A survey of medicinal plants used by the Deb barma clan of the Tripura tribe of Moulvibazar district, Bangladesh

Abstract

Background

The number of tribes present within Bangladesh has been estimated to approximate one hundred and fifty. Information on traditional medicinal practices, particularly of the smaller tribes and their clans is lacking. It was the objective of the study to document the tribal medicinal practices of the Deb barma clan of the Tripura tribe, which clan can be found residing in Dolusora Tripura Palli of Moulvibazar district of Bangladesh. A further objective was to determine the extent of the community households who still prefer traditional treatment to other forms of treatment, particularly allopathic treatment.

Methods

Interviews of the tribal healer and the tribal community regarding their ethnomedicinal practices were carried out with the help of a semi-structured questionnaire and the guided field-walk method. All together 67 clan members were interviewed including the Headman, tribal healer, 19 Heads of households and 46 other adult members of the clan. Information on number of members of household, their age, gender, educational status, occupation of working household members and preferred mode of treatment was obtained through the semi-structured questionnaire. In the guided field-walk method, the healer took the interviewers on field-walks through areas from where he collected his medicinal plants, pointed out the plants, and described their uses.

Results

The clan had a total of 135 people distributed into 20 households and had only one traditional healer. Use of medicinal plants, wearing of amulets, and worship of the evil god ‘Bura debta’ constituted the traditional medicinal practices of the clan for treatment of diseases. The healer used a total of 44 medicinal plants distributed into 34 families for treatment of various ailments like pain, coughs, cold, gastrointestinal disorders, cuts and wounds, diabetes, malaria, heart disorders, and paralysis.

Conclusions

Available scientific reports validate the use of a number of plants by the traditional healer. A number of the plants used by the clan healer had reported similar uses in Ayurveda, but differ considerably in their therapeutic uses from that reported for other tribes in Bangladesh. The present survey also indicated that in recent years the Deb barma clan members are inclining more towards allopathic medicine.

Background

Since the advent of human beings, it is very much possible that they were afflicted with diseases and in course of time started using various ingredients including plants, animals, insects, or minerals for treatment. It has been reported that human beings were aware of the medicinal properties of plants even around 5,000 years ago [1]. Since then, even after the introduction of modern or allopathic medicine, medicinal plants have played a vital role in the traditional medicinal systems of many countries, as well as being the sources of many modern drugs. Indeed, it has been reported that a number of important allopathic drugs like aspirin, atropine, ephedrine, digoxin, morphine, quinine, reserpine, artemisinin and tubocurarine have been discovered through close observations of traditional medicinal practices of indigenous peoples [2].

Bangladesh is home to a number of tribes or indigenous communities. Latest ethnographic research suggests that the number of tribes within the country approximates 150 instead of the previously estimated about a dozen tribes [3]. Most of the indigenous communities and particularly the smaller ones (i.e. communities whose population is below 500 persons) are on the verge of disappearance because of decline in population, loss in tribal habitat, or because of merging with the mainstream Bengali-speaking population. As a result, the culture and knowledge possessed by these tribes are also fast disappearing, including their traditional medicinal practices. Adequate documentation of such knowledge, and especially traditional medicinal practices, is important because tribal medicinal practitioners or healers through long association with plants around their vicinity have acquired quite extensive knowledge on the medicinal properties of these various plant species. Notably, tribal medicinal knowledge is usually passed from one generation to the next through members of the family or persons serving as apprentices to the practitioner. Thus such tribal medicinal knowledge reflects knowledge acquired and accumulated over centuries and even possibly millennia.

Scientists as well as general human beings can gain a considerable amount of information from adequate documentation of tribal medicinal practices. Adequate documentation can not only indicate the possible therapeutic values of any given plant species, but also provide scientists with a general background on the basis of which they can study the plant species for isolation of bioactive constituents. Documentation of medicinal plants used in the country in various traditional medicinal systems existing within the country can also spur conservation efforts of these plants, many of which are getting endangered through continuous deforestation and increase of human habitat. Bangladesh has several ancient medicinal systems, which are still in practice. Although to a certain extent, some of these various traditional medicinal systems influence and overlap one another, these systems can broadly be classified as Ayurveda, Unani, homeopathy, and folk and tribal medicine. Of these systems, Ayurveda, Unani, and folk and tribal medicinal systems rely quite extensively on medicinal plants, which are used in simple or complex formulations for treatment of different diseases. Among these systems, Ayurveda and Unani are more organized and each system has their own well-established formulary, and practitioners who graduate from Ayurveda or Unani colleges in the country. On the contrary, folk medicinal practitioners (known as Kavirajes or Vaidyas) and tribal medicinal practitioners each have their own field of expertise and unique repertoire of medicinal plants, which can vary greatly from tribe to tribe and between individual Kavirajes of even the same area.

