Evaluation of the Anti-osteoporosis and Antioxidant Activities of Phenolic Compounds from Euphorbia maculata

Antioxidant and anti-osteoporosis activities of extracts and chemical constituents from the whole plant of Euphorbia maculata were investigated. The MeOH extract, as well as EtOAc and H2O fractions (10.0 mu g/mL), exhibited potent antioxidant activities. Their oxygen radical absorbance capacity and cupric ion reducing antioxidant capacity values were 27.07 +/- 0.31 to 28.47 +/- 0.36 and 43.86 +/- 0.26 to 46.67 +/- 0.34 fold higher than those of 1.0 mu M Trolox, respectively. The MeOH extract and EtOAc fraction (at 10.0 mu g/mL) also significantly suppressed excessive bone resorption by osteoclasts with tartrate-resistant acid phosphatase (TRAP) activity values of 154.90 +/- 4.25 and 163.95 +/- 9.77%, respectively. Bioassay guided isolation of the EtOAc and H2O fractions afforded 19 known compounds (1-19). Of these, compounds 18, and 13-15 showed good antioxidant activity based on peroxyl radical-scavenging and reducing capacity assays, whereas compounds 1, 4, 7, and 14 showed the most significant inhibitory effect with TRAP activity values ranging from 121.31 +/- 1.41 to 110.00 +/- 3.74% relative to the control.