[Rapid determination of aesculin and aesculetin in Fraxini Cortex by high performance liquid chromatography-ultraviolet at equal absorption wavelength].

Fraxini Cortex is a traditional Chinese herbal medicine that has been used for thousands of years to treat dampness-heat diarrhea, dysentery, red or white vaginal discharge, painful swelling or redness of the eyes, and nebula. It contains various chemical components, including coumarins, iridoids, phenolic acids, and flavonoids. Coumarins are important active ingredients in Fraxini Cortex and have antibacterial, anti-inflammatory, antioxidant, antitumor, and antiviral activities. Aesculin and aesculetin are two major coumarin components of Fraxini Cortex that are widely used in its quality evaluation. Previous HPLC methods for determination of aesculin and aesculetin present several limitations, such as long analysis times and high solvent and reference compound consumption. In this study, a rapid, eco-friendly and cost saving HPLC method for the determination of aesculin and aesculetin in Fraxini Cortex was established by using the core-shell column and equal absorption wavelength (EAW). Different factors influencing the extraction process, such as the extraction solvent, temperature, and time, were assessed to obtain the optimal extraction conditions. The results showed that Fraxini Cortex samples could be well extracted by ultrasonic extraction for 5 min with a 25% ethanol aqueous solution. A core-shell column was used, and different mobile phases and flow rates were investigated to obtain the best rapid-HPLC separation conditions. The optimized HPLC conditions were as follows: a Poroshell 120 EC-C18 column (50 mm×4.6 mm, 2.7 µm), acetonitrile-0.1% formic acid aqueous solution (6∶94, v/v) as the eluent, a flow rate of 1.5 mL/min, and a column temperature of 25 ℃. The EAW of aesculin and aesculetin was a key factor in their determination using a single reference compound. EAW selection was performed in two steps. First, the UV spectra of two equimolar concentrations of the reference compounds (aesculin and aesculetin) were compared to determine the EAW of the two analytes. The EAW results were then verified by the HPLC analysis of the reference compound solutions. The final EAW of aesculin and aesculetin was 341 nm. The determination of aesculin and aesculetin using only one reference compound (i. e., aesculin) was achieved by HPLC-UV at this EAW. The newly developed HPLC method revealed a good linear relationship between the two target analytes (r=1.0000). The limits of detection (LODs) and limits of quantification (LOQs) were 1.5 µmol/L and 3.0 µmol/L, respectively, and the average recoveries of aesculin and aesculetin were 99.0% and 97.5%. The stabilities of the sample solutions were examined, and the two analytes demonstrated good stability for 24 h. The contents of the target analytes in 10 batches of Fraxini Cortex were determined using the proposed EAW method and the classic external standard method (ESM), and comparable concentrations were obtained. The contents of aesculin and aesculetin in the 10 batches of Fraxini Cortex were 0.26%-2.80% and 0.11%-1.47%, respectively. A t-test was conducted to compare the results of the proposed EAW technique with those obtained via the method reported in the Chinese Pharmacopoeia, and no significant difference between the two assay methods was noted (P>0.05). Comparison of the newly established EAW method with those reported in the literature revealed that our method required only 10 min to complete and used as little as 0.5 mL of the solvent and only one standard. Therefore, the developed EAW method is a rapid, simple, eco-friendly, and cost-effective analytical method that is suitable for the determination of aesculin and aesculetin in Fraxini Cortex and its related products. The proposed technique is an improved method for determining aesculin and aesculetin and contributes to the enhancement of the quality evaluation of Fraxini Cortex.

On-line pre-column FRAP-based antioxidant reaction coupled with HPLC-DAD-TOF/MS for rapid screening of natural antioxidants from different parts of Polygonum viviparum.

Polygonum viviparum L. (PV) is a widely used resource plant with high medicinal, feeding and ecological values. Our studies show that PV has strong antioxidant activity. However, up to date, the antioxidant activity and components in other parts were not fully elucidated. In the present study, a new online pre-column ferric ion reducing antioxidant power (FRAP)-based antioxidant reaction coupled with high performance liquid chromatography-diode array detector-quadrupole-time-of-flight mass spectrometry (HPLC-DAD-TOF/MS) was developed for rapid and high-throughput screening of natural antioxidants from three different parts of PV including stems and leaves, fruits and rhizomes. In this procedure, it was assumed that the peak areas of compounds with potential antioxidant activity in HPLC chromatograms would be greatly diminished or vanish after incubating with the FRAP. The online incubation conditions including mixed ratios of sample and FRAP solution and reaction times were firstly optimized with six standards. Then, the repeatability of the screening system was evaluated by analysis of the samples of stems and leaves of PV. As a result, a total of 21 compounds mainly including flavonoids and phenolic acids were screened from the three parts of PV. In conclusion, the present study provided a simple and effective strategy to rapidly screen antioxidants in natural products.

[Effects of electroacupuncture on urinary bladder function after radical hysterectomy].

OBJECTIVE: To observe the effect of electroacupuncture on recovery of urinary bladder function after radical hysterectomy. METHODS: One hundred and ten cases were randomly divided into an electroacupuncture (EA) group and a control group, 55 cases in each group. In the control group, the urinary tube was placed and kept with routine method and the urinary bladder was rinsed, and from the eighth day the abdomen was radiated with TDP, 30 min each day, for 5 days. In the EA group, on the basis of treatment in the control group EA was given at Sanyinjiao (SP 6), Zusanli (ST 36), Waiguan (TE 5), Shuidao (ST 28), Guilai (ST 29), etc. from the eighth day to twelfth day after operation. The recovery time of urinary bladder function after radical hysterectomy, urine dynamic indexes and hospitalization days were compared between the two groups. RESULTS: The cases of the bladder function recovery, retention of urine, urinary incontinence were 51(51/55), 4(4/55), 0 on the 14 th day after operation and 53(53/55), 2(2/55), 0 on the 28 th day in the EA group, and 27(27/55), 25(25/55), 3(3/55) on the 14 th day and 43(43/55), 11(11/55), 1(1/55) on the 28th day in the control group, respectively, with a very significant difference between the two groups (P < 0.01); the EA group in residual urine volume, bladder volume, mean urinary flowing rate was better than the control group on the 14 th day after operation (P < 0.01 or P < 0.05); the hospitalization days after operation was (21.1 +/- 3.3) days in the EA group and (25.5 +/- 3.5) days in the control group, the former being shorter than the later (P < 0.01). CONCLUSION: EA can promote recovery of bladder function, shorten the keeping time of urinary tube after radical hysterectomy, which is benefit to decreasing incidence rate of urinary system infection and shortening hospitalization days.