Terpenic and phenolic glycosides from leaves of Breynia officinalis HEMSL

From the leaves of Breynia officinalis, collected on Okinawa Island, six terpenic glucosides and six phenolic glycosides were isolated. Two of the terpenic glucosides were found to be known, and they were identified as turpinionoside B and betulalbuside A. The structures of the remaining terpenic glucosides were elucidated to be megastigmane glucosides, named breyniaionosides A-D, using spectroscopic analyses. The absolute structure of breyniaionoside D was determined using the modifed Mosher's method. The absolute structure of the known compound betulalbuside A was determined for the first time in this study. Six phenolic glycosides were found to be arbutin and its derivatives. Two known compounds were found to be robustaside A and eximine. New compounds were named isorobustaside A, and breyniosides A and B, and their structures were elucidated from spectroscopic evidence.