Bangladesh J. Plant Taxon. 29(2): 345-360, 2022 (December) DOI: https://doi.org/10.3329/bjpt.v29i2.63533 © 2022 Bangladesh Association of Plant Taxonomists DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE OF MEDICINAL PLANTS OF THAKURGAON DISTRICT FARHANA YESMIN MITU, ATIYA BEGUM RIFAT, TAHMINA HAQUE, MD. ABDUL MAZID1 AND MOHAMMAD ZASHIM UDDIN* Department of Botany, University of Dhaka, Dhaka-1000, Bangladesh Keywords: Informant consensus; Fidelity level; Medicinal plants; Thakurgaon district; Bangladesh. Abstract Consensus in the use of medicinal plants is one of the criteria to find the potential medicinal plants for further in-depth investigation. The present study was conducted with the aim to determine the people consensus in the use of medicinal plants in Thakurgaon district. Data of medicinal plants were recorded using key informant interviews, semi structured interviews and group discussion. A total of 102 medicinal plant species under 49 families with 185 formularies to treat 54 ailments were recorded from the study area. The most frequently utilized plant species are trees (38%) followed by herbs (34%), shrubs (18%) and climbers (10%). The major part used for medicines was leaf. Oral consumption was the main mode of treatment in the study area followed by external application. The top Fic value was obtained in case of heart diseases (0.92). The most cited species used to treat this ailment was Allium sativum, Phyllanthus emblica, Spondias pinnata and Terminalia arjuna. The second highest Fic value was found in respiratory disorders (0.89) followed by cuts and wounds (0.85), skin diseases (0.84) and gastrointestinal disorders (0.81). In case of Fl value, Allium sativum, Spondias pinnata, Cynodon dactylon, Lawsonia inermis, Zingiber officinale, Saccharum officinarum, Tagetes erecta and Baccaurea ramiflora were showed 100%. The species of higher citation frequency were Allium sativum, Phyllanthus emblica, Spondias pinnata, Terminalia arjuna, Cynodon dactylon and Ocimum sanctum. This study recommends that the species which showed high Fic, Fl, Cf values could be used for further phytochemical analysis to investigate active compounds for the discovery of new drugs from medicinal plants. Introduction Ethnobotanical investigation is the gateway in identifying new plant products of potential commercial values (Uddin et al., 2015). Documented medicinal plants with high degree of consensus can serve as a basis for future investigation of modern drug (khan et al., 2014). The world market for herbal medicines based on traditional knowledge is now estimated at US$ 60 billion (Breevot, 1998). In 1992, the world leaders met in Rio de Janeiro to formulate biodiversity conservation policy including agenda 21 which also gave emphasis on the documentation and sustainable utilization of traditional knowledge of medicinal plants. Indigenous knowledge of using medicinal plants for healing human ailments is however in danger of gradually become extinct, because this knowledge is passed on orally from generation to generation without the aid of a writing system (Kaido et al., 1997). Most culture possess a huge store of undocumented traditional knowledge of applying herbal remedies in the treatment of diseases (Offiah et al., 2011). In addition, documenting the results of scientific research into traditional medicine may *Corresponding author: zashim01@gmail.com 1Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka-1000, Bangladesh. https://doi.org/10.3329/bjpt.v29i2.63533 mailto:zashim01@gmail.com 346 MITU et al. also help to conserve an important part of an indigenous people's cultural heritage for the future generations (Mahwasane et al., 2013). Ethnobotanical studies have got attention in all over the world. Unless the plants are conserved and the ethnobotanical knowledge is documented, there is a danger that both the valuable medicinal plants and the associated indigenous knowledge of the ethnic groups could vanish forever due to lack of documentation. The documentation of indigenous knowledge of herbal medicine is an important aspect of conservation approach (Umair et al., 2017). Many studies have been done on indigenous knowledge of medicinal plants in different parts of Bangladesh. Today a substantial number of drugs are developed from plants which are active against number of diseases (Principe, 2005). In spite of tremendous advances in synthetic drugs and medicine, a large number of people still believe on herbal drugs with hope of safety and efficacy (Verma et al., 2008). Plants may serve as the alternative sources