LAOYING TEA

Popular Healthful Beverage Tea of Sichuan Province

by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon

Actinodaphne longifolia, a long leaf version of the herb that is used for Laoying Cha.

Laoying Cha (eagle tea) is made from the dried leaves of a type of a Laurel tree, Actinodaphne cupularis (see Appendix 1 for significance of the botanical name). The tree is evergreen with thick dark green leaves, and it grows abundantly in the mountainous areas of Sichuan province. The family of Laurel trees (Lauraceae) includes the well-known Chinese herb sources for cinnamon and lindera. These herbs, like Laoying Cha, have essential oils that give them their characteristic fragrance and taste (see Appendix 2 for related plants, and Appendix 3 about use of their oils). In the case of Laoying tea, the main essential oil components that have been identified are sesquiterpenes: isocaryophyllene and germacrene. These ingredients are found in some of the mint family herbs, including the Chinese herb elscholtzia (xiangru) that is sometimes used as an aromatic beverage tea. Germacrene is also found in the aromatic bark of magnolia; isocaryophyllene is also found in the spicy herb cloves. Laoying Cha has been consumed for centuries in Sichuan Province, particularly in the city of Chongqing. This tea is made available in tea houses and restaurants along with ordinary green tea or black tea and is considered a must to consume with the typical oily dishes of Sichuan to balance the taste, promote digestion, and help clear the fats from the system. It has a reputation for lowering blood lipids, including cholesterol.

A variety of Laoying Cha grows in neighboring India: leaves from the tree Actinodaphne hookeri. It is commonly called "pisa" and is reputed to help people with diabetes control their blood sugar (cinnamon bark also has this use). In India, pisa is known for its ability to remove excess heat of the body, thus lowering pitta (fire). In the Chinese system, Laoying tea is said to aid in cooling the body, but it is classified as having a warm nature; it cools by aiding the surface circulation (alleviating heat through the surface). In this, it is like the botanically unrelated herb elsholtzia, mentioned above, which has a pungent and warm nature, but is used to dispel summer heat and reduce feverish feeling. The taste of Laoying Cha is very pleasant, and the spiciness is mild, not like the hot spiciness of some herb teas, such as ginger.

3-D representation of germacrene, a major constituent of the essential oil of Laoying tea.

APPENDIX 1: About the Botanical Names

The Lauracea family is named for its most frequently used member, the noble laurel tree: Laurus nobilis, often called bay laurel; it is a small Mediterranean tree prominent in history and literature. The ancient Greeks and Romans fashioned bay laurel leaves into wreaths, to be worn as crowns by the victors in sporting events and military campaigns. Julius Caesar and other Roman leaders wore just such a wreath (Emperor Claudius is depicted below right).

Ever since, the foliage of bay laurel trees has been a symbol of victory. It is still used as such for the Olympics (see below left, the Olympic laurel wreath award; in 2004, olive wreaths were used instead, but the laurel wreath appears on the medals).

The Olympic laurel wreath award.

Depiction of Emperor Claudius wearing laurel wreath.

In Greco-Roman mythology the nymph, Daphne, was transformed into a laurel tree, to save her from Apollo's unwelcome advances. Apollo was chasing this daughter of the river-god Peneus through the woods when the magical metamorphosis occurred. Thereafter, Apollo wore a wreath of laurel to show his love for Daphne. The tale of her transformation has been passed down to us by the Roman poet, Ovid, in his work Metamorphoses. The scene of the transformation, occurring just as Apollo catches up to Daphne, is presented in a statue, produced around 1625, now displayed in Rome. Actinodaphne, includes the prefix meaning star-shaped or radial (actino-), referring to how the leaves of the plant radiate from the stems, and daphne, indicating its connection to the laurel trees. The species name cupularis refers to the fruit cupule, a "cap" that holds the fruit; it has, in this case, a notable "cup-like" form. A prominent example of such structures is seen in acorns (see the fruit cap of Actinodaphne in the picture at the beginning of this article.).

          
Calling Actinodaphne leaves "eagle tea" may refer to the growing location of the plant, in the mountains where eagles soar.

