Phytochemistry, Vol. 48, No 3, pp. 511 514, 1998 Pergamon . 1998 Published by Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0031-9422(97)01088-1 0031 9422~98 $19.00+000 TWO ACYLATED MONOTERPENE GLUCOSIDES FROM PAEONIA PEREGINA IVANKAN. KOSTOVA,* MARIO F. SIMEONOV,DANIELAI. TODOROVAand PETJA L. PETKOVA Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria (Received 26 September 1997) Key Word Index--Paeonia pereyrina ; Paeoniaceae ; roots ~ "cage-like" monoterpenes : paeon- idaninols A and B ; paeoniflorin ; benzoylpaeoniflorin. Abstract--The roots of Paeonia peregrina afforded two new acylated "cage-like" monoterpene glucosides, named paeonidaninols A and B, the known monoterpenes, paeoniflorin and benzoylpaeoniflorin, as well as glucose, galactose and sucrose. The structures of the new compounds were elucidated on the basis of spectral data. 4:) 1998 Published by Elsevier Science Ltd. All rights reserved INTRODUCTION 753) and NMR (IH and ~3C) data. Elucidation of the The genus Paeonia has been reported to pro- structures of these compounds was achieved by one- and two- dimensional (COSY, HMQC, HMBC and duce unique "cage-like" monoterpene glucosides. NOESY) NMRstudies. Recently, various compounds of this type have been Comparison between the ~H and 13C NMR spectra isolated, including paeonisuffrone (1), paeonidanin (2) (Table 1) of 6a, 6b and paeonidanin tetraacetate (2a) and many derivatives of paeoniflorin (3) [1-3]. The occurrence of these interesting metabolites in this [2] showed a close similarity regarding the mono- terpene moiety. However, instead of the C-9 methoxyl genus prompted us to continue our studies [2] on the group in 2a, an additional OAc appeared in 6a and roots of P. peregrina native to Bulgaria. Our recent 6b. The presence of OAc at C-9 in the epimeric acetates investigations resulted in the isolation of two new was suggested by the downfield shift of H-9 (6 6.28 epimeric "cage-like" monoterpene glucosides, along and 6.12) and confirmed by the HMBC correlation with the two known monoterpenes, paeoniflorin (3) from these protons to the carbonyl signal at 6 170.2 and benzoylpaeoniflorin (4), as well as glucose, gal- (OCOCH3). actose and sucrose. Here, we describe the isolation The proposed arrangement of the monoterpene and structural elucidation of the new compounds nucleus of 6a and 6b was further supported by the paeonidaninol A (5a) and paeonidaninol B (5b). following long-range heteronuclear shift correlations : (a) from H-9 to C-2 (6 87.5), C-5 (6 47.5) and C-6 (6 RESULTS ANDDISCUSSION 62.9), (b) from H-8 to C-1 (6 87.9), C-5 (6 47.5), C-6 (3 62.9) and C-9 (3 98.3), (c) from Me-10 to C-2 (6 Roots of P. pereyrina worked-up as described in the 87.5) and C-3 (6 48.5), and (d) from H-3, H-5 and H- Experimental, yielded four "cage-like" monoterpene 7 to C-4 (6 204.9). glucosides, sucrose, glucose and galactose. Two of the The remaining ~H and ~3C NMR signals disclosed monoterpenes proved to be the known compounds the presence of glucose and two benzoyloxy units paeoniflorin (3) and benzoylpaeoniflorin (4), whereas (Table 1). The HMBC correlation from H-I' to C-1 5a and 5b have not been described previously. (6c 87.9) gave evidence for the location of glucose at Paeonidaninol A (5a) and paeonidaninol B (5b) C-1. The three-bond correlations from H-2', 3' and 4" were isolated as an epimeric mixture of their acetates to the carbon signals at 6 169.7 and 170.2 (OCOCH3) 6a and 6b (see Experimental) in a ratio 1.5 : 1.0 as suggested the attachment of OAc groups to C-2', 3' deduced from their JH NMR spectrum. A molecular and 4', and indicated the position of the benzoyloxy formula of C3sH400~6 was established for 6a, b on the units at C-8 and C-6'. basis of the FAB mass spectrometry ([M+H] + m/z The NOE cross-peak H-9 (6 6.28)/H-1' (6 4.83) observed in the NOESY spectrum of 6a, b suggested that, in the epimer 6a, H-9 is directed towards the exo- side of the molecule. The observation of this cross- * Author to whom correspondence should be addressed, peak also indicated that for 6a a conformation having 511