ETHNOBOTANICAL USES AND INFORMANT CONSENSUS FACTOR OF MEDICINAL PLANTS IN BARISAL DISTRICT , BANGLADESH U

An ethnobotanical study was carried out to identify ethnomedicinally important plants of Barisal district of Bangladesh, document their traditional uses, and determine the consensus factor among the Folklore Medicinal Practitioners (FMPs). A total of 106 ethnomedicinal species under 55 families have been identified from Barisal district, which are used for treating 51 ailments with 120 formularies. Among the species, herbs constituted 59%, shrubs 15% and tress 26% of the total. Leaf was found to be the most frequently utilized plant part (44.33%), and most of the medicines were prepared in the form of juice (36%). The Factor of Informants Consensus (FIC) value ranged from 0.622 to 0.951 and the highest FIC value was found in cut, wound and bleeding. The highly cited species for these ailments are Mikania cordata (Burn.f.) Robinson, Cynodon dactylon (L.) Pers. and Chrozophora tinctoria (L.) A. Juss. Citation frequency (Cf) ranged from 20.93 to 67.44, and 11 species were found to have over 50% of Cf value. Fidelity level (Fl) value ranged from 69 to 100% and 17 species attained 100% Fl value. Our findings could provide baseline data to establish a tie between the traditional health practitioners and scientific communities, and finding out potential bioactive compounds for novel drug discovery. Introduction Bangladesh is endowed with wealth of ethnomedicines that includes Ayurveda, Unani, Homeopathy, Folk medicines and Tribal medicines. Over 80% of the world’s population depends on herbal and alternative medicines for their primary health care (WHO, 2001; Kong et al., 2009). Moreover, herbal medicines have entered into the mainstream of global economy (UNEP, 2001). Traditional and alternative medicines reform health sector globally. Folk medicine is probably the most common among the aforesaid traditional medicinal practices and folk medicinal practitioners (FMPs) depend mainly on medicinal plants. Medicinal plants used for treatment of particular disease varies considerably among FMPs. In Bangladesh, studies investigating documentation and the sustainability of the commercial trade in medicinal plants are at an initial stage. For documentation of the practices along with plants used by FMPs, ethnomedicinal surveys among various FMPs and tribal medicinal practitioners of Bangladesh are in progress. Ethnomedicinal knowledge of plants has been decreasing at alarming rate from the nature before proper documentation and evaluation (Udddin et al., 2015). In Bangladesh, several attempts have been made to document traditional knowledge of ethnomedicinal plants, and folk medicine has experienced a revival since last two decades (Hassan and Khan, 1986; Mia and Huq, 1988; Alam, 1992; Alam et al. 1996; Yusuf et al., 2006; Uddin and Hassan, 2014). All those studies listed medicinal plants of particular community, particular diseases or particular areas of Department of Botany, University of Dhaka, Dhaka-1000, Bangladesh. Corresponding author: E-mail: prof.oliurrahman@gmail.com 242 HOSSAIN AND RAHMAN Bangladesh (Uddin et al., 2015). However, many unexplored areas and communities remain in the country and many more medicinal plants used as sources of herbal drugs by the ethnic, FMPs and local people of Bangladesh yet to be revealed. In this context, no study has been carried out on documentation and quantitative analyses of ethnomedicinal plants used by rural people and folk medicinal practitioners of Barisal district. Therefore, the objectives of the present study include: to identify the most and frequently used medicinal plant species used by the local people and FMPs in Barisal district through Informant Consensus Factor, to document their traditional uses, to determine the consensus of medicinal uses, and finally to make a basis for future investigation for potential drug candidates through quantitative analyses. Materials and Methods Study area: Barisal as one of the riverine southern district of Bangladesh lies between 22o27 ́ and 22o52 ́N and 90o01 ́ and 90o43 ́E. The district is demarked by Madaripur, Shariatpur and Chandpur districts on the north, Patuakhali, Barguna and Jhalkhati districts on the south, Bhola and Lakshmipur districts on the east, and Pirojpur, Jhalkhati and Gopalganj districts on the west. Barisal district consists of 10 upazillas, viz., Agailjhara, Babuganj, Bakerganj, Banaripara, Barisal Sadar, Gaurnadi, Hizla, Mehendiganj, Muladi and Wuzirpur. The area enjoys tropical climate with high rainfall during monsoon period. The soil texture of the area is clay loam and saline in habitat (Shil and Saleque, 2016). Though there is no any natural forest in Barisal except the governmental planned afforestation program in coastal belt, banks of rivers and all homesteads are usually covered by dense green foliage of wide variety of both native and exotic species resulting in vegetation enrich in biodiversity. Plant samples and data collection: Plant samples were collected from the study area during field surveys in different seasons from May 2017 to April 2018. The data of medicinal uses were gathered through semistructured interviews, key informant discussions and informal conversations with folk medicinal practitioners (FMPs) called herbal practitioners or locally known as Kabiraz (Alexiades, 1996). A total of 43 informants mostly male with the age ranging from 24 to 75 years of old were interviewed. Education levels of the informants were from Secondary School Certificate (SSC) to Bachelor of Science (BSc) degrees. Some of the informants were diploma trained in folk medicinal practice from Ayurveda or Unani College at home or abroad. Professionally they were mostly farmers, small shopkeepers, street hawkers, school teachers and volunteer FMPs. Information on uses of plants for treating different ailments, parts used and mode of preparation as well as administration was gathered during the field study. Specimens of each medicinal plant were collected, critically studied and identified by experts and using standard literature (Hooker, 1872-1897; Prain, 1903; Dassanayake and Fosberg, 1980-1991; Ahmed et al., 2008-2009). Voucher specimens were prepared using standard protocol (Hyland, 1972; Alexiades, 1996) and preserved at the Department of Botany, University of Barisal. Data analysis: Factor of informant consensus (Fic): Factor of informant consensus (Fic) was computed using the following formula:


Introduction
Bangladesh is endowed with wealth of ethnomedicines that includes Ayurveda, Unani, Homeopathy, Folk medicines and Tribal medicines.Over 80% of the world's population depends on herbal and alternative medicines for their primary health care (WHO, 2001;Kong et al., 2009).Moreover, herbal medicines have entered into the mainstream of global economy (UNEP, 2001).Traditional and alternative medicines reform health sector globally.Folk medicine is probably the most common among the aforesaid traditional medicinal practices and folk medicinal practitioners (FMPs) depend mainly on medicinal plants.Medicinal plants used for treatment of particular disease varies considerably among FMPs.In Bangladesh, studies investigating documentation and the sustainability of the commercial trade in medicinal plants are at an initial stage.For documentation of the practices along with plants used by FMPs, ethnomedicinal surveys among various FMPs and tribal medicinal practitioners of Bangladesh are in progress.
Ethnomedicinal knowledge of plants has been decreasing at alarming rate from the nature before proper documentation and evaluation (Udddin et al., 2015).In Bangladesh, several attempts have been made to document traditional knowledge of ethnomedicinal plants, and folk medicine has experienced a revival since last two decades (Hassan and Khan, 1986;Mia and Huq, 1988;Alam, 1992;Alam et al. 1996;Yusuf et al., 2006;Uddin and Hassan, 2014).All those studies listed medicinal plants of particular community, particular diseases or particular areas of Bangladesh (Uddin et al., 2015).However, many unexplored areas and communities remain in the country and many more medicinal plants used as sources of herbal drugs by the ethnic, FMPs and local people of Bangladesh yet to be revealed.In this context, no study has been carried out on documentation and quantitative analyses of ethnomedicinal plants used by rural people and folk medicinal practitioners of Barisal district.Therefore, the objectives of the present study include: to identify the most and frequently used medicinal plant species used by the local people and FMPs in Barisal district through Informant Consensus Factor, to document their traditional uses, to determine the consensus of medicinal uses, and finally to make a basis for future investigation for potential drug candidates through quantitative analyses.