for the development of new anticoagulant agents due to their biological activities. Currently medicinal plants and traditional knowledge have been eroding because of anthropogenic pressure, deforestation, pollution, modern agriculture practices, lack of awareness, unwilling to practice forefather tradition, climate change, modern culture, migrating towards urbans and no written documents. Some of such knowledge is going to be eliminated before documentation which is alarming to sustain cultural heritage (Uddin et al., 2017). So, it is essential to document all traditional knowledge about herbal medicine and all medicinal plants. In order to protect such knowledge, documentation of ethnobotanical plants is already started in Bangladesh. A number of articles have been published in this field, for example, Mia and Huq (1988), Hassan and Khan (1986, 1996), Alam (1992), Alam et al. (1996), Uddin (2006), Uddin et al. (2001), Khan et al. (2002), Yusuf et al. (2002), Uddin et al. (2004), Uddin et al. (2006), Yusuf et al. (2006), Uddin and Roy (2007), Uddin et al. (2008), Uddin et al. (2012), Haque et al. (2014) and Uddin and Hassan (2014), Kona and Rahman 2016, Nahar et al. 2016, Faruque et al. (2018,2014) and Uddin et al. (2019). These articles listed a good number of medicinal plants of particular community or particular diseases or particular areas of Bangladesh. But there are still more medicinal plants which are being used as the sources of herbal drugs by the ethnic and local people of Bangladesh but yet to be identified scientifically. Unfortunately, no such work has covered the documentation of ethnomedicinal plants of rural people of Thakurgaon district. The houses homesteads of rach village of Thakurgaon are rich with natural plant diversity in its unique original ecosystems. The indigenous livelihood is mainly based on cultivation system. They mainly cultivate rice as a principal food and also cultivated other diversity of minor crops in and around their homes. Many indigenous species are disappearing from the area as well as many new invasive, alien species are occupying its habitats. Such loss of indigenous species might have an adverse effect on the food security and livelihoods of the area. So, there is a great necessity for recording the existing medicinal plant species through adequate ethnobotanical studies in the area before their disappearance from the natural habitats. Traditional practitioners of the area also use the medicinal plants in the treatment of various diseases. Currently medicinal plants, healthcare knowledge of medicinal plants and their habitats are vulnerable because of many threats such as lack of awareness, deforestation, urbanization, agricultural expansion, illegal logging and poaching etc. If the situation continues, important medicinal plants will be eliminated before their documentation. In the present study an attempt was made to record ethnomedicinal use of plants and to determine the consensus of local people in the use of medicinal plants for the treatment of ailments. DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE 347 Materials and Methods Thakurgaon is a district in the northwest of Bangladesh under Rangpur division. It is located between 25°40' and 26°12' N latitudes and 88°05' and 88°39' N longitudes. The district is bounded by Panchagarh district on the north, Panchagarh and Dinajpur districts on the east, and the West Bengal state of India on the south and west. This district consists of six thanas named as Thakurgaon Sadar, Ruhia, Baliadangi, Pirganj, Ranishankail, and Haripur. The climate of the district is mainly tropical dry with late monsoon. The monsoon usually begins in June and ends in October, with an average rainfall of 1700 mm. The summer average temperature is 31 °C, and the winter average temperature is 19 °C (Banglapedia, 2014). There are five forest beats present in the Thankurgaon forest range. The most dominant species in such forest beats is Sal (Shorea robusta). A good number of herbs, shrubs, and climbers are grown with dominant Sal trees those may have medicinal values (personal communication and observations). The study area was visited five times in different seasons of 2018 and 2019. Each field trip lasted for five to eight days. The data on medicinal uses were collected through semi–structured interviews, key informant discussions, and informal conversations with local people and also herbal practitioners. Participant observation, plant interview, field interview, and group interview were also followed to collect data (Alexiades, 1996). A