Ethnobotanical study on traditional medicinal recorded in the Naxi Dongba Sutras


 Background: The Naxi people, living in Southwest China, have a long history and a rich characteristic culture. Their ancestors recorded their life practices by ancient hieroglyphs and gradually formed the Dongba Sutras, which, among other knowledge, included the traditional knowledge of Naxi medicine. In the past, most studies on the Dongba Sutras focused on the humanistic culture of Naxi people, whereas studies have rarely focused on Naxi herbal medicinal plants described in the Dongba Sutras. Studying this aspect is helpful for exploring the traditional culture of Naxi people from the perspective of traditional medicine.Methods: From February to September 2019, we screened the medicinal plants from the Dongba Sutras with the help of Dongba. Then, we carried out field investigatios and collected voucher specimens of traditional medicinal plants with the help of 104 Naxi folk healers. The specimens were identified and stored in the Herbarium of Yunnan Branch, Institute of Medicinal Plants, Chinese Academy of Medical Sciences (IMDY). Through semi-structured interviews, we obtained ethnobotanical information of medicinal plants. The obtained quantitative data were analysed using the informant consensus factor (ICF) method and the number of citations.Results: A total 85 species of medicinal plants belonging to 51 families and 71 genera were recorded in the Dongba Sutras. Among them, 25 species were endemic to China, and eight species were only distributed in Naxi distribution areas. These medicinal plants were mainly obtained from the wild, and 22 species could be used as food. The most frequent method of taking medicinal materials was oral-taking after decoction, followed by topical and sometimes buccal. The methods of processing these medicinal materials included water decoction, warm water flushing, and drinking after soaking. The medicinal plants in the Dongba Sutras are used to treat 96 conditions classified into 13 disease groups according to the International Classification of Primary Care second edition. Further analysis indicated that most of these plant species were utilised for treating diseases from the digestive (D) group, followed by the those from the respiratory (R) group, musculoskeletal (L) group, general, and unspecified (A) group. Moreover, the Naxi people have high consensus on the treatments of diseases from these four pathological groups. Conclusions: Naxi traditional medicine is simple and unique. The ancient Naxi people recorded their highly developed medical culture in the Dongba Sutras. Natural plant resources found around them were their primary choices for both medicine and diet therapy. The ecological ethics of Naxi people have positive significance for the conservation of wild resources in their area.

less Naxi people use (or even recognize) traditional medicinal plants. Thus, it becomes very urgent and necessary to study medicinal plants recorded in the Dongba Sutras.

Materials And Methods
Study area Lijiang is a prefecture-level city in Yunnan Province, Southwest China. It is located in Hengduan Mountains, between 25°23'-27°56'N and 99°23'-101°11'E. The total area of Lijiang City covers 20 600 km 2 [7]. The terrain of the area is high in the northwestern part and low in the southeastern part, with the highest altitude of 5 596 m and the lowest altitude of 1 015 m. The maximum altitude difference of Lijiang is 4 581 m [8].
The climate of Lijiang belongs to subtropical humid climate [9]. There is abundant rainfall and a distinct dry and wet season. The average annual rainfall is about 1 000 mm, and the rainy season lasts from May to October being particularly pronounced in July and August. The annual average temperature is between 13 ℃ and 20 ℃, the average temperature of the hottest month is 18-26 ℃, and the average temperature of the coldest month is 4-12 ℃. Lijiang has 2 500 h of annual sunshine and 147 kcal/cm 2 of annual solar radiation [9].
Lijiang has a forest coverage rate of 70%. The area is rich in medicinal materials and other exploitable biological resources, and is known as the 'kingdom of alpine plants' and 'hometown of medicinal materials' [8].
The key areas of the present study were Gucheng District and Yulong County in Lijiang City, Yunnan Province, China. This area is the most concentrated area of Naxi population in the world, with about 210 000 people, accounting for 68.5% of the total Naxi population. Naxi people live in mountainous areas with inconvenient transportation and abundant biological resources, which is why their traditional is the most convenient mean of resisting diseases. At the same time, inheritance model of Dongba culture is masters teaching apprentices, that makes a better inheritance of the Naxi traditional medicinal culture.

