693 0009-3130/15/5104-0693  2015 Springer Science+Business Media New York Chemistry of Natural Compounds, Vol. 51, No. 4, July, 2015 A NEW DITERPENE ISOLATED FROM THE RESIN OF Hymenaea courbaril P. N. Bandeira, 1* H. S. Santos, 1 M. R. J. R. Albuquerque, 1 T. L. G. Lemos, 2 and R. Braz-Filho 3 Hymenaea courbaril, a traditional medicinal plant from Brazil, produces a resin rich in terpenoid compounds, mainly diterpenes. The resin and others parts are used in folk medicine for treatment of several pathologies. Fractionation of the resin by silica gel open column chromatography afforded two compounds: (5S,9S,10R)-ent-labd-8(17)-en-15 ethyl acetate (1) and copalic acid [5-(2-methylene-5,5,8a- trimethyl-(1R,4aR,8aR)-decahydronaphthalen-1-yl)-3-methylpent-2E-enoic acid] (2). This is the first report of compound 1. Keywords: Hymenaea courbaril, resin, diterpene, labdane, NMR data. The genus Hymenaea consists of 14 species, 13 of which are distributed through Central America, South America, and the West Indies, and one that occurs in East Africa [1]. In Brazil, Hymenaea courbaril is widely distributed from the Amazon rainforest to seasonal forests in the Southeast [2–4]. Species of the genus Hymenaea are sources of several biologically active secondary metabolites [5–8]. Kaurane and labdane diterpenes are present in several species [9–11]. The absence of phytochemical studies on the resin of H. courbaril motivated us to carry out the present study. Herein, we present data on the isolation and identification of two compounds, a new diterpene (1) and copalic acid (2). The resin from H. courbaril was collected in September 2009 in Ubajara, Ceara State, Brazil. The resin (587 g) was subjected to chromatographic separation on silica gel using hexane, EtOAc, and MeOH, in order of increasing polarity. The resulting fractions were successively chromatographed on silica and Sephadex LH-20 columns. The fractions were combined based on analysis by thin-layer chromatography (TLC). Compounds 1 and 2 were thus obtained, and their structures were elucidated by spectroscopic and spectrometric data and comparison with literature data. Compound 1 was isolated as a white resin. Its IR spectrum exhibited an absorption (1735 cm –1 ) characteristic of an ester carbonyl and absorption bands (1643 and 1155 cm –1 ) compatible with the stretches of a carbon–carbon double bond and a carbon–oxygen bond, respectively. The HR-ESI-MS spectrum, in the positive mode, revealed a peak at m/z 335.2226 [M + H] + , indicating the molecular formula C 22 H 38 O 2 , corresponding to four degrees of unsaturation and implying the presence of four unsaturated bonds and/or ring structures. The 1 H NMR spectrum (Table 1) showed signals at  4.80 (br.s) and 4.47 (br.s), consistent with olefinic protons. A set of signals in  0.94–1.25 was characteristic of methyl groups and two doublets at  2.27 (dd) and 2.10 (dd) was interpreted as a methylene group bound to a carbon containing an oxygen. The 13 C NMR data (DEPT 135) showed the presence of 22 carbon signals, represented by five methyls, ten methylenes, three methines, and four quaternary carbon atoms. The 13 C NMR revealed the presence of a carbonyl functionality at  173.6 (C-15) and a disubstituted double bond at  106.4 (C-17) and 149.0 (C-8) (Table 1). 1) Center for Science and Technology, State University Valley Acarau, Sobral-Ce 62040-370, Brazil, e-mail: bandeirapn@yahoo.com.br; 2) Department of Organic and Inorganic Chemistry, Federal University of Ceara, 60451-970 Fortaleza-Ce, Brazil; 3) Laboratory of Chemical Sciences, CCT, State University of North Fluminense Darcy Ribeiro, Campos RJ 28013-602, Brazil. Published in Khimiya Prirodnykh Soedinenii, No. 4, July–August, 2015, pp. 598–600. Original article submitted July 12, 2013. DOI 10.1007/s10600-015-1386-5