Sundarbans Mangroves Reveal a Living Pharmacy Backed by Science

In the tidal labyrinth of the Indian Sundarbans, where the Ganges delta meets the Bay of Bengal, the world’s largest mangrove forest has long been treated by local communities as something more than a buffer against cyclones and storm surges. For generations, fishers, crab catchers, and honey collectors have turned to these salt-tolerant trees for medicines, harvesting bark, leaves, and fruits to treat ailments ranging from stomach disorders to infected wounds. A new study published in Plant Biosystems now provides the first integrated, quantitative assessment of that traditional knowledge across all 23 true mangrove species recorded in the Indian Sundarbans, and it arrives at a striking conclusion: the plants that local people trust most are, in many cases, the same ones that modern laboratory science is beginning to vindicate.

The research, led by Mehebub Sarwar Hossain and colleagues at Aliah University in Kolkata, was built on direct engagement with the communities who know these forests best. Rather than relying on earlier floristic records, the team identified species through field observation, herbarium voucher collection, and guided walks with local informants. Data came from semi-structured and group interviews with 106 informants, 55 men and 51 women aged between 40 and 70 years, including experienced fishers, crab catchers, and professional honey collectors. All interviews followed standard ethical protocols with prior informed consent, an important safeguard in research involving traditional knowledge held by vulnerable coastal communities.

To move beyond anecdote, the researchers applied four widely used quantitative ethnobotanical indices: use value (UV), fidelity level (FL), relative frequency of citation (RFC), and the informant consensus factor (ICF). These metrics, developed over decades of ethnobotanical research, allow scientists to measure how culturally salient a species is and how consistently different informants agree on its uses. A high fidelity level, for instance, indicates that a large proportion of the people who cite a plant for a particular ailment use it specifically for that purpose, while a high informant consensus factor signals strong agreement across a community about which plants work for which disease category.

The results paint a vivid picture of a pharmacopoeia rooted in the mud. Bruguiera gymnorhiza emerged as one of the most significant species, with a fidelity level of 85.71, a relative frequency of citation of 0.4, and a use value of 0.45. Aegiceras corniculatum recorded a fidelity level of 81.36 with the highest relative frequency of citation among the priority taxa at 0.56, while Bruguiera parviflora achieved a fidelity level of 81.25 and the highest use value of the group at 0.74. Sonneratia apetala, Xylocarpus granatum, and Heritiera fomes also ranked prominently, each combining high citation rates with substantial use values, indicating that these species occupy central positions in both daily livelihood practices and household medicine.

Perhaps the most compelling finding concerns the degree of consensus around particular disease categories. The informant consensus factor ranged from 0.73 for pregnancy-related disorders to a remarkable 0.96 for gastrointestinal disorders, based on 10 species and 254 individual reports. Conditions grouped as other ailments, including cuts, wounds, infections, and haemorrhage management, achieved an ICF of 0.95 from 10 species and 190 reports. In ethnobotanical terms, values this high are rare and meaningful: they suggest that independent informants, scattered across ten localities in the South 24 Parganas district, converge on the same plants for the same problems, a pattern that ethnopharmacologists interpret as evidence of genuine therapeutic efficacy rather than random cultural association.

That interpretation gains substantial weight from the study’s pharmacological cross-validation. The authors systematically compared their ethnobotanical findings with recently published laboratory literature and confirmed antibacterial, antioxidant, antidiabetic, anti-inflammatory, anti-ulcer, and antidiarrheal activities in all of the priority taxa. Heritiera fomes bark, for example, has been shown in experimental studies to stimulate insulin secretion and lower blood glucose, while Xylocarpus granatum bark extracts have ameliorated hyperglycaemia and oxidative stress in diabetic mouse models. Extracts of Sonneratia apetala fruit and seed have demonstrated antidiarrheal, analgesic, and antimicrobial effects, and Avicennia marina has repeatedly shown antibacterial activity, including against biofilm-forming bacteria and pathogens relevant to aquaculture.