Towards building up a comprehensive database of medicinal plants of the country and their traditional uses, we had been interviewing and documenting the traditional medicinal practices of folk and tribal medicinal practitioners for a number of years [4–11]. The Tripura (also known as Tripuri, Tiprah or Tipperah) tribe is one such indigenous community in Bangladesh, whose various clans can be found in the Chittagong and Sylhet Divisions in the southeast and northeast parts, respectively, of the country. The various clans of the Tripura tribe include Deb barma (also known as Tiprah), Reang or Bru, Jamatia, Koloi, Noatia, Murasing, Halam, Harbang, and Uchoi. We have previously documented the ethnomedicinal practices of the Harbang clan of the Tripura tribal community residing in Chittagong Division of Bangladesh [12].

The objective of the present study was to document the ethnomedicinal practices of the Deb barma clan of the Tripura tribe residing in Dolusora Tripura Palli, which falls within Moulvibazar district in Sylhet Division of Bangladesh (Figure 1). The whole clan consisted of 20 households and had a total population of 135. They resided in a single village named Dolusora Tripura Palli, the Palli name indicating village or area of residence. The Palli itself fell within Moulvibazar district of Sylhet Division in the northeastern part of Bangladesh. The Headman, namely, Mahendra Lal Deb barma of Tripura Palli is considered a renowned person among the Deb barma clan members. The clan had only one tribal healer, named Shorbanando Tripura (otherwise also known as Shorbanando Deb barma). Every individual household had a person acting as the Head of the household. The Head of household was in all cases the most elderly but still active member of the house irrespective of gender. A secondary objective was to conduct a survey among this tribal community to determine the extent of preference for tribal medicine versus allopathic medicine within members of the community.

Figure 1

Map of Bangladesh showing survey site area. (A) Bangladesh with Moulvibazar district highlighted in red and (B) Dolusora Tripura Palli (site of survey, indicated with a yellow dot) in Moulvibazar district.

The Deb barma clan claimed themselves to be Hindus. They worshipped the Hindu god ‘Shiva’ and the Hindu goddess ‘Kali’. However, they mentioned to the interviewers that they also worshipped fourteen other gods and goddesses of their own. The Headman mentioned that once upon a time all Tripura clans were animists, but now all clans have become Hindus but still retained many of their animist traditions. The Deb barma clan also mentioned that they believe in evil spirits and demons. Among the gods and goddesses that the Deb barma clan believed in was the god whom the Headman referred to as ‘Bura debta’, signifying old god. Bura Debta was considered an evil god by the Deb Barma clan and it was considered that the clan must always appease him through ‘pujas’ (worship) and ‘archanas’ (offerings). As a result, the Deb barma clan performs two types of pujas per year in which offerings are made to satisfy Bura debta.

It was mentioned by the Deb barmas that disease occurs to a person if Bura debta gets angry for some reason and curses that person. However, the Deb barmas also said that they believe that diseases can be caused by evil spirits and demons who reside in the forest areas. When evil spirits cause disease(s), according to them, it is known as ‘upuri’ (paranormal diseases). Such paranormal diseases (like being possessed by ‘genies’ or ‘ghosts’) are due to black magic, and the clan believes that diseases caused by black magic can be cured through the interventions of a Tantrik, i.e. a person who is knowledgeable in and can perform black magic. On the other hand, a traditional medicinal healer (Kaviraj) can cure them from diseases caused through the wrath of Bura debta. The Kaviraj can also be a Tantrik. Thus Deb barma clan traditional healing is a mixture of medicinal plant formulations received from the Kaviraj, wearing of amulets as prescribed by the Kaviraj, pujas of Bura debta, as well as counter-black magic performed by a Tantrik. However, at present, the Deb barma clan did not have any specialized Tantriks among them; they only had one traditional medicinal healer, who also took care of problems like being possessed by ‘genies’ or ‘ghosts’.

Since ethnomedicinal surveys of various tribes and folk medicinal practitioners are still at an early stage in Bangladesh, the primary objective of the present study was to document the hitherto unreported traditional medicinal practices of the Deb barma clan of the Tripura tribe. Secondary objectives were (I) to determine whether such medicinal practices have been influenced by the most ancient form of traditional medicine in Bangladesh, namely Ayurveda, (II) to determine whether the use of medicinal plants by the Deb barma healer could be scientifically validated on the basis of available scientific studies on pharmacological properties of any specific plant, (III) to analyze comparative uses of the medicinal plants by the Deb barma healer with other reported ethnomedicinal uses from Bangladesh, and (IV) to determine to what extent individual households of the Deb barma clan are still utilizing the services of their traditional healer or in the present age switching to other modes of treatment like allopathic medicine.

