Enantiomeric composition of (E)- and (Z)-sabinene hydrate and their acetates in ?veOriganum spp.

The enantiomers of (E)- and (Z)-sabinene hydrate and of (E)- and (Z)-sabinene hydrate acetate from extracts of Origanum ramonense Danin, O. dayi Post, O. majorana L., O. vulgare L. ssp. vulgare and O. syriacum L. ssp. syriacum were analysed by GC–MS with chiral and non-chiral capillary columns. The order of elution, the enantiomeric ratios and relative percentages of the four pairs of enantiomers were determined. The (1S)-enantiomers of (E)-sabinene hydrate and (E)-sabinene hydrate acetate were predominant in O. dayi, whereas in the other Origanum spp. the (1R)-enantiomers were predominant. (Z)-sabinene hydrate acetate was not detected in O. syriacum, while the (1R)-enantiomer was present in an optically pure form in O. ramonense, O. majorana and O. vulgare; in O. dayi the enantiomeric purity was 97%. The enantiomeric distributions of (E)- and (Z)-sabinene hydrate and their acetates were determined for the first time in Origanum spp.