Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to
24 months(2-8C).
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20C. Generally, these will be useable for up to two weeks. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.
Need more advice on solubility, usage and handling? Please email to: service@chemfaces.com
The packaging of the product may have turned upside down during transportation, resulting in the natural compounds adhering to the neck or cap of the vial. take the vial out of its packaging and gently shake to let the compounds fall to the bottom of the vial. for liquid products, centrifuge at 200-500 RPM to gather the liquid at the bottom of the vial. try to avoid loss or contamination during handling.
Chem Pharm Bull (Tokyo). 2000 Jul;48(7):1055-61.
Prolyl endopeptidase inhibitory activity of fourteen Kampo formulas and inhibitory constituents of Tokaku-joki-to.[Pubmed:
10923840]
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.