Methods

The survey was conducted between August 2012 and May 2013 at Dolusora Tripura Palli (Palli meaning village). A number of visits (8, each visit lasting 2-4 days) were made to the Deb barma clan to build up rapport with the Headman, healer, and members of the Deb barma clan. Prior Informed Consent was obtained from the Headman, healer, Heads of households and adult members of the clan to interview them as to their traditional medicinal practices (healer) and to their choice of traditional medicine versus allopathic medicine (rest of the persons interviewed). Essentially, the Headman, healer and Heads of households provided the answers with other adult members of households concurring with the opinions of the Head of each respective household. As such, although 67 members were interviewed, the actual number of actively responding members were 21, comprising of 1 healer [male], 1 Headman [also the Head of a household (male)], and 19 other Heads of households [13 males and 6 females]. With the exception of 2 Heads of households (both males) who mentioned their ages as 43 and 47 years, the rest of the Heads of households (including the Headman) and the healer were above 50 years old. Allopathic medicine was provided to them by an allopathic doctor, who belonged to a NGO (non-Governmental organization), which organization worked in the general area of Srimangal (where the Tripura Palli was located) among the rural people, including both mainstream Bengali-speaking people, as well as the Deb barma clan of the Tripuras. Actual interviews of all persons, and especially the traditional healer were conducted with the help of a semi-structured questionnaire and the guided field-walk method of Martin [13] and Maundu [14]. Through the semi-structured questionnaire, information was obtained from the healer and other clan members as to their age, gender, educational status, occupation and monthly income, number of family members, food habits, what they thought of diseases as well as medical preferences. The healer was further queried with the help of the semi-structured questionnaire as to plants used, disease(s) treated, mode of collection and preservation of plants, formulations, mode of administration, and any precautions which needed to be followed during medication period together with any other details which the healer wanted to provide. Briefly, in the guided field-walk method, the healer took the interviewers on guided field-walks through areas from where he collected his medicinal plants, pointed out the plants, and mentioned their use(s).

The adult clan members as well as a few young members (under 18 years of age) worked as agricultural laborers in a nearby tea estate, where the female members were engaged in plucking tea leaves, and the male members engaged in maintaining tea gardens (including plantation, fertilization, weeding, and watering). The socio-economic status of the clan households were poor and every household reported that their daily income was below the poverty level, which has been defined by the Government of Bangladesh as less than US$ 1 per day. The adult clan members were illiterate; a few children attended schools but were quickly taken out of school before they reached Grade VI so as to work in the tea estate and augment the family income. Housing and conditions of living were in a primitive state with poor hygienic conditions and lack of proper sanitation facilities.

It was observed that all plants used by the healer were collected within Dolusora Tripura Palli or from adjoining sites, i.e. within 10 km of Dolusora Tripura Palli. Plants or plant parts were collected free of cost. Most plants were perennial, i.e. available throughout the year. If any plant part was not available (e.g. fruits) throughout the year, the healer used dried fruits as in the cases of Phyllanthus emblica, Terminalia bellirica, and Terminalia chebula. Allium sativum, another plant used by the healer is also an annual plant, but bulbs of this plant (garlic) were used, which were available throughout the year in the dried form. However, if any plant or plant part necessary for a formulation was not found, the healer did not treat the disease that the plant or plant part was intended to be used. Plant specimens were photographed and collected on the spot. They were then pressed, dried and brought back to Dhaka. Identification of plants was done by Mr. Manjur-Ul-Kadir Mia, ex-Curator and Principal Scientific Officer of the Bangladesh National Herbarium. Voucher specimens were deposited with the Medicinal Plant Collection Wing of the University of Development Alternative. Interviews were conducted in the Bengali (Bangla) language; all Tripura community members were found to be quite fluent with this language of the mainstream population through long-term association with the mainstream people. The Bangladesh Government has opened a Bangla-medium primary school near the Tripura Palli and several students attended or are still attending the school.

Results

Medicinal plants and diseases treated by the tribal healer

Of the twenty households of the Deb barma clan, the Head of household of 14 families were males and that of 6 families were females, these persons being the most elderly but still active (i.e. working) members of the house. The traditional medicinal healer mentioned that he uses a total of 44 medicinal plants for treatment of a variety of ailments. These plants were distributed into 34 families and are shown in Table 1. The various ailments treated by the healer included malaria, skin infections, tuberculosis, respiratory disorders, bleeding from external cuts and wounds, chest pain, gastrointestinal disorders, rheumatic pain, burning sensations during urination, bone fracture, snake bite, toothache, headache, bleeding from gums, paralysis, skin disorders, helminthiasis, chicken pox, diabetes, jaundice, eye disorders, weakness, and being possessed by ‘genies’ or ‘ghosts’. Two plants parts (bulb of Crinum latifolium along with bulb of Allium sativum) were also used in combination for treatment of bloating in cattle (see Serial Number 5), and one plant, Scoparia dulcis, used to prepare wine (See Serial Number 37). In this context, it is interesting to note that the clan healer advised wearing an amulet containing the plant, Asparagus racemosus, for all diseased persons, irrespective of the disease or other medicinal plants used. This particular plant was considered to have special magical properties that appease Bura debta.

