Ursolic acid analogues: non-phenolic functional food components in Jamaican raspberry fruits

The Rubus genus produces numerous species that are known for their medicinal properties. Rubus rosifolius, called the red raspberry, grows wild in elevated regions in Jamaica. Phytochemical examination of the ethyl acetate extract of the fruit yielded eight compounds of the 19-α-hydroxyursane type: euscaphic acid (1), 1-β-hydroxyeuscaphic acid (2), hyptatic acid B (3), 19α-hydroxyasiatic acid (4), trachelosperogenin (5), 4-epi-nigaichigoside F1 (6), nigaichigoside F1 (7), and trachelosperoside B-1 (8), as confirmed by NMR spectroscopy. Inhibition of cell proliferation by these compounds were determined by using MCF-7 (breast), SF-268 (CNS), NCI H460 (lung), HCT-116 (colon) and AGS (gastric) human tumour cells. Among the human tumour cell lines assayed, only compounds 3 and 6 displayed significant growth inhibition and was specific to colon tumour cells by 56% and 40%, respectively. These ursolic acid analogues were also tested for anti-inflammatory activity using in vitro cycloxegenase-1 (COX-1) and cycloxegenase-2 (COX-2) enzyme inhibitory assays. Compounds 1, 2 and 3 showed selective COX-1 enzyme inhibitory activity (13%, 25% and 35%) at 25 μg/ml. In the lipid peroxidation (LPO) inhibitory assays, compounds 2, 4, 7 and 6 inhibited LPO by 62%, 60%, 53% and 68%, respectively, at 25 μg/ml.