The knowledge of traditional medicinal plants of the Chuanqing
The traditional medicinal knowledge in the Chuanqing was mastered mainly by men aged 61-80 years (Fig. 2). According to the data of the National Bureau of Statistics, in 2010, the illiteracy rate of men in the rural areas was 29%, and that of women was 71 %. Men who received higher education might learn more medicinal plant knowledge. Moreover, the family collaboration model in the local Chuanqing’s areas was " men work outside and women stay home " [45], so men had more opportunities to identify and collect medicinal plants in the field.
The main families of medicinal plants in the Chuanqing were the Orchidaceae and Asparagaceae families. As one of the typical karst areas in the world, Guizhou’s unique geographical location and complex natural environment provided suitable conditions for wild orchids [46]. Moreover, Orchidaceae plants were widely used in TCM. There are 1,240 species of orchids in 171 genera in China, of which 343 species of 82 genera were used for medicinal purposes [47,48]. In addition, most plants in Asparagaceae, such as Polygonatum kingianum Collett & Hemsl., and Asparagus filicinus Buch.-Ham. ex D.Don were used frequently because their thick root tubers were attractive to herb collectors. Moreover, the two plants were traditional Chinese herbal medicine widely used by Chinese Han people. Therefore, a large amount of TCM was used in the Chuanqing due to the Chuanqing had been influenced by the traditional Chinese medical system for a long time.
Roots, rhizomes and tubers were frequently used as medicinal parts in TCM, more than one-fourth of the medicinal plants added in over 400 preparations were derived from roots and/or rhizomes [49]. Underground parts (the sum of roots, rhizomes, and root tubers) of the Chuanqing medicine accounted for 46%. Therefore, underground parts were frequently used. The whole plant (accounted for 36%) was a commonly used medicinal part because of the whole plant was easy to obtain and convenient for them to use by local people. In addition, local people had no systematic knowledge of drug use, so they did not usually subdivide medicinal parts to treat diseases.
Decoction (44%) was the most common preparation method for the Chuanqing. The decoction was the most commonly used TCM compound dosage form by traditional Chinese doctors, and it was also the longest and most widely used preparation in the history of China [50]. Therefore, the Chuanqing’s medicine was affected by TCM, the decoction was also the most commonly used preparation method for the Chuanqing. Alcohol maceration was the second commonly preparation method (accounting for 19%). Alcohol maceration was also a traditional Chinese medicinal preparation in China, with unique curative effect, convenient preparation and wide application [51]. So it was widely used. In addition, the Chuanqing also had some other special usages, such as making a soup with glutinous rice wine and steaming with eggs.
Most medicinal materials were used to treat diseases of the musculoskeletal system (34 mentions). According to statistics, the diseases with the fastest increase in hospitalization and expenses in 2015 were musculoskeletal diseases in China [52]. Moreover, people lived in humid climates and engaged in agriculture, which led to a variety of musculoskeletal systems diseases, such as rheumatism [53], traumatic injuries and other diseases, as does the Chuanqing. For instance, Artemisia argyi H.Lév. & Vaniot (UV=0.10), Hedera sinensis (Tobler) Hand.-Mazz. (UV=0.29), and Lysimachia paridiformis var. stenophylla Franch. (UV=0.10) were all used to treat rheumatism;Liparis campylostalix Rchb.f., Rhodiola yunnanensis (Franch.) S. H. Fu, and Cynanchum inamoenum (Maxim.) Loes. ex Gilg. & Loes. were used to treat traumatic injuries.
In the long-term struggle with the natural environment and diseases, the Chuanqing made use of rich plant resources to treat diseases. In addition, they utilized places such as the herbal market at the DBF to constantly exchange traditional medicinal knowledge among the surrounding ethnic groups, and gradually formed a unique traditional medicinal knowledge system for the Chuanqing.
Comparison with ChP, the QSG and Southeast Asian medicines
The existing studies on the Chuanqing showed that it was closely related to the Han and the local ethnic groups in Guizhou such as the Miao in their social culture [20,21,54] or medical research [55]. Eleven medicinal plants were also recorded in the ChP, the QSG and the Chuanqing’s medicine coinstantaneously. The result indicated the diseases treated with medicinal plants by the Chuanqing were similar to those found in ChP, the QSG. For example, Aconitum carmichaelii Debeaux was used to treat noxious sore and had the function of restoring yang for resuscitation, Tinospora sagittata Gagnep. was used to treat neck pain, laryngitis, dysentery, abdominal pain, and Ligusticum striatum DC. was used to relieve pain in ChP, QSG and the Chuanqing’s medicine. However, the diseases treated with some medicinal plants of the Chuanqing were different from both ChP and QSG. For example, Cynanchum paniculatum (Bunge) Kitag. ex H.Hara was used to relieve pain in ChP and QSG, but it was used to treat gynaecopathy in the Chuanqing’s medicine and some researchers found it could treat gynecological inflammation disease because of anti-inflammatory effects [56]. Gleditsia sinensis Lam. was used to treat osteodynia, arthralgia rather than psychiatric disorders in ChP and QSG, and some studies found its analgesic effects [57]. Lysionotus pauciflorus Maxim. was firstly found to treat rheumatism, Paris polyphylla Sm was firstly found to treat cardiopathy. Sanguisorba officinalis L. was firstly found to treat diarrhoea in the Chuanqing, and this function had been proved in the reports of being used to treat diarrhea of humans and livestock [58-60].
