Isolindleyin

Prolyl endopeptidase inhibitory activity of fourteen Kampo formulas and inhibitory constituents of Tokaku-joki-to.[Pubmed: 10923840]

Chem Pharm Bull (Tokyo). 2000 Jul;48(7):1055-61.

Prolyl endopeptidase (PEP, EC 3.4.21.26) is an enzyme playing a role in the metabolism of proline-containing neuropeptides which have been suggested to be involved in learning and memory processes.
METHODS AND RESULTS:
In screening for PEP inhibitors from fourteen traditional Kampo formulas, we found that Tokaku-joki-to shows a significant inhibitory activity. Examination of the constituents of the Kampo formula resulted in the isolation of two new compounds, cis-3,5,4'-trihydroxystilbene 4'-O-beta-D-(6-O-galloyl)glucopyranoside (10) and 4-(4-hydroxyphenyl)-2-butanone 4'-O-beta-D-(6-O-galloyl-2-O-cinnamoyl)glucopyranoside (16), along with twenty-five known compounds, cinnamic acid (1), protocatechuic acid (2), gallic acid (3), torachrysone 8-O-beta-D-glucoside (4), emodin (5), emodin 8-O-beta-D-glucoside (6), 3,5,4'-trihydroxystilbene 4'-O-beta-D-glucopyranoside (7), 3,5,4'-trihydroxystilbene 4'-O-beta-D-(2-O-galloyl)glucopyranoside (8), 3,5,4'-trihydroxystilbene 4'-O-beta-D-(6-O-galloyl)glucopyranoside (9), 4-(4-hydroxyphenyl)-2-butanone 4'-O-beta-D-glucopyranoside (11), Isolindleyin (12), lindleyin (13), 4(4-hydroxyphenyl)-2-butanone 4'-O-beta-D-(2,6-di-O-galloyl)glucopyranoside (14), 4-(4-hydroxyphenyl)-2-butanone 4'-O-beta-D-(2-O-galloyl-6-O-cinnamoyl)glucopyranoside (15), 1-O-galloylglucose (17), 1,2,6-tri-O-galloylglucose (18), gallic acid 4-O-beta-D-(6-O-galloyl)glucopyranoside (19), liquiritigenin (20), liquiritigenin 4'-O-beta-D-glucoside (21), liquiritigenin 7,4'-diglucoside (22), liquiritigenin 4'-O-beta-D-apiofuranosyl-(1-->2)-beta-D-glucopyranoside (23), licuroside (24), (-)-epicatechin (25), (-)-epicatechin 3-O-gallate (26) and (+)-catechin (27).
CONCLUSIONS:
Among these compounds, twelve (7-10, 14-16, 18, 19, 24-26) showed noncompetitive inhibition with an IC50 of 22.9, 3.0, 14.9, 2.8, 10.5, 0.69, 8.2, 0.44, 9.39, 26.5, 28.1 and 0.052 microM, respectively.

Zhongguo Zhong Yao Za Zhi. 2017 Dec;42(23):4514-4519.

Simultaneous content determination of 14 components in Rhei Radix et Rhizoma by high performance liquid chromatography method.[Pubmed: 29376246]

METHODS AND RESULTS:
To establish an HPLC (high performance liquid chromatography) method for the simultaneous content determination of gallic acid, (+)-catechin, (－)-epicatechin-3-O-gallate, Isolindleyin, 4-(4'-hydroxyphenyl)-2-butanone, emodin, chrysophanol, physcion, aloe-emodin, rhein, lindleyin, 4-(4'-hydroxyphenyl)-2-butanone-4'-O-β-D-(2″-O-galloyl-6″-O-cinnamoyl)-glucopyranoside, sennoside A and sennoside B in Rhei Radix et Rhizoma. The analysis was performed on Agilent Zorbax SB-C₁₈ (4.6 mm×150 mm, 5 μm) with 0.05% phosphoric acid solution (A) - acetonitrile (B) as mobile phase for gradient elution. The flow rate was 1 mL•min⁻1, with column temperature of 40 ℃ and the wavelength was set at 268 nm. All calibration curves showed good linearity (r > 0.999 9) within the concentration range. Both the intra- and inter-day precision for 14 analytes was less than 3.1%, with the mean recovery at the range of 91.80%-104.1%. Meanwhile, quantitative determination was carried out for 10 qualified samples from Rheum palmatum and 10 qualified samples from R. tanguticum, respectively. It was found that the content of 4-(4'-hydroxyphenyl)-2-butanone and aloe-emodin were higher in the R. tanguticum and R. palmatum, respectively, and the content of all the compounds was different in each sample.
CONCLUSIONS:
The established HPLC method for simultaneous content determination of 14 compounds from Rhei Radix et Rhizoma could be used for quantitative assessment and quality control of Rhei Radix et Rhizoma.