Phenolics-Enhancing Piper sarmentosum (Roxburgh) Extracts Pre-Treated with Supercritical Carbon Dioxide and its Correlation with Cytotoxicity and α-Glucosidase Inhibitory Activities

Piper sarmentosum was found to have various phytochemicals such as polyphenols and flavonoids but also contains asarone isomers, which were reported as carcinogenic in several preclinical studies. Therefore, reducing asarone isomers from this functional food is important while retaining its functional properties. This study compares the total phenolics, total flavonoids, vitexin and naringenin contents, cytotoxicity, and anti-hyperglycaemic activity between various solvent extracts using a two-step extraction with SC-CO2 pre-treatment and a single-step conventional solvent extraction without SC-CO2 pre-treatment. The findings showed that phenolic content was significantly enhanced in ethanol, 50% ethanol, and water extracts pre-treated with SC-CO2, significantly correlated with α-glucosidase inhibitory activity. SC-CO2 pre-treated extracts enhanced the viability of two normal fibroblasts NIH/3T3 and CCD-18Co cell lines. It is concluded that SC-CO2 extraction offers a rapid pre-treatment step to produce safer extracts with better quality and efficacy.