Medicinal Plants Used by Traditional Healers in Barguna District, Barishal Division, Bangladesh

1. Introduction

Medicinal plants have served as the foundation of traditional healthcare systems for millennia, providing therapeutic solutions for diverse ailments across cultures and geographic regions (Fabricant & Farnsworth, 2001). The World Health Organization estimates that approximately 80% of the global population, particularly in developing countries, relies on traditional plant-based medicines for primary healthcare needs (Ekor, 2014). This dependence is especially noticeable in rural and coastal communities where access to modern healthcare facilities remains limited and traditional knowledge continues to guide therapeutic practices.

Bangladesh, situated in the Indo-Burma biodiversity hotspot, harbors rich floristic diversity with approximately 3,611 angiosperm species, many of which possess significant medicinal properties (M. Rahman, 2018). The country's traditional medicine system, deeply rooted in Ayurvedic and Unani practices combined with indigenous knowledge, has evolved over centuries through empirical observations and intergenerational transmission (Rahmatullah et al., 2009).

Barguna District, located in the southern coastal region of Barishal Division, encompasses an area of approximately 1,939.39 square kilometers with a population exceeding 1,000,000 inhabitants (BBS, 2022). The district experiences a tropical monsoon climate characterized by high humidity, seasonal rainfall exceeding 2,500 mm annually, and temperatures ranging from 12°C to 35°C (Md. M. Rahman et al., 2000). The region's geography is dominated by tidal rivers, mangrove forests, agricultural lands, and homestead vegetation, creating diverse ecological niches that support varied plant species. The coastal ecosystem, influenced by the Bay of Bengal and intersected by numerous rivers including Payra, Bishkhali, and Baleshwar, provides unique habitats for both terrestrial and mangrove-associated medicinal plants (M. M. Islam et al., 2020).

Despite the ecological significance and cultural heritage embedded in traditional medicinal practices, systematic ethnobotanical documentation from Barguna District remains scarce. Previous ethnobotanical studies in Bangladesh have primarily focused on northern, central, and southeastern regions (Hossan et al., 2010; Md. K. Islam et al., 2014; Rahmatullah et al., 2009), leaving coastal districts relatively underexplored. The erosion of traditional knowledge due to modernization, migration of younger generations, and declining interest in traditional healing practices necessitates urgent documentation efforts (Pieroni, 2009). Furthermore, traditional healers, who serve as custodians of this invaluable knowledge, are aging, and their expertise risks being lost without systematic recording and validation.

Ethnobotanical research serves multiple critical functions: preserving indigenous knowledge, identifying potential candidates for pharmaceutical development, promoting biodiversity conservation, and supporting sustainable healthcare solutions for underserved communities (Heinrich et al., 2018). Quantitative ethnobotanical approaches, including Informant Consensus Factor (F_IC) and Citation Frequency (Cf), provide robust methodological frameworks for assessing knowledge consensus and cultural significance of medicinal plants (Tardío & Pardo-de-Santayana, 2008).

Given this context, the present study was designed with the following objectives: (1) to document medicinal plant species utilized by traditional healers in Barguna District; (2) to record traditional knowledge regarding therapeutic applications, plant parts used, and preparation methods; (3) to calculate quantitative ethnobotanical indices to evaluate knowledge consensus and cultural importance; and (4) to contribute to the sustainable utilization of medicinal plant resources in coastal Bangladesh.

2. Materials and Methods

2.1. Study Area

The study was conducted in Barguna District (22°09′N 90°07′E), Barishal Division, southern Bangladesh, covering approximately 1,939.39 km² (BBS, 2022). The district comprises six upazilas: Amtali, Bamna, Barguna Sadar, Betagi, Patharghata, and Taltali. Traditional healers, locally known as "kabiraj" or "boiddo," continue to provide healthcare services, particularly in remote areas where modern medical facilities are limited.