total of 250 local informants, including 58% males and 42% females, were interviewed during the ethnobotanical survey. The education levels of the informants ranged from illiterate up to B.S. degrees. The informants were mainly farmers, housewives, herbal practitioners, shopkeepers, businessmen, teachers, and students. The age of the informants ranged from 21 to 80 years. Information on the uses of plants to treat humans, parts used, modes of treatment, and administration were collected during the field survey. The vernacular names were collected with the help of the local people. The recorded medicinal plants were collected from fields and gardens with notes on field characters. Voucher specimens for each medicinal plant were processed using standard herbarium techniques (Hyland, 1972 and Alexiades, 1996). Identification of plant species was done by experts in both the field and laboratory and consulting standard literature (Siddiqui et al., 2007; Ahmed et al., 2008-2009). In case of confusion in identity, standard literature was consulted, and relevant voucher specimens available at the Dhaka University Salar Khan Herbarium (DUSH) were also compared. All voucher specimens were deposited at DUSH. To determine people’s consensus in the use of medicinal plants, factor informant’s consensus (Fic), fidelity level (Fl), and citation frequency (Cf) values were calculated using standard mathematical models according to Heinrich et al. (1998) and Friedman et al. (1986). Results and Discussion Present study was recorded a total of 102 medicinal plant species under 49 families. These medicinal plants were used for the management of 54 aliments through 185 formularies in the study area. Maximum medicinal plant species (67%) were found under 17 families and rest medicinal plants species (37%) were found in 32 families (Fig. 1). Among the families, Araceae, Rutaceae, Cucurbitaceae, Poaceae, Fabaceae, Liliaceae, Solanaceae, Verbenaceae, Asteraceae, and Caesalpiniaceae were the dominant families with the common medicinal plant species in the study area. For each species, the scientific name, local name, family, habit, parts-use, ailments, and modes of treatment have been presented in the Table 1. It is evident from a preliminary investigation that the study area still has a huge variation of knowledge about the uses of medicinal plants. Such knowledge has been passed down orally from generation to generation and no written document found on this knowledge. 348 MITU et al. Table 1. Ethnobotanical data on medicinal plants and uses in the study area (S=Shrub, H= Herb, T=Tree, C=Climber). Scientific name Local name Family Habit Parts use Ailments Treatment mode Abroma augusta (L.) L. f. Ulotkombol Sterculiaceae S leaf Heart disease Juice is taken. Stem Jaundice Soaked in water at night then drunk in morning. Justicia adhatoda L. Bashak Acanthaceae S Leaf Cough Leaf chewed Cold treatment Chewed leaf is taken worm Juice is taken Asthma Leaf juice is taken with ginger and honey Aegle marmelos (L.) Corr. Bel Rutaceae T Leaf Diarrhoea Leaf juice is taken Fruit Constipation Fruit juice is taken Gastric Fruit juice is taken Jaundice Fruit juice is taken Dysentery Juice is taken twice per day Albizia procera (Roxb.) Benth. Koroi Mimosaceae T Leaf Allergy Leaf paste is applied Allium cepa L. Peaj Liliaceae H Bulb Flue Juice is taken Allium sativum L. Rosun Lilliaceae H Bulb Heart disease 2-3 cloves are eaten in the morning Alocasia macrorrhizos( L.) G. Don Mankachu Araceae H Rhizome Rheumatic pain Cooked rhizome is taken Aloe vera(L.) Burm. f. Aloevera Aloaceae H Leaf Diabetes Inside portion of leaf is eaten Skin disease Paste is applied externally Stomachache Leaf juice is taken Alstonia scholaris (L.) R. Br. Chatim Apocynaceae T Bark Cough Bark juice is taken Amaranthus tricolor L. Lalshak Amaranthaceae H leaf Pressure reduce Cooked leaf is eaten Amorphophallus paeoniifolius (Dennst.) Nicolson Olkachu Araceae H Rhizome Rheumatic pain Cooked rhizome is taken Ananas comosus (L.) Merr. Anaros Bromiliaceae H Leaf Gastric Leaf juice taken. Stomachache Juice is taken Andrographis paniculata (Burm.f.) wall. ex Nees Kalomegh Acanthaceae H Leaf Cold treatment Leaf chewed Constipation Juice is taken Cough Chewed leaf is taken Arachis hypogaea L. Badam Fabaceae H seed Heart disease Fruit juice is taken Areca catechu L. Supari Arecaceae T Root Stomachache Root juice is taken DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE 349 Scientific name Local name Family Habit Parts use Ailments Treatment mode Artocarpus heterophyllus Lamk. Kathal Moraceae