Study area:
Barisal as one of the riverine southern district of Bangladesh lies between 22º27´ and 22º52´N and 90º01´ and 90º43´E.The district is demarked by Madaripur, Shariatpur and Chandpur districts on the north, Patuakhali, Barguna and Jhalkhati districts on the south, Bhola and Lakshmipur districts on the east, and Pirojpur, Jhalkhati and Gopalganj districts on the west.Barisal district consists of 10 upazillas, viz., Agailjhara, Babuganj, Bakerganj, Banaripara, Barisal Sadar, Gaurnadi, Hizla, Mehendiganj, Muladi and Wuzirpur.The area enjoys tropical climate with high rainfall during monsoon period.The soil texture of the area is clay loam and saline in habitat (Shil and Saleque, 2016).Though there is no any natural forest in Barisal except the governmental planned afforestation program in coastal belt, banks of rivers and all homesteads are usually covered by dense green foliage of wide variety of both native and exotic species resulting in vegetation enrich in biodiversity.

Plant samples and data collection:
Plant samples were collected from the study area during field surveys in different seasons from May 2017 to April 2018.The data of medicinal uses were gathered through semistructured interviews, key informant discussions and informal conversations with folk medicinal practitioners (FMPs) called herbal practitioners or locally known as Kabiraz (Alexiades, 1996).A total of 43 informants mostly male with the age ranging from 24 to 75 years of old were interviewed.Education levels of the informants were from Secondary School Certificate (SSC) to Bachelor of Science (BSc) degrees.Some of the informants were diploma trained in folk medicinal practice from Ayurveda or Unani College at home or abroad.Professionally they were mostly farmers, small shopkeepers, street hawkers, school teachers and volunteer FMPs.Information on uses of plants for treating different ailments, parts used and mode of preparation as well as administration was gathered during the field study.Specimens of each medicinal plant were collected, critically studied and identified by experts and using standard literature (Hooker, 1872(Hooker, -1897;;Prain, 1903;Dassanayake andFosberg, 1980-1991;Ahmed et al., 2008Ahmed et al., -2009)).Voucher specimens were prepared using standard protocol (Hyland, 1972;Alexiades, 1996) and preserved at the Department of Botany, University of Barisal.

Data analysis:
Factor of informant consensus (Fic): Factor of informant consensus (Fic) was computed using the following formula: Fic = Where, N ur is the number of use reports in each category and N taxa is the number of species in each category (Heinrich et al., 1998).

Nur -Ntaxa
Nur -1 Citation frequency of medicinal plants (Cf %): Cf values are useful to determine most common medicinal plants in the study area.Citation frequency values of medicinal plants were estimated using the formula: Citation frequency (Cf %) = ×100 Where, n refers to number of people interviewed citing species, N refers to total number of people interviewed (Friedman et al., 1986).
Fidelity level (Fl %): The percentage of informants claiming the use of a plant species for the same major purpose was estimated using the Fidelity level index as determined by the following formula: Where Ip denotes to number of informants who indicate use of a species for the same major ailment, Iu refers to total number of informants who mentioned the same plant for any other use (Friedman et al., 1986).

