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.
Table 1 Demographic features of the respondents
Demographic features
|
Number
|
Proportion (%)
|
Age
|
|
|
|
31–40
|
7
|
6.73
|
|
41–50
|
14
|
13.46
|
|
51–60
|
28
|
26.92
|
|
61–70
|
24
|
23.08
|
|
71–80
|
24
|
23.08
|
|
81 and above
|
7
|
6.73
|
Sex
|
|
|
|
Female
|
4
|
3.85
|
|
Male
|
100
|
96.15
|
Education level
|
|
|
|
Illiterate
|
10
|
9.62
|
|
Primary school
|
61
|
58.65
|
|
Junior middle school
|
12
|
11.54
|
|
Senior middle school
|
8
|
7.69
|
|
Teacher training school
|
1
|
0.96
|
|
School of health
|
2
|
1.92
|
|
Polytechnic school
|
5
|
4.81
|
|
Junior college
|
4
|
3.85
|
|
University
|
1
|
0.96
|
Nationality
|
|
|
|
Naxi
|
74
|
71.15
|
|
Lisu
|
16
|
15.38
|
|
Han
|
5
|
4.81
|
|
Zang
|
5
|
4.81
|
|
Bai
|
3
|
2.88
|
|
Yi
|
1
|
0.96
|
Ways of learning medicine
|
|
|
|
Ancestral
|
73
|
70.19
|
|
Ancestral,*master
|
8
|
7.69
|
|
Master
|
7
|
6.73
|
|
Ancestral,self-taught
|
6
|
5.77
|
|
Master,self-taught
|
4
|
3.85
|
|
Ancestral, learning at school
|
2
|
1.92
|
|
Ancestral,self-taught, learning at school
|
1
|
0.96
|
|
Master, learning at school
|
1
|
0.96
|
|
Master,self-taught, learning at school
|
1
|
0.96
|
|
Self-taught
|
1
|
0.96
|
*Master: an authority qualified to teach apprentices
Diversity of medicinal plants in the Dongba Sutras
According to our investigation, a total of 85 species of medicinal plants belonging to 51 families and 71 genera were recorded in the Dongba Sutras (Table 2). In the middle and high altitude areas, the main tree species belonged to the families Pinaceae, Cupressaceae, Ericaceae, and Fagaceae. Almost all parts of these plants can be used as medicine, especially their branches, which are often used by Naxi priests for various sacrificial activities. The highest numbers of plant species recorded belonged to the families Asteraceae (six species) and 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 officinale 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. officinale recorded in the Pharmacopoeia of People’s Republic of China.
Table 2 Number of medicinal plants contained in the Dongba Sutras
Category
|
Number of families
|
Number of genera
|
Number of species
|
Fungi
|
3
|
3
|
3
|
Pteridophyta
|
3
|
3
|
3
|
Gymnospermae
|
2
|
3
|
5
|
Angiospermae
|
43
|
62
|
74
|
Total
|
51
|
71
|
85
|
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.
Table 3 Habits of medicinal plants contained in the Dongba Sutras
Living habits
|
Number of species
|
Proportion (%)
|
Herbs
|
49
|
57.65%
|
Trees
|
21
|
24.71%
|
Shrubs
|
5
|
5.88%
|
Woody vines
|
4
|
4.71%
|
Climbing shrubs
|
3
|
3.53%
|
Herbaceous climbers
|
3
|
3.53%
|
Total
|
85
|
100.00%
|
The medicinal parts of 85 medicinal plant species used by the respondents are indicated in Tables 4 and 10. The Naxi people knew that different medicinal parts have different effects. According to our analysis, in addition to plant’s medicinal efficacy, the difficulty of its collection also affects which parts would be used. The Naxi people preferred to collect easily collectable plant parts as raw materials for medicinal preparations. Among plant life forms, herbs and small shrubs are most commonly used as medicines, and the respondents reported that for this purpose, they used Whole plants, roots, or rhizomes, whereas when trees, big shrubs, or woody vines are used for medicinal preparations, the respondents used stems, branches, leaves, or bark. The flowering and fruiting periods of these plants are short; therefore, their fruits, seeds, flowers, and buds are seldom used as medicinal parts. Plant secretions are rarely used as medicinal materials because of the difficulty of their collection.
