Ethnobotany-guided exploration of plant-derived photosensitizer candidates for photodynamic therapy

The integration of photosensitization with Indigenous knowledge offers a promising framework for exploring more sustainable therapeutic approaches. This review explores how the ethnobotanical knowledge of the Dayak communities of Borneo (Indonesia), particularly the traditional use of brightly coloured medicinal plants for dermatological treatments, may provide a biologically informed framework for prioritizing plant-derived photosensitizer candidates. The biosynthetic pathways and photochemical potential of key metabolites associated with selected Dayak medicinal taxa (Curcuma longa, Etlingera elatior, Calophyllum inophyllum, Ageratum conyzoides, and other selected additional representatives of the Zingiberaceae family) are analyzed to assess their potential as light-activated ROS generators. In addition, the review discusses strategies to optimize the production and delivery of promising plant-derived candidates through metabolic engineering, including heterologous expression in microbial chassis such as Escherichia coli and Saccharomyces cerevisiae. A comparative evaluation based on green chemistry principles suggests that plant-derived candidates may offer potential advantages related to renewable sourcing, although their biodegradability, safety, and overall environmental performance remain insufficiently characterised. Finally, the review outlines an ethical framework for integrating Dayak traditional knowledge into scientific research while promoting equitable benefit-sharing and biocultural protection. Overall, this work proposes a transdisciplinary perspective for photomedicine in which ethnobotanical knowledge, photochemistry, and sustainable biotechnology converge to guide the identification, evaluation, and development of plant-derived photosensitizer candidates.