Cannabis in Chinese Medicine : Are Some Traditional Indications Referenced in Ancient Literature Related to Cannabinoids?
E. Joseph Brand and Zhongzhen Zhao
Frontiers in Pharmacology, 2017, vol 8, Article 108, 1-11.
doi : 10.3389/fphar.2017.00108
Cannabis sativa L. (Cannabaceae) has a long history of utilization as a fiber and seed crop in China, and its achenes (“seeds”) as well as other plant parts have been recorded in Chinese medical texts for nearly 2000 years. While the primary applications of cannabis in Chinese medicine center around the use of the achenes, ancient indications for the female inflorescence, and other plant parts include conditions such as pain and mental illness that are the subject of current research into cannabinoids such as cannabidiol (CBD) and delta 9-tetrahydrocannabinol (THC). However, little previous research has been conducted to analyze the Chinese medical literature in light of recent advances in the pharmacology and taxonomy of cannabis, and most of the relevant Chinese historical records have not yet been translated into Western languages to facilitate textual research. Furthermore, many key questions remain unresolved in the Chinese literature, including how various traditional drug names precisely correspond to different plant parts, as well as the implications of long-term selection for fiber-rich cultivars on the medical applications of cannabis in Chinese medicine. In this article, prominent historical applications of cannabis in Chinese medicine are chronologically reviewed, and indications found in ancient Chinese literature that may relate to cannabinoids such as CBD and Delta9-THC are investigated.
Keywords: Cannabis, Chinese medicine, historical changes, bencao, cannabidiol
Cannabis sativa L. has been cultivated in China for millennia for use as a fiber, food, and medicine. References to cannabis are found throughout classical Chinese literature, including inmany famous works of philosophy, poetry, agriculture, and medicine. Fiber-rich biotypes of cannabis (hemp) were extensively used in ancient China for clothing and the production of paper, rope, and fishing nets (Dai, 1989), and the achenes (“seeds”) of cannabis have been continuously used in Chinese medicine for at least 1800 years. Today, China is regarded as one of the world’s ancient epicenters of hemp cultivation, resulting in a diverse germplasm with genetically distinct regional varieties of fiber-rich hemp that are adapted to local environmental conditions throughout the country (Gao et al., 2014; Zhang et al., 2014).
The prominence of hemp in ancient Chinese culture can be seen by its occurrence in classical literature from the Warring States Period (475–221 BC), including philosophical works by Confucius, Mencius, Xunzi, Zhuangzi, and Mozi, as well as the Classic of Poetry (Shi Jing; Sun, 2016). By the first to second century AD, the ancient Shuowen dictionary (Shuo Wen Jie Zi) featured multiple Chinese characters that illustrate knowledge of the dioecious nature of cannabis and discriminate based on gender (Liu, 1999).
In the sixth century AD, the agricultural text Essential Techniques for the Welfare of the People (Qi Min Yao Shu) described techniques for the cultivation of hemp in great detail, and its monograph on cannabis cultivation features one of the first textually documented applications of fertilizer in the history of Chinese agriculture (Shi, 1957). This text also demonstrates the knowledge that removal of male plants at the initiation of flowering will result in a lack of seeds; however, the text focuses exclusively on cultivation and harvesting practices to maximize the production of seeds and the quality of fiber and does not reference the deliberate production of seedless cannabis (Shi, 1957).
It is notable that most classical Chinese references focus on the use of cannabis for its seeds and fiber, with few, if any, explicit references to drug effects seen outside of the medical literature. Although early Chinesemedical literature suggests that both drug and fiber biotypes of cannabis were known in ancient times,more research is needed to clarify the implications of these different biotypes in medical applications. Additionally, further research is needed to probe whether the medical applications of cannabis in ancient Chinese literature may relate to non-psychoactive cannabinoids such as cannabidiol (CBD), which may have been present in ancient fiber biotypes as well as drug biotypes (see Figure 1).
CANNABIS IN CHINESE MEDICINE
Cannabis has been continually documented in Chinese medicine for ∼1800 years. In the modern era, its achenes (commonly referred to as “seeds” and known in TCM as huomaren 火麻仁) are frequently used as a moistening laxative and are official in the Chinese Pharmacopeia (CP, 2015). All parts of the cannabis plant have been recorded in historical Chinese medical texts, including the achene (seed), female inflorescence, leaf, and root, as well as the cortex of the stalk and the water used to process the stalk into fiber. However, only the achenes (seeds) are currently used in clinical practice (Brand and Wiseman, 2008).
In contrast to the prominent use of the achenes in Chinese medicine, many applications of cannabis in early Western medicine focused on preparations made from the female flowering tops of drug varieties of cannabis, which were featured in early Western pharmacopeia texts from the nineteenth to twentieth century (Wood, 1918). In the modern era, the investigation of cannabis for medical purposes in the West has continued to primarily focus on cannabinoids, resulting in prescription medicines such as the botanically derived drug “Sativex” by GW Pharmaceuticals (a mixture of 19-THC and cannabidiol in an oromucosal spray that is sold by prescription in 15 countries, including the UK, Germany, Italy, Canada, Australia, and Spain; Russo et al., 2007).
The notable contrast between the medical applications of cannabis in traditional Chinese medicine and Western medicine has been poorly explored in current ethnopharmacological literature. Despite the fact that cannabis preparations have been extensively and consistently documented in Chinese bencao (materia medica) texts for ∼1800 years, no Englishlanguage publications have systematically assessed the medicinal indications of cannabis in the Chinese bencao literature and historical changes in the plant parts used. Few reliable translations of Chinesemonographs on cannabis fromtraditional bencao texts exist, which has led to significant gaps in the Western understanding about how cannabis was used in Chinese medicine.
Additionally, many problems related to cannabis in TCM remain unresolved in the contemporary Chinese literature. Modern Chinese journal articles as well as historical authors have attempted to clarify the complicated nomenclature of the female inflorescence in bencao literature (Liu and Shang, 1992; Liu, 1999; Liu et al., 2009; Wei et al., 2010), and monographs in modern TCM texts detail different plant parts and their use across a range of historical texts (Editorial Committee, 1977; Cui and Ran, 1993). However, a number of modern and historical Chinese sources contradict each other in terms of which plant parts correspond to certain traditional drug names such as mafen (麻蕡), mahua (麻花), and mabo (麻勃), complicating the interpretation of their medical actions.