The Medicinal Value of Loquat Leaf (Pipaye)
Pipaye (loquat leaf) is the leaf of the loquat plant, Eriobotrya japonica, of the Rosaceae family. The loquat fruit can be eaten and can also be used as a medicinal for stopping cough; its leaf can also be used as medicine. Loquat leaf has a long history of medicinal use; when Tao Hongjing of the Liang dynasty compiled the Mingyi Bielu (Records of Famous Physicians), he already included loquat leaf in it.
TCM holds that loquat leaf is bitter and slightly acrid in taste, slightly cold in nature, and enters the lung and stomach meridians. It has the actions of clearing the lung and quenching thirst, harmonizing the stomach and downbearing counterflow, and stopping thirst. It is indicated for lung-heat cough, consumptive cough of yin deficiency, coughing of blood, nosebleed, vomiting of blood, stomach-heat vomiting and hiccup, pernicious vomiting of pregnancy, infantile milk vomiting, wasting-thirst (xiaoke), as well as lung-wind facial sores and red, acne-ridden nose (rosacea). Modern pharmacological research shows that the amygdalin contained in loquat leaf is broken down by microbial enzymes in the lower digestive tract to release trace amounts of hydrocyanic acid; hydrocyanic acid has a sedative effect on the respiratory center, which is why loquat leaf has a cough-stopping and wheezing-calming effect. But hydrocyanic acid is toxic, so using loquat leaf in large doses can also cause poisoning.
The ancients discovered that a layer of fuzz on loquat leaf could irritate the human respiratory mucosa and cause coughing, so when using loquat leaf as medicine, the fuzz on the leaf is usually brushed off. To achieve a cough-stopping effect, loquat leaf is sometimes also honey-fried. The processing method is: for every 100 kg of loquat leaf, add 20 kg of refined honey, spread evenly, then roast over fire. Loquat leaf processed by different methods is used for different purposes; for stopping vomiting, stir-fried loquat leaf is mostly used. The method of stir-frying loquat leaf is to place the leaf in a pan, heat over low flame, and stir-fry until slightly charred, or stir-fry it together with ginger juice; once an aroma is released, remove it and allow it to cool, and it is ready for medicinal use.
Loquat leaf is a commonly used Chinese medicinal for treating cough; many cough-stopping formulas include loquat leaf. For lung-heat cough, loquat leaf may be combined with sangbaipi (mulberry root bark), huangqin (scutellaria root) and digupi (lycium bark); for wind-cold cough, loquat leaf may be combined with yansui (coriander), qianhu (peucedanum root) and aiye (mugwort leaf); for wind-heat cough, loquat leaf may be combined with xingren (apricot kernel), sangbaipi, juhua (chrysanthemum flower) and niubangzi (burdock fruit); for lung-dryness cough, loquat leaf may be combined with sangye (morus leaf) and maogen (cogongrass rhizome); for paroxysmal cough caused by lung-qi inhibited counterflow and phlegm obstruction, loquat leaf may be combined with qianhu, fangfeng (saposhnikovia root), bohe (mint), xingren, sangbaipi, gualouren (trichosanthes seed), jiegeng (platycodon root), shengma (cimicifuga) and gancao (licorice). Commonly used Chinese patent medicines such as loquat leaf extract, compound loquat leaf extract, cough-relieving loquat granules, juhong pipa tablets and loquat syrup all have a cough-stopping effect.
Another major effect of loquat leaf is stopping vomiting. Loquat leaf alone can treat vomiting; loquat leaf may also be used together with other antiemetic Chinese medicinals such as shidi (persimmon calyx), chenpi (tangerine peel), zhuru (bamboo shavings), changpu (acorus), huoxiang (agastache), peilan (eupatorium), fabanxia (processed pinellia), dannanxing (bile arisaema) and dingxiang (clove), to achieve a better antiemetic effect.
The "Pipaye San" in the Yuyuan Fang (Formulas from the Imperial Pharmacy) is precisely loquat leaf (fuzz removed) and chenpi (white pith removed), in equal parts, prepared into a powder. Each time take 5 qian (15 g), add 1-2 slices of ginger, and decoct together; take warm, three times daily. It treats vomiting or dysphagia caused by stomach-spleen qi counterflow-a condition roughly corresponding to modern reflux esophagitis or incomplete pyloric obstruction.
The Gujin Yijian (Medical Mirrors Ancient and Modern) also has a formula called "Pipa San" for treating incessant vomiting. This formula consists of loquat leaf (fuzz removed) and juhong (red tangerine peel), each 30 g; banxia (pinellia, soaked in hot water), chifuling (red poria, peeled) and renshen (ginseng), each 15 g; maimendong (ophiopogon, core removed) and qingzhuru (green bamboo shavings), each 36 g; and gancao (licorice) 12 g. Prepare all together into a powder; each time take 15 g, add three slices of ginger, and decoct in water. The author often adds loquat leaf and sugeng (perilla stem) and other qi-downbearing, antiemetic medicinals to formulas used to treat chemotherapy-induced vomiting in cancer patients, with excellent results.
Loquat leaf also has a fairly good anti-inflammatory and diuretic effect; it can be used to treat difficult urination or painful dribbling urination caused by chronic nephritis, cystitis and urethritis. For the above conditions, decoct loquat leaf together with cheqianzi (plantain seed) and gancao, and take orally; the effect is very good. The ancients held that loquat leaf stops thirst, but this is mostly because when loquat leaf is used together with other medicinals it can treat respiratory tract infections, and patients with respiratory tract infections easily feel thirsty.
Loquat leaf is an inexpensive and readily available Chinese medicinal. In many rural areas, loquat trees are planted in front of and behind houses. In summer, loquat leaves are picked, processed, dried in the sun and properly stored, and can be used all year round. The usual adult dose of dried loquat leaf is 9-15 g per day; large doses may reach 30 g. The usual dose of the fresh herb is 15-30 g; children take half the adult dose, and infants reduce it to one-quarter to one-third of the adult dose. When decocting loquat leaf, it is best to wrap it in a non-woven cloth bag, to prevent the fuzz on the leaf from entering the decoction and irritating the trachea and causing coughing fits.