The Medicinal Value and Side Effects of Suoluozi (Buckeye Fruit)
On October 1st, on my way home from picking vegetables in the garden, I passed the Hanhe River Park at the foot of Fragrant Hill and happened upon a large grove of Aesculus trees, uncommon in the north. The Aesculus (seven-leaf tree) is named for its seven leaflets growing together; the ground beneath was strewn with fallen fruit. Its fruit is formally called Suoluozi, also known as Suopozi. "Saha" was originally a Buddhist term; the Saha world means this imperfect world we inhabit. I do not know why the Aesculus fruit came to be called Suopozi; perhaps by coincidence.
The Aesculus is mainly distributed in western Jiangxi, southwestern Henan, western Hubei, Hunan, northern Guangdong, Sichuan, Guizhou, and Yunnan; the Beijing trees must have been introduced for landscaping. The fruit ripens and is collected in October each year. After harvest, sun-dry for 7–8 days, then finish drying over low heat; before baking, prick the fruit skin with a needle to prevent bursting and to speed drying. It may also be sun-dried directly, or peeled and sun-dried.
Suoluozi has a husk very much like a lychee shell; after peeling, the inside looks remarkably like a chestnut, and it is indeed also called Tianshi chestnut or monkey chestnut. Cut open, the flesh inside resembles chestnut flesh, but tastes very bitter. I tasted it: it is not only bitter but also irritates the throat. Yet the TCM materia medica textbooks say it is sweet and warm, because the properties, flavors, and meridian entries in those textbooks are sometimes based not on the herb's actual taste but on its effects.
Suoluozi belongs to the qi-regulating herbs in Chinese materia medica. It soothes the liver and regulates qi, harmonizes the stomach and stops pain; it is used for distending pain in the hypochondrium from liver-qi depression, or chest, hypochondrial, epigastric, and abdominal distending pain from liver-stomach qi stagnation. For these conditions it may be combined with Qingpi (Citri Reticulatae viride Pericarpium), Foshou (Citri Sarcodactylis Fructus), and Zhiqiao (Aurantii Fructus). Suoluozi is also used for liver-qi stagnation, premenstrual breast distending pain and dysmenorrhea in women, where it may be combined with Lulutong (Liquidambaris Fructus), Xiangfu (Cyperi Rhizoma), and Yujin (Curcumae Radix). It is also used for mammary gland lobular hyperplasia; in Zhejiang folk, 9–15 g of Suoluozi decocted in water as a tea is used alone for lobular hyperplasia.
Suoluozi has some toxicity and side effects, but the usual adult dose (5–10 g in decoction, or burned to ash and taken with wine) is only about one three-hundredth of its LD50, so it is a very safe dose; only a few patients feel nausea or vomiting afterward. It should be used cautiously in children, who are relatively sensitive to the sodium beta-aescin in Suoluozi; abroad there have been 5 cases of children developing renal failure after overdose (10–20 times the usual dose).
Modern pharmacological studies show Suoluozi has anti-inflammatory and cholesterol-lowering effects. Suoluozi preparations for coronary heart disease effectively relieve chest pain and chest tightness: the effective rate for chest pain reaches 90.4%, and for chest tightness 73%. In 11 patients with severe angina treated with Suoluozi granules or tablets, 9 had their angina relieved.
Suoluozi saponin also has good efficacy for intracranial hypertension from traumatic brain injury and for cerebral edema after brain surgery. There are also reports that sodium aescin, an extract of Suoluozi, has a total effective rate as high as 88.1% for concussion, cerebral contusion, and intracranial hypertension syndrome. But in children the dose should not be too large. These actions show the herb promotes recovery of brain cells, corrects brain dysfunction, reduces cerebral edema and intracranial pressure to some degree, and speeds absorption of chronic intracranial hematomas.
Suoluozi is also used for anal canal edema, burns, and postoperative exudate and swelling in plastic surgery patients, with effective rates over 85%, showing this product reduces inflammatory exudate and swelling and promotes wound healing.