Ethnomedicine Study on Medicinal Plants Used by Communities in West Sumatera, Indonesia

Currently, the development of conventional medicine is getting more advanced, it cannot be denied that medicinal plants still occupy their main role as medicine for various human diseases, especially in developing countries. This is rooted in the knowledge of the local community about plants that can be used as medicine for various diseases. Ethnomedicine is a field of study that raises local knowledge of the community to maintain their health. From numerous studies on the field, 33 species of plants have been found which are believed by the natives to West Sumatra as medicine. Ethnomedicinal data were analyzed using Index of Cultural Significance (ICS) value. The results of the analysis showed that the species of plants that is voted most important for the community were soursop ( Annona muricata ) and red betel ( Piper sp .). In general, the part of plant that is most often used as medicine is the leaf, and the way to consume it is by boiling it so that you can get the herbs from the plant extract.


Introduction
Indonesia has around 25,000-30,000 species of plants and is inhabited by around 300-700 ethnicities. These ethnic groups use it for various purposes, one of which is for medicinal purposes. The use of plants as medicinal substances is mostly passed down orally, so they are prone to degradation. Ethnomedicine study is a method that can be used to document the use of plants by ethnic groups with scientifically acceptable research methods. This paper aims to explain the study of ethnomedicine especially in West Sumatra and its research methods.
One of the local wisdoms possessed by Indonesians is to utilize the natural biological resources in the vicinity. Every local community uses their vegetable resources to fulfill their daily needs, one of which is to maintain their health which is known as medicinal plants. Knowledge on the use of medicinal plants is generally passed down orally, so that knowledge is limited to certain groups of people and is susceptible to degradation due to cultural acculturation and modernization.
The use of plants to maintain health has long been carried out in Indonesia in line with the development of civilization. Indonesia has been formulating and using medicinal plants (traditional medicine) since the era of Hindu-Javanese kingdom. In West Sumatra itself, medicinal plants have been an alternative treatment since the time of our ancestors. One of the plants that is widely used in the experiment is the soursop plant (Latin name), betel plant (Latin name) and castor plant (Latin name). The part of the plant that is used as medicine is the leaves.

Ethnomedicine study on medicinal plants used by local communities
in West Sumatera, Indonesia

Ethnomedicine
Ethnomedicine is a branch of medical anthropology which deals with the origin of disease, causes, and treatment according to certain groups of people. The ethnomedicine aspect is an aspect that appears along with the development of human culture. in the field of medical anthropology, ethnomedicine gives rise to various therminologies. This branch is often called folk medicine, primitive medicine, however ethnomedicine is considered more appropriate [1].
Ethnomedicine is a field of ethnobotany studies that reveals local knowledge of various ethnicities in maintaining their health. Empirically, it can be seen that traditional medicine uses both plants and animals. However, in terms of the number and frequency of use, plants are more widely used than animals. Eventually, this resulted in traditional medicine being identical to medicinal plants.
Currently, ethnomedicine research is aimed at finding new chemical compounds that are useful in the manufacture of modern drugs for dangerous diseases, such as cancer drugs. Up until now, most of the drugs used for cancer treatment are still extracted directly from plants because synthetic compounds cannot be made or their production costs are much more expensive than direct extraction from plants. In addition, treatment for diseases which are currently developing, the new purpose of ethnomedicine research is to find new compounds with fewer side effects, the emergence of resistant effects from existing drugs, and also to anticipate the emergence of new diseases. This has resulted in ethnomedicine research continuing to develop, especially in countries rich in biodiversity such as Indonesia.
The use of plants as herbs and medicine traditionally or often referred to as empirical is often associated with uses that have no scientific basis at all. Even though research is so advanced, it is very possible that in the past the use of traditional medicine was only based on lineage and undocumented experience and there was no scientific data.

West Sumatera
West Sumatra is one of the provinces in Indonesia located on the west coast in the central part of Sumatra island which consists of lowlands on the west coast and volcanic plateaus formed by the Bukit Barisan on the eastern side. This province has a land area of 42,297.30 km 2 which is equivalent to 2.17% of Indonesia's area. More than 45.17% of this area is still covered by protected forest. The coastline of this DOI: http://dx.doi.org /10.5772/intechopen.96810 province is entirely in contact with the Indian Ocean along 2,420,357 km with a sea area of 186,580 km 2 . Mentawai Islands, which are located in the Indian Ocean, are included in this province (Figure 1).
Astronomically, West Sumatra is located between 00.54 'North Latitude and 30.30' South Latitude and between 98.36' − 101.53 'East Longitude and is traversed by the equator or the equator. Based on its geographical position, West Sumatra Province has the following boundaries: North -North Sumatra and Riau Provinces; South -Indian Ocean; West -Indian Ocean; East -Jambi and Bengkulu Provinces. Located on the west coast of the central part of the island of Sumatra with an area of approximately 42.2 thousand square kilometers.
Like other regions in Indonesia, the climate of West Sumatra is generally tropical with temperatures quite high, between 22.6 ° C to 31.5 ° C. This province is also traversed by the equator, precisely in Bonjol city, Pasaman district. There is a number of large rivers flow from this province into the east coast of Sumatra, such as Batang Hari, Siak, Inderagiri (referred to as Batang Kuantan in the upper part), and Kampar. Meanwhile, the rivers that flow into the west coast are Batang Anai, Batang Arau, and Batang Tarusan.

Study area
This research was conducted to identify plants used by the people of West Sumatra as medicinal plants. This research was conducted in several areas in West Sumatra, namely Padang city, Padang Pariaman district, Pariaman city, Padang Panjang city, Bukittinggi city, and Payakumbuh city.

Data collection
Field observations were carried out in January-April 2020. Using the purposive sampling method, ethnomedicine data were collected through semi-structural interviews and discussions from 18 informants. Information regarding local medicinal plants, parts used, method of application and preparation is recorded. Data on the gender, age and educational status of informants were also collected. Plant specimens were also collected to help identify the medicinal plant species obtained.

Demographic data of informants
In this study, 18 informants were involved, consisting of 12 men and 6 women. 4 informants came from Padang city, 3 from Padang Pariaman district, 3 from Pariaman city, 5 from Padang Panjang city, 2 from Bukittinggi city and 1 from Payakumbuh city. The highest number of informants is over 50 years old ( Table 1).
From this research, it can be seen that older informants have more knowledge about medicinal plants than younger informants. This may be due to the lifestyle of the younger group which is more modern, they are not too interested in natural medicinal plants and prefer modern medicines obtained from doctors [3,4].
Knowledge about the use of medicinal plants is largely derived orally (75%) from their ancestors, this type of inheritance method is common for traditional healers [5]. thus seldom is there documentation for their practice and therefore there is an urgent need to document all information about the traditional practice of using medicinal plants especially for the treatment of growth determinants.

Plant inventory
There are 33 medicinal plants (Figure 2) that are believed by the local community as medicinal plants that can cure various diseases, a complete list of plants is presented in the Table 2. Local names, taxonomic names, parts used and method of preparation are also given.

Plant parts being used and preparation
From the PPV (Figure 3) it was revealed that the leaves were the most widely used part, namely 58% followed by fructus 11%. The findings of this study are similar to those of other ethnomedicine studies [6][7][8], and most traditional healers use the leaves perhaps because it is relatively abundant and also to preserve and preserve medicinal plant species. Herb, direct eating (raw parts or juice) and direct use (crushed plant parts topically) are various methods used in traditional healing for medicinal plants. Decoction of plant parts is the most commonly used method followed by direct consumption of plants (raw or juice parts). This study aims to document and quantify medicinal plants used by communities in West Sumatra, Indonesia. The plant species collected from this study are mostly common medicinal plants used by traditional healers and are frequently documented in ethnobotany studies in Indonesia [9-13].

Cultural significance index
The significance value of plant species in the study area is calculated using the following formula: Where q is the quality value for each species (1)(2)(3)(4)(5), I refer to the intensity value and e is the exclusivity value. The results obtained from the ICS calculations are then categorized based on the value proposed by Turner [14] shown in Table 3.     Table 3.
The ICS value was proposed by Turner [14]. The index of cultural significance (ICS) is a reference used to calculate and predict the level of importance of a plant species in a certain area [14,15], its value can be seen in Table 4. ICS analysis is usually carried out to calculate the usefulness of complete plants (food, medicine, rituals, construction, etc.) [14,16], but because this study focuses more on medicinal plants that are trusted by the local community or known as ethnomedicine so for this study the only use calculated for medicinal purposes only.
Turner calculates the ICS value using the researcher's subjective allocation approach. Turner only uses three variables to calculate the ICS value, namely quality of use, intensity of use, and exclusivity of use [14]. The ICS value is obtained from the result of the multiplication of three variables when the calculation can also occur the addition of the product, this is done if a plant species has more than one use. Turner allocated 5 weight scales for the variables of use quality and intensity of use, namely 5, 4, 3, 2, 1 and allocated 3 scales for the use exclusivity variable, namely 0.5, 1, and 2.
From the research conducted and based on the mathematical calculation of the ICS value, it was seen that only two plant species had moderate significance (ICS = 30). The two plants that have ICS of moderate significance are red betel and soursop. These two plants are trusted by the public to prevent and treat cancer, so these plants are very popular and are considered important by the local community. As for the other plants, it is categorized as low significance. From the ICS calculation data, a plant for the local community can be used as raw material for medicine or herbal plants [17]. Although Turner's ICS ranks plant species used for food, especially staple foods, as the type of quality that has the highest score in determining cultural importance (CS).

Conclusion
From the ethnomedicine research conducted, it is known that there are 33 plants that are used as medicinal plants by people in West Sumatra, Indonesia. Mostly, the plant leaves are used as raw material for medicine through direct consumption (juice of the plant parts) or by boiling, which is the most common way of preparation. Quantitative ethnomedicine data can be analyzed using the Index of Cultural Significance (ICS). To determine ICS, three variables are needed, namelyquality of use, intensity of use, and exclusivity of use. Akar Table 4. ICS for each plant.