Chemical constituents from fermented Noni juice / 中国中药杂志

The present work was launched to study the chemical constituents from fermented Noni juice. Ten compounds were isolated by using silicagel,Sephadex LH-20 and pre-HPLC. The structures of these compounds were identified by 1D and 2D NMR. Their structures were established as norimester( 1),cyclo( R-Pro-S-Phe)( 2),cyclo-( L-Pro-L-Leu)( 3),trans-cyclo-( D-tryptophanyl-Ltyrosyl)( 4),cyclo( L-Trp-N-methyl-L-Ala-)( 5),4-allyl-2-hydroxyphenyl 1-O-β-D-apiosyl-( 1 → 6)-β-D-glucopyranoside( 6),2-methoxy-4-vinylphenyl β-D-apiofuranosyl-( 1→6)-β-D-glucopyranoside( 7),( +)-lirioresinol A( 8),( ±)-syringaresinol( 9),and2-formyl-1 H-pyrrole-1-butanoic acid( 10). All compounds were tested for their antibacterial activity and α-glucosidase inhibitory activity. Compound 1 was a new compound. All compounds were isolated from fermented Noni juice for the first time. Compound 1 showed significant inhibitory activity against α-glucosidase [IC50 value of( 4. 22±0. 03) μmol·L-1].

Content Determination of Four Triterpenes in Caragana sinica by HPLC and α-glucosidase Activity Assay in Vitro / 中国药学杂志

OBJECTIVE: To establish HPLC methods for the determination of betulinic acid, oleanolic acid, ursolic acid, and lupeol in Caragana sinica roots, and investigate the α-glucosidase activity of the four compounds in vitro. METHODS: An Agilent Eclipse XDB-C18 column (4.6 mm × 250 mm, 5 μm) was applied with methanol-water-phosphoric acid (85:15:0.1) as the mobile phase at a flow rate of 0.6 mL·min-1 to separate betulinic acid, ursolic acid, and oleanolic acid. An Inert Sustain C18 column (4.6 mm × 150 mm, 5 μm) was applied with acetonitrile-water (70:30) as the mobile phase at a flow rate of 0.8 mL·min-1 to separate lupeol. RESULTS: Good linearities were achieved for betulinic acid, oleanolic acid, ursolic acid, and lupeol within the range of 0.56-5.58, 0.42-4.20, 0.19-1.92, and 6.10-61.00 μg, respectively. The average recoveries were 99.79%, 98.51%, 98.05%, and 99.47%, and the RSDs were 1.53%, 1.74%, 1.78%, and 1.94%, respectively. CONCLUSION: The developed methods are accurate and can be used for the quality control of Caragana sinica. In addition to betulinic acid, the other three compounds show good α-glucosidase inhibitory activity and are expected to be developed as new hypoglycemic drugs.

Phenolic constituents from twigs of Acer rubrum and their anti-oxidation and anti-α-glucosidase activities / 中草药

Objective: To isolate and identify the phenolic constituents with anti-oxidant and anti-α-glucosidase activities from the methanol extract in the twigs of Acer rubrum. Methods: The twigs of A. rubrum were extracted by methanol then partitioned by system solvents with different polarity. The ethyl acetate extract was separated on silica gel, Sephadex LH-20, ODS columns, and by semi-preparative HPLC. The isolated compounds were identified by physicochemical properties and spectral analyses. The DPPH free radical scavenging and anti-α-glucosidase activities of the compounds were also evaluated. Results: Ten phenolic compounds were isolated and purified from the twigs of A. rubrum and were identified as catechin (1), epicatechin (2), epicatechin-3-O-gallate (3), quercetin-3-O-α-L-rhamnoside (4), quercetin-3-O-3″-galloyl-rhamnoside (5), quercetin-3-O-2″-galloyl-rhamnoside (6), phloridzin (7), ginnalin A (8), ginnalin B (9), and ginnalin C (10). Conclusion: Compounds 3 and 5-7 are isolated from the twigs of A. rubrum for the first time. Compound 7 is the only one chalcone isolated from the plants in Aceraceae for the first time. All of the compounds show the good anti-oxidant activities. Compounds 3 and 8 show the strong anti-α-glucosidase activities.