Diterpene constituents of leaves from Juniperus brevifolia Ana M.L. Seca a , Artur M.S. Silva b, * , Isabel L. Bazzocchi c , Ignacio A. Jimenez c a Department of Technologic Sciences and Development, University of Azores, Rua Ma ˜e de Deus, 9501-801 Ponta Delgada, Azores, Portugal b Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal c Instituto Universitario de Bio-Orga ˆnica ‘‘Anto ´ nio Gonza ´ lez’’, Universidad de La Laguna, Av. Astrofisico Francisco Sanchez, 2, 38206 La Laguna, Tenerife, Spain Received 31 May 2007; received in revised form 21 July 2007 Available online 12 September 2007 Abstract The dichloromethane extract from leaves of Juniperus brevifolia, through chromatographic fractionations yield six compounds: 3b- hydroxy-abieta-8,11,13-trien-7-one, 18-hydroxy-sandaracopimara-8(14),15-dien-7-one, sandaracopimara-8(14),15-dien-18-yl formate; and the first examples of sandaracopimaranes and abieta-8,11,13-triene diterpenoids with a large aliphatic chain on C-18, abieta- 8,11,13-trien-18-yl hexadecanoate, 7-oxoabieta-8,11,13-trien-18-yl hexadecanoate, sandaracopimara-8(14),15-dien-18-yl hexadecanoate. Moreover fifteen known compounds were also isolated, some of them for the first time identified on Juniperus genus. The compound abieta-8,11,13-trien-18-yl formate is reported for the first time as a natural product. All the structures were established by spectroscopic methods. 2D NMR techniques have allowed the revision of certain previously reported 13 C NMR assignments. Studies on the isolated new compounds showed those possessing a diterpenol ester of a long-chain fatty acid present lipophilicity very distinct from other dit- erpenoid compounds. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Juniperus brevifolia; Cupressaceae; Cedro do mato; Abietanes; Sadaracopimaranes; Fatty acid diterpenol ester 1. Introduction Being isolated in the middle of the Atlantic Ocean and having several natural resources, Azores becomes very interesting as a source of possible new bioactive com- pounds and/or with chemosystematic significance. One of these sources may be the Juniperus brevifolia (Seub.) Antoine (Cupressaceae), locally known as ‘‘cedro-do- mato’’ and well known for its durability and resistance to rotting. This species is the unique conifer tree endemic of Azores and it is a typical component of the primitive lau- risilva forest (Scha ¨fer, 2002). No evidence has been found for the use of J. brevifolia in traditional medicine. However, the wide range of biological activities reported for other species of this genus as well as for their constituents (Seca and Silva, 2006) stimulated our interest to study the chem- ical composition of J. brevifolia. Previous studies on this plant described the components of its essential oil (Adams, 1999; Da Silva et al., 2000) and hexane extract (Seca and Silva, in press). We report herein on the isolation and struc- tural elucidation of six new diterpenes and fifteen known compounds from the dichloromethane extract of J. brevifo- lia leaves and on the correction of some literature 13 C NMR assignments for abieta-8,11,13-trien-18-yl formate. 2. Results and discussion The analysis of the dichloromethane extract of the leaves of J. brevifolia led to the isolation of three new abie- tanes (1–3) and three new pimaranes (4–6); three of them being esters of the long-chain fatty hexadecanoic acid and other ester of formic acid (Fig. 1). Moreover, fifteen known compounds were also identified, by comparison 0031-9422/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.phytochem.2007.07.026 * Corresponding author. Tel.: +351 234 370714; fax: +351 234 370084. E-mail address: artur.silva@ua.pt (A.M.S. Silva). www.elsevier.com/locate/phytochem Available online at www.sciencedirect.com Phytochemistry 69 (2008) 498–505 PHYTOCHEMISTRY