Flavonoids as effective protectors of urease from ultrasonic inactivation in solutions

Abstract

Inactivation of soybean urease in aqueous solution at pH 5.4, 36 degrees C, and high-frequency sonication (2.64 MHz, 1.0 W/cm2) is substantially reduced in the presence of seven structurally different flavonoids. A comparative kinetic study of the effect of these flavonoids on the effective first-order rate constants that characterize the total (thermal and ultrasonic) inactivation k(i), thermal inactivation k(i)*, and ultrasonic inactivation k(i)(US) of 25 nM enzyme solution was carried out. The dependences of the three inactivation rate constants of the urease on the concentrations of flavonoids within the range from 10(-11) to 10(-4) M were obtained. The following order of the efficiency of the flavonoids used in respect of the urease protection from ultrasonic inactivation was found: astragalin > silybin > naringin > hesperidin > quercetin > kaempferol > morin. The results confirm a significant role in the inactivation of the urease of HO* and HO2*, free radicals, which are formed in the ultrasonic cavitation field.

Naringin induces apoptosis of gastric carcinoma cells via blocking the PI3K/AKT pathway and activating pro‑death autophagy

“…Nar has an anti-cancer effect on esophageal cancer stem cell xenotransplanted tumor mouse models without altering the body and liver weight and the combination of Nar and doxorubicin can reduce the side effects of doxorubicin (29). Nar is both effective and safe as an anti-cancer drug (30). The present study found that Nar arrested SNU-1 cells in the G 0 /G 1 phase, promoting apoptosis in a dose-dependent manner.…”

Sono‐activation of food enzymes: From principles to practice

“…It is noteworthy that depending on the specific operational conditions, the modification effect on enzyme molecules can be activation or inactivation. Generally speaking, a stable cavitation effect caused by mild ultrasonic conditions (i.e., low intensity and short time) can cause oscillating resonance bubbles to form microcurrents through the surrounding solution, thereby producing milder shear stress in the solution (Tarun et al., 2006). The mechanical effect at this level can modify the enzyme structure in a way that loosens its spatial conformation and increases the exposure of more active sites, and thereby improve the enzyme activity (Bashari et al., 2013a; Subhedar & Gogate, 2013).…”

Cerastes Cerastes Venom

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