APPENDIX 2. Lauraceae Herbs in Chinese Medicine

Actinodaphne is closely related to another genus, Litsea, and many species of plants have been categorized under both names; hence the source of Laoying tea is described as Actinodaphne cupularis and as Litsea cupularis. Litsea is perhaps best known to herbalists through the plant Litsea cubeba, which gives "cubeb fruits." According to Ling Yourun (A New Compendium of Materia Medica, 1995), Litsea has the same use in traditional Chinese Medicine as lindera (wuyao).

The Lauracea family to which these herbs belong includes a number of internationally recognized plants, many used as spices. It is a large family, with about 30-45 genera (depending on classification methods) and nearly 2,500 species, primarily distributed over the tropics and subtropics, almost always as trees and shrubs. Many species contain essential oils that give the desirable spicy taste and fragrance. Among the important groups are:

Cinnamomum species, such as:

Cinnamomum burmannii (Indonesian cinnamon)
Cinnamomum camphora (Chinese camphor tree)
Cinnamomum cassia (Cassia; Chinese cinnamon)
Cinnamomum loureirii (Vietnamese cinnamon)
Cinnamomum tamala (Indian cinnamon)
Cinnamomum zeylanicum aka C. verum (Ceylon cinnamon)

The "bay leaf" sources, including:

Laurus nobilis (common bay leaf)
Litsea glaucescens (Mexican bay leaf)
Umbellularia californica (Californian bay leaf)

and other fragrant plants, notably:

Sassafras albidum (Sassafras)
Lindera benzoin (Spice bush)

The latter, named for its spicy fruits that are likened to allspice, is related to the Chinese herb Lindera strychnifolia, commonly called lindera. As pointed out by Ling Yourun, many species of these genera are used for dispelling cold-evils by warming the interior. All the commonly used Lauracea herbs in China (listed in the table below) are classified as being of warm nature and spicy taste.

Yang Yifan, in her book Chinese Herbal Medicines: Comparisons and Characteristics (2002), comments on the actions of cinnamon and lindera, the most commonly used Lauraceae herbs of Chinese medicine. These herbs are included in her list of those for "stimulating yang":

Stimulating the yang, warming the internal organs and the meridians, and expelling cold directly is a method carried out by pungent and hot herbs….It is used to treat excessive internal cold syndrome characterized by cold extremities, cramping of the muscles, stiffness of the body, and severe pain….The commonly used herbs are aconite, dried ginger, lindera, artemisia, cinnamon twig, and cinnamon bark.

Although not included in this listing, litsea is also classified as an herb that stimulates yang to expel cold. As to cinnamon bark, the most warming of the group:

Cinnamon bark is able to warm and tonify the fire of the mingmen, and it is used for treating floating yang syndrome, a syndrome that appears when the kidney yang is extremely weak and internal cold in the lower burner is at its maximum. In this situation, the cold pushes the yang to go upwards and the manifestations are a flushed face, a floating red color that appears only on the cheeks, heavy sweating, weak and cold limbs….This floating yang syndrome is a dangerous situation like collapse of yang….Cinnamon bark is able to lead the floating fire back to its source....Cinnamon bark warms the kidney and the blood, scatters cold, and stimulates the blood circulation to alleviate pain, especially when the pain is in the abdomen, back, and knees.

Cinnamon bark need not be reserved for cases as advanced as floating yang; it can be used for pain due to cold. For cinnamon twig, Yang points out:

Cinnamon twig, compared with cinnamon bark, is less hot and pungent; the young twig has an aromatic smell that gives this herb a thin pungent property, which makes it move quickly and lightly. It can particularly warm the blood, stimulate the heart, and promote the blood circulation, therefore it can treat cold hands and feet, cramping of the muscles, and pain due to cold obstruction in the blood circulation. In comparing the ability of cinnamon bark and cinnamon twig to expel cold and warm the interior, cinnamon twig is more active and mainly works on the periphery, whereas cinnamon bark stays in the lower burner and warms the base of the body….Cinnamon twig treats wind-cold syndrome. Here the therapeutic result is achieved by warming the blood, promoting blood circulation, opening the meridians, and activating the yang qi to expel wind and cold.

For lindera, she notes:

Lindera enters the lower burner and can regulate the liver qi in the liver meridian. It is the warmest of the herbs used to promote liver qi movement, and it especially warms the liver meridian, expels cold, and spreads the liver qi. It is particularly effective for relieving pain in the lateral sides of the lower abdomen and genital area. It treats dysmenorrheal, hernia, frequent urination, and urinary incontinence.