T Leaf Scabies leaf boil with mustards oil then oil then taken on the affected area. Asparagus racemosus Willd. Satamuli Liliaceae C Root Gastric Root is powdered and then taken Averrhoa carambola L. Kamranga Oxalidaceae T Fruit Cough fruit juice is taken daily for 3-4 days. Azadirachta indica A. Juss. Neem Meliaceae T Leaf Diabetes juice is taken Pox Paste is applied externally Skin rash Leaf paste is applied Baccaurea ramiflora Lour. Lotkon Euphorbiaceae T Fruit Anti-oxidant Fruit juice is taken Bambusa tulda Roxb. Talla bash Poaceae T stem Impotence Stem is cooked and then taken Basella alba L. Puisak Basellaceae C Leaf Wound Leaf paste is applied in the affected area Bombax ceiba L. Shimul Bombacaceae T Root Impotence Juice is taken Borassus flabellifer L. Tal Arecaceae T Young apex Cough Juice is taken Bryophyllum pinnatum(Lamk.) Oken Patharkuchi Crassulaceae H Leaf Cold treatment juice is taken Diabetes juice is taken Jaundice juice is taken Acne Paste is applied externally Cajanus cajan (L.) Millsp. Orhor Fabaceae S Leaf Jaundice juice is taken Calotropis procera (Ait.) R.Br. Akanda Asclepiadaceae S Leaf Ringworm Leaf paste is applied Carica papaya L. Pepe Caricaceae S Fruit Gastric Eating fresh fruit or as vegetable piles Eating fresh fruit or as vegetable Jaundice Eating fresh fruit or as vegetable Constipation Cooked fruit is taken Cassia fistula L. Sonalu Caesalpiniaceae T Fruit Constipation Juice is taken Leaf Ringworm Leaf paste is applied on affected area Catharanthus roseus ( L.) G. Don Noyontara Apocynaceae H Flower Diabetes Flower chewed Leaf Diabetes Leaf juice is taken twice per day Centella asiatica(L.) Urban Thankuni Apiaceae H Leaf Diarrhoea Leaf paste is eaten Brain sharping Leaf chewed Constipation Leaf paste is taken Dysentery Leaf paste is eaten 350 MITU et al. Scientific name Local name Family Habit Parts use Ailments Treatment mode Cinnamomum tamala Nees & Eberm. Tejpata Lauraceae T Leaf Cough Leaf is boiled with water and then the water is taken Cinnamomum verum J. S. Presl Darchini Lauraceae T Bark Stomachache Paste is used with warm water Citrus aurantifolia (Christm. & Panzer) Swingle Kagolilebu Rutaceae S Fruit Toothache Juice is taken Vomiting Juice is taken Citrus grandis (L.) Osbeck Jambura Rutaceae T Fruit Fever Fruit is eaten with pepper Citrus limon (L.) Burm. f. Lebu Rutaceae S Fruit Cold treatment Bud is boiled with water and taken with tea Digestion Bud is eaten raw Clerodrendrum viscosum pers. Vat Verbenaceae S Leaf Fever Young leaf juice is taken Stem Jaundice 1 cup juice per day for 7 days Root Daud Root blended with Zinger then the paste is applied Leaf Dysentery Leaf paste taken internally Coccinia grandis (L.) Voigt Telakucha Cucurbitaceae C Leaf Dysentery 1 glass of leaf juice is taken Jaundice juice is taken internally Diabetes leaf juice is taken Cocos nucifera L. Narikel Arecaceae T Fruit Pox Juice is taken Diarrhoea Juice is taken Jaundice Juice is taken Dysentery Juice is taken Colocasia esculenta (L.) Schott Kochu Araceae H Leaf Brain tonic Cooked and taken internally. Coriandrum sativum L. Dhonia Apiaceae H Seed Fat remove Soaked in water then water is taken Bannicasa hispida (Thunb.) Cogn. Chalkumra Cucurbitaceae C Stem Toothache Stem decoction for gargling Curcuma longa L. Holud Zingiberaceae H Rhizome Blood purifier Juice is taken Scabies & fungal lesion Paste is applied in the affected area Cuscuta reflexa Roxb. Swarnalata Cuscutaceae C Stem Dewormimg Juice is taken Cynodon dactylon (L.) pers. Durba Poaceae H Leaf Cuts & wounds Leaf paste is applied Dalbergia sissoo Roxb. Shishu Fabaceae T Leaf Jaundice Leaf juice is taken Datura metel L. Dhutura Solanaceae S Leaf Skin disease Leaf is cooked Skin disease Leaf paste is applied externally Paralysis Dried crushed leaf is applied DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE 351 Scientific name Local name Family Habit Parts use Ailments Treatment mode Daucus carota L. Gajor Apiaceae H Root Heart disease Root juice is taken Dillenia indica L. Chalta Dilleniaceae T Leaf Headache Leaf paste is applied externally Tumor Leaf paste is applied Fruit Diarrhoea Fruit juice is taken internally Leaf Diarrhoea Leaf paste is applied Diospyros malabarica (Desr.) Kostel. Gab Ebenaceae T Leaf Headache Leaf paste is applied externally Diplazium esculentum (Retz.) Sw. Deki shak Athyriaceae H Leaf Pressure reduce Leaf is cooked Eclipta prostata (L.) Hassk. Kalokeshi Asteraceae H Leaf Hair treatment Leaf paste is applied Elaeocarpus robustus Roxb. Jolpai Elaeocarpaceae T Fruit Appetizer Fruit juice is taken Enhydra flactuans