The objective of the study is to analyse the phytochemical content by quantitative and qualitative methods and to investigate the antioxidant properties on Clinacanthus nutans leaves and stems from different areas: Yik Poh Ling (YPL) un-shaded sample (exposed to direct sunlight) and You Dun Chao (YDC) un-shaded and shaded (with black shade netting) samples. Extracts were prepared by dissolving fine powder of C. nutans in 1:10 solvent using ultrasonic extraction for an hour. Preliminary screening and quantitative estimation of phytochemical (alkaloids, flavonoids, cardiac glycosides, saponins, steroids, terpenoids, phenols and tannins) analysis were conducted. Then, determination of antioxidant properties (total phenolic content, TPC, ferric reducing/ antioxidant power, FRAP and radical-scavenging activities, DPPH) were conducted. All the samples contained alkaloids, flavonoids, cardiac glycosides, saponins, steroids, terpenoids, phenols and tannins. Un-shaded leaves of C. nutans from YDC exhibited significantly higher result in antioxidant properties (966.00mg GAE/g of dried sample in TPC, 20.44mg TE/g of dried sample in FRAP and 11.14mg TE/g of dried sample in DPPH) than the other samples (p < 0.05). As a conclusion, C. nutans has a good potential to be an alternative antioxidant source.