Herbal plants traded at the Kaili medicinal market, Guizhou, China

Background Marketplaces reflect not only the commerce of an area, but also its culture. In Qiandongnan Miao and Dong Autonomous Prefecture with Kaili as its capital, Guizhou Province, China, traditional medicine is thriving in both rural and urban areas. The local people rely extensively on plants for traditional medicines, and these are commonly sold in local specialized markets. The Kaili medicinal market is the biggest in the prefecture. However, ethnobotanical study on herbal plants traded in the traditional market in Kaili has not been performed. The aims of this study are: (1) to document medicinal plants traded in the Kaili traditional market and the associated traditional knowledge; and (2) to analyze the level of agreement among vendors in the purported uses of medicinal plants by using informant consensus (FIC) and the fidelity level (FL). Methods Market surveys were conducted in 2014–2019 to collect information about medicinal plants and associated traditional knowledge. Information including vernacular names, preparation methods, and plant uses was obtained by interviewing 116 vendors of herbal plants. Specimens of fresh and dried herbs, collected as vouchers, were identified by the authors and other botanists at the Minzu University of China, and deposited in the herbarium at Minzu University of China. The level of agreement among information provided by different vendors was assessed using the FIC, and the percentage of vendors claiming the use of a certain medicinal plant for the same indication was assessed with the FL. Results The Miao people comprise 53.4% of all informants in this study of medicinal plants. In total, 237 medicinal plant species traded in the Kaili traditional market were recorded. They belong to 219 genera and 107 families. These plants have been categorized into their purported treatments for 20 medical conditions. The inflammation category showed the highest FIC value of 0.95, showing the best agreement among market vendors claiming its usefulness to treat this condition. The FL index helped to identify 15 culturally important medicinal plant species based on the reported uses by 20 or more vendors in the market. Three medicinal plant species, Eleutherococcus gracilistylus, Sargentodoxa cuneata, and Stephania cepharantha, had an FL > 90%, being used to treat sprains/traumas, rheumatism, and heat/toxins. Conclusions The medicinal plants sold in the Kaili market are highly diverse and have unique medicinal characteristics. The Miao people often use traditional herbal plants for disease prevention and thereby prioritize the use of medicinal plants in everyday life. The future of this medicinal marketplace, however, is uncertain since few young people (< 30 years old) are vendors or customers. Therefore, it is urgent to conserve traditional ethnomedicinal culture in local communities and pass on the associated traditional knowledge to future generations in this prefecture. And the next step should include further studies on FL > 90% plants’ chemistry, pharmacology, biological activity, and toxicity for potentially developing functional foods or pharmaceutical products.