Litsea is not as commonly used in Chinese herbalism. It has several Chinese names, none of which have become dominant; some practitioners use the fruit, others the root, and still others the root with stems. All parts are aromatic and warming. Litsea is most often used for abdominal pain due to cold, including stomach ache and cramping diarrhea. Actinodaphne, except for use as a folk remedy in southwest China (for injuries and stomach ache), is mainly relied upon as a beverage tea. Still, its medicinal properties are like those of these other Lauraceae plants, though not as warming as cinnamon bark. It is comparable to lindera, cinnamon twig, and litsea as a remedy for alleviating chills and abdominal pain, and it is useful for promoting blood circulation. Additionally, it may help with diabetes and hyperlipidemia. Because of its light nature and its relatively mild warm property, it is used to open the surface circulation to relieve heat.

APPENDIX 3. Use of Essential Oils of Lauracea

Cubeb oil is distilled from the small, pepper-like fruits of Litsea cubeba, mainly of Chinese origin, where it occurs naturally and has been successfully cultivated in central and eastern China, south of the Yangzi River. The fruits contain 3-5% of an essential oil that is rich in citral (about 75%) and has an intensely lemon-like, fresh, sweet fragrance. To a limited extent, it competes, with the citral-rich lemongrass oil, in fragrance applications such as household sprays and fresheners. Its major use, however, both in China and in international markets, is as a raw material source for the isolation of citral. This isolate is used for flavor and fragrance purposes or converted by the chemical industry to a number of important derivatives such as violet-like fragrance oils and certain vitamins (vitamin A and the carotenoids, and vitamin E). Although cheap synthetic citral is readily available and has displaced much of the citral extracted from lemongrass, there has remained a significant market for natural citral that low-priced litsea oil has been able to meet. Chinese production is estimated to be in the range of 500-1,500 tons of litsea oil each year. The leaves of the Litsea plant also yield citral, but much less of it (the leaves have more cineole than citral).

The genus Cinnamomum comprises several hundred species which occur naturally in Asia and Australia. They are evergreen trees and shrubs; C. verum, the source of cinnamon bark and leaf oils, is indigenous to Sri Lanka, although most oil now comes from cultivation. Cinnamomum cassia, the source of cassia oil, occurs wild as a bush in the mountains of southern China but is now cultivated for oil production, mainly in the southeast provinces of Guangxi and Guangdong. The other cassias occur wild in Sumatra, Java, Indonesia, Vietnam, India, and Nepal; in all cases the trees are also cultivated. The most important Cinnamomum oils in world trade are those from C. verum (cinnamon bark and leaf oils), C. cassia (cassia oil) and C. camphora (sassafras and "ho leaf" oils). Cinnamon bark oil possesses the characteristic aroma of the spice and a sweet and pungent taste. Its major constituent is cinnamaldehyde. It is used in the flavoring industry. Cassia oil is distilled from a mixture of leaves, twigs, and fragments of bark; cinnamaldehyde is the major constituent for it as well. These two have slightly different tastes due to secondary components. Cassia oil is used mainly for flavoring cola-type drinks, with smaller amounts used in bakery products, sauces, confectionery, and liqueurs. Cinnamon leaf oil has a warm, spicy, but rather harsh odor, lacking the rich body of the bark oil. Its major constituent is eugenol (a characteristic taste and aroma ingredient of clove oil) rather than cinnamaldehyde. It is used as a flavoring agent in seasonings and savory snacks. The oil's high eugenol content makes it valuable as a source of this chemical for subsequent conversion into iso-eugenol, another flavoring agent.

Cinnamon bark oil, the most expensive and difficult to obtain of the cinnamon products, is a now mainly obtained from Sri Lanka, which produces up to 3 tons in a year. It has an aldehyde content of 55-78%. World demand for cinnamon leaf oil, which contains about 85% eugenol (with a maximum of 5% cinnamaldehyde) has been around 120-150 tons per year, almost entirely from Sri Lanka. When eugenol is required for further conversion into iso-eugenol, that produced from cinnamon leaf oil possesses a more desirable aroma and flavor than when derived from the cheaper clove leaf oil.

