Pergamon Phytochemistry, Vol. 44, No. I, pp. 173-177, 1997 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved PII: S0031-9422(96)00461-X 0031-9422/97 $17.00 + 0.00 PHENYLPROPANOIDS FROM BUPLEURUM FRUTICOSUM GUILLERMO M. MASSANET,*FRANCISCO M. GUERRA,ZACARfAS D. JORGEand LLqS G. CASALV.~ZQUEZ Departamento de Qufmica Org~nica, Facultad de Ciencias, Universidad deCfidiz, Apdo. 40, 11510 Puerto Real, Cfidiz, Spain (Received in revised form 22 May 1996) Key Word Index--Bupleurum fruticosum; Umbelliferae; Apiaceae; phenylpropanoids. Abstract--The aerial parts of Bupleurum fruticosum yielded, in addition to spinasterol and erythrodiol, nine phenylpropanoids, of which eight are new natural products. Their structures were established by spectroscopic means. Copyright © 1996 Elsevier Science Ltd INTRODUCTION allyloxy moiety [8 4.81 (2H, dd, J = 6.4, 1.1 Hz, H-l), 6.21 (1H, dt, J= 15.8, 6.4 Hz, H-2), 6.59 (1H, dt, 15.8, The genus Bupleurum L. which comprises about 200 species is primarily located in the northern hemisphere, 1.0 Hz, H-3)]. The presence of three methoxyl groups [6 3.87 (6H, s), 3.84 (3H, s)] and two aromatic protons Eurasia and North Africa. The more investigated taxa come from China and Japan (B. falcatum, B. chinense [6 6.60 (2H, s, H-2', H-6'] accounted for a O-sinapyl and B. rad/x) and have been used for stimulant, alcohol derivative structure. The ~3C NMR data (Table diuretic, antithermic and expectorant purposes in Often- 2) confirmed the placement of the three methoxyl resonances at C-3', C-4' and C-5'. Thus C-4' appears at tal medicine. Bupleurum falcatum, for instance, is an 6 138.9, shielded by two adjacent oxygen substituents, important original plant of the crude drug 'saiko', and 4'-OCH 3 at 8 60.9, typical of an o-disubstituted which possesses similar activity to 'ginseng' (Panax ginseng), position. The alternative C-2', C-4' and C-6' pattern A relatively small number of plants of this genus would also have led to two equivalent aromatic protons. have been subjected to phytochemical investigations. The remaining signals were attributed to a diester side chain constituted by a sarracinate unity [6 6.47 (1H, qt, They revealed the presence of saponins [1, 2], ter- J = 7.3, 0.9 Hz, H-3", 4.84 (2H, br s, 2H-5"), 2.13 (3H, penoids [3], coumarins [4, 5], flavonoids [1, 6], poly- acetylenes [7-9] and lignanes [10-13]. dt, J = 7.2, 0.8 Hz, C-4" Me)] esteftfied with an ange- late group [6 6.03 (1H, qq, J= 7.3, 1.4 Hz, H-3"), 1.94 Bupleurumfrutieosum L. is a shrub often localized in shaded holm-oak forests on calcareous grounds. Essen- (3H, dq, J = 7.3, 1.4 Hz, C-4" Me), 1.85 (3H, dq, tial oils of this plant have been investigated by Italian J = 1.4, 1.4 Hz, C-5" Me)]. 1H-1H, 1H-~3C correlations and DEPT experiments confirmed these assignations. chemists at the beginning of this century [14, 15]. Essential oil composition was subsequently re-ex- The presence of this diester moiety also followed from amined [16, 17]. Further reports showed the presence of its EI-mass spectrum showing fragments at mlz 304, triterpene saikosaponins [18, 19], coumarins [20] and 223, 207, 176 and 83 (base peak) (Fig. 1). From the phenylpropanoids [20]. above data, stxucture 1 is proposed for this new natural As a part of our chemical investigation on plants of compound. The second metabolite 2, an oily substance, had a the Apiaceae family, we report the isolation and molecular formula C21H260 6. The EI-mass spectrum structural elucidation, in addition to spinasterol and showed the molecular ion at mlz 374 and fragments at erythrodiol, of nine phenylpropanoids, of which eight 274, 193, 177 and 83 (base peak). The IH NMR of 2 are new compounds from this species. (Table 1) was very similar to that of 1 except for the signals corresponding to the aromatic ring, for which the 1',3',4' substitution pattern was easily established RESULTS AND DISCUSSION [66.90 (1H, dd, J=8.1, 2.0Hz), 6.92 (1H, d, J= Compound 1, C22H2807, [M] + at m[z 404, showed 2.0Hz), 6.81 (1H, d, J= 8.1 Hz)]. This compound has IR bands for t~,fl-unsaturated esters (1714cm -~) and been recently isolated by Pistelli et al. [20] from the double bonds (1651, 1584cm-a). Its 1H NMR spec- same plant. trum (Table 1) indicated the presence of a 3-aryl-trans- Compound 3 had the molecular formula C21H2606 on the basis of an ion peak at m/z 374 in its EI-mass spectrum. Its ~H NMR spectrum (Table 1) exhibited *Author to whom correspondence should be addressed, close similarities to those of 1 and 2. Signals of the 173