A simplified and miniaturized glucometer-based assay for the detection of ß-glucosidase activity.

ß-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants. The drawbacks of the existing methods are high consumption of both time and reagents, complexity in operation, and requirement of expensive instruments and highly trained personnel. The present study provides a simplified, highly selective, and miniaturized glucometer-based strategy for the detection of ß-glucosidase activity. Single-factor experiments showed that optimum ß-glucosidase activity was exhibited at 50 °C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min. The procedure for detection was simplified without the need of a chromogenic reaction. Validation of the analytical method demonstrated that the accuracy, precision, repeatability, stability, and durability were good. The linear ranges of ß-glucosidase in a buffer solution and rat serum were 0.0873-1.5498 U/mL and 0.4076-2.9019 U/mL, respectively. The proposed method was free from interference from ß-dextranase, snailase, ß-galactosidase, hemicellulase, and glucuronic acid released by baicalin. This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid (DNS) assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter. Miniaturization of the method resulted in a microassay for ß-glucosidase activity. The easy-to-operate method was successfully used to detect a series of ß-glucosidases extracted from bitter almonds and cultured by Aspergillus niger. In addition, the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing of ß-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.

Simultaneous determination of dihydromyricetin and resveratrol in Ampelopsis sinica (Miq.) W.T. Wang by high-performance liquid chromatography coupled with a diode array detection method.

Yeputaoteng is the dried ground part of Ampelopsis sinica (Miq.) W.T. Wang, which is widely used in traditional Chinese medicine for preventing and treating tumors, chronic nephritis, hepatitis, rubella, traumatic bleeding, stomach heat and vomiting. A simple and reliable method using high-performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the simultaneous determination of dihydromyricetin and resveratrol in Yeputaoteng. The chromatographic analysis was performed on a Dikma C18 column (250 × 4.6 mm, 5 µm) at 30°C with a gradient elution of acetonitrile and 0.1% phosphoric acid at a flow rate of 1 mL/min, and used ultraviolet detection at 292 and 306 nm. The established method was validated in terms of linearity, precision, reproducibility, stability and recovery. The calibration curves showed good linear regression (R(2) > 0.9994). Limits of detection and quantification fell in the ranges of 1.47-2.48 and 2.93-4.97 µg/mL, respectively. The mean recovery of dihydromyricetin and resveratrol was 104.1% [relative standard deviation (RSD): 2.94%] and 100.8% (RSD: 2.80%), respectively. The quantitative results indicated that the HPLC-DAD method can be effectively applied to the quality control of Yeputaoteng and its preparations.