Antioxidant, Antiproliferative Activities and Chemical Profile of Clinacanthus nutans Leaf Extracts Processed Using Two Different Pre-Extraction Drying Methods

Introduction: Clinacanthus nutans (CN) is a medicinal herb that is traditionally used in Southeast Asia as a treatment for disease and prevention of cancer. Objective: The goal of this study was to investigate the effects of different drying processes on properties of CN. Methods: Air dried (ADDCM) and oven dried (ODDCM) leaves were extracted using the dichloromethane (DCM) Soxhlet extraction method. Antioxidant activity of the extracts was measured using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. The chemical profile of the extracts was determined using gas chromatography-mass spectrometry (GC-MS) analysis, and the antiproliferative activity was tested using MCF-7 (breast cancer) and MCF- 10A (normal breast) cell lines and the Sulphoromide B assay. Results: The percentage of scavenging ability was 12.354 ± 0.003% and 13.151 ± 0.009% for ADDCM and ODDCM, respectively, with r2 values of 0.969 and 0.968. The total content of DPPH scavenging radicals in the ADDCM and ODDCM extracts significantly correlated with their trolox relaxation effects (r2 >0.9, p<0.05). GC-MS identified 89 major phytochemical compounds present in both extracts. The antiproliferative effects of both extracts on MCF-7 cells were dose dependent. No antiproliferative effect was detected for MCF-10A cells. Conclusion: Both extracts exhibited free radical scavenging activity, but the ADDCM extract contained a greater amount of chemical compounds. Additionally, the DCM extracts showed selective antiproliferative activity against MCF-7 but not MCF-10A.