominal distress complicated by liver fire, including hepatitis with liver pain. The formula is mainly given for cases of liver qi stagnation and liver fire in which pain is the main symptom of concern, particularly when the pain is located in an area where the liver meridian passes. In Formulas and Strategies it is explained that: "The liver prefers orderliness and regularity; liver dysfunction is thus accompanied by intermittent pain that follows the swell of emotion. Over time, constraint of the liver gives rise to fire. This is manifest as irritability and heat-aggravated pain...."
As an example of modifying a traditional formula to include Jin Lingzi San, consider the recommendation of Yan Wu in the treatment of lateral costal pain (15). For cases involving liver yin deficiency with heat symptoms and pain, he recommends Yiguan Jian (sometimes called "Linking Formula" because it links liver and kidney yin dysfunction), a formula that includes melia. Corydalis is added "to increase the pain-relieving effects of this prescription."
To compare Shixiao San and Jin Lingzi San, it is helpful to examine two of the main ingredients. Yang Yifan (9) compares corydalis to trogopterus (wulingzhi):
Corydalis and trogopterus enter the liver and spleen meridians. Both are able to promote blood circulation and remove congealed blood. They are very effective for relieving pain.
Corydalis is pungent, warm, and slightly bitter. It is characterized as entering the qi and blood level and promoting the qi movement and blood circulation. It is an excellent herb for relieving pain and its action is steady and strong. In clinical practice, it can be used alone and in TCM is considered to be a painkiller. If it is fried with a little vinegar, this increases its effect in relieving pain.
Trogopterus is bitter, sweet, and warm. It can promote blood circulation and stop pain but its action is gentler and slower than that of corydalis. Meanwhile, unlike corydalis, it has no function in promoting qi movement. The strong point of this substance is that it dissolves congealed blood in a gentle but a constant way. It is effective for removing congealed blood without the side effect of injuring the normal part of the blood, so it is used for chronic diseases in which congealed blood is not easily and quickly removed.
This highly aromatic formula is comprised of equal amounts of galangal and cyperus; the former is first washed with wine, and the latter with vinegar, then both are dried by baking and ground to powder, then formed into pills with ginger juice or water. It is taken in the amount of 6 grams each time. This is a warming preparation used for cold-type pain. The formula is simply named for its two ingredients.
Galangal (gaoliangjiang) is in the ginger family, a species of Alpinia (see Figure 3), which has a large concentration of oils and resins that have some analgesic qualities as also found in ginger and cardamom. It is described as an herb for warming the interior. All of the herbs used for warming the interior, including aconite, dry ginger, cinnamon bark, evodia, zanthoxylum, long pepper, clove, and fennel, are considered analgesic. A cold syndrome usually involves pain; according to the text New Practical Syndrome Differentiation of TCM (10), exterior cold is usually manifest as severe general aching and headache, while internal cold is usually manifest as abdominal pain. Cyperus (xiangfu) is a highly aromatic qi regulating herb; according to Yang Yifan:
Cyperus is so effective for regulating qi, it is regarded in TCM as the chief of all the herbs that regulate the qi....It is the most commonly used herb to promote the liver-qi movement. Since it is gentle and effective, it can be applied for treating both excess and deficiency syndromes that are associated with the liver qi stagnation....
The aromatic components are volatile oils (mainly cyperone, cyperol, and cyperene) that have analgesic and anti-inflammatory qualities (11). This formula is mainly used for abdominal pain that responds favorably to warmth (a typical treatment is to apply a heating pad or hot water bottle to the painful area). Yan Wu suggests an extended prescription for acute and sudden abdominal pain that can be decreased by application of heat, namely combining two cyperus-based formulas, Liang Fu Wan and Zhengqi Tianxiang San (Lindera and Cyperus Formula); the latter includes lindera, dried ginger, perilla leaf, and citrus. Like Liang Fu Wan, Zhengqi Tianxiang San is also an interior warming combination that is very fragrant (tianxiang means heavenly fragrance).