2.2. Selection of Informants and Data Collection

Traditional healers were identified through snowball sampling and consultation with local community leaders (Bernard, 2018). Selection criteria included: (1) age ≥40 years; (2) active practice for at least 10 years; (3) community recognition; and (4) voluntary participation. A total of 27 traditional healers participated in the study. Fieldwork was conducted from April to June 2025, spanning pre-monsoon and early monsoon seasons. Semi-structured interviews were conducted in local Bengali language, lasting 60-120 minutes each. Interview protocols covered: botanical identity, local nomenclature, plant parts utilized, ailments treated, preparation methods, dosage, administration routes, and knowledge sources.

2.3. Ethical Considerations

Prior informed consent was obtained verbally from all participants following principles outlined in the International Society of Ethnobiology Code of Ethics. Healers were informed about the study objectives, their right to withdraw, and confidentiality measures. All data were anonymized, and no personally identifiable information was recorded. Traditional knowledge documentation followed the Nagoya Protocol on Access and Benefit Sharing. This study was conducted in accordance with ethical guidelines for ethnobotanical research (ISE, 2006), and approval was obtained from Research Cell, Department of Agricultural Science, Daffodil International University (Approval ID: RC/AGS/26/012).

2.4. Plant Identification and Authentication

Plant specimens were collected during field visits with the assistance of traditional healers. Voucher specimens were prepared following standard herbarium techniques, assigned collection numbers (BRG001-BRG067), and deposited at Daffodil International University Agricultural Herbarium. Taxonomic identification was performed using morphological characteristics and verified by comparison with authenticated specimens. Taxonomic identification was performed using morphological characteristics and standard references including Flora of Bangladesh, Encyclopedia of Flora and Fauna of Bangladesh (Ahmed et al., 2007; Khan & Ara, 1975), and online databases (POWO, 2025). Scientific nomenclature follows the Angiosperm Phylogeny Group IV classification system (APG, 2016).

2.5. Data Analysis

The Informant Consensus Factor was calculated to assess the degree of agreement among informants regarding the use of plants for specific ailment categories (Heinrich et al., 2018). The formula is:

F_IC = (Nur-Nt)/(Nur-1)

Where, Nur is the number of use citations in each category, and Nt is the number of species reported in each category.

Citation Frequency was calculated to determine the cultural importance of each plant species based on the number of informants who independently cited it (Tardío & Pardo-de-Santayana, 2008). The formula is:

Cf = Fc / N

Where, Fc = Number of informants who mentioned the species, N = Total number of informants

Use-reports (Nur) were defined as individual citations of a plant species for treating a specific ailment, recorded from each informant. When an informant cited the same species for multiple ailments, each ailment was counted as a separate use-report. For preparations combining multiple plant species, each species was counted independently. Ailments were categorized into 12 major disease categories based on biomedical classification and informant descriptions (Table 3).

3. Results

3.1. Demographic Profile of Informants

The demographic characteristics of the 27 traditional healers interviewed in Barguna District are presented in Table 1. The majority of informants were male (70.4%), reflecting the gender patterns typical of publicly practicing traditional healers in rural Bangladesh. All informants were aged 40 years or above, with the age distribution showing 33.3% in the 40-50 years range, 48.2% in the 51-60 years range, and 18.5% above 60 years of age.

Educational levels varied considerably, with 44.4% having no formal education, 33.3% having completed primary education (grades 1-5), 18.5% having secondary education (grades 6-10), and only 3.7% having higher secondary or above. Most healers (22 informants, 81.5%) acquired their knowledge through family inheritance, while 5 informants (18.5%) learned through apprenticeship with experienced practitioners. The years of experience in traditional healing ranged from 8 to 45 years, with a mean of 23.7 years, indicating substantial accumulated practical knowledge.

The primary occupations of informants included traditional healing as a full-time practice (29.6%), farmers who practiced healing part-time (40.7%), and individuals engaged in small businesses, fishing, or religious services who also provided traditional medical care to their communities (29.6%). This occupational diversity reflects the integration of traditional healing knowledge within various community roles rather than its restriction to specialized practitioners.

