Hidden Medicines in Herbarium Collections: Medicinal Plant Diversity and Ethnopharmacological Knowledge from GSUH, Nigeria

Abstract

Herbarium collections represent an important but frequently underutilized source of information for documenting medicinal plant diversity and preserving ethnomedicinal knowledge. We assessed the medicinal plant diversity represented in herbarium records from the Gombe State University Herbarium (GSUH), Nigeria, and evaluated patterns in taxonomic composition, therapeutic applications, and plant parts reported for medicinal use. We also tested the hypothesis that the plant parts used medicinally are not randomly distributed across therapeutic or ailment categories, but that particular plant parts are disproportionately associated with specific therapeutic applications. The resulting dataset comprised 1,576 specimen records, including 768 recorded as medicinal plant species across 94 families and 1,426 medicinal-use records (Table S1). Fabaceae was the most species-rich family (15.8%), followed by Asteraceae (9.3%), Malvaceae (4.8%), Lamiaceae (4.4%), Rubiaceae (3.2%), and Apocynaceae (3.2%). The most frequently represented therapeutic themes were infections and sexually transmitted diseases (50.7%), gastrointestinal disorders (41.9%), pain, inflammation, and rheumatism (41.9%), fever and malaria (40.2%), and skin diseases and wounds (40.0%). Individual species had a mean of 2.98 therapeutic themes, with medicinal breadth ranging from 1 to 7 themes. A species-aware permutation test confirmed that the observed plant-part and therapeutic-theme association was significantly stronger than expected under random association (9,999 permutations, P < 0.0001). These findings demonstrate the value of herbarium collections as taxonomically anchored resources for recovering information on medicinal plant diversity. Integrating herbarium records with published ethnomedicinal knowledge provides a reproducible framework for linking plant diversity, taxonomy and traditional medicinal applications and highlights the potential of underutilised African herbaria for ethnopharmacological research.