The wound-healing tradition also stands on firmer ground than sceptics might expect. A topical ointment containing leaf extract of Aegialitis rotundifolia, one of the species highlighted in the Sundarbans assessment, has been shown to accelerate excision, incision, and burn wound healing in rats. Antioxidant compounds isolated from Bruguiera parviflora and Kandelia candel, along with antibacterial and cytotoxic activities documented in related mangrove genera, collectively suggest that the salty, oxygen-poor environments in which these trees survive may drive the production of chemically unusual secondary metabolites with real pharmaceutical potential. Mangroves, in other words, are not merely ecological engineers that trap sediment and shield coastlines; they are chemical factories shaped by some of the most stressful growing conditions in the plant kingdom.

Yet the study’s conservation findings add urgency to any bioprospecting ambitions. Using IUCN Red List assessments, the team found that 19 of the 23 true mangrove species are currently listed as Least Concern, but three, Phoenix paludosa, Aegialitis rotundifolia, and Ceriops decandra, are classified as Near Threatened, and Heritiera fomes, one of the most culturally and medicinally valued species in the region, is listed as Endangered. The irony is sharp: the tree whose bark shows documented antidiabetic activity and whose local use value ranks among the highest in the forest is also the one sliding fastest toward extinction. Overharvesting, habitat conversion, salinity changes driven by upstream water diversion, and the intensifying effects of climate change all press on the Sundarbans ecosystem, and the communities that depend on it most closely are often those with the fewest alternatives.

This is where the study’s integrated framework becomes more than an academic exercise. By simultaneously linking quantitative ethnobotanical salience, livelihood dependency, conservation urgency, and pharmacological evidence within a single analytical matrix, the researchers have produced what they describe as an evidence-based priority tool for conservation planning, primary healthcare integration, and pharmaceutical bioprospecting. Species that score highly across all four dimensions, such as Heritiera fomes and Aegiceras corniculatum, become obvious candidates for targeted protection and cultivation programmes, while the strong informant consensus around gastrointestinal and wound-care applications points toward realistic pathways for incorporating validated traditional remedies into formal primary healthcare in remote delta villages where clinics are scarce and travel is difficult.

The broader implications reach well beyond West Bengal. Mangrove forests are among the most carbon-dense ecosystems on Earth and provide storm protection, fisheries nursery habitat, and livelihoods for millions of coastal people, yet they continue to disappear at alarming rates worldwide. Studies like this one add a dimension that purely ecological valuations often miss: the cultural and medicinal capital embedded in these forests, and the risk that losing the trees also means losing centuries of accumulated human knowledge about how to use them. With the World Health Organization increasingly engaging with traditional medicine at a global policy level, and with drug discovery programmes actively screening coastal flora for novel compounds, the Sundarbans findings arrive at a moment when the case for protecting mangroves has never been richer in evidence. The people of the delta have known for generations that these trees heal. Science, species by species and compound by compound, is finally catching up, and the race now is to ensure that both the forest and the knowledge survive long enough for that convergence to matter.

Subject of Research: Ethnobotanical and pharmacological assessment of true mangrove species in the Indian Sundarbans

Article Title: Ethnomedicinal knowledge, quantitative ethnobotanical indices, socioeconomic benefits, and conservation priorities of true mangroves in the Indian Sundarbans, West Bengal: a community-based integrated assessment

Article References: Hossain, M. S., Bera, A., Ulla, S. S., Alam, S. R., Laila, S., Sk, A., Chakraborty, M., Parveen, S. I., Molla, M. M. R., & Imam Saadi, S. M. A. (2026). Ethnomedicinal knowledge, quantitative ethnobotanical indices, socioeconomic benefits, and conservation priorities of true mangroves in the Indian Sundarbans, West Bengal: a community-based integrated assessment. Plant Biosystems, 160(5), Article 270. https://doi.org/10.1007/s44473-026-00286-3

Image Credits: AI Generated

DOI: 10.1007/s44473-026-00286-3

Keywords: Sundarbans, mangroves, ethnobotany, ethnomedicine, pharmacological validation, conservation, IUCN Red List, Heritiera fomes, traditional knowledge, bioprospecting, West Bengal, informant consensus factor