3.2. Diversity of Medicinal Plants

A total of 67 medicinal plant species belonging to 34 families were documented from traditional healers in Barguna District (Table 2). The recorded species represent a diverse array of taxonomic groups, indicating the rich ethnobotanical knowledge present in the coastal region of Bangladesh.

The family-wise analysis revealed that Fabaceae was the most represented family with 7 species (10.4%), followed by Lamiaceae with 6 species (9%), and Rutaceae, Euphorbiaceae and Apocynaceae each with 4 species (6%). Other well-represented families included Acanthaceae, Cucurbitaceae, and Moraceae each contributing 3 species (4.5%). The remaining 26 families were represented by one or two species each. The predominance of Fabaceae is consistent with patterns observed in other ethnobotanical studies from Bangladesh and neighboring regions (Md. K. Islam et al., 2014; Rahmatullah et al., 2009). These families are known for their diverse secondary metabolites and widespread distribution in tropical and subtropical regions.

The analysis of growth habits showed that trees constituted the largest proportion of medicinal plants with 24 species (35.3%), followed by herbs with 22 species (32.3%), shrubs with 12 species (17.9%), and climbers with 9 species (13.3%). The predominance of tree species reflects their abundance in the study area, ease of cultivation in homestead gardens, and accessibility for harvesting. Various plant parts were utilized in medicinal preparations, with leaves being the most frequently used (32.4%), followed by roots (18.6%), fruits (14.7%), seeds (10.8%), whole plant (8.8%), bark (7.8%), stem (4.9%), and flowers (2.0%). The high utilization of leaves is advantageous from a conservation perspective as leaf harvesting, when done sustainably, causes less damage to plant populations compared to root or bark extraction.

3.3. Ethnomedicinal Uses and Ailment Categories

The documented medicinal plants were used to treat a wide range of ailments, which were categorized into 12 major disease categories: gastrointestinal disorders, respiratory ailments, dermatological conditions, fever and inflammatory conditions, diabetes and metabolic disorders, cardiovascular diseases, reproductive and urinary disorders, musculoskeletal problems, hepatic disorders, ophthalmic conditions, nervous system disorders, and poisoning/antidote applications.

Gastrointestinal disorders represented the most commonly treated ailment category (22.8% of total use-reports), including conditions such as diarrhea, dysentery, stomach pain, indigestion, constipation, and intestinal worms. Respiratory ailments (16.4%) included cough, asthma, bronchitis, and cold. Dermatological conditions (14.2%) encompassed skin infections, wounds, burns, eczema, and fungal infections. Diabetes and metabolic disorders (10.7%) formed another significant category, reflecting the increasing prevalence of lifestyle-related diseases even in rural areas.

3.4. Citation Frequency (Cf)

Citation Frequency values ranged from 0.11 to 0.89. The ten most frequently cited species were:

These high Cf values indicate widespread recognition and use of these species among traditional healers, suggesting their cultural importance and perceived efficacy in treating various ailments.

3.5. Informant Consensus Factor (F_IC)

The F_IC values for different ailment categories ranged from 0.62 to 0.89 (Table 3). Gastrointestinal disorders showed the highest consensus (F_IC = 0.89), followed by respiratory ailments (F_IC = 0.85), and diabetes and metabolic disorders (F_IC = 0.82). These high values indicate strong agreement among informants regarding the efficacy of specific plants for these ailment categories, suggesting well-established traditional knowledge for treating these conditions. Dermatological conditions (F_IC = 0.78), fever and inflammatory conditions (F_IC = 0.76), and cardiovascular diseases (F_IC = 0.74) also demonstrated relatively high consensus values. Lower F_IC values were observed for ophthalmic conditions (F_IC = 0.62) and nervous system disorders (F_IC = 0.65), possibly reflecting either less common occurrence of these ailments in the community or greater diversity in treatment approaches.

