¹H and ¹³C assignments of five cembrenes from guggul

Abstract

Chemical shift assignments of (1)H and (13)C of five cembrene compounds isolated from the hexane extract of guggul, the resin of Commiphora mukul, are reported. Using (1)H, (13)C, and 2D NMR methods their structures were determined as cembrene (1-isopropyl-4,8,12-trimethyl-cyclotetradeca-2,4,7,11-tetraene), cembrene A (1-isopropenyl-4,8,12-trimethyl-cyclotetradeca-4,8,12-triene), cembrenol (1-isopropyl-4,8,12-trimethyl-cyclotetradeca-3,7,11-trienol), mukulol (1-isopropyl-4,8,12-trimethyl- cyclotetradeca-3,7,11-trienol), and verticillol (4,8,12,15,15-pentamethyl-bicyclo[9.3.1]pentadeca-3,7-dien-12-ol).

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

“…The diterpenes 1-4 were isolated from fractions Bs-1 (1 and 2), Bs-5, and Bs-15, respectively, and identified by comparison of their mass-and NMR-spectroscopic data with literature as the known (1S,3E,7E,11R)-verticilla-3,7,12(18)-triene (1) [6], cembrene A (2) [7] (note that the compound is just named "cembrene" in [7]), serratol (3) [5], and 1S,3E,7R,8R,11E-7,8-epoxycembra-3,11-dien-1-ol (4) [8], respectively. Structures of all isolated diterpenes are given in ▶ Fig.…”

“…Only serratol, a diterpene iso-In the course of our ongoing search for new natural products as leads against protozoal diseases, the dichloromethane extract of Indian frankincense, the oleo-gum-resin obtained from Boswellia serrata, showed in vitro activity against Plasmodium falciparum. 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.…”

The first structure of a bacterial diterpene cyclase: CotB2

“…S6), 1 H NMR and the specific rotation (Vanderah et al, 1978;Schwabe et al, 1988) as R-cembrene A (Fig. 2b) (Bai & Jain, 2008). The CotB2 F107A variant results in a change in the shape and the volume of the active-site pocket.…”

Exploring the catalytic cascade of cembranoid biosynthesis by combination of genetic engineering and molecular simulations

“…S2 and Supplemental Table S4) and (−)-casbene (Supplemental Fig. S3 and Supplemental Table S5 ) using previously reported NMR reference spectra [44] , [45] . Interestingly, NMR based identification of the third substance could only be accomplished after TMS (trimethylsilyl) derivatization and comparison to a TMS-silylated thunbergol standard.…”