(+)/(-)-Phaeocaulin A-D, four pairs of new enantiomeric germacrane-type sesquiterpenes from Curcuma phaeocaulis as natural nitric oxide inhibitors.

ABSTRACT: Germacrane-type sesquiterpenes, with a flexible 10-membered ring unit as the structural and conformational features, play a central role in the biosynthesis and synthesis of other sesquiterpenes. In this report, two pairs of new sesquiterpene alkaloids, (+)/(-)-phaeocaulin A [(+)-1/(-)-1] and B [(+)-2/(-)-2], and two pairs of new sesquiterpenes, (+)/(-)-phaeocaulin C [(+)-3/(-)-3] and D [(+)-4/(-)-4], along with one related known analog (5), were isolated from the rhizomes of Curcuma phaeocaulis. The absolute configurations of (+)-1/(-)-1, (+)-2/(-)-2, (+)-3/(-)-3 and (+)-4/(-)-4 were unambiguously determined by analysis of single-crystal X-ray diffractions and quantum chemical electronic circular dichroism (ECD) method. It is noteworthy that (+)/(-)-phaeocaulin A [(+)-1/(-)-1] and B [(+)-

SUBMITTER: Xia GY 

PROVIDER: S-EPMC5341095 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature