Beyond bioactivity: A critical review of underexplored factors affecting the quality of Sungkai (Peronema canescens Jack) leaves

Abstract

Sungkai (Peronema canescens Jack) is a medicinal plant widely used in traditional Indonesian medicine and has attracted increasing scientific interest due to its diverse pharmacological activities, including antioxidant, immunomodulatory, antibacterial, and anticancer effects. These activities are mainly attributed to bioactive compounds, including flavonoids, alkaloids, phenolics, saponins, and terpenoids. This review critically evaluates existing studies on Sungkai leaves, with a particular focus on identifying gaps in processing methods and raw material variability. The review was conducted following PRISMA guidelines using Scopus and PubMed databases. The analysis shows that most studies rely on conventional extraction techniques, particularly ethanol-based maceration, and primarily emphasize biological activity screening rather than process optimization. Crucially, key factors influencing raw material quality remain largely overlooked. Drying, an essential step in herbal preparation, is often poorly reported, with limited information on temperature, duration, and drying method. In addition, the roles of geographic origin and leaf maturity in determining phytochemical composition and bioactivity are rarely investigated. This lack of standardization contributes to variability in findings and limits reproducibility across studies. Therefore, future research should adopt a more systematic approach by evaluating drying parameters, including temperature, relative humidity, and air velocity, as well as the influence of geographic origin and leaf maturity. Such efforts are essential to improve consistency, ensure quality control, and support the development of Sungkai-based medicinal and functional products.