Lour. Helencha Asteraceae H Leaf Ulcer Leaf juice is taken Eye treatment Cooked leaf is taken Diabetes Cooked leaf is taken worm Cooked leaf is taken Jaundice Leaf juice is taken Ficus bengalensis L. Bot Moraceae T Fruit Diabetes Cooked fruit is taken Ficus racemosa L. Jogdumur Moraceae T Fruit Diabetes Cooked leaf taken Gloriosa superba L. Ulotchandal Lilliaceae C Root Stomachache Juice is taken Glycosmis pentaphylla (Retz.) A. DC. Motkila Rutaceae S Leaf Diarrhoea juice is taken internally Stem Toothache Stem used as brushing teeth Hibiscus rosa- sinensis L. Joba Malvaceae S Leaf Liver control Leaf soaked in water at night then taken in the next morning Flower Hair fall Flower paste is applied over head Leaf Hair tonic Leaves are used in preparation of hair tonic Dysentery Leaf juice is taken internally twice a day Ipomea aquatica Forssk. Kalmi shak Convolvulaceae H Leaf Eye treatment Leaf is cooked Lagenaria siceraria (Molina.) Standl. Lau Cucurbitaceae C Seed Kidney infection Cooked seed is eaten Lawsonia inermis L. Mehedi Lythraceae S Leaf Hair treatment Leaf paste is applied externally Leucas aspera (willd.) Link Dondokolos Lamiaceae H Leaf Cold treatment Juice is taken 352 MITU et al. Scientific name Local name Family Habit Parts use Ailments Treatment mode Litsea glutinosa (Lour.) Robinson Menda Lauraceae T Bark Dysentery Bark soaked in water and then taken Leaf Diarrhoea Leaf juice is taken Mangifera indica L. Aam Anacardiaceae T Leaf Diarrhoea crushed and then taken in empty stomach once per day Heart disease Young leaf juice is taken Toothache Chewed young leaves Fruit Jaundice Fresh fruit juice is taken Diabetes Fresh fruit juice is taken seed Liver control Leaf juice is taken Melia azedarach L. Ghora neem Meliaceae T Leaf Piles Juice is taken Skin disease Leaf paste is applied Menstrual disorder Juice is taken Mentha arvensis L. Pudina Lamiaceae H Leaf Stomachache Leaf juice is taken Mimosa pudica L. Lajjaboti Mimosaceae H Stem Fever Paste is applied externally Root Pain Root paste is applied externally Leaf piles juice is taken internally Momordica charantia L. Karolla Cucurbitaceae C Fruit worm Fruit juice is taken Diabetes Fruit juice is taken Momordica cochinchinensis (Lour.) Spreng Kakrol Cucurbitaceae C Fruit Diabetes Cooked fruit is taken Moringa oleifera Lamk. Sajna Moringaceae T Fruit Diarrhoea Juice is taken Stomachache Cooked fruit is taken Murraya paniculata (L.) Jack. Kamini Rutaceae S Leaf Toothache Juice is taken Musa acuminata Colla Kola Musaceae H Flower Heart disease Fruit juice is taken internally Piles Flower paste is eaten Fruit Dysentery Young fruit paste is eaten Nigella sativa L. Kalojira Ranunculaceae H Seed Liver control Crushed seed is taken Nyctanthes arbor-tristis L. Shiuliful Verbenaceae S Leaf Fever Juice is taken Ocimum sanctum L. Tulshi Lamiaceae H Leaf Constipation Dried crushed leaf is taken with raw honey Tuberculosis Leaf juice is taken with Ada Ringworm Leaf paste is applied Cough Leaf juice is taken with honey Oryza sativa L. Dhan Poaceae H Seed Diarrhoea Powder is taken Phyllanthus emblica L. Amlaki Euphorbiaceae T Fruit Heart disease Juice is taken Constipation Fruit juice is taken Hair fall juice is applied overhead DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE 353 Scientific name Local name Family Habit Parts use Ailments Treatment mode Piper betle L. Pan Piperaceae C Leaf Cuts& wounds Leaf juice is applied Psidium guajava (L) Peyara Myrtaceae T Fruit Dysentery Young leaves is eaten with little salt Fruit Bad smell Fruit is taken internally Punica granatum L. Dalim Punicaceae S Fruit Diarrhoea Juice is taken Ricinus communis L. Verenda Euphorbiaceae S Seed Vomiting juice is applied Constipation Oil is taken Saccarum officinarum L. Akh Poaceae H Stem Jaundice Juice is taken Scoparia dulcis L. Chinipata Scrophulariaceae H Leaf Dysentery Leaf juice is taken. Senna alata ( L.) Roxb. Dadmardan Caesalpiniaceae S Leaf Skin disease Paste is applied Ring worm Paste is applied Sesamum indicum L. Til Pedaliaceae H Seed Gastric 5/6 till taken with honey internally. Solanum melongena L. Begun Solanaceae S Fruit Fat remove Boiled fruit is eaten Solanum nigrum L. Titbegun Solanaceae H Fruit Allergy Fruit is taken internally. Solaunum tuberosum L. Alu Solanaceae H Tuber Cuts & wounds Paste is applied externally Spondias pinnata (L. f.) Kurz Amra Anacardiaceae T Fruit Heart disease Fruit juice is taken Sterculia villosa Roxb. ex Smith Udal Sterculiaceae T Petiole Impotence Juice is taken Swietenia mahagoni Jacq. Mehogony Meliaceae T Seed Diabetes Juice is taken Syzygium