How illness categories shape medicinal plant selection in the Zagros Mountains of western iran: A biocultural perspective on traditional ecological knowledge and ethno-pharmacological evidence

Abstract

Background: Medicinal plant use in the Zagros Mountains of western Iran is closely linked to local understandings of illness, healing, and the environment. Although Ilam Province has been extensively documented floristically, limited attention has been paid to the cultural concepts and ecological knowledge that guide medicinal plant selection and therapeutic decision-making. This study investigated the relationships among emic illness categories, traditional ecological knowledge (TEK), and medicinal plant use in Ilam Province, Iran.

Methods: Between January 2024 and May 2026, ethnobotanical fieldwork was conducted in rural and peri-urban communities across Ilam Province using semi-structured interviews and focus group discussions with 78 knowledgeable informants, including traditional healers and experienced herbal practitioners. A total of 912 use-reports were documented. Emic illness terms were recorded in Lori and Kurdish and analyzed as the primary framework for interpreting therapeutic practices. Eighteen culturally salient medicinal species were selected for detailed phytochemical and pharmacological assessment. To contextualize field observations, a structured literature review guided by PRISMA 2020 principles was undertaken, resulting in the inclusion of 79 relevant publications.

Results: Medicinal plant use was organized around locally recognized illness categories rather than biomedical disease classifications. Gastrointestinal disorders constituted the most important therapeutic domain, with Soozesh-e Mede (stomach burning) accounting for 37.5% of all recorded use-reports. Strong agreement among informants was observed for several illness categories, particularly those associated with digestive, respiratory, wound-healing, and nervous system conditions. Evaluation of the 18 culturally salient species revealed broad agreement between traditional therapeutic applications and published pharmacological evidence. Patterns of medicinal plant selection were further influenced by floristic distribution, habitat availability, and locally transmitted ecological knowledge related to plant collection, preparation, and use.

Conclusions: The findings show that medicinal plant use in Ilam Province is shaped by culturally defined illness concepts and practical ecological knowledge accumulated through experience. The observed agreement between local therapeutic applications and published pharmacological evidence indicates that many commonly used remedies warrant further investigation. At the same time, the continued erosion of traditional knowledge highlights the need to document and preserve local medical traditions in the Zagros region.

Keywords: Cultural salience; Knowledge transmission; Medicinal flora; Pharmacological validation; Traditional healing.