Table 4 Medicinal parts of plants recorded in the Dongba Sutras
Medicinal parts
|
Number of species
|
Proportion (%)
|
Roots or rhizomes
|
29
|
24.37%
|
Whole plants
|
22
|
18.49%
|
Leaves
|
19
|
15.97%
|
Stems or branches
|
17
|
14.29%
|
Fruits or seeds
|
9
|
7.56%
|
Flowers or flower buds
|
8
|
6.72%
|
Bark
|
8
|
6.72%
|
Aerial parts
|
3
|
2.52%
|
Fungi (Fruit body)
|
3
|
2.52%
|
Secretions
|
1
|
0.84%
|
Total
|
119
|
100.00%
|
Note: One or more parts of the same plant can be used as medicine, which is why the total number of medicinal parts exceeds the total number of species.
Most of the medicinal plants in the Dongba Sutras are common plants in the studied area. The abundance of medicinal plants, determined according to the classification of abundance by Germany Ecologist Oscar Drude [25], is shown in Table 5. According to this classification, the highest number of species used by the respondents is forest species, such as Quercus aquifolioides, Q. aliena var. acuteserrata, Populus rotundifolia var. bonatii, and Pinus yunnanensis. The group with few or dispersed plants included only three species: Poria cocos, Dobinea 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.
Table 5 Abundance of medicinal plants contained in the Dongba Sutras
Abundance*
|
Number of species
|
Proportion (%)
|
Soe
|
4
|
4.71%
|
Cop3
|
13
|
15.29%
|
Cop2
|
17
|
20.00%
|
Cop1
|
38
|
44.71%
|
Sp
|
10
|
11.76%
|
Sol
|
3
|
3.53%
|
Un
|
0
|
0.00%
|
Total
|
85
|
100.00%
|
*Soe (Sociales): High number of individuals, the above ground plant part is closed;
Cop3 (Copiosae): High number of individuals, but the above ground plant part is not closed;
Cop2: Large and common plants;
Cop1: Large plants, but small populations;
Sp (Sparsal): Low number of plants, scattered;
Sol (Solitariae): Low number of plants, sparse;
Un (Unicum): Only one individual.
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.
Table 6 Sources of drugs contained in the Dongba Sutras
Sources
|
Number of species
|
Proportion (%)
|
Wild
|
65
|
76.47%
|
Cultivated
|
7
|
8.24%
|
Mixture of wild and cultivated
|
13
|
15.29%
|
Total
|
85
|
100.00%
|
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.
