~ Pergamon PIh S0031-9422(97)00228-8 Phytochemisto', Vol. 46, No 1, pp. 161 164 ~2~ 1997 Elsevier Scien All rights reserved. Printed in Great I 0031~422/97 S17.00 DITERPENES AND SESQUITERPENES FROM MIKANIA BA NISTERIA E* G. O. LOBITZ,G. TAMAYO-CASTILLO~" and I. MERFORT~§ Institut for Pharmazeutische Biologie,Universit~it Di~sseldorL Universit~itsstr.1, D-40225 Dtisseldorf, Germany; ? Universidad de Costa Rica, Escuela de Quimica, San Jos6, Costa Rica; § Institut f/ir Pharmazeutische Biologie, Universit~it Freiburg, ScMnzlestr. 1, D-79104 Freiburg, Germany (Received in revised form 3 February 1997) Key Word lndex--Mikania banisteriae; Asteraceae; diterpenes; ent-kauranes; sesquiterpenes; eudesmane; eudesmanolides; biological studies. Abstract--Two new ent-kaurane diterpenes, 18,19-diacetoxy-ent-kaur- 16-ene and 17-oxo-ent-kaur- 15(16', 18-oic acid, were isolated from the aerial parts of Mikania banisteriae, together with the known ent-kaur ent-kaur- 16-en- 18-oic acid and ent-kaur- 16-en- 18-ol. The structures were established by mass spectrom4 1H NMR and partly ~3CNMR spectroscopy. In addition, the sesquiterpene lactones eudesma-4(15),7(1 l)-c 8/3,12-olide and eudesma-4(15),7(11),8(9)-trien-12-olide as well as the sesquiterpenes 1/3,6:t-dihydroxyeu& 4(15)-ene and caryophyllenoxide were identified by direct comparison (TLC, GC, GC-MS) with auth~ samples. The chemotaxonomic significance is briefly discussed, ent-Kaur-16-en-18-oic acid and ent-kaux en-19-oic acid showed no antifeedant, antimicrobial and antiinflammatory properties. ':D 1997 Elsevier Sci Ltd. All rights reserved INTRODUCTION The large genus Mikania (tribe Eupatorieae) with nearly 430 species is distributed over the tropical parts of America, Africa and Asia [1]. Some Mikania species are used in the traditional medicine of Costa Rica because of their antiinflammatory and antimicrobial effects [2]. Looking for further Mikania species with biological activities, we have studied M. banisteriae DC., from which only kaurane derivatives have been reported up to now [3]. RESULTSAND DISCUSSION From the lipophilic extract of the aerial parts of M. banisteriae the kaurane derivatives ent-kaur-16-en-18- oic acid (1), en t-kaur- 16-en- 18-ol (2), 18,19-diacetoxy- ent-kaur-16-ene (3) and 17-oxo-ent-kaur-15(16)-en- 18-oic acid (4) were isolated. To the best of our knowl- edge, compounds 3 and 4 are described for the first time in nature. Additionally, the eudesmane, 113, 6~-dihydroxyeudesm-4(15)-ene (5), the eudesmano- lides eudesma-4(15),7(11)-dien-8/3,12-olide (6) and eudesma-4(15),7(11),8(9)-trien-12-olide (7) as well as * Part I in the series 'Phytochemical and BiologicalStudies of Costa Rican Asteraceae'. Author to whom correspondence should be addressed. caryophyllenoxide (8) were found to be present. the exception of diterpene 1 all compounds are for the genus Mikania. The structure of compound 3 was deduced fron mass and NMR (~H, IH-~H COSY) spectra. Th mass spectrum displayed a [M] + peak at m/z Peaks at m/z 328 and 268 were derived from the cessive loss of two acetic acid molecules. In accord with this, the tH NMR spectrum exhibited single 2.07 and 2.04 due to acetoxy methyl groups, w in turn were attached to C-18 and C-19, since one singlet for a tertiary methyl group occurred 1.07 (H-20). The remaining methyl equivalents found to be the AB system from two substitutec droxymethyl groups (H-18/18': 6 4.03 and i H-19/19': 6 4.30 and 4.04). Additionally, the sp~ contained the typical low field signals ofa conju8 exocyclic H-17/17' at 6 4.80 and 4.74 and a deshie proton at 6 2.65, characteristic for kaurenoid penes. All signals agreed well with those reporteq 18-acetoxy-ent-kaur-16-ene [3], already known'. M. banisteriae, with the exception of protons at and C-19. The structure of compound 4 followed from its : and NMR (~H, JH-~H COSY) spectra. The E1 spectrum showed, besides a [M] + at m/z 316, the cal fragment ions for a kaurene diterpene with a boxyl group at C-4 [4]. The 'H NMR spectrum tained singlets for two methyl groups and its chei 161