cumini (L.)Skeels Kalojam Myrtaceae T Leaf Dysentery One cup leaf juice is taken with honey in the morning. Fruit Diabetes Juice is taken Syzygium samarangense (Blume) Merr. & Perry Jamrul Myrtaceae T Leaf Stomachache Juice is taken Tagetes erecta L. Gada Asteraceae H Leaf Cuts & wounds Leaf paste is applied Tamarindus indica L. Tetul Caesalpiniaceae T Fruit Heart disease Juice is taken Leaf Jaundice Leaves decocted and the water is taken in every morning. Tectona grandis L. f. Shegun Verbenaceae T Leaf Tooth ache Juice is taken Terminalia arjuna (Roxb. ex DC.) Wight & Arn. Arjun Combretaceae T Bark Heart disease Powdered bark is mixed with amlaki & Bohera then taken 1 spoon twice per day Gastric Bark soaked in water and the water is taken Jaundice Bark soaked in water and the water is taken Heart disease Powdered bark is taken in empty stomach early in the morning 354 MITU et al. Scientific name Local name Family Habit Parts use Ailments Treatment mode Terminalia bellirica (Gaertn.) Roxb. Bohera Combretaceae T Bark Deworming Fruit shell is taken for 7 days seed Skin disorder seed oil is used Bark Diabetes Juice is taken Terminalia chebula Retz. Haritaki Combretaceae T Fruit Blood purifier Fruit soaked in water then water is taken Gastrointestinal disorders Fruit soaked in water then water is taken Diabetes Juice is taken Vitex trifolia L. f. Nishinda Verbenaceae S Leaf Insomnia Leaf is kept under pillow Zingiber officinale Rosc. Ada Zingiberaceae H Rhizome Cough Rhizome juice is taken with tea Ziziphus mauritiana Lamk. Boroi Rhamnaceae T Leaf Wound Leaf is applied Plant species recorded as medicinal plants were classified into trees (38%), herbs (34%), shrubs (18%), and climbers (10%) (Fig. 2). It was observed that local people use trees more than herbs, shrubs, and climbers to cure different kinds of diseases. They took these medicinal plants because of their easy availability in collection, lack of side effects, and abundance in the area. In the present study, different plant parts are used in the treatment of different ailments, which were also documented. Leaves were the leading parts used (Fig. 3). From the present study, it was observed that 79% of treatments were taken internally and 21% were applied externally (Fig. 4). These data indicated that Thakurgaon district still supports rich medicinal plants with diverse applications. Figs 1-4: 1. Different medicinal plants families. 2. Different life forms of species. 3. Different plant parts used for medicines. 4. Application modes of medicinal plants. DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE 355 The reported ailments in the study area were classified into 8 different major disease categories to calculate the Fic values including heart diseases, gastrointestinal disorders, diabetes, skin diseases, respiratory disorders, cuts and wounds, jaundice and kidney diseases, and others. The results could be useful in prioritizing medicinal plants for further scientific validation of plant products as pharmacologically effective remedies with higher Fic values. The product of this factor ranges from 0 to 1. A high value (close to 1.0) indicates that relatively few taxa are used by a large proportion of the informants. A low value indicates that the informants disagree on the taxa to be used in the treatment within a category of illness. Higher Fic values can thus be used to pinpoint particularly interesting species for the search of bioactive compounds. Maximum values of Factor of Informant Consensus (Fic) were obtained in the cases of heart diseases (0.92) followed by respiratory disorders (0.89), cuts and wounds (0.85), skin diseases (0.84), gastrointestinal disorders (0.81), and others (0.58) (Table 2). Table 2. Values of factor of informant consensus in the uses of medicinal plants among the informants. Category No. of use report ( Nur) No. of species (Ntaxa) Factor of informant consensus (Fic) Heart diseases 171 14 0.92 Gastrointestinal disorders 191 38 0.81 Diabetes 56 15 0.75 Skin diseases 148 24 0.84 Respiratory disorders 100 12 0.89 Cuts & wounds 35 6 0.85 Jaundice 66 18 0.74 Others 79 34 0.58 In order to identify medicinally important plant species in the study area, the fidelity level (Fl) was calculated. The medicinal plants that are widely used by the local people for particular ailment have a higher value than those that are less used. The fidelity level (Fl) of the 15 most important plant species ranged from 60.98% to 100% (Table 3). Allium sativum L., Spondias pinnata (L. f.) Kurz, Cynodon dactylon (L.) pers., Lawsonia inermis L., Zingiber