Detergent Plants of Northern Thailand: Potential Sources of Natural Saponins

The natural forests of Northern Thailand are the mother source of many utilisable natural products because of their diverse flora and fauna. Northern Thai people have learned to utilise plants, in particular those of plants with cleansing properties, since the beginning of time. Several local species of detergent plants in Thailand are traditionally used by the locals and indigenous people. However, these plants may become extinct because their habitats have been replaced by industrial agriculture, and their uses have been replaced by chemically synthesised detergents. Researchers need to study and communicate the biology, phytochemistry, and the importance of these plants to conserve natural biodiversity of Northern Thailand. Of many utilisable detergent phytochemicals, natural saponins are known as bio-based surfactant and foaming agents. Their physiochemical and biological properties feature structural diversity, which leads to many industrial applications. In this review, we explained the term “detergent” from the physiological mechanism perspective and the detergent effects of saponins. We also compiled a list of Thai local plants with cleansing properties focusing on the saponin-containing plants. Future studies should investigate information relative to plant environment, ethnobotanical data, and the bioactive compound content of these plants. The knowledge acquired from this study will promote the maintenance of the local biodiversity and the conservation of the detergent plant species found in Thailand.