Table 1 Medicinal plants and formulations of the Deb barma clan healer

Preferred mode of treatment by Deb barma clan households

Interview with all Heads of households and the adult persons of both sexes of the Deb barma clan suggested that in recent years, the clan is moving away from their traditional medicine towards treatment with allopathic medicine. In terms of household, 35% of households reported using only their traditional medicine and visiting their traditional medicinal healer, 20% reported visiting only allopathic doctors, 40% reported visiting both their traditional healer as well as the allopathic doctor, and 5% reported a combination of allopathic and homeopathic treatment. In terms of actual percent of persons using the various systems of medicine, 44.4% of the total clan population visited only their own clan healer, 14.8% visited only the allopathic doctor, 37.8% visited both their traditional clan healer as well as the allopathic doctor, and 3% of the total clan population received both allopathic and homeopathic treatments. The results are shown in Table 2. On further inquiries, the persons who visited the allopathic doctor only, mentioned that they have lost faith in their traditional healing methods, because allopathic treatment gave them quicker recoveries. People who visited both their clan healer as well as allopathic doctor mentioned that they visit their clan healer for simple diseases but go to allopathic doctor for treatment of life-threatening diseases. Sometimes, they visit their clan healer first, and if his treatment fails, they go to the allopathic doctor for treatment. People who visited both allopathic and homeopathic practitioners constituted a minority of the clan population. They visited the homeopathic physician for common diseases and also because homeopathic treatment was cheaper, and the allopathic physician for life-threatening diseases. When asked as to which diseases they thought to be common, it was the view point of most clan members that coughs and cold, or fever that goes away within a few days, or gastrointestinal disorders like flatulence were common diseases; most other diseases were regarded as complicated and which could become life-threatening. However, paranormal diseases like being possessed by ‘genies’ or ‘ghosts’ were always treated by their traditional healer. They also further mentioned that obtaining treatment from an allopathic doctor was a relatively new occurrence for them, and it happened only after a NGO operating in the area brought in the services of an allopathic doctor and advised the clan people to visit the doctor instead of their traditional healer.

Table 2 Preferred mode of treatment by Deb barma clan households

Discussion

A number of the plants used by the Deb barma healer have been scientifically studied, or their use in traditional medicinal systems, particularly Ayurveda, has been described. Ayurveda is possibly the most ancient form of highly organized traditional medicinal system in the Indian sub-continent and dates back to almost 5,000 years ago. It is very much possible that since the Tripura tribe possibly came to India at least 2,000 years ago, there have been mutual interactions between the Ayurvedic medicinal system and the tribal medicines of the Tripura tribe including the Deb barma clan.

Plants used in malaria

The Deb barma tribal healer used the plant, Andrographis paniculata, for treatment of malaria, a disease characterized by high fever. The plant is known in Ayurveda as ‘Kaalmegha’ and is used as a febrifuge, i.e. a medication that reduces fever [15]. Notably, in scientific studies, extract of this plant has been shown to possess anti-malarial activity through growth inhibition of Plasmodium falciparum, the parasite causing malaria [16]. However, the other plant used by the healer, Justicia gendarussa, to treat malaria, does not have any scientifically reported anti-malarial activity, and so is a promising plant for anti-malarial studies. On the other hand, Justicia gendarussa is known in Ayurveda as ‘Krishna Vaasaa’ and is used in the Ayurvedic formulary as a febrifuge.

Plants used in skin diseases, tuberculosis and helminthiasis

Justicia adhatoda was used by the healer to treat skin infections and tuberculosis. Ethnomedicinal uses of the plant for treatment of tuberculosis have been reported from India [17]; in Ayurveda, the plant is known as ‘Vaasaka’ and is used as expectorant, and for bronchial and pulmonary afflictions, which would include tuberculosis [15]. Leaves of Azadirachta indica were used by the healer to treat ringworm infections, while bark was used to treat helmintic infections. In Ayurveda, the tree is known as ‘Nimba’, and the leaves and bark are considered anthelmintic and useful for treating skin infections. Feeding leaves, seeds or bark to small ruminants has also been shown to get rid of helminths from the ruminants [18]. Extract of leaves of the plant has also been reported to be effective against ringworm infections [19]. Senna alata leaves were used by the healer to treat eczema. In Ayurveda, the plant is known as ‘Dadrughna’ and is used to treat eczema [15]. Eczema is a disorder of the skin, and management of superficial skin infections with the use of soap containing Senna alata leaves have been reported [20].

