An examination of the rubiaceae of Hong Kong. Part VIII. The structure of spinosic acid A, a new triterpenoid sapogenin from Randia spinosa(Thunb.) Poir.

Abstract

Spinosic acid A, one of the sapogenins from Randia spinosa, has been shown to be 38.1 9P-dihydroxyolean-12-en-28-oic acid. Other sapogenins isolated include oleanolic acid, siaresinolic acid, and another new triterpenoid. spinosic acid B.t The sterols, p-sitosterol and stigmasterol have also been obtained. * Metastable peak observed.19-hydroxy-substituent in a P-amyrin skeleton since all the remaining possible secondary hydroxy-positions possess at least two neighbouring hydrogens and suggests that spinosic acid is either the 18a-H (VIII) or 19p-OH (I) isomer of siaresinolic acid, the latter being favoured on biogenetic grounds. Ruzicka et a1.' prepared a compound which was considered to be (VIII) * by forced

New Biologically Active Triterpenoid Saponins from Scabiosa tschiliensis

“…The IR spectrum exhibited absorptions at 3419 cm -1 (-OH), 1742 cm -1 (ester carbonyl), and 1644 cm -1 (double bond). The seven tertiary methyl groups (δ 0.90 × 3, 1.10, 1.14, and 1.27 × 2) and one trisubstituted olefinic proton (δ 5.42, br s) observed in the 1 H NMR spectrum coupled with the information from the 13 C NMR spectrum (seven sp 3 carbons at δ 15.7, 33.1, 23.7, 17.5, 17.2, 28.2, and 26.1 and two sp 2 olefinic carbons at δ 122.9 and 144.2) indicated that the aglycon possessed an olean-12-ene skeleton. After an extensive 2D NMR study, the aglycon was identified as oleanolic acid.…”

“…The seven tertiary methyl groups and one trisubstituted olefinic proton observed in the 1 H NMR spectrum coupled with the information from the 13 C NMR spectrum (seven sp 3 carbons and two sp 2 olefinic carbons at δ 123.0 and 144.3) indicated that the aglycon possessed an olean-12-ene skeleton. After an extensive 2D NMR study, the aglycon was identified as siaresinolic acid . Hydrolysis of 10 with cellulase yielded the aglycon, which showed NMR data identical to those of an authentic sample .…”

“…A methanolic extract of the whole plant of S. tschiliensis was suspended in H 2 O and then partitioned successively with n-hexane, EtOAc, and n-BuOH. The n-BuOH-soluble fraction, on chromatographic purification over Diaion HP-20, followed by repeated medium-pressure liquid chromatography (MPLC) and HPLC purification, afforded 11 new compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11), along with two known saponins, hookeroside A (12) and B (13). All these compounds were found to possess gentiobiose, that is, a β-D-glucopyranosyl-(1f6)β-D-glucopyranoside unit directly linked to C-28 of the aglycons.…”

“…Scabiosaponin A (1) had a molecular formula of C 64 H 104 O 30 determined from its matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectra (m/z 1375 [M + Na] + , 1391 [M + K] + ) and from positive HRFABMS data for the [M + Na] + ion at m/z 1375 (measured m/z 1375.6511, calculated m/z 1375.6510) as well as 13 C DEPT NMR spectra. The spectral features and physicochemical properties suggested 1 to be a triterpenoid saponin.…”

“…The chemical shifts of C-3 (δ 88.7) and C-28 (δ 176.5) revealed that 1 was a bisdesmosidic glycoside. Of the 64 carbon signals observed in the 13 C NMR spectrum of 1 (Tables 1 and 2), 30 were assigned to the aglycon and 34 to the oligosaccharide moieties. The 1 H and 13 C NMR spectra of compound 1 exhibited six sugar anomeric protons at δ 4.86 (d, J ) 6.0 Hz), 5.04 (d, J ) 7.6 Hz), 5.05 (d, J ) 7.8 Hz), 5.28 (d, J ) 7.8 Hz), 6.24 (br s), and 6.27 (d, J ) 8.0 Hz) and carbons at δ 95.…”