Ethnopharmacology, phytochemistry, and pharmacology of Sterculia lychnophora Hance (Pangdahai)

The matured, ripen, and dried seeds of Scaphium affine (Mast.) Pierre, known as Pangdahai (PDH) in Chinese and recorded as Sterculia lychnophora Hance (scientific synonym) in the 2015 edition of the Chinese Pharmacopeia, have been widely used in traditional Chinese medicine, Japanese folk medicine, Vietnamese traditional medicine, traditional Thai medicine and Indian traditional medicine. The decoctions of the seeds are used as a remedy for pharyngitis, laryngitis, constipation, cough, menorrhagia, and pain management. This review is aimed at fully collating and presenting a systematic and comprehensive overview of the ethnopharmacological uses of PDH, its phytochemical constituents, pharmacological activities, and toxicological profile. Additionally, this review aims to reveal the therapeutic potentials as well as the important scientific gaps in the research of this traditional medicine that need to be filled so as to provide a comprehensive data for its development, utilization and application. From our extensive review of literatures, the teas (water decoctions) of PDH, which largely contain very polar constituents like polysaccharides, are used in the treatment of constipation, pharyngitis, and pain traditionally and ethno-medicinally and their use have been justified by pharmacological studies carried out on the polysaccharides and aqueous extracts. Additionally, this review has revealed that the organic (ethanolic and methanolic) extracts of PDH possess diverse pharmacological (anti-inflammatory, anti-ulcer, anti-pyretic, anti-microbial, anti-obesity and analgesic) effects, yet have received little attention. Most studies on PDH have been focused on the polysaccharides (large molecular weight metabolites), resulting in a major scientific gap in our knowledge on PDH. Furthermore, this review has also shown that few studies have been done in the areas of quality control, pharmacokinetics, and toxicological studies of PDH.