Background
The use of plants for medical treatment and therapy is a practice as old as humanity, dating as far back as the oldest known written documents and found in nearly every known culture [1][2][3]. Approximately 80% of the world's population currently use traditional herbal medicines [4][5][6], and a large number of ethnic medicinal plants are used as raw materials in the pharmaceutical industry. Therefore, millions of people rely on medicinal plants not only for primary health care but also for their livelihood. For example, according to the Guizhou provincial government, the market for Miao medicinal products has doubled in the last 5 years to over 20 billion RMB ($2.95 billion in USD), exceeding the total sum of the Tibetan, Uygur, and Mongolian medicines [7]. Therefore, traditional medicinal plants provide valuable information for the synthesis of new drugs and play an important role in modern society. Traditional markets around the world are known for the trade of plants, minerals, and animals, and regional trade represents an important expression of culture [8][9][10][11]. And trade of these products also has been the backbone of the economy in many rural areas, most of which consist of wild harvested goods [12]. In recent years, some ethnobotanical research on traditional markets had been conducted in China, including those in Bijie [13], Jingxi [14], Yangchun [15], Gongcheng [16], Dechang [17], Jianghua [18,19], Zhenfeng, and Xingren [20]. These studies have contributed to the understanding of plant diversity involved in the trade of medicinal plant species [21,22].
The Qiandongnan Miao and Dong Autonomous Prefecture is an area with rich biological and cultural diversity in Guizhou Province, Southwest China. It is also well known for its unique karst topography with elevations from 137 to 2178 m above sea level and remarkable vertical climate stratification. There are more than ten ethnic groups native to Qiandongnan Prefecture, making it an ethnic minority group hot spot.
The Miao people live primarily in southern China's mountainous areas, including Guizhou, Yunnan, Hunan, Guangxi, Chongqing, Sichuan, Hubei, Guangdong, and Hainan. The Qiandongnan Miao and Dong Autonomous Prefecture is the largest Miao community in China, with a population of about 1.86 million, accounting for about 42% of the prefecture's population [23].
Herbal medicines are an integral part of Miao health and development. Medical clinics in Miao communities are relatively inaccessible and treatments are often costly. The Miao villages are normally surrounded by forests with many medicinal plants, and thus they often use locally sourced herbal medicines. Thus, the Miao people have developed their own traditional medicine with associated indigenous knowledge. In the past decades, some publications have documented Miao medicinal research achievements [24][25][26]. The Miao medicine is a highly regarded discipline in China and is becoming increasingly popularized in the country.
However, with the rapid development of the Miao medicinal industry, the traditional markets are rapidly decreasing because of the emerging e-trade systems in China and the growth of mini-supermarkets and shops throughout the countryside, but some Miao people in Kaili still keep the custom of trading medicinal plants. Every week, the Miao people who generally live more than 30 km far from urban areas bring medicinal plants to trade in the Kaili medicinal market. It is not easy to conserve the traditional medicinal knowledge maintained by a small population. Although this marketplace is large in scale, it has not been investigated ethnobotanically. It is therefore urgent to document these medicinal plants and the associated traditional knowledge of the Miao people. Research regarding traditional marketplaces can help producers, sellers, healers, and consumers develop an ongoing relationship through knowledge-based supply and demand of medicinal plants and their derivatives.
Therefore, our study focuses on this understudied medicinal marketplace, which reflects the diversity of medicinal plants in the prefecture. There are two primary aims of this study: (1) to record the current use of medicinal plants in Kaili market and associated traditional knowledge; and (2) to explore connections between medicinal plants and vendors using the method of informant consensus (FIC) and to determine the most frequently sold medicinal plant species using the method of fidelity level (FL). Through our study, we try to provide policymakers, researchers, and local people with the necessary information and data for the conservation and sustainable use of traditional Miao medicinal plants people (< 30 years old) are vendors or customers. Therefore, it is urgent to conserve traditional ethnomedicinal culture in local communities and pass on the associated traditional knowledge to future generations in this prefecture. And the next step should include further studies on FL > 90% plants' chemistry, pharmacology, biological activity, and toxicity for potentially developing functional foods or pharmaceutical products. and associated traditional knowledge. Furthermore, this study may provide valuable information for future development and also give comprehensive and scientific guidance for local people to consume medicinal herbs more safely.

Study site
Kaili is the capital of the Qiandongnan Miao and Dong Autonomous Prefecture, located in southeast Guizhou ( Fig. 1) at nearly 850 m above sea level. The population of Kaili is dominated by the Miao people who comprise about 63% of the total population. There are dozens of rivers in Kaili that flow into the Yuanjiang River, a branch of Yangtze. The sinkholes and underground caverns in the area are well developed because of its karst topography.

Kaili medicinal market
The Kaili medicinal market was founded about 200 years ago by local people, and the trade of medicinal plants was likely developed in conjunction with the sale of other necessities (Fig. 2). In 2016, with the assistance of the local government and urban planners, the market was moved to a new site and developed into a tourist attraction, thereby integrating traditional medicinal culture and economy. The current market includes two subsectors: traditional medicinal plants and pharmaceutical/ready-to-usedrug markets. The former comprise raw or dried plants with little or no processing. The latter contain processed  medicinal plant products (Fig. 3). A variety of participants are involved in the sale of medicinal plants at Kaili traditional market, such as rural harvesters, small retailers, and licensed vendors (Table 1).

Ethnobotanical surveys
A total of 116 vendors (71 male and 45 female) selling medicinal plants in the market were interviewed, ranging in age from 20 to 87 years old, with a mean age of 65.
To gather information about medicinal plants in the market, semi-structured interviews with vendors were conducted (Fig. 4). Information from vendors was recorded, including vernacular names of medicinal plants, medicinal uses, parts used, habitat of plants, and therapeutic prescriptions. Eighteen key informants were selected to interview who were either local healers or important custodians and practitioners with rich traditional knowledge of medicinal plants. All these local healers were males. When interviewing vendors, samples of fresh herbs were purchased at the regular price from each medicinal market as voucher specimens. For the dry herbs sold in the market, we collected specimens from the field, with assistance from local people. Voucher specimens were prepared and deposited in the herbarium at the Minzu University of China in Beijing, China, for future reference. The botanical identities of voucher specimens were confirmed by the authors and other botanists at the Minzu University of China. Plant names were checked with Flora of China (http:// flora. huh. harva rd. edu/ china/) and botanical Web sites including http:// www. tropi cos. org/ and http:// www. thepl antli st. org.