Diversity of medicinal plants -Habit, habitat and parts used:
The present study revealed identification and documentation of 106 medicinal plant species belonging to 96 genera and 52 families from Barisal district used by local folklore medicinal practitioners (FMPs) for 51 ailments with 120 formularies (Table 1).In the present study, the highly reported species were herbs (59%) followed by trees (26%) and shrubs (15%) (Fig. 1A).Several authors reported the common use of herbaceous medicinal plants (Addo-Fordjour et al., 2008), and the herbs attributed to their wide range of bioactive ingredients (Gazzaneo et al., 2005).Herbs, and trees are most commonly used as medicine by the traditional healers (Uniyal et al., 2006), which were supported by our study.Among the species reported 47.16 % was found to be cultivated, 33.01%wild and 19.81% wild but cultivated in home gardens.
The study area represents diverse habitats including homestead gardens, roadsides, arable lands, river side, wastelands, muddy area etc. and medicinal plants were collected from those habitats.The highest number of ethno-medicinal plants were collected from homestead garden representing 24% followed by arable lands covering 23% of the total species (Fig. 1B).The family Asteraceae was found to be the highest represented family in terms of number of species (5.7%), followed by Apocynaceae and Rutaceae (4.7% each).The families Apiaceae, Arecaceae, Convolvulaceae and Euphorbiaceae constitute 3.8% each of total species, while Acanthaceae, Caesalpiniaceae, Combretaceae, Cucurbitaceae, Lamiaceae, Myrtaceae and Poaceae represent 2.8% each of the total ethnomedicinal plants identified from the study area.The other families provide less than 2% representation of the species.With respect to the parts used, the study showed that plant parts used by the local FMPs of Barisal for treating different diseases were mainly leaves, fruits and seeds.In the case herbaceous plants aerial parts or sometimes the whole plant was employed.Leaf was found to be most frequently utilized plants part (44.33%), followed by fruits (24.5%), stems (8.5%), roots, flowers and stem barks (5.7% each), and latex, whole plant and seeds (4.7% each) (Fig. 2).The predominant use of leaf used by the folk medicinal practitioners for different therapies has been attested by other studies.
In an ethnobotanical survey of medicinal plants of two villages of Gaurnadi upazila in Barisal district, Biswas et al. (2011) showed that leaves constituted the major part of plants used by the folk medicinal practitioners.While conducting an ethnobotanical survey in the Garo ethnic community Ramatullah et al. (2009) found that leaves formed the major plant part used followed by whole plant and fruits.Recently, Uddin et al. (2015) reported leaf as frequently used plant part for folk medicine preparation.In addition, several tribal communities utilized leaves for preparation of herbal medicines (Prabhu et al., 2014;Vijaykumar et al., 2015).Leaves are used mostly in herbal preparation because collection of leaves is easier than underground parts, flowers or fruits (Giday et al., 2009).Our results were found consistent with other studies where leaf was reported as frequently used plant part for folk medicine preparation (Yigra, 2010; Ullah et al., 2013).However, Ribeiro et al. (2014) reported that stem bark had the highest number of citations, followed by leaves, fruits and roots.This could be explained by the fact that the prime use of stem bark is common among people in the semi-arid region for different ailments, even when other structures, for instance leaves, are obtainable (Albuquerque et al., 2012).
During this ethnobotanical survey it was observed that the demand for folklore medicine is increasing day by day.As a result, a good number of medicinal plant species or plant parts are being used by the FMPs.Excessive use of roots, flowers, fruits, seeds and sometimes whole plant may destroy the plant or make hindrance in regeneration, and have impact on population existence.For sustainable use of these medicinal plants conservation measures through both in-situ and exsitu methods to be adopted, and traditional healers to be very cautious during harvesting these parts at least keeping some plants for sustainable regeneration.

Modes of preparation and administration:
The modes of preparation of herbal medicines were in the forms of paste, powder, decoction, juice, raw and fumes.The majority of the plant remedies was prepared by juice (36%) followed by raw (17%), powder (13%), boiled (12%), decoction (10%), paste (8%) and seed oil (4%) (Fig. 3A).In terms of administration, oral administration was found as the principal mode of intake of medicine (65%) followed by administration of dermal (19%), nasal (9%) and others (7%) (Fig. 3B).We have found that, FMPs in the investigated area often mix water as a solvent for preparation of juice after crushing, and sometimes milk or honey is added as a solvent to increase the viscosity of the preparation.It has also been reported that different parts of some toxic plants are boiled into water to wash out the toxic substances and mixed with milk to make medicines.In an ethnoveterinary study Parthiban et al. (2016) showed that paste was the frequently used mode of preparation, which was found inconsistent with the present study.