Plants used in pain or some diseases causing pain

Crinum latifolium was used by the healer to treat chest pain. Many Crinum species are in use worldwide in traditional medicinal systems for their analgesic properties [21]. Colocasia esculenta, used by the healer to treat rheumatic pain is known in Ayurveda as ‘Pindaaluka’ and is used in Ayurveda and other traditional medicinal systems of India for treatment of arthritis [22]. Psidium guajava leaf, used by the healer for treatment of tooth infections, has been shown to have beneficial effects on tooth ache [23], which usually accompanies tooth infections. The analgesic activity of Plumbago indica has also been reported [24], a plant used by the healer for treatment of pain. That the Deb barma healer possessed a good knowledge of the medicinal properties of plants is also evidenced by his use, respectively, of Jatropha curcas leaves and Phyllanthus emblica fruits for treatment of tooth ache and headache. Scientific studies have shown that the leaf extract of Jatropha curcas possess analgesic property [25, 26]. Analgesic and anti-pyretic activity has also been reported for Phyllanthus emblica fruits [27].

Plants used in gastrointestinal disorders

Centella asiatica was used by the healer to treat stomach disorders; the plant is also used in Ayurveda for treatment of gastrointestinal disorders, where the plant is known as ‘Manduukaparni’. The tribals of Meghalaya State in northeast India use the whole plant for treatment of diarrhea [28]. The Deb barma healer used the plant, Ageratum conyzoides, for treatment of stomach disorders. Use of this plant in traditional medicine for treatment of diarrhea has been reported from Nigeria [29].

Fruits of Phyllanthus emblica were used by the healer to increase appetite. In Ayurveda, the plant is known as ‘Aaamalaki’, and the fruits have multiple uses including that of being carminative, anti-diarrheal and as a gastrointestinal tonic [15]. The fruits of Terminalia bellirica were used along with fruits of Terminalia chebula and Phyllanthus emblica by the healer to increase appetite. Terminalia bellirica is known in Ayurveda as ‘Bibhitaka’ and its fruits are used for treatment of dyspepsia. Terminalia chebula is also considered an Ayurvedic plant (known in Ayurveda as ‘Haritaki’) and its fruits are used for treatment of flatulence and digestive disorders.

The stems of Phyllanthus reticulatus were used by the healer for treatment of diarrhea in children. In Ayurveda, the plant is known as ‘Kaamboji’, and the leaves are considered anti-diarrheal. Leaves of the plant (and possibly stems) are reported to contain lupeol [30]; the anti-diarrheal property of lupeol has been reported [31]. Thus the anti-diarrheal use of this plant by the Deb barma healer is in common with other traditional medicinal (Ayurveda) uses of the plant as well as scientifically validated.

Aegle marmelos, used by the healer for treating stomach disorders, is known in Ayurveda as ‘Bilva”, and considered a very specific plant for treatment of stomach complaints. Paederia foetida, also used by the healer for treatment of diarrhea, is known in Ayurveda as ‘Talanili’, and is considered an anti-diarrheal plant in this traditional medicinal system [15]. Leaves of Lantana camara, used by the healer to treat flatulence, are used by the Malayali tribals of Chitteri Hills in India to improve digestion in children [32]. It may be noted that flatulence can be caused because of indigestion.

Plants used in coughs

Fruits of Garcinia cowa have been reported to be used in traditional medicines of Thailand for treatment of coughs [33], which use was similar to the use by the Deb barma healer. The flowers of Leucas aspera were used by the healer for treatment of coughs in infants. In Ayurveda, the plant is known as ‘Dronpushpi’, and the flowers are used to treat coughs and colds in children. The leaves of Ocimum gratissimum were used by the healer to treat rheumatic pain as well as coughs and mucus. Ayurvedic texts describe the plant as ‘Vriddha Tulasi’ and its uses for neurological and rheumatic afflictions [15]; scientific studies have validated the use of leaves of the plant for treatment of pain [34]; in homeopathy, the leaves are used to treat coughs.