Data analysis
The data were summarized using Microsoft Office Excel and organized for statistical analysis. All of the local therapeutic uses of medicinal plants were grouped into 20 medical categories, which were based on the information gathered from the interviewees.
The FIC index was used to measure consensus among vendors regarding the therapeutic use of each medicinal plant [27][28][29]. The formula is listed as follows: Nur refers to the number of therapeutic use reports, grouped in a medical category, from market vendors for a particular medicinal plant, and Nt refers to the total number of medicinal plant species used in a particular medical category. The FIC values range between 0 and 1, where 1 indicates the highest level of market vendor consensus. FIC = (Nur−Nt)/(Nur−1).  The FL index [30] indicates the percentage of vendors claiming the use of a certain medicinal plant for the same therapeutic use, which was grouped in a specific medical category [31][32][33]. The FL was calculated according to the following formula: FL (%) = (Ip × 100/Iu), where Ip is the number of market vendors who independently claim a therapeutic use of a medicinal plant species to treat a specific illness or disease and Iu is the total number of market vendors that sold the same medicinal plant to treat any given illness or disease.

Demographic features of the vendors
A total of 116 medicinal plant vendors (71 male and 45 female) were interviewed at the market. Of these, 62 were Miao people ( Table 2). The Miao ethnic people comprised 53.4% of the total interviewees, corresponding with ethnic composition of Qiandongnan Prefecture. The large number of vendors made this market an especially good place to conduct ethnobotanical surveys. We found 50 vendors, ranging in age from 31 to 90, with a median of 60 years old, and few vendors under 30 years old. Most of those younger vendors collect wild medicinal plants and sell them as a part-time activity, while the older generation do this full time. As for the gender structure of the vendors, the number of men and women older than 60 years old was almost the same, while for those under 60 years old, almost twice as many men as women in this group. Most vendors were small retailers, as Table 3 summarizes the number of all the vendors surveyed.

Miao medicinal plants traded at traditional market
We recorded 237 medicinal plant species traded at the Kaili traditional medicinal market, which were grouped into 219 genera and 107 families. The results provided the following information for each species: scientific name, Chinese name, local name, botanical family, plant part used, disease treated, route of administration, and use value ( Table 4). The dominant plant family was Compositae with 23 species (9.6% of the total species), followed by 16 species of Rosaceae (6.7%), 10 species of Labiatae (4.2%), 9 species of Liliaceae (3.8%), while another 63 families were mostly represented by 1 species. Vendors in the marketplace sold different plant parts for the preparation of traditional drugs (e.g., leaves, roots, seeds, barks, and fruits). The whole plants were the most common plant material used, followed by roots. Life forms showed that herbaceous plants constituted the highest proportion with 144 species (60.8%), while there were 47 shrubs (19.8%), 25 trees (10.5%), and 21 lianas (8.9%). The majority of remedies could be prepared from either dried or fresh materials, and some were prepared only from fresh materials, while a few were prepared from dried materials.                             (Fig. 5), Eleutherococcus nodiflorus (Fig. 6), and Sargentodoxa cuneata (Fig. 7) are used for conditions like sprains/   [37], and thus it is the most prosperous time on Kaili medicinal market. Acorus calamus is widely used by the Miao not only as a medicinal herb, but also it is used symbolically to ward   off evil spirits by displaying it on doors or using it in a medicinal bath. The Miao healers often use the rhizomes of Acorus calamus to treat aphasia, traumas, diarrhea, snake bites, and stomach ache [38]. Some local Miao people soak their feet daily in hot water baths infused with Acorus calamus rhizomes to drive the cold away, balance yin and yang, and boost their immunity. When an elder dies, the Miao people boil Acorus calamus in water to scrub the corpse. They believe that Acorus calamus water will wash away unhappiness and allow the deceased to rest peacefully. Some medicinal plant species are traditionally used as starters for preparing fermented beverages by Miao people, similar to a practice in the Shui communities [39]. In Kaili, the fifth and eighth months of the lunar calendar are considered the best times to buy wild fruits of Ficus tikoua, Actinidia chinensis, Rubus setchuenensis, and Rosa roxburghii for brewing wine or liquor.

Diseases treated by products from traditional markets
Most of the knowledge on herbal remedies is handed down orally to the young people in the community by elders. In this market, 66.4% of vendors were male, probably because women are dedicating themselves to housework, childcare, keeping livestock, and farmyard management, while the men collect wild medicinal herbs from the high mountains [40]. Most medicinal plant vendors are small retailers who have common knowledge of Miao medicine and other ethnomedicine.

