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Crossostephium chinensis (L.) (CC) Makino is a common traditional Chinese medicinal plant used to dehumidify and cure rheumatism and arthralgia. The water and methanol extracts of C. chinensis (CCW and CCM) were evaluated for their antioxidant and antiproliferative activities. The antioxidant activities of CC were evaluated by using ABTS radical scavenging, DPPH radical scavenging, nitric oxide scavenging and superoxide scavenging methods. Iron chelating activity, lipid peroxidation, total polyphenol contents, total flavonoid contents and total flavonol contents were also detected. In all the tested models, both CCW and CCM showed their ability to scavenge the free radicals in a does-dependent manner. CCW had higher antioxidant and antiproliferative activities than CCM. In LC-MS-MS analysis, the chromatograms of CCW with good antioxidant activities were established. Rutin might be an important bioactive compound in CCW. The antiproliferative activities of CCW and CCM were also studied in vitro by using human hepatoma HepG2 cells. CCW exhibited good antiproliferative activity. These results indicated that CCW might be used as a potential source of natural antioxidants and as an anti-tumor agent.

This study evaluated the antioxidant and antiproliferative activities of the crude extract and fractions of Desmodium triflorum (L.) DC. The total phenolic content, 1,1-diphenyl-2- picrylhydrazyl hydrate (DPPH) free radical scavenging activity, trolox equivalent antioxidant capacity (TEAC), reducing power, total flavonoid content of D. triflorum were evaluated for the exploration of its antioxidant activities. Furthermore, its antiproliferative activities were investigated through the MTT method. It was compared with the antioxidant capacities of known antioxidants, including catechin, α-tocopherol, trolox and ascorbic acid. Among all fractions, ethyl acetate fraction was the most active in scavenging DPPH and TEAC radicals, of which 0.4 mg was equivalent to 186.6 ± 2.5 μg and 82.5 ± 2.1 μg of α-tocopherol and trolox respectively. The total phenolic and flavonoid contents of the crude extract were equivalent to 36.60 ± 0.1 mg catechin and 45.6 ± 0.6 mg rutin per gram respectively. In the reducing power assay, 1.25 mg of crude extract was similar to 61.2 ± 0.3 μg of ascorbic acid. For the assessment of the safety and toxicity of D. triflorum, LD₅₀ of the crude extract was greater than 10 g/kg when administered to mice through gastric intubation. The above experimental data indicated that D. triflorum was a potent antioxidant medicinal plant, and such efficacy may be mainly attributed to its polyphenolic compounds.

The in vitro antiproliferative and antioxidant activities of the aqueous, chloroform and methanol extracts of Muntingia calabura leaves were determined in the present study. Assessed using the 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay, the aqueous and methanol extracts of M. calabura inhibited the proliferation of MCF-7, HeLa, HT-29, HL-60 and K-562 cancer cells while the chloroform extract only inhibited the proliferation of MCF-7, HeLa, HL-60 and K-562 cancer cells. Interestingly, all extracts of M. calabura, which failed to inhibit the MDA-MB-231 cells proliferation, did not inhibit the proliferation of 3T3 (normal) cells, indicating its safety. All extracts (20, 100 and 500 μg/ml) were found to possess antioxidant activity when tested using the DPPH radical scavenging and superoxide scavenging assays with the methanol, followed by the aqueous and chloroform, extract exhibiting the highest antioxidant activity in both assays. The total phenolic content for the aqueous, methanol and chloroform extracts were 2970.4 ± 6.6, 1279.9 ± 6.1 and 2978.1 ± 4.3 mg/100 g gallic acid, respectively. In conclusion, the M. calabura leaves possess potential antiproliferative and antioxidant activities that could be attributed to its high content of phenolic compounds, and thus, needs to be further explored.