Plants used in diabetes and cardiovascular disorders

Bark of Terminalia arjuna was used by the healer to treat chest pain due to heart disorders; the aqueous extract of the bark has been shown to exert a cardiotonic effect on adult ventricular myocytes [35]. The therapeutic potential of bark of this plant in cardiovascular disorders has been reviewed [36]. It has further been shown that administration of bark extract of the plant improved myocardial function in streptozotocin-induced diabetic rats [37]; it is to be noted that diabetes can cause cardiovascular complications following onset of this disease. The plant is known in Ayurveda as ‘Arjuna’ and is used in Ayurvedic medicines as a cardioprotective and cardiotonic in angina and poor coronary circulation.

Leaves of Lawsonia inermis were used by the healer to treat diabetes; hypoglycemic activity of leaf extract has been reported in alloxan-induced diabetic mice [38]. The use of another plant by the Deb barma healer has been scientifically validated. Fruits of Ficus hispida were used by the healer to treat diabetes; bark extract of the plant has been shown to demonstrate hypoglycemic activity in normal and diabetic albino rats [39].

Plants used in jaundice and other ailments

Leaves of Moringa oleifera, used by the healer to treat jaundice, have been shown to have hepatoprotective effect [40]. The hepatoprotective property of Clerodendrum viscosum has been shown [41], a plant used by the healer for treatment of jaundice. The leaves of Melastoma malabathricum were used by the healer to stop bleeding from external cuts and wounds; in some parts of India, the bark is also used for the same purpose [15].

Comparative analysis of Deb barma tribal use of medicinal plants with other reported tribal uses in Bangladesh

We have previously conducted ethnomedicinal surveys of the Harbang clan of the Tripura tribe [12], who inhabits the southeastern portion of Bangladesh, as well as Tripura tribal communities residing in other parts of the country. The present survey was conducted on the Deb barma clan of the same tribe, who inhabits the northeastern part of Bangladesh. It is of interest that the medicinal plants used by the two clan healers (Harbang and Deb barma), with the exception of a few plants, were totally different. Even when the plants used were the same, the ailments treated were different. For instance, Justicia adhatoda was used by the Deb barma healer to treat skin infections and tuberculosis, but used by the Harbang clan healer to treat coughs and asthma. Ageratum conyzoides was used by the Deb barma healer to treat stomach disorders, but used by the Harbang healer to treat asthma. However, Terminalia arjuna was used by both clan healers for treatment of heart disorders. It is possible that the two clans being separated into two regions used different medicinal plants more available in their vicinity for treatment. It is also possible that the choice of Deb barma medicinal plants were influenced by interactions with Ayurvedic practitioners, while the Harbang clan selection of medicinal plants reflects choices of a more indigenous nature, i.e. influenced by experiences of their own tribal healer. More studies need to be conducted in this regard on possible interactions of Ayurveda with medicines of various Tripura tribal clans.

Our previous studies on various tribes point to both similarities and differences between medicinal uses of plants between the Deb barma clan and other tribes, with differences being more than similarities. For instance, the Santal tribe of Rangpur district, Bangladesh use whole plants of Colocasia esculenta for treatment of diarrhea, dysentery, piles, and wounds [4]; the Deb barma healer used tubers of the plant for treatment of rheumatic pain. The Hodi tribe uses the same plant for treatment of prolapse of uterus [6]. The plant is used for treatment of stomach pain and hiccup by the Tripura community of Hazarikhil in Chittagong district [42]; and for treatment of diabetes by the Teli clan of the Telegu tribe [43]. Ageratum conyzoides was used by the Santal healer for treatment of impotency [4], but by the Deb barma healer against stomach disorders. The plant was used as an insect repellent and for treatment of wounds and itches by the Garo tribe inhabiting Netrakona district [44]; and for treatment of bleeding, acidity, stomach pain by the Marma tribal community residing in Naikhongchaari, Bandarban district [45]. The plant was also used for treatment of bleeding from cuts and wounds by the Naik clan of the Rajbongshi tribe of Moulvibazar district [46]; and for treatment of severe headache by the Sigibe clan of the Khumi tribe residing in Thanchi sub-district of Bandarban district [47]. Thus, in this case, the Deb barma use was the same as the Marma tribal use in the sense that both tribes used the plant for stomach disorders but differed from the rest of the tribes surveyed.

