Longipinene derivatives from Stevia porphyrea Eugenio SaÂnchez-Arreola a , Carlos M. Cerda-GarcõÂa-Rojas a , Luisa U. RomaÂn b , Juan D. HernaÂndez b , Pedro Joseph-Nathan a, * a Departamento de QuõÂmica, Centro de Investigacio Ân y de Estudios Avanzados, Instituto Polite Âcnico Nacional, Apartado 14-740, Mexico, DF 07000, Mexico b Instituto de Investigaciones QuõÂmico-Biolo Âgicas, Universidad Michoacana de San Nicola Âs de Hidalgo, Apartado 137, Morelia, Michoacan 58000, Mexico Received 19 November 1998; received in revised form 24 February 1999 Abstract The new longipinene derivatives 8a-angeloyloxy-7b-hydroxy-9a-isovaleroyloxylongipin-2-en-1-one, 7b-angeloyloxy-8a,9a- dihydroxylongipin-2-en-1-one and 7b-angeloyloxy-9a-hydroxy-8a-isovaleroyloxylongipin-2-en-1-one together with ®ve known longipinenes, friedelin and stigmasterol were isolated from the roots of Stevia porphyrea. The positional assignment of individual ester residues was done by HMBC experiments. # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Stevia porphyrea; Compositae; Sesquiterpenes; Longipinene derivatives 1. Introduction Chemical studies revealed that sesquiterpene lac- tones, diterpenes and longipinene derivatives are the main secondary metabolites of the genus Stevia, as recently reviewed (Herna ndez, Catala n & Joseph- Nathan, 1998). In continuing our studies on the chemi- cal constituents of Stevia species (Guerra-RamõÂrez, Cerda-GarcõÂa-Rojas, Puentes & Joseph-Nathan, 1998; Herna ndez, Catala n, Cerda-GarcõÂa-Rojas & Joseph- Nathan, 1995, 1996), we describe herein the isolation and structure elucidation of three new longipinene de- rivatives (1±3) from the hexane extracts of the roots of S. porphyrea McVaugh. These components were obtained together with stigmasterol (Wright et al., 1978), friedelin (Patra & Chaudhuri, 1987) and the known longipinenes, 4 (Bohlmann, Suwita, Natu, Czerson & Suwita, 1977b), 5 (Sa nchez-Arreola, Cerda- GarcõÂa-Rojas, Joseph-Nathan, RomaÂn & HernaÂndez, 1995), 6 (Bohlmann et al., 1977a), 7 (Amaro, AdriaÂn, Cerda & Joseph-Nathan, 1988) and 8 (RomaÂn et al., 1981). 2. Results and discussion Diester 1 was isolated as an oil by CC. Its IR spec- trum showed typical absorptions for a hydroxyl group (3540 cm À1 ), a saturated ester group (1732 cm À1 ), an a,b-unsaturated ester group (1719 and 1648 cm À1 ) and an a,b-unsaturated ketone (1674 and 1618 cm À1 ). The mass spectrum of 1 showed a molecular ion, [M] + at m/z 432, in agreement with the molecular formula C 25 H 36 O 6 . The 1 H NMR spectrum showed a vinylic proton at d 6.14 and vinylic methyl groups at d 2.02 and 1.84 characteristic of an angelate ester. The pre- sence of an isovalerate ester was indicated by a multi- plet at d 2.24, a multiplet at d 2.09 and a doublet for two methyl groups at d 0.96 (J = 6.5 Hz). The signals for the protons geminal to oxygen atoms appeared as a doublet at d 5.50 (J = 3.2 Hz, H-9), a double doub- let at d 5.27 (J = 3.2 and 11.2 Hz, H-8) and a double doublet at 3.91 (J = 4.2 and 11.2 Hz, H-7), which upon addition of D 2 O collapsed to a doublet J = 11.2 Phytochemistry 52 (1999) 473±477 0031-9422/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0031-9422(99)00217-4 * Corresponding author. Fax: +52-57-47-7113. E-mail address: pjoseph@nathan.chem.cinvestav.mx (P. Joseph- Nathan)