3.6. Mode of Preparation and Administration

Various preparation methods were documented, with decoction being the most common (34.6%), followed by paste application (23.4%), juice extraction (18.2%), powder form (12.3%), raw consumption (7.8%), and infusion (3.7%). Decoctions were typically prepared by boiling plant materials in water for 15-30 minutes, while pastes were made by grinding fresh plant parts with water or other ingredients.

The primary routes of administration were oral (61.2%), topical (32.4%), and less commonly nasal or ophthalmic (6.4%). Many preparations involved combinations of multiple plant species or the addition of adjuvants such as honey, sugar, salt, or cow's milk to improve palatability or enhance therapeutic effects.

4. Discussion

The present study documented 67 medicinal plant species from 34 families used by traditional healers in Barguna District, revealing substantial ethnobotanical diversity in coastal Bangladesh. This finding aligns with previous regional studies reporting 50-85 medicinal species from various Bangladeshi districts (Mollik et al., 2010; Rahmatullah, 2019), though coastal areas remain comparatively underexplored. The taxonomic diversity observed reflects the unique ecological convergence of terrestrial, mangrove, and homestead vegetation in this coastal region, contributing distinct halophytic species such as Avicennia officinalis and Sonneratia apetala alongside widespread medicinal plants.

The predominance of Fabaceae (10.3%) and Lamiaceae (8.8%) corresponds with ethnobotanical patterns documented across South Asian tropical ecosystems (Ong & Nordiana, 1999; Umair et al., 2017). These families possess rich phytochemical profiles including alkaloids, flavonoids, and terpenoids, validating their therapeutic applications (Wink, 2015). The prevalence of tree species (35.3%) reflects practical considerations including rapid growth cycles, ease of cultivation, and accessibility for resource-limited communities (Kayani et al., 2014). This pattern suggests sustainable harvesting potential, as herbaceous plants regenerate more rapidly than woody species.

Leaf utilization (32.4%) emerged as the predominant harvesting practice, consistent with conservation-friendly approaches documented in other South Asian studies (Abbasi et al., 2010; Malik et al., 2019). Sustainable leaf harvesting, when practiced judiciously, minimizes plant mortality compared to destructive root or bark extraction (FAO, 2003). However, the substantial use of roots (18.6%) and bark (7.8%) necessitates urgent attention to sustainable harvesting protocols and potential cultivation initiatives for vulnerable species.

The high Informant Consensus Factor values across most ailment categories (0.62-0.89) demonstrate remarkable knowledge homogeneity among traditional healers despite varied educational backgrounds and knowledge acquisition pathways. The highest consensus for gastrointestinal disorders (F_IC = 0.89) reflects the prevalence of waterborne diseases in coastal areas with limited sanitation infrastructure (Hossan et al., 2010). Similarly, elevated consensus for respiratory ailments (F_IC = 0.85) and diabetes (F_IC = 0.82) indicates well-established therapeutic protocols addressing both infectious diseases and emerging non-communicable conditions in rural Bangladesh (Md. K. Islam et al., 2014).

Citation frequency analysis identified Azadirachta indica (Cf = 0.89), Ocimum sanctum (Cf = 0.81), and Curcuma longa (Cf = 0.78) as culturally significant species. These findings corroborate their widespread use in traditional Ayurvedic and Unani medicine systems (Amalraj & Gopi, 2017; Sen et al., 2011). Modern pharmacological investigations have validated numerous bioactivities of these species, including antimicrobial, antidiabetic, and cardioprotective properties (Alzohairy, 2016; Cohen, 2014), supporting their continued therapeutic relevance.

The demographic profile revealing 81.5% family-based knowledge transmission underscores the vulnerability of this indigenous wisdom. With 44.4% of healers lacking formal education and 18.5% aged above 60 years, intergenerational knowledge transfer faces substantial erosion risks (Quinlan & Quinlan, 2007). Modernization, youth migration, and declining interest in traditional practices threaten this irreplaceable cultural heritage (Reyes-Garcia et al., 2003).

