**1. Introduction**

Customary medical understanding is undergoing augmented consideration globally in health sector. The importance of traditional medicine in catering the health needs cannot be undermined. The herbal medicine sector commercially is already booming with the annual turnover crossing billions of dollars. With the passage of time newer knowledge is being incorporated substantially thereby highlighting the significance of documentation aspects pertaining to these medicinal plants and practices associated with herbal medicine.

Documentation based upon ethnomedicinal survey along with interaction with local healers practicing traditional system of medicine can be said to be the basis for establishing a systematic protocol for validating traditional medical knowledge.

### **2. Ethnomedicinal survey area**

Assam was selected as the targeted study area due to the rich diversity in flora, fauna and above all due to the presence of diverse ethnic groups with a

**Figure 1.** *Map of Assam showing different districts where ethnomedicinal survey was conducted.*

wide array of traditional practices. Several geographically distinct zones, encompassing seven administrative districts spread across Assam were considered for the study (**Figure 1**).

The selected areas in which the ethnomedicinal survey was done are as follows:


#### **2.1 Survey area: Dibrugarh**

Dibrugarh is known as the Tea City of North-East.To the north and east lays Dhemaji and Tinsukia district respectively. South-east and south-west parts of Dibrugarh are bounded by Tirap and Sivsagar district [1–4].

Two places in Dibrugarh district were selected for ethnomedicinal survey viz. Nagakhelia and Jokai. Nagakhelia is a small village, consisting of around hundred households under Barbaruah block of Dibrugarh district lays about 6 km from Dibrugarh University [5]. The village is located on the banks of river Brahmaputra and the area boasts of thick vegetation which serves as a prime source of medicinal plant materials for the local healers of the area practicing traditional medicine.

Jokai comes under Barbaruah block in Dibrugarh district. It is located about 10 km south from Dibrugarh University. It is also home to the over twelve hectare Jokai reserve forest within which Jokai Botanical Garden cum Germplasm Centre is located. The reserve forest is endowed with different flora species of medicinal, oil bearing and aromatic plants. It also has diverse fauna species like flying squirrel, black panther and leopard including various species of butterflies and fishes. The villages surrounding the forest areas in Jokai has a rich heritage of prescribing traditional medicine, mostly from plants for many types of ailments like jaundice, diabetes, malaria, fever, skin infection etc.

## **2.2 Survey area: Golaghat**

Golaghat is an important district of upper Assam having its own historical and cultural heritage. Golaghat is bordered by the Brahmaputra River in north, towards south lays Nagaland, whereas in the east it is bounded by Jorhat district and the western side lays Karbi Anglong and Nagaon district [4]. The major rivers of the district are Brahmaputra, Dhansiri, Kakodonga, Doyand, Gelabil and Diplolu [6]. The vast geography of Golaghat district also includes tropical evergreen and semi evergreen forest; tropical grassland in Kaziranga National Park and swampy vegetation. The topography of Golaghat is dominated by a diverse array of flora and fauna [7, 8].

Borghoria and Naojan were the areas selected for ethnomedicinal survey in Golaghat district. Borghoria village and Naojan are located about 30 km and 60 km from Golaghat town and about 2.5 km and nearly 70 km from Numaligarh Refinary township, respectively. Naojan, due to its close proximity to Barpathar, an archeological site where the remains of an 8th century temple made of square bricks and a stone inscription of Brahmi characters belonging to the 5th century were excavated along with the hot water springs and Garampani Wildlife Sanctuary of Garampani, has a very rich abundance of diverse flora and fauna. Borghoria situated in the vicinity of Dhansiri river has an exposure to vast and varied natural resources. Traditional healers around the area are mainly engaged in agricultural activities and prescriptions of traditional medicine by these healers are done on philanthropic basis [3].

