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A new ferulic acid ester named 4-methyl-3-trans-hexenylferulate (1), together with eight known phenolic acid esters (2-9), was isolated from the methanolic extract of the roots and rhizomes of Notopterygium incisium. Their structures were elucidated by extensive spectroscopic techniques, including 2D NMR spectroscopy and mass spectrometry. 4-Methoxyphenethyl ferulate (8) NMR data is reported here for the first time. The uptake and transepithelial transport of the isolated compounds 1-9 were investigated in the human intestinal Caco-2 cell monolayer model. Compounds 2 and 6 were assigned for the well-absorbed compounds, compound 8 was assigned for the moderately absorbed compound, and compounds 1, 3, 4, 5, 7, and 9 were assigned for the poorly absorbed compounds. Moreover, all of the isolated compounds were assayed for the inhibitory effects against nitric oxide (NO) production in the lipopolysaccharide-activated RAW264.7 macrophages model and L-N⁶-(1-iminoethyl)-lysine (L-NIL) was used as a positive control. Compounds 1, 5, 8, and 9 exhibited potent inhibitory activity on NO production with the half maximal inhibitory concentration (IC50) values of 1.01, 4.63, 2.47, and 2.73 μM, respectively, which were more effective than L-NIL with IC50 values of 9.37 μM. These findings not only enriched the types of anti-inflammatory compounds in N. incisum but also provided some useful information for predicting their oral bioavailability and their suitability as drug leads or promising anti-inflammatory agents.

A feruloyl esterase (StFaeC) produced by Sporotrichum thermophile was purified to homogeneity. The native StFaeC was homodimer with a subunit of M-r 23,000 and pI 3. 1. The enzyme activity was optimal at pH 6.0 and 55 degrees C. The esterase displayed remarkable stability at pH 10.0 and retained 50% of its activity after 133 and 55 min at 55 and 60 degrees C, respectively. Determination of k(cat)/K-m revealed that the enzyme had a broad spectrum of activity against the (hydroxyl) cinnamate esters indicating a type C feruloyl esterase. The enzyme was active on substrates containing ferulic acid ester linked to the C-5 and C-2 linkages of arabinofuranose and hydrolysed 4-nitrophenyl-5-O-trans-fer-uloyl-alpha-L-arabinofuranoside three times more efficiently than 4-nitrophenyl-2-O-trans-feruloyl-alpha-L-arabinofuranoside. Ferulic acid was efficiently released from wheat bran when the esterase was incubated together with xylanase from S. thermophile (a maximum of 41% total ferulic acid released after 1 h incubation). StFacC by itself could release FA but at a level almost 10-fold lower than that obtained in the presence of xylanase. The potential of StFaeC for the synthesis of various phenolic acid esters was examined using as a reaction system a ternary water-organic mixture consisting of n-hexane, 1-butanol and water. Also StFaeC catalyzed the transfer of the feruloyl group to L-arabinose in a similar system using t-butanol, with about a 40% conversion of L-arabinose to feruloylated derivative was achieved. This work is the first example of enzymatic feruloylation of a carbohydrate. (c) 2004 Elsevier Inc. All rights reserved. Enzyme and Microbial Technology