officinale Rosc., Saccharum officinarum L., Tagetes erecta L., and Baccaurea ramiflora Lour. species showed 100% fidelity level (Fl). Medicinal plant species obtained maximum Fl value is the valid indication to investigate further for new drugs. Citation frequency was calculated to determine the most popular medicinal plants in study area. A total of 11 medicinal plant species of different citation values are presented in the Table 4. Allium sativum L. is the most cited species in study area. Second cited medicinal species is Phyllanthus emblica L. These two medicinal plant species are very popular in the study area to treat heart disease. Ethnobotanical information is today recognized as the most effective method of identifying new medicinal plants or refocusing on those plants reported in earlier studies for the possible extraction of beneficial bioactive compounds. At the global level, about 80% of local people depend on old-style herbal systems to cure their health disorders. In the past, due to a shortage of doctors and hakims, people used medicinal plant species for various diseases because they were considered to have fewer side effects and could be easily obtainable. Ethnobotanical knowledge is transferred from generation to generation, but without proper documentation, such knowledge may disappear. 356 MITU et al. Table 3. Fidelity level (Fl) values of the frequently reported plants and their major uses. Scientific name Ip Iu Fl (%) Allium sativum L. 51 51 100 Spondias pinnata (L. f.) Kurz 24 24 100 Cynodon dactylon (L.) pers. 20 20 100 Lawsonia inermis L. 15 15 100 Zingiber officinale Rosc. 15 15 100 Saccharum officinarum L. 11 11 100 Tagetes erecta L. 10 10 100 Baccaurea ramiflora Lour. 10 10 100 Tamarindus indica L. 15 16 93.75 Azadirachta indica A. Juss. 15 18 83.33 Terminalia arjuna (Roxb. ex DC.) Wight & Arn. 20 26 76.92 Ocimum sanctum L. 16 23 69.57 Glycosmis pentaphylla (Retz.) 11 16 68.75 Citrus aurantifolia (Crist)Sw. 15 22 68.18 Coccinia grandis (L.) Voigt 12 19 63.16 Phyllanthus emblica L. 25 41 60.98 Table 4. Citation frequency of most cited medicinal plants. Scientific name Local name Citation Citation frequency (Cf) Allium sativum L. Rosun 51 20.4 Phyllanthus emblica L. Amlaki 25 10 Spondias pinnata (L.f.) Kurz Amra 24 9.6 Terminalia arjuna (Roxb. ex DC.) Wight & Arn. Arjun 20 8 Cynodon dactylon (L.) pers. Durba 20 8 Ocimum sanctum L. Tulshi 16 6.4 Citrus aurantifolia (Christm. & Panzer) Swingle Kagogilebu 15 6 Lawsonia inermis L. Mehedi 15 6 Zingiber officinale Rosc. Ada 15 6 Citrus limon L. Lebu 15 6 Tamarindus indica L. Tetul 15 6 Azadirachta indica A. Juss. Neem 15 6 In the present study, carried out in Thakurgaon district, 102 plant species have been used for the treatment of different ailments. The present ethnobotanical survey showed that there is variation in the uses of medicinal plants by the local people. Among the plant parts, leaves were the most commonly utilized plant parts for the preparation of plant-based medicine, which was similar to (Uddin et al., 2017; Sajib and Uddin, 2013). It has been reported that the use of leaves is better for the survival of medicinal plants compared to the whole plant, roots, and stem, which may pose a severe threat to the local flora (Zheng, 2009). DETERMINATION OF LOCAL PEOPLE CONSENSUS IN THE USE 357 From the present study, the maximum number of species under 49 families were identified for the treatment of several diseases. Among them, Araceae and Rutaceae were the most commonly used families for medicinal purposes, followed by Cucurbitaceae, Poaceae, Fabaceae, Liliaceae, Solanaceae, Verbenaceae, Asteraceae, and Caesalpiniaceae in the study area. The most commonly cited mode of preparation is juice, which is made by the local people of the study area. There are many other modes of preparation of medicine, such as paste, decoction, crushing, and cooking. Maximum local people are administered orally or internally. The results are supported by Uddin et al. (2017) and Uddin et al. (2015), who observed the same in different regions of Bangladesh. Highest Fic values were found in cases of heart dieases. The most commonly cited species used to treat this ailment are Allium sativum L., Phyllanthus emblica L., Spondias pinnata (L.f.) Kurz, and Terminalia arjuna (Roxb. ex DC.) Wight & Arn. Another report showed that the bulb of Allium sativum L. is used to reduce chest pain, relieve pressure, and treat ringworm (Uddin et al., 2015). Terminalia aurjuna (Roxb. ex DC.) Wight & Arn. is used for the treatment of heartache, which is also used for the same purpose