In general, after thousands of years of development, TCM had formed a mature theoretical system, such as “ the theory of Four Qi and Five Flavors, the theory of Visceral Manifestation, and the theory of Yin-Yang and Five Elements”. According to our survey, the Chuanqing’s medicine was still in the stage of summarizing specific knowledge and experience, such as circulated in form of rhymes.
Some studies showed many cross-border ethnic groups in Southeast Asia, such as Han and Miao [61,62], and there were also a large number of the Han and the Miao lived in the Chuanqing's living area[63]. Therefore, the Chuanqing and Southeast Asian countries may have a similarity in medicinal plants to a certain extent. Leguminosae was widely used in traditional medicines of the Southeast Asian countries, and Asparagiaceae and Orchidaceae were widely used by the Chuanqing. The reason for this difference was that Leguminosae was widely distributed in tropical flora and provided many medicinal species in these countries [33-42]. The living area of Chuanqing people was a typical karst landform, with the most plants distributed in Asparagaceae and Orchidaceae [46-48]. Leaves were frequently used in Southeast Asian countries, because Southeast Asia had a subtropical rainforest climate and many evergreen plants grew up there, the leaves were abundant and easy to obtain. The Chuanqing's residential areas in Guizhou Province had a northern subtropical monsoon climate, with high altitude (1050 to 2476 m) and distinct four seasons. In autumn and winter, the whole plant and underground parts could be used without leaves. In Southeast Asian countries, the most common diseases treated by traditional plants were digestive system diseases. Some studies pointed out that it was mainly related to living conditions, living habits and health facilities. For example, in Southeast Asian countries, people who worked in agriculture and lived in poverty were prone to the diseases of digestive system, such as gastritis and diarrhea [33,38]. Moreover, alcoholism was also the reason for digestive system diseases [42]. The reasons why the Chuanqing’s medicine mainly treat musculoskeletal diseases had been discussed above. Although Thailand, Laos, Vietnam and Myanmar in Southeast Asia were different from the Chuanqing in dominant family, medicinal part and treatment of diseases, but the most common preparation method among them was decoction. Because the decocting was the most convenient and easy way. Therefore, the similarity between the Chuanqing’s medicine and traditional medicine of South Asian countries was low.
The dilemmas and solution of the traditional medicine culture of the Chuanqing
The traditional medicinal knowledge in the Chuanqing was mastered by people aged from 61 to 80 years. This led to the serious aging of people who mastered the knowledge of medicinal plants in the Chuanqing. In addition, a large number of rural young people had chosen big cities for work and living in recent years, which aggravated the problem of the aging population. These were not conducive to the inheritance and development of traditional medicinal plant knowledge in the Chuanqing. Meanwhile, people's lifestyle had been changed by the impact of modern industrial civilization, and people's medical choices had been changed by the popularization of modern medicine. These led to the decline of the social recognition of traditional medical knowledge and the decrease of users, which further endangers the application and protection of this knowledge. It’s significant to strengthen the collection and protection of the local traditional medicinal knowledge, conduct a comprehensive interview with the older generation of ethnic doctors, and collect the diagnosis and treatment methods with ethnic characteristics.
In recent years, with the increasing demand for natural medicines, many wild medicinal materials had been plundered without scientific protection and development measures. For example, the whole plant and underground parts as the most commonly used medicinal part was not conducive to the regeneration of wild plant populations. Moreover, we found the phenomenon of selling wild protected animals and plants, such as Paris polyphylla Sm, Taxus wallichiana var. chinensis (Pilg.) Florin and Tylototriton kweichowensis Fang and Chang (listed as Vulnerable (IUCN, 2012) and as Category II State Major Protected Wildlife in China). It indicated that the locally rare wild plant and animal resources had been destroyed, and legal risk existing in the herbal market of DBF . In the face of this situation, the government and non-governmental agencies should strengthen the natural protection of wild species by increasing law enforcement and strengthening the popular science education of local people. For the species with significant economic value, scientific institutions should speed up the scientific research of artificial breeding and cultivation, instead of utilizing wild populations.
Due to the lack of modern scientific and technological means & government guidance, the development of industrialization and modernization planning of the Chuanqing’s medicine were almost absent. To a certain extent, the situation led to the loss of cultural knowledge of the Chuanqing’s medicine and the dilemmas of sustainable development. We had noticed that China's DBF was added to the United Nations Educational,Scientific,and Cultural Organization's Intangible Cultural Heritage list in 2009. Moreover, many regions had upgraded traditional ethnic medicinal markets at the DBF into well-known cultural tourism products. For example, the DBF medicinal market of the Zhuang in Jinxi County had been selected as the intangible cultural heritage of the Guangxi Zhuang autonomous region [64]. Pu'er City of Yunnan Province promoted the local herbal market at the DBF as a "Baicao Gen Food and Cultural Tourism Festival" [16]. These examples provided the reference for inheriting and promoting the traditional medical culture of the Chuanqing.