13.

Two New and Four Known Triterpenoids from Boswellia sacra Fluckiger

Liaqat Ali, Javid Hussain, Ahmed Al-Rawahi and Ahmed Al-Harrasi

UoN Chair of Oman’s Medicinal Plants and Marine Natural Products, University of Nizwa, Nizwa-616, Oman; Department of Biological Sciences and Chemistry, College of Arts and Sciences, University of Nizwa, P. O. Box 616, Nizwa, Oman

Abstract: Two new O-acetyl derivatives of pentacyclic triterpenic acids, 3α-acetoxyurs -5:12-dien-24-oic acid ( 1 ) and 3α-acetoxylup -12:20 (29)-dien-24-oic acid ( 2 ) were isolated from Omani frankincense of Boswellia sacra Flueckiger along with four known compounds: commic acid-D (3), 9,11-dehydro-β-boswellic acid (4), 3β-Hydroxy-11-oxours-12-ene (5), and 11β-Hydroxy-3-oxours-12-ene (6) . The structures of new compounds 1 and 2 were elucidated on the basis of detailed mass and NMR spectroscopic analysis using 1H NMR, 13C NMR, HMQC, HMBC, COSY, and HREIMS techniques. The relative configurations of 1 and 2 were assigned by comparative analysis of the NMR spectral data with the related known triterpenoids together with NOESY experiments. The structures of the known compounds 3-6 were confirmed by the comparative analysis of the reported mass and NMR data.

Keywords: Omani Frankincense; HPLC; Pentacyclic Triterpenoids; Boswellia sacra. © 2014 ACG Publications. All rights reserved.