Contribution of Resveratrol in the Development of Novel Urease Inhibitors: Synthesis, Biological Evaluation and Molecular Docking Studies

The Effect of Yucca schidigera Extract on Serum Metabolites of Angus Crossbreed Steers with Metabolomics

This study was conducted to explore the potential effect of Yucca schidigera extract (YSE) on the metabolism of beef cattle. Thirty Angus crossbreed steers were selected, with an initial mean body weight of 506.6 ± 33.3 kg, and assigned to two treatments: a diet with no additives (CON group) and a diet supplemented with 1.75 g/kg of YSE (YSE group) (on a dry matter basis). The experiment lasted for 104 days, with 14 days for adaptation. The results showed that adding YSE could significantly improve the average daily gain (ADG) from 1 to 59 d (15.38%) (p = 0.01) and 1 to 90 d (11.38%) (p < 0.01), as well as dry matter digestibility (DMD) (0.84%) (p < 0.05). The contents of alanine aminotransferase, aspartate aminotransferase, and bilirubin and the total antioxidant capacity were increased and blood urea was reduced in the YSE group, compared to the CON group (p < 0.05). Both the glycerophospholipids and bile acids, including phosphocholine, glycerophosphocholine, PC(15:0/18:2(9Z,12Z)), PE(18:0/20:3(5Z,8Z,11Z)), PE(18:3(6Z,9Z,12Z)/P-18:0), LysoPC(15:0), LysoPC(17:0), LysoPC(18:0), LysoPC(20:5(5Z,8Z,11Z,14Z,17Z)), deoxycholic acid, glycocholic acid, and cholic acid, were upregulated by the addition of YSE. In summary, YSE may improve the ADG by increasing the blood total antioxidant capacity and glycerophospholipid synthesis, maintaining steers under a healthy status that is beneficial for growth. Furthermore, YSE may also increase the expression of bile acid synthesis, thereby promoting DMD, which, in turn, offers more nutrients available for growth.

Coptisine: A natural plant inhibitor of ruminal bacterial urease screened by molecular docking

Inhibition of ruminal bacterial urease activity could slow down the decomposition of urea to ammonia, which would lead to a decrease in urea synthesis in the liver and urea-N emission in the urine. In order to find a rumen bacterial urease specific inhibitor that is environmentally friendly, we used the homology model of rumen bacterial urease as the target to screen natural compounds from plants by molecular docking. The screening results showed that coptisine had the most potential to inhibit the activity of rumen bacterial urease with an IC₅₀ of 2.45 μM, which was superior to the traditional inhibitor acetohydroxamic acid. The enzyme kinetics results indicated coptisine was mixed type inhibitor of rumen bacterial urease with a K_i value of 0.68 μM. Coptisine significantly decreased the release of NH₃ and decomposition of urea and improved microbial fermentation in a rumen fermentation system in vitro. Thiol-containing compounds or boric acid significantly decreased the inhibitory capacity of coptisine toward rumen bacterial urease, which indicated that coptisine could interact with both the urease active center Ni and amino acid residues possessing sulfhydryl groups in the flap area. The molecular docking results showed that coptisine acted as the metal acceptor for one nickel ion in the active site, and formed hydrogen bonds with the amino acid residues His320 and His362, which were located in the active site and flap region, respectively. These findings emphasized the potential role of coptisine in reducing nitrogen emissions that originate from ruminants by regulating rumen bacterial urease activity.

A novel salvianolic acid A analog with resveratrol structure and its antioxidant activities in vitro and in vivo

E-DRS is a novel salvianolic acid A (SAA) analog, which was synthesized from resveratrol (RES) and methyldopate. Its structure is similar to that of SAA, but the 3',4'-dihydroxy-trans-stilbene group and the ester structure in SAA were replaced by the RES structure and an amine group, respectively. E-DRS scavenged free oxygen radicals effectively, including superoxide anion (ascorbic acid > E-DRS > SAA ≥ rutin > RES) and DPPH radical (rutin > E-DRS ≥ ascorbic acid > SAA > RES), and exhibited powerful total antioxidant capacity (ascorbic acid > E-DRS > SAA ≥ rutin > RES) in vitro. Furthermore, oral administration of E-DRS dose-dependently and significantly decreased CCl₄ -induced oxidative stress in mice as indicated by the decreased content of hepatic malondialdehyde (MDA). In addition, oral administration of E-DRS also increased the content of nonenzymatic antioxidant glutathione (GSH) and the activity of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) in the liver of mice. All these results demonstrated that E-DRS had good antioxidant activities both in vitro and in vivo, and could be a potential antioxidant agent after further optimization and evaluation.