Data collection
From February to September 2019, we screened the medicinal plants from the Dongba Sutras with the help of Dongba. Then, we carried out eld research with assistances from 104 Naxi folk healers and collected traditional medicinal plant specimens. The basic survey information such as age, and gender was collected and recorded. Using semi-structured interviews [10], ethnobotanical knowledge was obtained, including information about the local name, medicinal parts, harvesting methods, preparation methods, and indications of the medicinal plants from the Dongba Sutras. The informed consent of the participants was obtained before conducting the interviews, and the ethical guidelines prescribed by the International Society of Ethnobiology [11] were followed. The local names were transliterated from Naxi or local Chinese pronunciation into the Roman alphabet following the Scheme for the Chinese Phonetic Alphabet [12] and the Basic Rules for Hanyu Pinyin Orthography [13]. The diseases treated by the medicinal plants from the Dongba Sutras were classi ed according to the International Classi cation of Primary Care (ICPC-2) [14] of the WHO (World Health Organization) [15] [16].

Plant materials
With the help of Naxi folk healers, 3-5 specimens of each medicinal plant species were collected, and the information about their habitats (e.g., altitude, latitude, longitude, and vegetation type), plant morphology (e.g., plant height, colour of owers, and corolla type) and date of collection were recorded. The scienti c and Chinese names were recorded on the label. Plant specimens were stored at the Herbarium, Yunnan Branch, Institute of Medicinal Plants, Chinese Academy of Medical Science (IMDY).

Plant identi cation
The following literature was used to identify the family and species names of the collected plants: Flora of China [17], Flora Reipublicae Popularis Sinicae [18], and Flora Yunnanica [19]. The scienti c names were checked in The Plant List website [20]. All the plants listed are sorted at family level circumscription follows APG [21].

Data analysis
The data obtained in this study were analysed using Microsoft O ce Excel (2010) spreadsheet software. Quantitative data analysis was conducted using the informant consensus factor (ICF) method and the number of citations. ICF was calculated as ICF = (Nur -Nt)/(Nur -1), where Nur is the sum of plant species used by all the respondents to treat a particular disease, and Nt is the number of identical plant species used by all the respondents to treat a particular disease [22].

