Changes in phenolic content and biological activities of Plectranthus amboinicus (Lamiaceae) leaf extracts resulting from pectinase and cellulase treatments

Abstract

Enzyme-assisted extraction has emerged as an eco-friendly and effective method for enhancing the yield of phenolic compounds from plant materials. This study examined the effectiveness of pectinase and cellulase in extracting phenolic compounds from Plectranthus amboinicus leaves (PAL) and evaluated the biological activities of the resulting extracts. The effect of key extraction factors, including enzyme concentration, extraction time, and solid-to-liquid ratio, on the total phenolic content (TPC) was examined. Under optimal conditions, cellulase treatment increased the TPC by 24%, 39%, and 56% compared to pectinase, 30% ethanol, and water extractions, respectively. Phenolic-rich extracts obtained through enzymatic methods exhibited significantly superior bioactivities, including antidiabetic, anti-inflammatory, and antioxidant properties, compared to conventional methods. Among the tested extracts, the cellulase-treated extract demonstrated the highest 2-diphenyl-1-picrylhydrazyl radical scavenging activity (IC50 value of 57.81 μg/ml), albumin denaturation inhibition (IC50 value of 136.36 μg/ml), and α-amylase inhibition (IC50 value of 135.25 μg/ml). Hierarchical clustering and principal component analyses further revealed strong correlations between the biological activities of PAL extracts and the extraction method employed. These findings highlight cellulase-assisted extraction as a promising eco-friendly and efficient alternative to solvent-based techniques for recovering phenolic compounds with enhanced bioactivities, offering potential applications in functional foods, nutraceuticals, and herbal medicine. © The Author(s) 2025. Published by Oxford University Press on behalf of Institute of Food Science and Technology.

Keywords Antidiabetic, Antioxidant, Enzyme, Extraction, Plectranthus Amboinicus