A simplified and miniaturized glucometer-based assay for the detection of β-glucosidase activity / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

β-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 β-glucosidase activity. Single-factor experiments showed that optimum β-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 β-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 β-dextranase, snailase, β-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 β-glucosidase activity. The easy-to-operate method was successfully used to detect a series of β-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 β-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.

Triterpenoid saponins from Patrinia scabra / 中国天然药物

AIM@#To study the chemical constituents and bioactivity of the roots of Patrinia scabra Bunge.@*METHODS@#The chemical constituents were isolated using various chromatographic methods, and the structures were elucidated on the basis of spectral analysis and chemical methods. In addition, cytotoxic activities toward HepG2 cells were tested by the MTT method.@*RESULTS@#A new triterpenoid saponin, 3-O-(4'-isovaleryl)-O-β-D-xylose-12,30-dihydroxy-oleanane-28,13-lactone-22-O- β-D-glucoside (1), along with two known triterpenoid saponins, acanthopanax saponin CP3 (2) and foetoside C (3), were isolated.@*CONCLUSION@#The aglycone of compound 1 was a new skeleton derivative of oleanolic acid. Compound 2 showed strong cytotoxicity to HePG2 cells (IC50 1.49 μmol·L(-1)).

Chemical constituents of Euphorbia tibetica and their biological activities / 中国天然药物

AIM@#To investigate the chemical constituents and their biological activities of the aerial parts of Euphorbia tibetica.@*METHOD@#Compounds were isolated and purified by various chromatographic methods, and their structures were elucidated through the use of extensive spectroscopic techniques including 2D-NMR, the structures of compounds 5 and 6 were confirmed by single-crystal X-ray crystallography. Bioactivities of all the isolated compounds were evaluated by the MTT method on A549 and anti-angiogenesis assay.@*RESULTS@#One new compound, methyl 4-epi-shikimate-3-O-gallate (1), together with twenty-three known constituents (2-24) were isolated from the aerial parts of E. tibetica.@*CONCLUSION@#Compound 1 is new, and the other compounds were isolated from this plant for the first time. Compounds 5-7, 9, 11, 17, 18 and 20 exhibited inhibitory effects on the growth of human lung cancer cell A549 and compounds 5, 7, 12, 13, 17 and 19 showed anti-angiogenic effects in a zebrafish model.

Chemical profiles and anticancer effects of saponin fractions of different polarity from the leaves of Panax notoginseng / 中国天然药物

AIM@#To evaluate the chemical profiles and cytotoxic effects among the total saponin fraction (TSF), 25% ethanol fraction (25EF), 50% ethanol fraction (50EF), and 85% ethanol fraction (85EF) prepared by macroporous resin from the leaves of Panax notoginseng.@*METHOD@#The simultaneous determination of thirteen main saponins, as well as the chemical profiles of saponin fractions of different polarity, was made by HPLC-DAD and LC-ESI-MS(n) analysis. The cytotoxic effects were determined against KP4 cells (human pancreatic cancer), NCI-H727 cells (human lung cancer), HepG2 cells (human hepatocellular cancer), and SGC-7901 cells (human gastric adenocarcinoma).@*RESULTS@#Chemical analysis indicated that 85EF possessed the most abundant cytotoxic protopanaxadiol saponins, including the marker saponins F2, 20(R)-Rg3, 20(S)-Rg3, and Rh2. The MTT assay showed that 85EF also had the strongest cytotoxic effects among the four fractions. 25EF showed no anti-proliferative effects, while 50EF and TSF exhibited weak anti-proliferative activity.@*CONCLUSION@#From the aspect of comprehensive utilization of resources, 85EF, enriched with low polarity PPD group saponins, is a new alternative source of anticancer saponins, and a promising botanical preparation for further anticancer studies.

Isolation and characterization of xanthine oxidase inhibitory constituents of Pyrenacantha staudtii / 药学学报

Six compounds have been isolated from the leaves of Pyrenacantha staudtii,two of which are new compounds.The new compounds have been characterized as kaempherol 3-O-β-rhamnopyranosyl (1→6)β-D-glucopyranoside (1) and 4-β-glucopyranosyl-(2-furyl)-5-methy-1,2-glucopyranoside phenylmethanone (2).The known compounds are 3-pyridinecarboxylic acid (3),β-sitosterol (4),sitosterol 3-O-β-glucopyranoside (5) and taraxerol (6).Their structures were determined by spectroscopic and chemical evidences.The two new compounds together with 3-pyridinecarboxylic acid showed significant in vitro xanthine oxidase inhibitory activity.To the best of our knowledge,this is the first report of these compounds from this plant.