Therapeutic effectiveness and popularity of medicinal plants
The medicinal plants from the market were used to treat 83 human ailments. Traumas, fevers, and skin diseases, for example, were common conditions among the Miao, which likely relates to their environment and culture [20]. Many Miao people face difficult living conditions in mountainous areas. When the Miao work in rugged mountainous terrain, they can be injured easily. That is likely the reason that herbs to treat traumatic injury occupy a large proportion of the medicinal market. The weather in Kaili and surrounding areas is wet and humid throughout the year [41]. From the theory of traditional Chinese medicine, those who live in damp areas should expel wind in the body regularly to relieve constipation and improve sleep quality, and then make their bodies feel better [42]. Thus, Miao people use many herbs to treat rheumatism. The Miao's living environment is also regarded to cause so-called heat, another concept from TCM; thus, the medicinal plants for heat-clearing and detoxifying are very popular in the market.
Inflammation was cited as the highest number of medicinal plants, revealing the importance of antiinflammatory treatment. In poor Miao villages, many people do not have the resources to purchase modern pharmaceuticals, so collection of herbs to treat inflammation is necessary. As a result, minor diseases can escalate to much more serious ones. Stomach, intestine, and liver diseases all have an FIC of = 0.82, showing a high level of agreement among the 116 vendors to treat these diseases.
The high FL values in this study highlight that the local vendors and residents have a strong dependence on these 15 species of medicinal plants. As such, all of these medicinal plants should be further studied, focusing on their chemistry, pharmacology, biological activity, and toxicity, as well as evaluation of efficacy and safety of local medicinal plants. For example, Eleutherococcus nodiflorus, Sargentodoxa cuneata, and Stephania cepharantha had an FL > 90%, which were used to treat traumatic injury and sprain, rheumatic problems, and heat-clearing and detoxifying. The most important nine species had an FL > 70%, have considerable agreement among market vendors on their particular use and credibility, and therefore could be further analyzed for potential development. Identifying plants with high values of FIC and FL is very important, as it will useful to support traditional medicine and establish related policies.

Preparation and dosage of medicinal plants-based remedies
The Miao people use fresh medicinal plants frequently [43], while dry plants are seldom used. This is because they believe the active ingredients of fresh plants are still intact, so this method can optimize effectiveness [44]. The Miao healers usually mixed several species instead of a single herb. For example, a Miao healer may treat cold with Dichondra repens, Arctium lappa, Taraxacum mongolicum, and Lonicera japonica, instead of using a specific single plant species. Rheumatism and traumatic injury were the most common problems for which the Miao people prepare remedies with more than one plant species. When administering medicinal herbs, some healers practice a form of personalized medicine by preparing dosages according to individual patients, rather than measuring consistent doses.
The Miao usually use processing methods such as decoction, medicinal liquor, external application, and medicated bath. Medicinal plants are often added to food with an egg or animal meat for the purpose of enhancing the body's immunity and supplement protein.
Meanwhile, the Miao people use different additives like alcohol, honey, salt, and sugar to improve the flavor and taste. In particular, the practice of combining plants and alcohol has a long history in Miao medicine. Miao healers use different procedures to administer their raw material/alcohol combinations. The medicinal plants are soaked in alcohol for about one month, and the resulting liquid then is drunk by the patient or applied externally to the affected parts. Alcohol can act as solvent instead of water, where fresh plant or dried plant powder is placed in alcohol and either drunk or applied externally [45]. It is believed that alcohol extracts contain more active components from the medicinal plants than water does, thus being more effective in curing diseases. For example, Alangium chinense, when soaked in alcohol, is far more effective in treating rheumatism than the fresh plant alone.

