Structure and conformation of incensole oxide

Terpenoids from the Oleo-Gum-Resin of Boswellia serrata and Their Antiplasmodial Effects In Vitro

“…For compound 7, obtained from fraction Bs-17, the APCI-MS gave a signal for [M + H] + at m/z 323.2565 indicating the molecular formula C 20 H 34 O 3 . 1 H-NMR and 13 C-NMR spectra were identical with literature values for isoincensol oxide [10,11]. The connectivity determined by 2D NMR experiments was in agreement as well, although the position of some carbons had to be revised due to their COSY and HMBC correlations (see ▶ Table 1).…”

“…In 1977 Kato et al [12] proposed the stereochemistry of the natural product as rel (1R,7S,8R,11R,12S) by comparison to the synthesized molecule. Because the absolute stereochemistry of C-1S has been evidenced by X-ray analysis for the similar compound 5 [13] and by CD spectroscopy for compound 3 [5], we prefer the enantiomeric assignment rel (1S,7R,8S,11S,12R). The interpretation of our NOESY spectra with the help of a molecular model was not in agreement with the published stereostructure.…”

“…Bioactivity-guided fractionation led to the isolation of eight diterpenes: (1S,3E,7E,11R)-verticilla-3,7,12 (18)-triene (1), cembrene A (2), serratol (3), 1S,3E,7R,8R,11E-7,8-epoxy-cembra-3,11-dien-1-ol (4), incensole oxide (5), rel (1S,3R,7E,11S,12R)-1,12-epoxy-4-methylenecembr-7-ene-3, 11-diol (6), isoincensole oxide (7), and isodecaryiol (8). Furthermore, 10 triterpenes, namely, oleanolic acid (9), 11-ketoβ-boswellic acid (10), 3-epi-neoilexonol (11), uvaol (12), βboswellic aldehyde (13), 5α-tirucalla-8,24-dien-3α-ol (14), isoflindissone lactone (15), isoflindissol lactone (16), rel (8R,9S,20R)-tirucall-24-ene-3β,20-diol (17), and rel (3α,8R, 9S,20R,24S)-20,24-epoxytirucalla-3,25-diol (18) as well as the sesquiterpene β-bourbonene (19), the monoterpene carvacrol (20) and the phenyl propanoids methyleugenol (21), and p-methoxycinnamaldehyde (22) were isolated. All compounds were identified by mass spectrometry and nuclear magnetic resonance spectroscopic measurements.…”

Bioactive Cembranoids from the Soft Coral Sinularia crassa

“…Cembranoids with a 1,12-oxa-bridged THF ring, such as compounds 1 – 3 , are rare in natural products. Incensole [ 22 ], incensole oxide [ 23 ], and incensole acetate [ 24 ] are the cembranoids of this class which were isolated from frankincense, the resin produced by the plant Boswellia carteri. It is also noteworthy that the formyloxyl cembranoid, such as 3 , and the 1,11-oxa-bridged tetrahydropyranocembranoids, such as 4 and 5 , were discovered for the first time.…”

Protein Targets of Frankincense: A Reverse Docking Analysis of Terpenoids from Boswellia Oleo-Gum Resins

“…The boscartins have been isolated from the oleo-gum resin of B. carteri [ 13 ]. Incensole oxide has been isolated from B. carteri and the X-ray crystal structure determined [ 13 , 14 ]; both incensole oxide and incensole oxide acetate have been detected in small concentrations in the essential oil from the resin of B. papyrifera [ 15 ]. Isoincensole oxide [ 16 , 17 ] and isoincensolol [ 17 ] were isolated from B. carteri resin.…”