#### **2.3 Survey area: Tinsukia**

Tinsukia is situated in the northernmost portion of Assam [2]. The district is surrounded on three sides by Arunachal Pradesh. The south part is ecompassed by Dibrugarh. As the district falls in the far east of North-East region of Assam (India), it is a part of global bio-diversity hot spot and has great biodiversity significance [9, 10]. The high biological diversity found in the district is often related to its forest cover, which is categorized into tropical wet evergreen forests. The important sanctuary located in the district is Dibru-Chaikhowa Sanctuary. It has an area of 640 sq. km and is famous for rare, endangered animals and birds such as white-winged wood duck, elephant, tiger, sambar, buffalo, aquatic avifauna and wild white horse. The other protected areas and important forests are Dum Duma-Dangori-Kumsong Reserve Forests, Tirap-Burihidihing, Sadiya plains, Upper Dihing (East) and Upper Dihing (West).

Ethnomedicinal survey in Tinsukia districted was conducted in Laipuli area. Laipuli is located at a distance of around 6 km from Tinsukia town [3].

#### **2.4 Survey area: Dhemaji**

Situated in the northern bank of the mighty river Brahmaputra, Dhemaji can be suitably described to be located in one of the remote area of north eastern region

of India. In its northern and eastern end the state of Arunachal Pradesh lies. The western part is bounded by Lakhimpur district followed by river Brahmaputra in the South. Dhemaji has a total geographical area of 3237 sq. km [1–4].

Two places selected for the ethnomedicinal survey in Dhemaji district were Majarbari and Sissiborgaon.

#### **2.5 Survey area: Karbi Anglong**

The district of Karbi Anglong is located in the central Assam region. The eastern part is surrounded by Golaghat district, in its west lies the state of Meghalaya and Morigaon district, the north is bounded by Nagaon and Golaghat district whereas North Cachar Hills and the state of Nagaland is located towards south. Karbi Anglong district is home to thick forest cover having numerous species of flora and fauna. It is to be noted that a new district, West Karbi Anglong was curved out from erstwhile Karbi Anglong district on 15th of August, 2015 [1, 3].

The district can be broadly divided into two physiographic units' viz. hills and plains. About 85 percent of the district is covered by hills [4]. Environmental and topology studies of Karbi Anglong specify a great degree of diversity among the existing plant and animal species. The forest areas serves as the natural gene bank of important types and sub types pertaining to various species.

Kathkatia village located in Silonijan of Karbi Anglong district was selected for the ethnomedicinal survey [11].

#### **2.6 Survey area: Goalpara**

Goalpara is sited towards the southern bank of Brahmaputra River. The district is surrounded by the state of Meghalaya in the South, towards east lays Kamrup district, the western end is bounded by Dhubri district and, the northern part is covered by the mighty Brahmaputra. In 1983, Goalpara Civil sub-division was separated from original Goalpara district to form the present Goalpara district [1, 2].

Dhupdhara selected for the ethnomedicinal survey, is a village in Rongjuli circle in Goalpara district of Assam. It is located about 58 km east of district headquarter Goalpara and 13 km from Rangjuli [3, 4].

#### **2.7 Survey area: Kokrajhar**

Kokrajhar district is the entry point to the NER of India. It is boardered by Bhutan in the north, followed by the district of Dhubri in its south, whereas Bongaigaon and West Bengal is situated in the east and west directions.

On the 1st of July, 1983 the Kokrajhar Sub-division was upgraded into Kokrajhar district with headquarter at Kokrajhar town [3]. The district is situated in a humid sub-tropical climate, which is the characteristic of the lower Brahmaputra Valley of Assam. The district also has one of the largest concentrations of forest in the state. About 55% of the total geographical area of the district is under reserved forest. The Bhutan hills are the source of a number of rivers that flow through the district and act as tributaries of the mighty Brahmaputra that flows from east to west far from the southern boundary of Kokrajhar district [4].

Dotma village in Kokrajhar district of Assam was selected for the survey for ethnomedicinal documentation. It is located about 17 km towards North from District head quarters Kokrajhar, 188 km from State capital Dispur towards East. Dotma is bounded by Kokrajhar town towards East, Kachugaon towards west, Rupshi towards west, Chapor-Salkocha towards west. Kokrajhar, Bilasipara, Bongaigaon, Gauripur are the nearby towns to Dotma [12].