Threats to medicinal plants and associated traditional knowledge
Compared with other herbal markets that only appear on the Dragon Boat Festival and Chung Yeung Festival (the 9 th day in September of lunar calendar), the Kaili medicinal market sold herbal medicines every week. These plants are in great demand and supply is limited. Lacking relevant development policies and protection measures in this area pose a serious problem, as some rare or endangered species were being sold. For example, Paris polyphylla is a common Miao medicinal plant in Guizhou. However, due to over-exploitation, the survival of wild populations is seriously threatened, and resources are dwindling. Therefore, the collection of plant resources and ex situ conservation of rare and endangered species are important missions, and selling endangered species in the market should be also controlled. Most Miao medicinal knowledge was handed down orally to the younger members of the community by elders [46]. However, nowadays, indigenous knowledge is less commonly passed down from the elders to the young generation. According to the age structure of the vendors (Table 2), groups 31-60 and 61-90 at roughly equal in size. There was only a small group of young people in the market. Few young Miao appear to be trained in traditional knowledge and sustainable harvesting of medicinal plants, likely because most herbal materials are collected from wild plant populations, and there is small quantity for each plant. Compared to working in the urban areas, collecting and selling wild medicinal plants were only temporary job; it is less profitable. Even Miao medicine has a lot of growth potential, but for reasons of cost and time, it is hard for untrained people to develop a successful business. In interviews, most young people also expressed disbelief that studying indigenous knowledge can earn money for their life [18,47]. Thus, in recent years a large number of rural young people have chosen to move to big cities to work and live. This phenomenon could have a negative influence on the inheritance and development of indigenous knowledge. It exposes the vulnerability of traditional medicinal knowledge if its transmission is limited by acculturation or inter-ethnic exchange from generation to generation [48].

The names of Miao medicinal plants
The Miao often name medicinal plants according to their features such as color, morphology, usage, and flavor [49,50], which is similar to the nomenclature of local people in Umnugobi Province, Mongolia [51]. There are three main types of nomenclature: (1) The word jab, which means medicine, is added to the medicinal plants. For example, the Miao name for Epimedium acuminatum is jab ngol xid which means "herbal medicine used to treat impotence. " Thus, this nomenclature can be formulated as "jab + usage"; (2) the used plant part is added to the name. For example, the Miao name for Ophiopogon japonicus is zend nangx ngol yut. These words mean tuber (zend), herb (nangx), and persistent cough (ngol yut). Thus, in Miao nomenclature Ophiopogon japonicus is clearly understood to be an herbaceous plant and its tubers can be used to treat persistent cough; (3) the Miao name for a medicinal plant may be adopted from the local dialect in the study area. For example, the Miao people's name for Bletilla striata is wul jut, which is the local dialect name for this plant.

How to protect the Miao people's traditional medicine culture?
Nowadays, the Chinese government has recognized ethnomedicine and issued a series of policies to support their protection and development after the foundation of the whole country [52,53]. However, it is still urgent to cultivate more professional talents in the field of ethnomedicine by issuing more preferential policies and funds.
Researchers from different agencies and enthusiasms are encouraged to strengthen the investigation of Miao medicine plants. Books and databases of medicinal plants can be published, with supports from foundations, and providing free access to local healers and those (especially young people) who are interested in Miao ethnomedicine. For species with significant economic value, scientific institutions should accelerate scientific research on artificial breeding and cultivation. The advanced theories and methods of pharmacology, chemistry, and molecular biology should be applied to study the traditional Miao medicinal knowledge and enhance Miao people's understanding and confidence. Because of its significance in economy and culture, the local government or administration agency may pay more attention to the medicinal market to provide a better environment for vendors and buyers. It is also necessary to encourage the Miao people to conserve medicinal plants in situ and ex situ, such as by planting endangered and preferred medicinal species in their home gardens or farmlands.

Conclusion
This study shows that sociocultural customs related to medicinal plants have brought about their own unique influences on daily life and become indispensable components in the folk culture and social custom in Kaili.
In this study, we analyzed the data collected from 116 vendors who sold fresh or dried herbal medicinal material of 237 plant species to treat a wide spectrum of illnesses and diseases. Most of these plants were used in the treatment of heat and detoxification, traumas, skin diseases, and wounds. Inflammatory diseases have the highest value of used citations, followed by stomach, intestine, and liver diseases. The occurrence of these diseases is likely associated with local living habits and environmental conditions. Three medicinal plant species, Eleutherococcus nodiflorus, Sargentodoxa cuneata, and Stephania cepharantha, which are used by the local people, have a particularly high public recognition and consistent patterns of use: The next step should include further studies on these plants' chemistry, pharmacology, biological activity, and toxicity for potentially developing functional foods or pharmaceutical products.
Although high numbers of medicinal plant species have been reported to be used for human health problems, many wild species are being threatened by various anthropogenic factors, while conservation efforts are less practiced in the study area.
Furthermore, the knowledge on herbal remedies is held by elders, who are less educated, while most young people prefer to look for jobs in urban areas instead of studying traditional medicinal knowledge in the countryside. It is therefore urgent to find solutions for conserving and transmitting the traditional medicinal knowledge in the study area.