Characterization of a novel cold-adapted GH1 ß-glucosidase from Psychrobacillus glaciei and its application in the hydrolysis of soybean isoflavone glycosides.

The novel ß-glucosidase gene (pgbgl1) of glycoside hydrolase (GH) family 1 from the psychrotrophic bacterium Psychrobacillus glaciei sp. PB01 was successfully expressed in Escherichia coli BL21 (DE3). The deduced PgBgl1 contained 447 amino acid residues with a calculated molecular mass of 51.4 kDa. PgBgl1 showed its maximum activity at pH 7.0 and 40 °C, and still retained over 10% activity at 0 °C, suggesting that the recombinant PgBgl1 is a cold-adapted enzyme. The substrate specificity, Km, Vmax, and Kcat/Km for the p-Nitrophenyl-ß-D-glucopyranoside (pNPG) as the substrate were 1063.89 U/mg, 0.36 mM, 1208.31 U/mg and 3871.92/s, respectively. Furthermore, PgBgl1 demonstrated remarkable stimulation of monosaccharides such as glucose, xylose, and galactose, as well as NaCl. PgBgl1 also demonstrated a high capacity to convert the primary soybean isoflavone glycosides (daidzin, genistin, and glycitin) into their respective aglycones. Overall, PgBgl1 exhibited high catalytic activity towards aryl glycosides, suggesting promising application prospects in the food, animal feed, and pharmaceutical industries.

Development of a Monoclonal Antibody-Based Indirect Competitive Enzyme-Linked Immunosorbent Assay for the Rapid Detection of Gallic Acid.

Gallic acid (GA) is closely related to the quality of herbal medicines and other agricultural products. In order to facilitate the rapid detection of GA, we developed a monoclonal antibody-based ic-ELISA method. Antigens with and without connecting arms were prepared. It was found that the introduction of connecting arms (linear carbon chain) was beneficial for immune response. By utilizing hybridoma technology, a specific mAb (anti-GA-M702) was screened and identified, which exhibited a 1:40,500 antibody titer and IgG2b antibody subtype. The ic-ELISA assay was established based on anti-GA-M702. The optimal working concentrations of the encapsulated antigen and antibody were 0.5 µg/mL and 0.67 µg/mL, respectively. The ic-ELISA method showed a linear detection range of 297.17-2426.61 ng/mL for GA with a sensitivity of 849.18 ng/mL. It displayed a good applicability for the determination of GA in Galla chinensis. In conclusion, the ic-ELISA method provides an efficient approach to the rapid detection of GA in products.

Siraitia grosvenorii (Swingle) C. Jeffrey: Research Progress of Its Active Components, Pharmacological Effects, and Extraction Methods.

Siraitia grosvenorii (Swingle) C. Jeffrey, a perennial vine of the Cucurbitaceae family, is a unique medicine food homology species from China. S. grosvenorii can be used as a natural sweetener in the food industry and as a traditional medicine for moistening the lungs, quenching a cough, smoothing the intestines, and relieving constipation. Additionally, the fruits, roots, stems, and leaves of S. grosvenorii are rich in active ingredients, and have pharmacological effects such as immune regulation, hypoglycemia, and antioxidant, hepatoprotective, and antitumor effects, etc. Therefore, S. grosvenorii has broad application prospects in the pharmaceutical industry. This paper reviews the bioactive components, pharmacological effects, and extraction methods of S. grosvenorii, summarizes them, and proposes their future development directions. This current overview highlights the value of S. grosvenorii. By documenting the comprehensive information of S. grosvenorii, the review aims to provide the appropriate guidelines for its future in-depth development and the utilization of S. grosvenorii resources for their roles as active ingredient (triterpenoids, flavonoids, and polysaccharides, etc.) sources in the food industry and in the development of functional foods.

Ultrasound and heating treatments improve the antityrosinase ability of polyphenols.

This paper focused on improving antityrosinase ability of quercetin, cinnamic acid, and ferulic acid (named Q-CA-FA) from Asparagus by combining heating with ultrasound treatments. Fluorescence spectroscopy and UPLC-MS were used to evaluate inhibitory mechanisms. Results showed that the impacts of combining heating (150 °C for 30 min) with ultrasound (600 W for 30 min) treatments were similar to heating treatment (150 °C for 120 min) alone, and the inhibition rate could reach 98.2% in the addition of 5 mM Q-CA-FA. Fluorescence quenching indicated that treated Q-CA-FA-tyrosinase complex was more stable, but combining treatments did not change the major force between tyrosinase and polyphenols. Thermodynamic analysis illustrated that the randomness of compounds was also increased. Interestingly, 2-hydroxy-3-(3-hydroxy-4-methoxy-phenyl)-propionic acid 4-(2,3-dihydroxy-propyl)-phenyl ester was newly detected, which might be the major reason for enhancing antityrosinase ability. Taken together, these results provide a creative insight on increasing antityrosinase activity by combining heating with ultrasound treatments.