reported from different areas of Bangladesh (Uddin et al., 2012; Uddin and Hassan, 2014). This plant is also used for stomachache, cough, diabetes, menstruation, gastric pain, and dysentery (Uddin et al., 2006, 2012, 2017; Islam et al., 2014; Uddin et al., 2015a, b). Terminalia arjuna (Roxb. ex DC) Wight & Arn. is a popular Indian medicinal plant, and its bark has been used for over centuries as a cardiotonic. The cardioprotective effects, particularly of the bark of Terminalia arjuna (Roxb. ex DC.) Wight & Arn., are well known. Such species can be used for further phytochemical analysis to find active compounds for heart disease (Uddin et al., 2019). Respiratory disorders scored the second-highest Fic values. Ocimum sanctum L., Zingiber officinale Rosc., and Adhatoda vasica Nees are the most cited species used to treat respiratory disorders. Ocimum sanctum L. showed the highest Fic value among them. Another study from Bangladesh found that the plant species Ocimum sanctum L. was also used for the treatment of cough disorders (Uddin et al., 2017; Sajib and Uddin 2015; 2013). The third highest Fic value was found for cuts and wounds. The most cited plant species was Cynodon dactylon (L.) Pers., used for the treatment of cut injury (similar to Khan et al., 2002, Uddin et al., 2017; Khatun and Rahman, 2018; Yasmin and Rahman, 2017). In the present study, Allium sativum L., Spondias pinnata (L. f.) Kurz, Cynodon dactylon (L.) Pers., Lawsonia inermis L., Zingiber officinale Rosc., Saccharum officinarum L., Tagetes erecta L., and Baccaurea ramiflora Lour. showed 100% fidelity level (Fl). Allium sativum L. obtained the highest Cf value, meaning that such species are very important plant species in the study area. Phyllanthus embelica L., Spondias pinnata (L. f.) Kurz, Terminalia arjuna (Roxb. ex DC.), Cynodon dactylon (L.) Pers., and Ocimum sanctum L. were also the most cited plant species in the study area. Phytopharmacological investigation has led to the discovery of plant-derived drugs that are effective in the treatment of certain diseases and has renewed interest in plant-based medicines. Therefore, these species should be increased and protected in the area. The present analysis has confirmed their popularity among the local people of the Thakurgaon district. The present survey revealed that 103 medicinal plant species were used for 54 ailments with 185 formulas by the local people of the study area. The record of 103 medicinal plant species is an indication of rich ethnobotanical knowledge among the local people of Thakurgaon district. Consensus of people in the use of medicinal plants has resulted in the recording of 102 medicinal plant species under 49 families with 185 formularies to treat 54 ailments. The present results are the indication of rich medicinal plant species with variation of health care knowledge in Thakurgaon. The results of this study will be useful in selecting potential medicinal plants for further study to find new sources of drugs. The top Fic (Factor informant consensus) value was obtained in case of heart diseases (0.92). The most cited species used to treat this ailment are Allium sativum L., Phyllanthus emblica L., Spondias pinnata (L.f.) Kurz, and Terminalia arjuna 358 MITU et al. (Roxb. ex DC.) Wight & Arn. The second highest Fic value was found in respiratory disorders (0.89) followed by cuts and wounds (0.85), skin diseases (0.84) and gastrointestinal disorders (0.81). In case of Fl (Fidelity level) value, Allium sativum L., Spondias pinnata (L.f.) Kurz, Cynodon dactylon (L.) Pers, Lawsonia inermis L., Zingiber officinale Rosc., Saccharum officinarum L., Tagetes erecta L. and Baccaurea ramiflora Lour. showed 100%. According to the Cf (Citation frequency) the most cited species are Allium sativum L., Phyllanthus emblica L., Spondias pinnata (L.f.) Kurz, Terminalia arjuna (Roxb. ex DC.) Wight & Arn., Cynodon dactylon (L.) Pers. and Ocimum sanctum L. From the study of people consensus, it is recommended that species which showed high Fic, Fl, Cf values could be used for further ethno- lead phytochemical analysis to investigate active compounds for the discovery of drugs from medicinal plants. The present study also revealed that the medicinal plants and traditional knowledge of such plants in the Thakurgaon district are in a threatened condition due to different disturbances, and some suggestions have been made for sustainable conservation. The findings of the present study are very preliminary. Further long-term studies are needed. 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