The cross-sectional design captured temporal knowledge snapshots without seasonal variation assessment. Gender representation (70.4% male) may have excluded women's specialized knowledge domains, particularly regarding reproductive and pediatric conditions (Voeks, 2007). Future investigations should employ longitudinal approaches, ensure gender-balanced sampling, and integrate phytochemical screening with ethnopharmacological documentation.

The coastal ecology of Barguna District uniquely influences medicinal plant diversity and selection. High salinity, seasonal flooding, and proximity to mangrove ecosystems contribute distinctive halophytic species (Avicennia officinalis, Sonneratia apetala, Excoecaria agallocha) not commonly documented in inland ethnobotanical studies. Coastal environmental stressors may enhance production of secondary metabolites with therapeutic properties, as plants develop chemical defenses against salt stress and tidal inundation. The prevalence of gastrointestinal disorder treatments (F_IC = 0.89) correlates with waterborne disease challenges in coastal areas with limited sanitation infrastructure, while mangrove-associated species address skin conditions exacerbated by humid, salt-laden environments.

4.1. Safety Considerations

This study documents traditional knowledge for academic purposes and does not constitute medical advice. Several documented species (e.g., Datura metel, Abrus precatorius, Gloriosa superba) contain toxic compounds and require careful dosage control. Clinical validation and professional medical guidance are essential before any therapeutic application.

4.2. Study Limitations

This study has several limitations requiring acknowledgment. The cross-sectional design provided a temporal knowledge snapshot without capturing seasonal variations in plant use and availability. Snowball sampling, while appropriate for accessing hard-to-reach traditional healer networks, may introduce selection bias favoring well-connected practitioners. The sample size (n=27) limits statistical power for analyzing fewer common ailments. Gender imbalance (70.4% male) may have excluded women's specialized knowledge domains. Geographic restriction to Barguna District limits generalizability across Bangladesh's diverse ecological zones. Future research should employ longitudinal approaches, gender-balanced sampling, larger sample sizes, and multi-seasonal data collection to address these limitations.

The gender imbalance in our sample (70.4% male) may have limited access to specialized knowledge domains traditionally held by female healers, particularly regarding reproductive health, maternal care, and pediatric treatments. Future research should employ gender-balanced sampling strategies to capture the full spectrum of ethnomedicinal knowledge, as women often serve as primary healthcare providers within households and may possess distinct plant knowledge related to women's health issues (Voeks, 2007).

Data collection during April-June (pre-monsoon and early monsoon) represents a temporal snapshot that may not capture seasonal variations in plant availability, harvesting practices, or treatment preferences. Year-round ethnobotanical surveys would provide more comprehensive documentation of seasonal medicinal plant use patterns in coastal ecosystems.

5. Conclusion

This ethnobotanical study documented 67 medicinal plant species from 34 families utilized by traditional healers in Barguna District, representing significant coastal biodiversity with therapeutic applications. High Informant Consensus Factor values (0.62-0.89) demonstrate robust knowledge homogeneity for treating gastrointestinal, respiratory, and metabolic disorders. The predominance of Azadirachta indica and Ocimum sanctum reflects their cultural significance and validated pharmacological properties. However, family-based knowledge transmission (81.5%) faces erosion risks from modernization and aging practitioners. Urgent conservation strategies, sustainable harvesting protocols, and systematic phytochemical validation are essential to preserve this invaluable ethnomedicinal heritage while supporting rural healthcare and drug discovery initiatives in coastal Bangladesh.

Urgent conservation strategies include: (1) establishing a digital repository for traditional knowledge documentation in collaboration with local healer associations; (2) implementing community-based cultivation programs for high-demand species (Azadirachta indica, Ocimum sanctum, Terminalia chebula); (3) developing sustainable harvesting protocols limiting root and bark extraction to <20% of plant biomass; (4) creating intergenerational knowledge transfer programs linking elder healers with interested youth through apprenticeship initiatives; (5) integrating traditional medicinal plant conservation into Bangladesh's National Biodiversity Strategy and Action Plan; and (6) establishing benefit-sharing mechanisms recognizing healer contributions to pharmaceutical bioprospecting activities.