No abstract

Bractin A (=(2S,3S,4R,5E)-2-{[(2R)-2-hydroxydodecanoyl]amino}triacont-5-ene-1,3,4-triol; 1) and bractin B (=(2S,3S,4R,5E,8E)-2-{[(2R)-2-hydroxyhexacosanoyl]amino}pentadeca-5,8-diene-3,4,15-triol 1-O-beta-D-glucopyranoside; 2), new sphingolipids, and bractic acid (=(5Z,10Z,15Z)-2-decyl-4,7,8,12,13,17,18-heptahydroxy-20,23-dioxopentacosa-5,10,15-trienoic acid; 3), a long-chain polyhydroxy acid, were isolated from the whole plant Ajuga bracteosa along with four known diterpenoids 4-7. Their structures were deduced by spectral studies including 1D- and 2D-NMR spectroscopy. Compounds 1-3 displayed inhibitory potential against enzyme lipoxygenase, while compounds 4-7 inhibited cholinesterase enzymes in a concentration-dependent manner with IC(50) values in the range 10.0-33.0, 14.0-35.2, and 10.0-19.0 microM for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively. Lineweaver-Burk, and Dixon plots, and their secondary replots indicated that all compounds exhibit non-competitive type of inhibition with K(i) values in the range of 9.5-35.2, 15.2-36.0, and 11.6-20.5 microM, for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively.

No abstract

The phenolic compounds methyl 2-O-feruloyl-1a-O-vanillactate (1), caffeic anhydride (2), and trans 4-hydroxycyclohexyl-2-O-p-coumaroyl beta-D-glucopyranoside (3) have been isolated from the AcOEt-soluble fraction of Ehretia obtusifolia, along with methyl rosmarinate (4) and rosmarinic acid (5), which are reported for the first time from this species. Their structures were determined by means of 1D- and 2D-NMR techniques. Compounds 1-5 inhibited lipoxygenase in a concentration-dependent manner, with Ki values ranging from 0.85-57.6 microM. Compounds 1, 2, 4, and 5 showed noncompetitive inhibition, whereas 3 was found to be an uncompetitive inhibitor of lipoxygenase.