Botanical Substitution in Traditional 'Rang Chuet' Preparations: Distinguishing the Potential Xenobiotic Modulation of Thunbergia laurifolia Lindl. from the Hepatotoxic Risks of Crotalaria spectabilis Roth.

Rang Chuet is a traditional Thai medicinal plant widely used for detoxification, although the name is applied to several botanically distinct species. This study investigated the ethnopharmacological basis and potential molecular mechanisms underlying this practice by integrating practitioner knowledge, botanical authentication, phytochemical profiling, and molecular docking. Structured interviews were conducted with 30 experienced traditional medicine practitioners from five regions of Thailand to document the therapeutic use and preparation of Rang Chuet. Botanical identification confirmed three species marketed under this name: Crotalaria spectabilis Roth, Curcuma rangjued Saensouk & Boonma, and Thunbergia laurifolia Lindl. Most practitioners used Rang Chuet primarily for detoxification, with C. spectabilis and T. laurifolia being the predominant species. LC-MS/MS analysis identified fifteen phytochemicals, including compounds common to both species, such as apigenin, quercetin, and caffeic acid, together with species-specific constituents including rosmarinic acid and α-spinasterol in T. laurifolia. Molecular docking suggested that selected phytochemicals may interact with xenobiotic-sensing receptors, with α-spinasterol showing favorable binding to the Pregnane X Receptor (PXR) and apigenin and catechin to the Aryl Hydrocarbon Receptor (AhR). However, C. spectabilis is a recognised source of hepatotoxic pyrrolizidine alkaloids, and because molecular docking cannot distinguish agonist from antagonist activity or establish functional receptor activation, these predicted interactions should not be interpreted as evidence of detoxification efficacy or safety. These findings provide a scientific framework linking traditional knowledge, botanical diversity, phytochemical composition, and potential receptor-mediated mechanisms, and highlight the public health risk of botanical substitution under the shared vernacular name "Rang Chuet." These findings are hypothesis-generating and warrant future functional and toxicological validation, particularly regarding C. spectabilis.