This formula is comprised of equal parts of peony (shaoyao) and licorice (gancao) and is named for the two herbs. Originally, the formula was presented in the Shanghan Lun as a treatment for cramping pain in the calves due to liver blood and yin deficiency. Later the combination was said to be highly effective for pain associated with spasms anywhere in the body, because its main effect is to alleviate the spasms. In Chinese Herbal Medicine Formulas and Strategies, it is pointed out that modern uses include intercostal neuralgia, sciatica, trigeminal neuralgia, chronic pelvic inflammatory disease, and primary dysmenorrhea (menstrual cramps). In Commonly Used Chinese Herb Formulas Companion Handbook (12), modern indications developed in Japan include: muscle spasms in the limbs, abdomen, back and lower back; smooth muscle spasms of the stomach, intestines, bronchi, gallbladder, and ureters; and sciatica, lumbago, shoulder stiffness in the elderly, and muscular rheumatism.
The traditional explanation of the way in which this formula works was set out in the book Dui Yao: The Art of Combining Medicinals (13), along with indications for its use:
Peony is sour, while licorice is sweet; peony focuses on the liver, licorice on the spleen; when these two medicinals are combined, sweet and sour engender yin. Together they effectively calm the liver and fortify the spleen, supplement the qi and blood, and harmonize the liver and spleen. In addition, they soothe the sinews and stop pain.....This combination is very effective for numerous problems accompanied by spasms and pain, such as gastritis or colitis, spasm of the gastrocnemius muscle in the leg, contraction of the limbs, tendonitis, lateral costal pain, and hiccup or stubborn vomiting caused by spasm of the diaphragm.
The authors of Formulas and Strategies (3) offer another view:
The chief herb, peony, nourishes the blood and preserves the yin while it softens the liver and alleviates pain. It thereby addresses the primary aspects of this condition [spasms and pain due to injury to the yin]. The liver is a hard, 'edgy' organ and its qi has a tendency to rebel transversely. This herb is effective in moderating the wayward inclinations of the liver qi and preserving the liver yin; this is what is meant by softening the liver. Honey-fried licorice tonifies and augments the qi of the middle burner, especially that of the spleen. Together, these herbs regulate the relationship between the liver and spleen and nourish the sinews. This formula is very popular for treating a wide variety of pain syndromes, especially the spasmodic or cramping pain accompanied by diarrhea that is associated with disharmony between the liver and spleen.
The main active component of peony is paeoniflorin, which has antispasmodic activities. Glycyrrhizin and other active components of licorice may influence the activity of paeoniflorin on muscles.
Mao Dexi outlined the basic pain syndromes with sample herbs that would be used (14). Following is a summary
|Draft (Wind) pain||External: muscles, joints, or ligaments are painful|
Internal: migrating pain, often affecting the limbs
|External: chiang-huo, tu-huo, cinnamon twig, siler, clematis, chin-chiu, angelica|
Internal: gastrodia, uncaria, haliotis, silkworm, scorpion, centipede, earthworm
|Cold pain||External: Cold evil congested and stagnated in the meridian vessels |
Internal: yang deficiency with internal generation of cold. Fixed location and spasmodic pain.
