A multipurpose medicinal tree under threat: biology, phytochemistry, propagation and conservation of Dillenia pentagyna Roxb.

Dillenia pentagyna Roxb. is a widely distributed yet increasingly threatened multipurpose tree of tropical Asia with significant ethnomedicinal, nutritional, and ecological importance. Despite its recognized value, a comprehensive synthesis integrating recent advances in phytochemistry, propagation biology, and conservation genetics remains limited. This review compiles current knowledge on taxonomy, distribution, traditional uses, phytochemical composition, pharmacological activities, propagation strategies, and conservation status based on literature available up to March 2025. The species is rich in bioactive compounds, particularly pentacyclic triterpenes, flavonoids, sterols, and phenolics, which underpin its antioxidant, anti-inflammatory, antimicrobial, antidiabetic, cardioprotective, and anticancer properties. However, most studies rely on crude extracts and short term assays, with limited mechanistic, pharmacokinetic, and long-term toxicological validation. Regeneration is constrained by low seed viability, recalcitrant seed behavior, and poor natural recruitment, while vegetative propagation methods show moderate success and emerging micropropagation approaches require further validation. Increasing anthropogenic pressures and habitat degradation have led to regional population declines, highlighting the need for comprehensive genetic, demographic, and conservation assessments. Future priorities include standardized phytochemical profiling, bioassay-guided isolation, rigorous toxicological evaluation, scalable propagation protocols, and population-level genetic studies to support sustainable utilization and long-term conservation.