Fatty Acid Esters of Triterpenoids and Steroid Glycosides fromGambeya africana

Abstract

Chemical studies of the CH2 Cl2 -MeOH extract of the seeds of Gambeya africana (Baker) Pierre led to the isolation of 15 compounds. Their structures were established on the basis of spectroscopic methods and chemical reactions. They comprised five new fatty acid esters of erythrodiol, [3 beta-octacosanoyloxy-12-oleanen-28-ol, 3 beta-triacontanoyloxy-12-oleanen-28-ol, 3 beta-dotriacontanoyloxy-12-oleanen-28-ol, 3 beta-tetratriacontanoyloxy-12-oleanen-28-ol and 3 beta-hexatriacontanoyloxy-12-oleanen-28-ol], one new steroidal glycoside, [3 beta-O-beta-xylopyranosylchondrillasterol] and nine known compounds, (3 beta-octadecanoyloxy-12-oleanene, 3 beta-eicosanoyloxy-12-oleanene, 3 beta-docosanoyloxy-12-oleanene, 3 beta-acetoxy-12-oleanene, erythrodiol, 28-hydroxy-beta-amyrone, chondrillasterol, chondrillasterone and 3 beta-O-beta-glucopyranosylchondrillasterol).

Oxidative Burst Inhibitory and Cytotoxic Activity of Constituents of the Fruits of Odyendyea gabonensis

“…From the above spectroscopic studies, the structure of compound 4 was determined as 9-hydroxy-5-methoxycanthin-6-one. [12,22]. The 13 C NMR spectrum (l " Ta This assignment was in agreement with the EI MS, which showed two prominent fragment ion peaks at m/z 149 (C 9 H 9 O 2 ) and 133 (C 9 H 8 O) arising from the retro-Diels-Alder fragmentation and the loss of a hydroxyl group [23,24].…”

Isolation and characterization of aromatase inhibitors from Brassaiopsis glomerulata (Araliaceae)

“…Bioassay-guided fractionation of the hexane extract led to the isolation of six compounds of the steroid and triterpenoid classes [spinasterone ( 1 ) (Wandji et al, 2002), stigmasterol ( 2 ) (Forgo and Kover, 2004), spinasterol ( 3 ) (Kojima et al, 1990), 7β-hydroxy-4,22-stigmastadien-3-one ( 4 ) (Ayyad, 2002), 6β-hydroxystigmasta-4-en-3-one ( 5 ) (Kontiza et al, 2006), and oleanolic acid ( 6 ) (Seebacher et al, 2003)]. The ethyl acetate extract of B. glomerulata was also found to exhibit moderate aromatase inhibition with the enzyme-based and cell-based AI assays (59.3 PCA at 20 μg/mL and 37.0 PCA at 20 μg/mL, respectively).…”

Amides from the Stem Bark ofFagara macrophylla

“…These data suggested the presence of a long chain linked to compound 5. The presence of a long chain was further confirmed by the 13 C-NMR spectrum, which showed characteristic signals at δ = 174.1 (C-1′′), 34.4 (C-2′′), 31.7-22.4 (CH 2 ) 17 , and 13.7 (CH 3 ) [11].…”

“…Comparison of the 1 H-NMR spectra of compound 5 and its O-acetyl derivative (5a) indicated the downfield acetylation shift of all proton resonances of the tyramine moiety, strongly suggesting that the free phenolic group was located at C-6 of the tyramine moiety. Transesterification of 5 yielded methyl docosanoate (5b) (identified by GC-MS, m/z = 354; the (+)-ESI-HR mass spectrum indicated a pseudomolecular ion at m/z = 372.3831 [M + NH 4 ] + , corresponding to a molecular formula of C 23 H 50 NO 2 ), vanillic acid (6), and tyramine (11). Vanillic acid and tyramine were identified by 13 C-NMR, 1 H-NMR, and EI-MS. From the above spectroscopic studies, compound 5 was characterized as N-[O-docosanoylvanilloyl]tyramine.…”

“…, which showed characteristic signals at δ = 174.1 (C-1′), 36.4 (C-2′), 34.4-22.4 (CH 2 ) n , and 13.8 (CH 3 )[11]. To confirm the linkage between the long chain and the tyramine, 2D-NMR such as HMBC and 1 H-1 H COSY experiments were used.…”