Note Triterpenoid Constituents of Borreria articularis K. S. Mukherjee, B. Mukhopadhyay, S. Mondal, D. Gorai and G. Brahmachari* Natural Products Laboratory, Department of Chemistry, Visva-Bharati University, Santiniketan - 731 235, West Bengal, India The chloroform extract of the aerial parts and roots of Borreria articularis yielded a new triterpene, 3a-acetoxy-oleana-12-en-29-oic acid along with b-amyrin. The structures were established by means of spec- tral as well as chemical studies. Keywords: Borreria articularis; Rubiaceae; Triterpenoids. INTRODUCTION Borreria articularis Linn. (Rubiaceae) is an important medicinal plant used widely in Indian folk medicine. 1 Leaf- extract of the plant is in use against haemorrhoids and gall- stones, while seeds are demulcent in diarrhoea and dysen- tery. 1,2 A few triterpenoid constituents from this plant were reported earlier. 3,4 The present communication deals with the isolation and structural elucidation of two more triterpenoids from the same plant. They have been characterized as b- amyrin ( 1) and 3a-acetoxy-oleana-12-en-29-oic acid ( 2), which appears to be reported here for the first time from a nat- ural source. RESULTS AND DISCUSSION The elemental analyses and molecular ion peak [M] + at m/z 498 exhibited by the compound (2) in its EIMS spectrum are consistent with a molecular formula C 32 H 50 O 4 . It re- sponded positively to the Liebermann - Burchardt test for pentacyclic triterpene. The IR spectrum of (2) showed char- acteristic absorption bands at 1740, 1257 (ester carbonyl), 1695 (carboxylic acid functionality), 1650, 980 (trisubsti- tuted double bond) cm -1 . The 1 H NMR spectrum displayed signals for (i) seven tertiary methyls at d 0.75 (3H, s), 0.87 (3H, s), 0.94 (3H, s), 0.98 (6H, s), 1.25 (6H, s), (ii) a three proton singlet at d 2.18 ascribable to an acetoxy methyl group, (iii) one proton multiplet at d 5.45 ( br., half-band width 7 Hz) assignable to the carbinol proton and (iv) one vinylic proton at d 5.28 (1H, m). The presence of these functionalities in the triterpenoid molecule received support from the appearance of the chemical shifts in the 13 C NMR spectrum at d 181.2 (COOH), 78.2 (C-OAc), 123.4 & 143.2 (>C=C<), 171.8 & 21.9 (OAc). The MS fragmentation pattern of the triterpene (2) is very similar to that of D 12 -oleanaene type of pentacyclic tri- terpenoids. 5 The significant mass fragments at m/z 249, 190 & 189 clearly suggest that the acetoxyl group is in the A/B ring portion, while the mass peaks at m/z 248, 203 & 202 indi- cate the location of the carboxyl function in the portion con- taining D/E rings of the triterpenoid nucleus. On alkaline hy- drolysis, the parent triterpene (2) furnished a hydroxy acid, C 30 H 48 O 3 (2a), which yielded a methyl ester, C 31 H 50 O 3 (2b) on esterification with methanolic hydrochloric acid. Subse- quently, compound (2b) on chromic acid oxidation afforded a keto-ester, C 31 H 48 O 3 ( 2c), identified as methyl ester of 3- keto-oleana-12-en-29-oic acid (borreric acid) 3 from a direct comparison of spectral properties and other physical con- Journal of the Chinese Chemical Society, 2004, 51, 229-231 229 * Corresponding author. E-mail: brahmg2001@yahoo.co.in H H R 1 R 2 1.R 1 =OH, R 2 = H, R 3 = CH 3 2.R 1 =H, R 2 = OAc, R 3 = COOH 2a.R 1 =H, R 2 = OH, R 3 = COOH 2b.R 1 =H, R 2 = OH, R 3 = COOCH 3 2c.R 1 R 2 R 3 = O, R 3 = COOCH 3