Results And Discussion
Demographic features of the respondents A total of 104 respondents were interviewed (Table 1). Among them, male respondents highly outnumbered the female respondents, and 79.81% of them were over 50 years old. Naxi people live in the mountainous areas and commonly collect medicinal plants. In this harsh environment, men have an advantage over women due to their physical abilities. Because the experience of treating diseases is based on long-term practice, the medical experience mastered by older healers is more comprehensive and reliable than those learned by younger healers. Moreover, it ensures reliability of the knowledge obtained in this survey.
The educational level of the respondents was generally low, and most of them had no higher education. However, this did not affect the reliability of the results, because the acquired traditional knowledge has truly maintained the characteristics of the Naxi people.
The respondents were mainly Naxi (71.158%), followed by the Lisu (15.38%). Other ethnic groups included Han, Tibetan, Bai, and Yi. All of these people lived in Naxi communities, and their medical skills were learned from Naxi healers. All the respondents were folk healers.
Although there are many ways to learn medical skills, most respondents (70.19%) developed their medical experiences with the help of their ancestors. None of the respondents had regular jobs, and many of them were local Dongba who were priests and folk healers. Polygonaceae (six species), followed by the Rosaceae (four species). It is worth mentioning that from the genus Rheum alone, we recorded three species. In addition to Rheum o cinale recorded in the Pharmacopoeia of People's Republic of China [23], we also recorded R. delavayi and R. likiangense, but their usage was different from that of R. o cinale recorded in the Pharmacopoeia of People's Republic of China. Of all recorded species, herbaceous plants (49 species) accounted for the greatest number (Table 3), followed by trees (21 species) and shrubs (5 species). As herbaceous plants can more easily survive in a new environment than trees and shrubs [24], especially in the alpine mountains inhabited by the Naxi people, there are lacks of diversity of tree species, whereas the low herbaceous plants were abundant. At the same time, herbaceous plants are more convenient to collect than other plant life forms. Thus, the utilisation rate of herbaceous plants is higher than that of trees and shrubs.  delavayi, and Panax japonicus var. major. Although the medicinal materials from these plants are rarely found in the wild, they have been cultivated in the area and thus have been successfully used as medicines. Since ancient times, Naxi people have lived in mountainous areas, where transportation is inconvenient. The medicines they used were collected in the mountains, and rare medicinal plants were cultivated in their courtyards in order to be convenient for collection. Therefore, the medicinal plants described in the Dongba Sutras were mainly wild plants, accounting for 76.47% of all medicinal plants described in the Dongba Sutras ( Table 6). Because of the small population of Naxi people, their use of wild medicinal plants does not present a threat to the stability of wild plant populations. Food therapy is an important characteristic of Chinese culture and traditional Chinese medicine (TCM). "One Root"26The life of the Naxi people is closely related with medical dietary plants, and their medicinal diets are indispensable to the health of their communities [27].
Among the medicinal plants in the Dongba Sutras, 22 species can be consumed as vegetables, fruits, dried fruits, or condiments (Table 7).
For example, Lagenaria siceraria, Brassica rapa, Foeniculum vulgare, and Allium ascalonicum are common vegetable species. Setaria italica var. germanica is also used as food. For a long time, the Naxi people considered that these foods and vegetables can be used to treat and prevent diseases. Thus, they recorded them in the Dongba Sutras. Some of these medicines are used to prepare tea, and do not have any negative side effects. For example, the Aerial parts of Elsholtzia rugulosa which has the effect of relieving summer heat. The plant as substitute for tea is easy to collect and prepare, and has widely been used by the Naxi people. This indicated that in the Naxi people, maintaining a healthy daily diet is a very important factor in disease prevention.

Medicine preparation methods and applications
The folk preparation methods of traditional Naxi medicine were relatively simple (Fig. 1A); most of them included washing and direct drying of the plant material (49.18%), followed by crushing (20.49%), soaking (13.93%), using fresh products (9.84%), blending with other agents (3.28%), and carbonisation (3.28%). The medium used in the soaking process was mainly wine or water, whereas the medium used in blending included edible oils, vinegar, honey, etc. The use of fresh plant parts as medicine is characteristic for Naxi medicine because this method is simpler to use than other methods. In this method, the medicinal parts are removed from the plants and washed, and they are used after mashing or chewing. In addition, juice extracted directly from plant is also a common method of fresh plant intake, and is mostly used for topical application. The main method of medicine consummation was oral, followed by topical and rarely buccal (Fig. 1B). Oral administration included three methods: boiling in water, washing in warm water, and drinking after soaking.

ICF, conditions and diseases treated by the studied plant species
The informant consensus factor (ICF) is a measure of information diversity. The higher the ICF value, the greater the difference among plant species used in the treatment of a given disease, and the lower the ICF value, the smaller the difference among plant species used in the treatment of a disease [22]. We found that the medicinal plants in the Dongba Sutras are used to treat 96 conditions, which can be classi ed into 13 disease groups according to ICPC-2 (Table 8 and [28], and (2) different Naxi folk healers may have different degrees of understanding of the same disease (e.g., some may be focused more on the symptoms of a disease, but ignore or miss the real cause of the disease).
The ICF values of these four disease groups were low: Group D: 0.60; Group R: 0.57; group L: 0.45; and group A: 0.75. These low values indicated that these four groups of diseases are common diseases in Naxi people living areas, and Naxi folk healers have high consensus on the treatment of these diseases.
For the treatment of diabetes (T89: Diabetes Insulin Dependent or T90: Diabetes Non-Insulin Dependent), which is an endocrine disease belongs to the group of endocrine/metabolic and nutritional, only one plant species was cited in the Dongba Sutras. Diaphragma juglandis fructus, the dry wood diaphragm tissue (xylem septa) that grows inside the walnut (Juglans regia), was reported as a medicinal plant that can be used to treat diabetes, and the consensus on this treatment was high. A pervious study reported that the avonoids from Diaphragma juglandis fructus have signi cant anti-diabetic activity [29]. This shows that as the knowledge on folk medicine is collected from long-term practical experience, its scienti c nature has yet to be proven by modern science. With more research, more information from traditional medicinal practices will be scienti cally proven.  (Table 9). Moreover, there are eight species only distributed in the areas inhabited by Naxi people (Fig. 2), including northwest Yunnan, southwest Sichuan, and Southeast Tibet. Examples include Populus rotundifolia var. bonatii, Rheum likiangense, Chesneya polystichoides, Geranium strictipes, Dobinea delavayi, Wikstroemia delavayi, Rhododendron wardii, and Scutellaria likiangensis.
The Naxi people consider human beings and nature as brothers. This ecological ethics concept lays the foundation for the Naxi people to live in harmony with nature; it shows the most primitive and simple concept of environmental conservation by human beings [30]. The distribution area of these plant species is very small. Although the Naxi people have been using these plants as medicinal materials for a long time, their populations are still stable, indicating that Naxi people attach great importance to plant conservation when collecting these medicinal plants.The Naxi people collect medicinal materials from their surroundings to treat many diseases. They never harm the environment during plant collecting, and they are grateful for being able to take advantage of wild medicinal plants. This fully embodies their idea of maintaining ecological balance.Meanwhile, arti cial cultivation was adopted to expand the population of medicinal plants with rare natural resources in order to minimise their impact on wild plant resources.  The basic features of traditional Naxi medicine The knowledge of traditional Naxi medicine are always in the hands of the elderly and clergy. The traditional apprenticeship between the elderly and the young make an assurance of the knowledge inheritance from age to age. Dongba, as the clergyman in Naxi people, record the most important medical knowledge in the Dongba Sutras for better inheritance.
In the processing of medicinal materials, Naxi people make good use of fresh products, medicinal liquids and plant powders. No complex processing is required from the raw plants to the medicine used, which is very convenient. Medicinal liquids can fully dissolve alcohol soluble active substances and are easy to store. Different types of mixed powder are used internally or externally suiting the remedy to the different cases, which not only brings convenient to clinical uses but also protect the intellectual property rights of the folk healers because it is hard to know which medicinal plants are used in the powders.
The Naxi ancestors inhabit mountainous areas and are seldom in uenced by alien cultures. As a result, the methods of medication are easy to follow, mainly inlcuding decocting, oral consumption with warm water, topical, etc. And the processing technology of Naxi medicine only include some simple procedures like washing, drying, and crushing.
Four groups of diseases are common diseases in Naxi people living areas, they are the group of digestive diseases (D), followed by the respiratory (R), musculoskeletal (L) and the general and unspeci ed disease group (A). The Naxi folk healers have high consensus on the treatment of these diseases.
The ecological ethics of Naxi people have positive signi cance for the conservation of wild plant resources Hengduan mounainous where Naxi people live own one of the greatest aboundent biodiversity in the world. Naxi people always keep the scienti c ecological ethics concept in mind. The Naxi people never harm the environment during plant collecting, and they are grateful for being able to take advantage of wild medicinal plants. Meanwhile, arti cial cultivation is adopted to expand the population of medicinal plants with rare natural resources in order to minimise their impact on wild plant resources.
Dongba Sutras are recorded in hieroglyphics, thus only the Dongbas, as the clergymen, can could fully understand them. Contents of the Dongba Sutras are all-encompassing. Medical knowledge only takes a small part of whole contents, and the records are not comprehensive enough. In addition, the folk medicinal knowledge orally passed down. Thus, it is necessary to further deepen the investigation and research efforts to systematically organise and catalogue the Naxi people's unique traditional medicine, exhibiting its due brilliance.