|External: aconite, ma-huang, asarum|
Internal: aconite, cinnamon bark, dry ginger, evodia, long pepper, galangal, fennel
|Wet pain||Rain evil and dew wetness obstruct the functioning of qi. Wetness is characteristically sticky, greasy, and stagnant, and the pain that arises is heavy, binding, and confining (as if wrapped tightly by a bandage), and aggravated by a rainy, wet environment.||atractylodes, stephania, acanthopanax, chaenomeles, coix, akebia, lysimachia (desmodium)|
|Heat pain||Heat toxin that exhausts and scorches ying and causes entanglement and stagnation of ying manifests as heat pain. Typically manifests with redness and swelling.||lonicera, forsythia, taraxacum, viola, subprostrata, paris, prunella, isatis root, sophora.|
|Qi pain||Caused by emotional factors, which lead to dysfunction of the qi of the viscera. Its feature is pain with distention, usually in the chest and abdomen and aggravated by emotional disturbance.||saussurea, cyperus, lindera, bupleurum, blue citrus, citrus, aquilaria, acronychia, litchi seed, citrus seed, melia|
|Blood stasis pain||Long-term stagnation with disturbance of blood vessels (e.g., chronic inflammation) or traumatic injury caused blood stasis pain. Its distinguishing feature is pin-prick (or stabbing) pain with a fixed location.||tang-kuei, cnidium, red peony, corydalis, salvia, leonurus, san-chi, myrrh, frankincense, trogopterus, persica, carthamus, sparganium, zedoaria.|
|Worm pain||Intermittent pain, generally around the umbilicus, caused by intestinal parasites||quisqualis, areca seed, torreya, omphalia|
|Food pain||Overindulgence in food and erratic eating and drinking habits cause food pain. It is intensified by applying pressure over the abdomen.||crataegus, malt, raphanus, gallus|
|Phlegm-fluid pain||Phlegm-fluid stagnation and retention produce fluid pain, which affects the upward and downward movement of qi with symptoms of chest and subcostal pain, usually related to difficulty in breathing and shortness of breath.||typhonium, sinapis, lepidium|
|Deficiency pain||Associated with the functional degeneration of the viscera and depletion and damage of the qi and blood. Typically manifests as persistent pain. Pain may be associated with qi deficiency (fatigue), blood deficiency (palpitations), yin deficiency (restless heat of the palms and feet), or yang deficiency (cold extremities).||Qi: astragalus, codonopsis or ginseng, atractylodes, licorice|
Blood: millettia, achyranthes, peony
Yang: epimedium, morinda, eucommia, cibotium, dipsacus, drynaria
Yin: turtle shell, loranthus, ligustrum
In this partial review of herb components with analgesic action, four categories of active ingredients will be mentioned: alkaloids, organic acids, volatile oils, and glycosides. Only those items obtained from plants are included in this discussion; there are animal agents that are very potent analgesics, most notably toad venom (which is highly toxic). The source of information for this section is Abstracts of Chinese Medicine (1987-1993), except as noted.
In a screening of 4,605 extracts, using various solvents, obtained from 1,116 plants from Taiwan, biological activity was noted in 17%. The most frequently observed activity was analgesia, with 237 items (5%) and the second most common was anti-inflammatory activity (197 items, 4%). Since reduction of inflammation often brings secondary pain relief, these two categories represent the main group of pain relieving herb materials. In a test of herbs with potential use for treatment of narcotic addiction, analgesic activity in morphine-addicted rats was measured. While a tiny amount of morphine, 5 micrograms per gram of body weight, produced virtually complete analgesia, the next best herb materials were corydalis extract at 4 mg/gram (800 times the dose of morphine), uncaria at 2-4 mg/gram, and wild chrysanthemum at 4 mg/gram, each of these producing about 60% the analgesic action of the morphine (16).
Tropane alkaloids compete with the neurotransmitter acetylcholine, thus blocking its action of transmitting nerve signals. They can be used for pain relief and for treatment of Parkinson's disease. Herbs that contain these alkaloids include datura, belladonna (Atropa), and valerian; all of these have been used in Western medicine. Atropine, originally obtained from belladonna, remains a standard drug with limited use. A representative alkaloid of this group is scopolamine, found in many Solanaceae plants. In modern Chinese research, anisodine, from Scopalia tangutica has been of great interest. Anisodine is less toxic than the other alkaloids, but still active. This plant is also a source for scopolamine and other tropane alkaloids. Hyoscyamus niger (tianxianzi) contains tropane alkaloids that have been shown useful in treating the pain of gallbladder attacks.
Side effects of tropane alkaloids include pupil dilation, dry mouth, and decreased intestinal motility. In larger doses, the alkaloids affect respiration and can cause death. Tropane alkaloids counteract the effects of cholinesterase inhibitors (drugs that reduce the rate of acetylcholine breakdown, thus increasing the level of acetylcholine) and vice versa. Cholinesterase inhibitors are used to treat poor memory and the muscular debility of myasthenia gravis.