Factors of informant consensus (Fic):
Factors of informant consensus were calculated to evaluate use diversity of the medicinal plants and to determine which plants are particularly interesting in search for bioactive compounds.Table 2 showed that the calculated Fic value varied from 0.622 to 0.951.The highest Fic value was found in cut, wound and bleeding (0.951) and subsequently in rheumatic pain (0.935), oral diseases (0.912), hypertension (0.902), hair tonic (0.857), dysentery and diarrhoea (0.847), abdominal pain (0.833), diabetes (0.818), dermatological diseases (0.813), cough, cold and fever (0.792), jaundice (0.769), urogenital and venereal problems (0.768), parasitic disease (0.706), and constipation and appetite loss (0.622) (Table 2).The highest Fic value for cut, wound and bleeding are noted in very few number of plant species.
The highly cited species for cut, wound and bleeding are Mikania cordata, Cynodon dactylon, and Chrozophora tinctoria and a large proportion of people employ these species to treat these ailments.Results obtained from this study were found consistent with Uddin et al. (2015) where B A they reported high Fic value for the ailments cut and wound in a survey in Feni district of Bangladesh.In a quantitative ethnobotanical study among indigenous communities in Bandarban district of Bangladesh, Faruque et al. (2018) found Fic value of the cut and wound ailment category as 0.59.They reported the highest Fic value in the digestive system disorders including gastritis, diarrhoea, ulcers, constipation, digestive aid, piles, carminative, flatulence, indigestion, colic and anthelmintic, which was not supported by the present study.Variation in Fic value might be due to availability and diversity of medicinal plants and its associated knowledge in a particular locality, restriction in exchange of ethnobotanical knowledge from one generation to another and one locality to other.The highest number of ethnomedicinal species were used to treat constipation and appetite loss (29 species) followed by treatment of urogenital and venereal diseases (17 species).Only two species were documented for treatment of rheumatic pain.

Citation frequency (Cf ):
The citation frequency in the investigated ethnomedicinal plants ranged from 20.93 to 67.44.Eleven species were found to have over 50% of Cf value, viz., Adhatoda zeylanica, Aegle marmelos, Andrographis paniculata, Bryophyllum pinnatum, Ficus racemosa, Gynura procumbens, Mikania cordata, Ocimum tenuiflorum, Piper chaba, Spondias pinnata and Syzygium cumini (Table 3).The high Cf value of medicinal plants is the signal of popular and common species in the study area which can be employed for further analysis to find out new drugs.

Fidelity level (Fl):
The fidelity level value is useful for identifying the informants' most preferred species in use for treating certain ailments.The analyzed results represented that fidelity level value ranged from 69 to 100%.A total of 17 species were found to have 100% Fl value and these are: Vitex negundo, Azadirachta indica, Piper chaba, Paederia foetida,, Ocimum tenuiflorum, Aegle marmelos, Dillenia indica, Mikania cordata, Gynura procumbens, Syzygium cumini, Bryophyllum pinnatum, Spondias pinnata, Elaeocarpus robustus, Abroma augusta, Azadirachta indica, Calotropis gigantea and Senna alata (Table 4).These high fidelity level values indicate that the informants do have inclination to rely on one specific plant species for treatment of one particular disease rather than several diseases.The present investigation is the first ethnobotanical effort to document and carry out quantitative analyses of medicinal plants used by the local folk medicinal practitioners in Barisal district.The study revealed that Barisal district has a plenty of medicinal plants and the amazing update is that a great portion of medicinal plants are found in homestead.The local people of the investigated area still depend on traditional medicine despite the modern medical facilities are accessible indicating the importance of traditional medicines.Documentation and preservation of traditional knowledge on indigenous medicinal plants is not only indispensable for the communities, but also valuable for ethnopharmacological studies.In novel drug discovery our findings could provide baseline data to launch a bridge between the scientific communities and traditional health practitioners.In this regard, further scientific investigation on these medicinal plants for phytochemical, biological and clinical studies is greatly needed.

Fig. 1 .
Fig. 1.Comparative analysis of ethnomedicinal plants of Barisal district.A. Percentage of habit; B. Percentage of habitat.

Fig. 2 .
Fig. 2. Use report of different parts of ethnomedicinal plants of Barisal district for treating different ailments.

Fig. 3 .
Fig. 3. Mode of preparation and administration of ethnomedicinal plants of Barisal district.A. Percentage of mode of preparation; B. Percentage of routes of administration.