Cassia bark oil, which has about 80% cinnamaldehyde, is produced mainly by China, which uses more than 500 tons annually; Japan is the main destination of exports (it takes about 60 tons per year, but much of it is re-exported, such as to the U.S.). Synthetic cinnamaldehyde, which is inexpensive, is sometimes used in the flavor industry now to mix with or replace the natural product.

Cinnamomum camphora was heavily exploited as a source of camphor in Japan and Taiwan until World War II. Trees were felled and logs, stumps, and branches were distilled to give crystalline camphor and camphor oil that was used topically as a remedy for pain, such as in cases of arthralgia. The species was introduced into India during the 1950s, and it is also widely grown in China. C. camphora is now an important source of natural linalool (which is still preferred over the synthetic form for some fragrance applications). Chinese camphor oil has largely displaced the use of rosewood as a source of natural linalool. Fractionation of the remaining camphor-free oil obtained after processing C. camphora provides an oil rich in safrole; this is usually described as Chinese sassafras oil. That oil (or oil from the American Sassafras albidum trees) is converted by the chemical industry into two important derivatives: heliotropin (piperonal) and piperonal butoxide (PBO). Heliotropin is widely used as a fragrance and flavoring; it is now being used as an aromatherapy. Research at Memorial Sloan-Kettering Cancer Center showed a 63 percent decrease in patient anxiety during magnetic resonance imaging (MRI) scans when the air was scented with the vanilla-like aroma of heliotropin. PBO is a key ingredient of pyrethroid insecticides (the preferred natural pesticide): natural pyrethrum is not an economical insecticide without the addition of PBO as a synergist.

Both camphor oil and sassafras oil were used extensively prior to concerns about their safety. Camphor is a potent heart stimulant; it sometimes caused poisonings when it was accidentally used in place of the intended castor oil (given as a folk remedy, often to children). Safrole was an important flavor and aroma ingredient in the beverage root beer. Laboratory animal studies indicated that safrole was a strong carcinogen in liver cells. Actually, this laboratory finding may not apply to humans (perhaps being dependent on metabolism of safrole in the liver of the animals), but regulations prevent use of carcinogens as food flavors if laboratory animal tests indicate carcinogenicity.

Laurus nobilis, commonly called bay laurel, is an evergreen shrub or small tree, indigenous to the Mediterranean Basin and the Near East. The dark green leaves of bay laurel are fragrant and aromatic; after drying, they are broken, cracked or cooked to release their characteristic aroma and flavor. Oil of bay or oil of laurel leaves is an essential oil obtained by steam distillation of bay leaves which has replaced the dry leaves in some food preparations.

Bay leaves are collected from both cultivated and wild plants in many Mediterranean countries. Commercial production centers include portions of Algeria, France, Greece, Morocco, Turkey, Portugal, and Spain. The leaves contain 1-3 percent essential oil on a fresh weight basis. The main constituents of this oil are cineole, pinene, sabinene, linalool, eugenol, and methyleugenol. This oil is employed as a natural flavoring and as a topical essential oil used by the cosmetics industry for creams, perfumes, and soaps. The leaves and berries of Laurus nobilis have also been used for treatment of rheumatism, skin rashes, earaches and other medical problems. Further, they are also used as an insect repellent.

Lindera oil (Kuromoji oil) is obtained by steam distillation of the leaves of the evergreen trees Lindera umbellate, L. membranacea, and L. sericea, native to the mountain ranges in Japan and China. The oil was produced in Japan as a linalol (which differs from linalool) source during the Second World War. The oil has a fresh odor due to the relatively large amount of cineol along with linalool in the oil. It is mainly used as an ingredient in perfumes.

Actinodaphne leaves are not yet used as a source of essential oils. However, the seeds are used for their fixed oils. For example, A. hookeri seeds contain 95% trilaurin, which is used in making soaps, shampoos, and cosmetics, usually after converting it to sodium laureth sulfate (trilaurin is more often obtained from coconut oil). In India, the A. hookeri seed oil is used topically in treatment of rheumatic pain. In order to increase the efficacy of seed oil, traditional healers boil Nirgundi (Vitex negundo) leaves in this oil. Actinodaphne is being further researched as a source of lactones and lignans of potential medicinal value.

Two new lactones isolated from Actinodaphne lancifolia; these have been called actinolides.

September 2004