densispicninsaandb,twounusualmonoterpenesfrompedicularisdensispicafranch.docVIP

HETEROCYCLES, Vol. 75, No. 1, 2008, pp. -. ? The Japan Institute of Heterocyclic Chemistry Received, 11th August, 2007, Accepted, 28th September, 2007, Published online, 2nd October, 2007. COM-07-11200 DENSISPICNINS A AND B, TWO UNUSUAL MONOTERPENES FROM PEDICULARIS DENSISPICA FRANCH Hong-biao Chu,a Du-qiang Luo,a,* Ning-hua Tan,b and Xuan Tianc aCollege of Life Science, Key Laboratory of Pharmaceutical Chemistry and Molecular Diagnosis, Hebei University, Baoding 071002, China bState Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China c State Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China * E-mail: duqiangluo@163.com; Fax: +86-312-5079364. Abstract – Two unusual monoterpenes, densispicnins A (1), B (2), together withthe four known monoterpenes, mussaenoside (3), yuheinoside (4), mussaenin A(5), argyol (6), were isolated from the whole plant of Pedicularis densispica Franch. The structures of 1 and 2 were elucidated mainly based on spectral data including 1D-, 2D-NMR (HSQC, HMBC, ROESY) and MS experiments. INTRODUCTION Genus Pedicularis L. comprises about 329 species in China,1 in which some species have been used to treat diseases.2 Many compounds were isolated from Pedicularis, including iridoids, phenylpropanoids and so on.3,4,5 Among them, some compounds showed biological activities of antioxidation and antitumour.6,7,8 In previous paper,9 we have reported the new iridoid glycosides from P. Dolichocymba. Herein we report on the isolation and structural elucidation of two new monoterpenes from P. Densispica Franch, named densispicnins A (1) and B (2), together with four known monoterpenes mussaenoside (3), 10yuheinoside (4),11 mussaenin A (5),12 argyol (6)13 (Figure 1). RESULTS AND DISCUSSION Compound 1 was obtained as a colorless solid. The molecular formula of 1 was determined to be C10H16O3 by positive HR-ESI-MS (calcd. for [M+N