Content analysis of loliolide in the leaves of Boehmeria nivea (Bn) collected from different region during four months (June, July, August, and September) was conducted by HPLC. The content of loliolide was detected in the leaves of B. nivea from Bns-2, -7, -10, -23, -38, -41, -67, -76, and -90 in June (5.02, 6.35, 6.93, 5.89, 4.31, 4.24, 4.91, 5.12, and 5.46 mg/g, respectively), July (4.32, 6.42, 7.72, 7.97, 4.05, 4.32, 5.65, 6.67, and 5.39 mg/g, respectively), August (3.52, 5.17, 3.90, 4.27, 3.26, 4.72, 3.82, 3.30, and 3.31 mg/g, respectively), and September (7.04, 7.25, 7.43, 7.86, 6.76, 6.38, 7.60, 6.79, and 4.77 mg/g, respectively). Among them, the highest content of loliolide was found in Bn-23 and in September. These results may be useful in determining the optimal harvest time at which phytochemical reaches a maximum level.

Four compounds were isolated from Suaeda japonica by repeated column chromatography. Their structures were identified as 2'-hydroxy-6,7-methylenedioxy-isoflavone (1), loliolide (2), dehydrovomifoliol (3), and uridine (4) by spectral analysis and comparison with the published data. All compounds were isolated for the first time from this plant.