Morphine, related compounds (e.g., codeine), and new derivatives of them, remain the choice analgesic for unremitting severe pain. These are isoquinoline alkaloids administered to patients suffering from accidents, post-surgical pain, and pain associated with advanced cancer. In the protoberberine series of isoquinoline alkaloids, there are certain items with strong analgesic qualities, these include tetrahydropalmatine from Stephania sinensis and Corydalis ambigua, used in the patent drug Jin Bu Huan (which has been banned in the U.S. due to rare liver sensitivity reactions that can be severe) plus other related compounds found in Corydalis species (Papavaraceae) and in various Menispermaceae plants (especially Menispermum, Sinomenium), the latter mainly used for treatment of arthralgia.
Tetrahydropalmatine (THP), which has been widely used, produces several effects similar to that of morphine: it induces sleep and analgesia, it can be excitatory in susceptible persons, and can cause nausea. In very large doses, it inhibits respiration, but in moderate doses it stimulates respiration. If tetrahydropalmatine is combined with dihydroetorphine and diazepam by IV, instant general anesthesia is produced. While morphine is highly addictive and also subject to tolerance, tetrahydropalmatine does not appear to have either of these effects. Corydalis is extensively used in traditional Chinese medicine for pain relief; the Bencao Gangmu says: "It kills pains anywhere in the body. Magical effects can be achieved if it is used appropriately."
The mechanism of action of tetrahydropalmatine is to block dopamine. Another component of stephania, stepholidine (which has a similar structure) is reported to be 5-6 times stronger than THP in inducing sleep, but the analgesic action is about the same. Other analgesic alkaloids from stephania species include tetrandrine and cycleanine. These are especially noted for their action as muscle relaxants.
Higenamine, an isoquinoline alkaloid, exerts beta adrenergic activity: cardiotonic, vasodilation, smooth muscle relaxant, lipid metabolism enhancing, and hyperglycemic. This agent is found in cold-dispelling herbs, such as aconite, evodia, and asarum. It is possible that individuals displaying a cold syndrome have low beta-adrenergic activity, which is corrected by these herbs. When beta blockers are given as drugs (to lower beta adrenergic activity), they may exhibit a strong cooling action: they slow the heart rate and reduce excitability of the heart and also impair sexual responses. The analgesic action of ten warming herbs was evaluated in a pharmacological study: evodia, aconite, fennel, clove, piper (cubeb), galangal, cinnamon bark, zanthoxylum, dry ginger, and white pepper. Galangal (gaoliangjiang) and cinnamon bark failed to produce substantial analgesic activity. Aconite (see below) and piper (bichengqie) produced analgesia, but the onset was slow (one hour). The other herbs produced analgesia in a dose of 10 grams/kg (a very high dose) in just thirty minutes. The analgesic action lasted for about 2.5 hours.
Aconite, a diterpene alkaloid, is the dominant analgesic herb used in China for arthralgia. There are dozens of species used, and the raw aconite is a frequently employed substance in China, cooked for two hours or so to reduce toxicity. Aconite poisoning occurs from time to time. In the West, processed aconite is always used. The analgesic action of 0.1 mg/kg of aconitine is stronger than 6 mg/kg of morphine; however, the quality of analgesia is different. Its activity is based on the alpha receptors and ganglions. Blocking serotonin may be part of its action (the serotonin-inhibiting alkaloid drug methysergide is used as a migraine preventive agent). Several chemical derivatives of aconitine found in a large number of Aconite species have been analyzed; they all appear to function via alpha-adrenergic receptors. Many alpha-adrenergic blocking agents also block the effects of serotonin.
Rauwolfia is a famous plant that is used as a source of the modern drug reserpine, based on observations of effective traditional use of the herb as a sedative. Reserpine is mainly used as an antihypertensive now, but was originally employed as a sedative as well (since replaced by other drugs for that purpose). Uncaria contains several alkaloids in the same class as rauwolfia alkaloids, notably rhynchophylline, which have sedative and anticonvulsant actions, and reduce blood pressure. The mechanism of action appears to be depletion of catecholamines and serotonin in the central and peripheral nervous systems. Uncaria is frequently recommended in China for treatment of headaches, and especially hypertensive headache.
Salicylic acid from willow (Salix species) and meadowsweet, is a useful analgesic, anti-inflammatory, anti-platelet sticking, and antipyretic drug. Its stomach irritant side effects are reduced when it is acetylated, to produce what is commonly known as aspirin.
