Antioxidant Activity of Natural Samwirin A: Theoretical and Experimental Insights.

Samwirin A (), a natural compound isolated from or , is known to exhibit potent antiosteoporosis activity and promote cell proliferation in rat osteoblast-like UMR 106 cells. Antiosteoporosis activity suggests that the compound must also exhibit antioxidant activity but this has not been studied thus far. In the present study, the antioxidant activity of was examined by experimental and computational studies. It was found that exhibits good hydroperoxyl scavenging activity, particularly in water at physiological pH ( = 1.01 × 10 M s). The single-electron transfer mechanism defines the HOO + SW reaction in water, while the activity in the lipid medium is moderate and it follows the formal hydrogen transfer mechanism. The rate constant of the HOO scavenging reaction in the aqueous solution is about 78 times higher than the reference compound Trolox. The computational results are in line with experimental data underscoring that is a promising radical scavenger in aqueous media at physiological pH.