The Santal healer used Moringa oleifera against constipation, epilepsy, skin eruptions, leucoderma, and as an astringent [4], while the Deb barma healer used the plant against jaundice. The Pahan tribe uses the plant against rheumatism, chicken pox, and as snake repellent [8]. The Sardar community used seeds and fruits of Terminalia bellirica against osteoporosis, diabetes, hysteria, cardiovascular disorders, and low density of semen and kidney problems [7], but the Deb barma healer used fruits of the plant to improve appetite. However, the fruits are used also to treat long-term fever, loss of appetite and as a sexual stimulant by the healers of Tripura tribe residing in Chittagong Hill Tracts [48]. In this case, regarding treatment of loss of appetite (or to improve appetite), the Tripura tribal use of fruits of Terminalia bellirica was the same between the Deb barma clan of the Tripura tribe (residing in Moulvibazar district in the northeast part of Bangladesh) and the Tripura tribal community residing in Chittagong Hill tracts (in the southeast part of Bangladesh). Notably, the plant and especially the fruits are also used as aphrodisiac, energizer, and for treatment of fever, and body ache by the Tonchongya tribal community of Roangchaari sub-district of Bandarban district [49]; treatment of urinary tract infection, hysteria by Tripura community of Hazarikhil in Chittagong district [42] (differences in the plant use by this Tripura community with the other Tripura clans and communities to be noted); treatment of anemia by the Pankho community of Bilaichari Union in Rangamati district [50]; treatment of coughs by the Kanda tribe of Sylhet district [51]; and treatment of coughs and diarrhea by the Rakhaing community of Cox’s Bazar district [52].

The Rai tribe uses Paederia foetida against insanity and mental disorders [10], but the Deb barma healer used the plant against diarrhea. The plant is used for treatment of rheumatic pain, burning sensations during urination by the healers (tribal medicinal practitioners or TMPs) of the Baburo, Haduga and Larma clans of the Chakma tribe residing in Rangamati district [53], and for treatment of toothache by the Bongshi tribe of Tangail district [54]. Taken together, the findings indicate that although certain therapeutic uses of the same plant may be similar, a higher degree of differences exist between medicinal uses of the same plant and its various parts between the various tribes of Bangladesh, which underscores the necessity of documenting medicinal practices of as many tribes as possible to get a comprehensive picture of the manifold uses of any given plant species.

Review of ethnomedicinal uses of Deb barma plants with other reported folk medicinal uses in Bangladesh

A review of the various reported ethnomedicinal uses in Bangladesh of the plants of the Deb barma healer is shown in Table 3. The Bangladeshi traditional medicine has been described as a “unique conglomerate of different ethnomedicinal influences” [55]. Besides the more widely known Ayurveda and Unani systems of medicine with their established colleges and pharmacopoeias, folk and tribal medicinal systems, respectively, play an important role in providing health care services to the mainstream particularly rural Bengali-speaking population and the tribal people. To some extent, some of our surveys [56] as well as Table 3 indicate that these medicinal systems influence each other (more so with Ayurvedic medicine influencing folk and tribal medicines as well as quite possibly the other way round). Folk and tribal medicinal practitioners have several things in common; primarily they rely on simple formulations of medicinal plants for treatment with occasional uses of animal parts, incantations and amulets. Also the medicinal formulations are to a great extent highly individualistic in the sense that formulations can vary greatly from practitioner to practitioner, even though the practitioners may be practicing in the same village or adjoining villages [57–60]. This can be also seen in Table 3, where healers from various areas of Bangladesh can be seen to use the listed plants in a highly diversified manner.

Table 3 Other reported ethnomedicinal uses in Bangladesh of medicinal plants of the Deb barma healer

Essentially, the Deb barma medicinal plants (Table 3) can be classified into four parts. First, a limited number of plants, which have many reported uses, but where there is a consensus among the various folk and tribal medicinal practitioners on the major use (even though there may be other reported uses) of the given plant. Examples of such plants are Justicia adhatoda (majority of healers using the plant for treatment of respiratory tract infections and particularly coughs), Terminalia arjuna (majority of healers using the plant for treatment of cardiovascular disorders), and Senna alata (most healers using the plant for treatment of skin diseases). Among the second category are plants with multiple reports of uses, but where use of the given plant for therapeutic purposes varies widely between different healers. Examples of these types of plants are Andrographis paniculata, Centella asiatica, Alstonia scholaris, Asparagus racemosus, Terminalia bellirica, Terminalia chebula, Azadirachta indica, Moringa oleifera, Aegle marmelos, Curcuma longa and Scoparia dulcis. The third category of plants include plants like Aerva sanguinolenta, Crinum latifolium, Colocasia esculenta, Sansevieria hyacinthoides, Melastoma malabathricum, Eichhornia crassipes, Physalis micrantha, Persicaria glabra, Smilax macrophylla, Sansevieria hyacinthoides, Garcinia cowa and Lantana camara, whose reported uses by FMPs or TMPs are less in number. In fact, Physalis micrantha, Persicaria glabra, Smilax macrophylla, Sansevieria hyacinthoides, Garcinia cowa and Lantana camara each have only one reported ethnomedicinal use in Bangladesh besides their use by the Deb barma healer. The fourth category includes plant like Pouzolzia zeylanica, whose use appears to be unique to the Deb barma healer in the sense that its ethnomedicinal uses in Bangladesh are yet to be reported to the best of our knowledge. Thus use of this plant by the Deb barma can be considered novel.