Qi Ye Lian, a Chinese patent made from extract of Schefflera arboricola (qiyelian), contains organic acids that are thought to be responsible for analgesic effects (17). These include fumaric acid, ?-hydroxybutyric acid (GABA), and succinic acid. The herb extract has been reported useful for trigeminal neuralgia and headache, as well as arthralgia and sciatica. The Qi Ye Lian tablet is made from 5 grams of crude herb (reduced to 300 mg extract), using an alcohol precipitated decoction. The dosage is 3-5 tablets each time, three times daily; or, a decoction of up to 30 grams/day may be used.
Ferulic acid, a component of kao-pen (gaoben), tang-kuei, cnidium, and cimicifuga, is likely responsible for some of the analgesic and sedative actions of these herbs. Sodium ferulate, the salt of this acid that is usually used in pharmacology experiments, is believed to act by inhibiting prostaglandins. While prostaglandins themselves do not cause much pain, they may reinforce the pain-producing action of bradykinin, a polypeptide involved in inflammatory responses. Cinnamic acids, such as methyl or ethyl cinnamate, are found in alpinia, liquidambar, cinnamon, and styrax; all used for the treatment of pain. These herbs also contain other active components that provide pain relief, perhaps by other mechanisms. A compound similar to cinnamic acid, shikimic acid, was determined to be the analgesic component of Illicum dunnianum (honghua bajiao). Achillea alpina (qicao) contains organic acids that are analgesic, sedative, and anti-inflammatory.
Volatile oil of asarum, which contains over two dozen individual components including asarone, asatone, and methyleugenol, is sedative and analgesic. Asarone and methyleugenol is also found in acorus; asatone is also found in nutmeg; eugenol and related compounds are found in galangal. Asarone has anti-aggression action in laboratory animals, and the action is synergistic with reserpine and other drugs. It appears that asarone and the whole oil from acorus each lowers 5-HT (serotonin; 5-hydroxytryptamine) and norepinephrine levels (adrenaline). The effects of asarone are inconsistent in laboratory testing. Most authors believe that asarone and the oil of acorus have an action similar to meprobamate, librium, and reserpine.
Several Umbelliferae plants, such as angelica, chiang-huo, cnidium, peucedanum, siler, tang-kuei, and tu-huo have marked analgesic activity in tests of arthritis-like inflammation. Presumably, the aromatic volatile oils are partly responsible for the analgesic action, but the mechanism has not been determined; the volatile components found in each plant are very diverse. Ferulic acid, mentioned previously, is another component in these herbs promoting analgesic response. Geraniol and related terpene alcohols and ethers found in geranium, magnolia, and zanthoxylum have notable analgesic effects. Murraya (juilixiang) is an aromatic plant containing such ingredients that is used to treat abdominal pain and arthralgia.
Glycosides represent a broad range of active components; they are compounds that include a sugar molecule. Most of the analgesic glycosides are terpene glycosides. The glycosides of several Cynanchum species (qingyangshen, xizhang, niupixiao, and baoyaoteng) have strong analgesic and anticonvulsive activity. Clematis henryi (xuelikai) contains a glycoside fraction, (clematoside) that is strongly analgesic and has a longer lasting analgesic action than tetrahydropalmatine. Akeboside from akebia is also analgesic. Saponin glycosides (triterpenes) from bupleurum are analgesic and anti-inflammatory; they produce a sedative effect similar to meprobamate, a drug that has a blocking action on spinal interneurons and which serves as a muscle relaxant. Monoterpene glycosides of Paeonia species, such as paeoniflorin, have antispasmodic, antiinflammatory, and analgesic components.
Many of the chemical components described in this appendix are potent substances that have an immediate effect on pain but also a potential for serious adverse reactions, especially the alkaloids. In a few cases, such as the organic acids, the compounds appear to be safe, but the potency may be limited, perhaps to cases of inflammation-induced pain. The traditional formulas described above contain some of the active components mentioned in this section: alkaloids of corydalis, volatile oils of galangal, and glycosides of peony. However, their mechanisms of action remain largely unknown, with most of the herbs' active components and pharmacological activities yet to be identified.
Figure 2: Corydalis yanhusuo.
Figure 3: Alpinia officinarum.