Phenols and γ-Lactams from the Aerial Part of Pseudolysimachion linariifolium subsp. dilatatum.

Linariifolioside II (1) and (2S)-2-hydroxy-5-oxoproline methyl ester (2), two new compounds along with 13 known compounds were obtained from the aerial part of Pseudolysimachion linariifolium Holub subsp. dilatatum (Nakai & Kitag.) D.Y. Hong. Their chemical structures were revealed mainly through NMR and MS data. The absolute configuration of 2 was deduced by comparing its experimental CD with the calculated ECD spectra. At a concentration of 1 mm, total antioxidant capacities of compounds 1-15 were measured using a rapid ABTS method in vitro. Compounds 1, 3-5, and 11-14 exhibited approximately equal antioxidant capacity to that of vitamin C (Vc).