Table 7 List of medicinal and edible plant species recorded in the Dongba Sutras
ID
|
Family
|
Scientific name
|
Resource type
|
Food type
|
1
|
Amaranthaceae
|
Amaranthus hypochondriacus
|
Wild
|
Vegetable
|
2
|
Amaryllidaceae
|
Allium ascalonicum
|
Cultivated
|
Vegetable
|
3
|
Amaryllidaceae
|
Allium hookeri
|
Cultivated, wild
|
Vegetable
|
4
|
Amaryllidaceae
|
Allium sativum
|
Cultivated
|
Vegetable
|
5
|
Apiaceae
|
Foeniculum vulgare
|
Cultivated
|
Vegetable
|
6
|
Brassicaceae
|
Brassica rapa
|
Cultivated
|
Vegetable
|
7
|
Cactaceae
|
Opuntia ficus-indica
|
Cultivated, wild
|
Fruit
|
8
|
Cannabaceae
|
Cannabis sativa
|
Cultivated, wild
|
Condiment
|
9
|
Cucurbitaceae
|
Lagenaria siceraria
|
Cultivated
|
Vegetable
|
10
|
Ebenaceae
|
Diospyros lotus
|
Cultivated, wild
|
Fruit
|
11
|
Fabaceae
|
Pueraria lobata var. thomsonii
|
Wild
|
Beverage
|
12
|
Juglandaceae
|
Juglans regia
|
Cultivated, wild
|
Dry fruit
|
13
|
Lamiaceae
|
Elsholtzia rugulosa
|
Wild
|
Beverage
|
14
|
Lauraceae
|
Neocinnamomum delavayi
|
Wild
|
Condiment
|
15
|
Pinaceae
|
Pinus armandii
|
Wild
|
Dry fruit
|
16
|
Poaceae
|
Setaria italica var. germanica
|
Cultivated
|
Food
|
17
|
Polyporaceae
|
Poria cocos
|
Wild
|
Vegetable
|
18
|
Rosaceae
|
Prunus mume
|
Cultivated, wild
|
Fruit
|
19
|
Rosaceae
|
Rubus biflorus
|
Wild
|
Fruit
|
20
|
Rosaceae
|
Rubus coreanus var. tomentosus
|
Wild
|
Fruit
|
21
|
Rosaceae
|
Rubus niveus
|
Wild
|
Fruit
|
22
|
Schizophyllaceae
|
Schizophyllum commune
|
Wild
|
Vegetable
|
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 classified into 13 disease groups according to ICPC-2 (Table 8 and 10). The highest ICF values were recorded for the eye group (F), cardiovascular group (K), and psychological group (P) (ICF = 1.50), followed by the neurological group (N), female genital group (X), and male genital group (Y) (ICF: 1.00). Among the medicinal plants provided by different respondents, there are very few (only one or none) identical plants that can be used to treat the same group of diseases. This showed that there are many differences among Naxi people in the methods of treating a specific disease, i.e., that they have low consensus about disease treatment methods. There are two possible reasons for this: (1) as the Naxi people live in biodiversity-rich areas, the abundant medicinal plant resources provided them with a wide choice of medicinal plants to use [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).
Further analysis indicated that most of the plant species were utilised for the group of digestive diseases (D; Nur=36, Nt=15), followed by the respiratory (R; Nur=29, Nt=13,), musculoskeletal (L; Nur=21, Nt=12) , and the general and unspecified disease group (A; Nur=21, Nt=5). 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 flavonoids from Diaphragma juglandis fructus have significant anti-diabetic activity [29]. This shows that as the knowledge on folk medicine is collected from long-term practical experience, its scientific nature has yet to be proven by modern science. With more research, more information from traditional medicinal practices will be scientifically proven.
Table 8 Informant consensus factor (ICF) values of the medicinal plants contained in the Dongba Sutras
Disease types
|
The sum of plant species (Nur)
|
The number of identical plant species used (Nt)
|
ICF
|
A: General and unspecified
|
21
|
6
|
0.75
|
D: Digestive
|
36
|
15
|
0.60
|
F: Eye
|
3
|
0
|
1.50
|
K: Cardiovascular
|
3
|
0
|
1.50
|
L: Musculoskeletal
|
21
|
12
|
0.45
|
N: Neurological
|
4
|
1
|
1.00
|
P: Psychological
|
3
|
0
|
1.50
|
R: Respiratory
|
29
|
13
|
0.57
|
S: Skin
|
11
|
2
|
0.90
|
T: Endocrine/metabolic and nutritional
|
1
|
1
|
-
|
U: Urological
|
12
|
4
|
0.73
|
X: Female genital
|
16
|
1
|
1.00
|
Y: Male genital
|
14
|
1
|
1.00
|
The plant species with the highest number of use reports were Rheum likiangense (13 use reports), Reineckea carnea (11 use reports), Rheum delavayi (10 use reports), and Hypericum augustinii (10 use reports). Rheum likiangense and R. delavayi are endemic to a small district, and Reineckea carnea and Hypericum augustinii are endemic to China. This emphasises the uniqueness of Naxi medicinal plants.