A number of medicinal plants used by the Deb barma healer had at least one reported similar ethnomedicinal use by FMPs or TMPs of Bangladesh. To cite a few instances, Andrographis paniculata used by the Deb barma healer for treatment of malaria has been reported to be used for treatment of malarial fever by the Bauri tribal community [61]. Justicia adhatoda has been reported to be used for treatment of skin infections by the Kanda tribe [51] and tuberculosis by FMPs in Tangail district [62]; the plant was used by the Deb barma healer to treat skin infections as well as tuberculosis. Justicia gendarussa, used by the Deb barma healer for treatment of coughs and malaria, has been reported to be used for treatment of coughs by the Naik clan of the Rajbongshi tribe [46]. Aerva sanguinolenta, used by the Deb barma healer for treatment of cuts and wounds, reportedly has similar use [61]. The same applies for the use of Crinum latifolium for treatment of bloating in cattle by the Deb barma healer; the plant has been reported to be used for indigestion in cattle (which can lead to bloating) by the Khasia tribe of Sylhet district [11]. However, some uses are unique to the Deb barma healer, being not reported from elsewhere in Bangladesh. These include use of Alstonia scholaris for treatment of formation of whitish layer on tongue, use of Terminalia arjuna for treatment of burning sensations during urination, use of Phyllanthus emblica for treatment of paralysis, use of Sansevieria hyacinthoides for treatment of snake bite and as snake repellent, the use of Garcinia cowa for treatment of coughs and colds, and use of Melastoma malabathricum for treatment of cuts and wounds, to cite a few examples.

Relevance of uniqueness of several Deb barma medicinal plants and their uses

The uniqueness of use of some medicinal plants for therapeutic purposes by the Deb barma healer suggests that these plants (like Physalis micrantha, Persicaria glabra, Smilax macrophylla, Sansevieria hyacinthoides, Garcinia cowa, Pouzolzia zeylanica and Lantana camara) be scientifically examined for their relevant pharmacological activities, which can validate their traditional uses. A number of plants used by the Deb barma healer have been shown earlier to have scientific validations in their traditional uses. Such scientific studies and validations can be important from at least three view points. First, it establishes confidence among scientists, doctors as well as the general people that traditional medicine can be useful and safe to use. Second, such scientific studies can lead the way to possible discovery of lead compounds and drugs from the medicinal plants. Third, the rural people can benefit a lot from using these plants for therapeutic purposes instead of allopathic drugs, which may be costly for them, or like in most rural areas of Bangladesh, inaccessible, due to absence of modern doctors and health facilities. As such, use of traditional medicine can lower the medical costs (because in general herbal drugs are cheaper than allopathic drugs in Bangladesh) and so benefit the poorer segments of the population, who form the majority of people in Bangladesh and other developing countries.

Conclusion

The Deb barma clan is a comparatively small clan of the Tripura tribe with its current total population at only 135 members in Srimangal of Moulvibazar district, Bangladesh. Their ethnomedicinal practices have not been previously reported although they have their own traditional medicinal system and their own traditional healer. Interviews with the healer and adult members of the clan indicated that they believed diseases to occur from the curses of a particular evil god, or caused by evil spirits and demons. Their traditional methods of curing included oral or topical use of medicinal plants, wearing of amulets, appeasement of the evil god through worship and offerings, and treatment of black magic-induced disease with counter-black magic.

A survey of the existing literature showed that the use of a number of plants by the traditional healer for treatment of specific ailments could be scientifically validated based on the reported pharmacological activities of the plants used. The tribal medicinal system of the Deb barma clan showed a notable similarity with Ayurvedic form of treatment (which is considered the most ancient form of treatment within the Indian sub-continent) in terms of plant used and ailments treated. Considering that the two systems had probably interacted with each other for at least two thousand years, it is very much plausible that each system could have influenced the other. However, medicinal uses of a number of the plants differed between the Deb barma clan and other tribes of Bangladesh, the medicinal practices of which have been documented. The differences indicate the importance of documenting the medicinal practices of as many tribes as possible to obtain an overall view of the diverse uses of any given plant species.

Our interviews further suggested that in recent years, the Deb barma clan members may have started to prefer allopathic system more than their traditional medicinal system. If this happens, the ethnomedicinal wisdom of the Deb barma clan may be lost forever, if not documented. Since already the usage of a number of their traditional medicinal plants has been validated through scientific research, it is important that the yet to be studied plants be examined scientifically as to their pharmacological properties and their phytochemical constituents. Such studies can be beneficial to human beings if new and more efficacious medicines can be discovered from these plants.