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Abietanes and a Novel 20‐Norabietanoid from Plectranthus cyaneus (Lamiaceae)
Author(s) -
Horvath Tibor,
Linden Anthony,
Yoshizaki Fumihiko,
Eugster Conrad Hans,
Rüedi Peter
Publication year - 2004
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200490210
Subject(s) - chemistry , plectranthus , lamiaceae , fractionation , stereochemistry , botany , organic chemistry , biology
Antioxidative‐activity‐guided fractionation of extracts of the aerial parts of the title plant yielded the two novel abietanoid diterpenoids 11,20‐dihydroxysugiol (=11,12,20‐trihydroxyabieta‐8,11,13‐trien‐7‐one; 3 ) and 1,11‐epoxy‐6,12‐dihydroxy‐20‐norabieta‐1(10),5,8,11,13‐pentaen‐7‐one ( 4 ) in addition to 11‐hydroxysugiol (=12‐ O ‐demethylcryptojaponol=11,12‐dihydroxyabieta‐8,11,13‐trien‐7‐one; 2 ) and the main constituent carnosolon (=6,20‐epoxy‐6,11,12‐trihydroxyabieta‐8,11,13‐trien‐7‐one; 1 ). The structures were established on the basis of spectroscopic, chiroptic, and X‐ray crystallographic evidence.