Analysis of endemic species
Among the medicinal plants in the Dongba Sutras, 25 species are endemic to China, accounting for 29.41% of the total number of medicinal plant species in the Dongba Sutras (85 species) (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, artificial cultivation was adopted to expand the population of medicinal plants with rare natural resources in order to minimise their impact on wild plant resources.
Table 9 Chinese endemic plant species recorded in the Dongba Sutras
ID
|
Family
|
Scientific name
|
Distribution*
|
Abundance**
|
Resource type
|
1
|
Anacardiaceae
|
Dobinea delavayi
|
SW
|
Sol
|
Wild
|
2
|
Boraginaceae
|
Ehretia corylifolia
|
SW
|
Cop1
|
Wild
|
3
|
Caryophyllaceae
|
Psammosilene tunicoides
|
SW
|
Sp
|
Wild
|
4
|
Compositae
|
Artemisia yunnanensis
|
SW,W
|
Cop2
|
Wild
|
5
|
Compositae
|
Crepis napifera
|
SW
|
Cop2
|
Wild
|
6
|
Cupressaceae
|
Cupressus duclouxiana
|
SW
|
Cop1
|
Wild
|
7
|
Ericaceae
|
Rhododendron racemosum
|
SW
|
Cop3
|
Wild
|
8
|
Ericaceae
|
Rhododendron wardii
|
SW
|
Cop1
|
Wild
|
9
|
Geraniaceae
|
Geranium strictipes
|
SW
|
Cop1
|
Wild
|
10
|
Gramineae
|
Fargesia orbiculata
|
SW
|
Cop1
|
Wild
|
11
|
Guttiferae
|
Hypericum augustinii
|
SW
|
Cop3
|
Wild
|
12
|
Labiatae
|
Scutellaria likiangensis
|
SW
|
Cop1
|
Wild
|
13
|
Leguminosae
|
Chesneya polystichoides
|
SW
|
Sp
|
Wild
|
14
|
Liliaceae
|
Asparagus meioclados
|
SW
|
Cop1
|
Wild
|
15
|
Magnoliaceae
|
Magnolia delavayi
|
SW
|
Sp
|
Cultivated
|
16
|
Pinaceae
|
Pinus yunnanensis
|
SW,S
|
Soe
|
Wild
|
17
|
Polygonaceae
|
Rheum likiangense
|
SW
|
Sp
|
Wild
|
18
|
Polygonaceae
|
Rheum officinale
|
SW,S,C
|
Cop2
|
Cultivated,wild
|
19
|
Rosaceae
|
Rubus coreanus var. tomentosus
|
SW,C,W
|
Cop2
|
Wild
|
20
|
Sabiaceae
|
Meliosma cuneifolia
|
SW,C,W
|
Cop1
|
Wild
|
21
|
Salicaceae
|
Populus rotundifolia var. bonatii
|
SW
|
Soe
|
Wild
|
22
|
Salicaceae
|
Salix variegata
|
SW,C,W
|
Cop3
|
Wild
|
23
|
Sapindaceae
|
Sapindus delavayi
|
SW,C
|
Sp
|
Cultivated,wild
|
24
|
Tamaricaceae
|
Myricaria paniculata
|
SW,C,W
|
Cop1
|
Wild
|
25
|
Thymelaeaceae
|
Wikstroemia delavayi
|
SW
|
Cop1
|
Wild
|
*Note:SW–Southwest China; C–Central China; W–West China; S–South China
**Soe (Sociales): High number of individuals, the above ground plant part is closed;
Cop3 (Copiosae): High number of individuals, but the above ground plant part is not closed;
Cop2: Large and common plants;
Cop1: Large plants, but small populations;
Sp (Sparsal): Low number of plants, scattered;
Sol (Solitariae): Low number of plants, sparse;
Un (Unicum): Only one individual.