Urease is an amidohydrolase enzyme that is responsible for fatal morbidities in the human body, such as catheter encrustation, encephalopathy, peptic ulcers, hepatic coma, kidney stone formation, and many others. In recent years, scientists have devoted considerable efforts to the quest for efficient urease inhibitors. In the pharmaceutical chemistry, the thiourea skeleton plays a vital role. Thus, the present work focused on the development and discovery of novel urease inhibitors and reported the synthesis of a set of 1-aroyl-3-[3-chloro-2-methylphenyl] thiourea hybrids with aliphatic and aromatic side chains 4a–j. The compounds were characterized by different analytical techniques including FT-IR, ¹H-NMR, and ¹³C-NMR, and were evaluated for in-vitro enzyme inhibitory activity against jack bean urease (JBU), where they were found to be potent anti-urease inhibitors and the inhibitory activity IC₅₀ was found in the range of 0.0019 ± 0.0011 to 0.0532 ± 0.9951 μM as compared to the standard thiourea (IC₅₀ = 4.7455 ± 0.0545 μM). Other studies included density functional theory (DFT), antioxidant radical scavenging assay, physicochemical properties (ADMET properties), molecular docking and molecular dynamics simulations. All compounds were found to be more active than the standard, with compound 4i exhibiting the greatest JBU enzyme inhibition (IC₅₀ value of 0.0019 ± 0.0011 µM). The kinetics of enzyme inhibition revealed that compound 4i exhibited non-competitive inhibition with a Ki value of 0.0003 µM. The correlation between DFT experiments with a modest HOMO-LUMO energy gap and biological data was optimal. These recently identified urease enzyme inhibitors may serve as a starting point for future research and development.

The main objective of the current study was the extraction, purification, and enzymatic characterization of a potent proteinaceous amylase inhibitor from Moringa oleifera. The antimicrobial potential and insecticide effects against C. maculates insect larvae were also studied. The α-amylase inhibitor was extracted in methanol (with an inhibitory activity of 65.6% ± 4.93). Afterwards, the inhibitor αAI.Mol was purified after a heat treatment at 70 °C for 15 min followed by one chromatographic step of Sephadex G-50. An apparent molecular weight of 25 kDa was analyzed, and the N-terminal sequence showed the highest identity level (89%) with the monomeric α-amylase inhibitor from Triticum dicoccoides. αAI.Mol was found to tolerate pH values ranging from 5.0 to 11.0 and showed maximal activity at pH 9.0. Thermal stability was remarkably important, since the inhibitory activity was maintained at 55% after 1 h of incubation at 70 °C and at 53% after an incubation of 45 min at 80 °C. The potency of the current purified inhibitor against amylases from different origins indicates that αAI.Mol seems to possess the highest affinity toward human salivary α-amylase (90% inhibitory activity), followed by the α-amylase of insects Callosobruchus maculatus and Tribolium confusum (71% and 61%, respectively). The kinetic parameters were also calculated, and the K_max and V_max of the digestive amylase were estimated at 185 (mmol/min/mg) and 0.13 mM, respectively. The inhibitor possesses a strong bactericidal effect against Gram+ and Gram- strains, and the MIC values were >1 against B. cereus but >6 against E. coli. Interestingly, the rates of survival and pupation of C. maculates insect larvae were remarkably affected by the purified αAI.Mol from Moringa oleifera.

Traditional wastewater treatments involve expensive mechanical and physiochemical methods, so researchers have been developing cost-effective, sustainable technologies that use enzymes to produce higher quality effluents and recover more energy and nutrients from wastewater. A thermostable, alkaline, and solvent-tolerant lipase was partially purified from thermophilic Bacillus stearothermophilus. The lipase displayed maximum activity at 50 °C and pH 11.0 and catalyzed both short- and long-chain triacylglycerols at similar rates. B. stearothermophilus lipase also exhibited high stability when incubated at 40 °C for 1 h with anionic and non-ionic surfactants. Studies show that thermostable enzymes can be improved through immobilization and modification of other reaction conditions. Therefore, B. stearothermophilus lipase was immobilized through adsorption on CaCO₃, Celite 545, and silica gel with the CaCO₃ support producing the best adsorption rate (89.33%). The optimal initial lipase activity was approximately 4500 U.g⁻¹ after 60 min. Interestingly, 93% of the initial lipase activity was retained after six cycles, and almost 50% of the initial activity remained after 12 cycles. Furthermore, immobilization improved storage stability with 98.85% of the initial lipase activity retained after 60 days of storage at 4 °C. The biochemical characteristics of immobilized lipase shifted toward a slightly alkaline region, reaching maximum activity at pH 12. The optimal temperature of immobilized lipase was 60 °C. Immobilization also improved enzymatic stability by widening the pH range from 5–9 (for free lipase) to 4–11, and thermostability by reaching 65 °C. The application of immobilized lipase in wastewater treatment was observed through oil layer biodegradation. Notably, treating wastewater for 10 days with immobilized lipase almost removed the chemical oxygen demand (COD) from 1950.1 down to 4.04 mg.L⁻¹. Similarly, lipid content was almost removed from 15,500 ± 546 mg.L⁻¹ down to 12 mg.L⁻¹. All results highlight the potential value of CaCO₃-immobilized lipase as an effective biocatalyst for hydrolyzing wastewater.

Durian (Durio zibethinus L.) grows widely in Southeast Asia. The pulp of the durian fruit contains carbohydrates, proteins, lipids, fibers, various vitamins, minerals, and fatty acids. This study was carried out to elucidate the anticancer mechanism of action of the methanolic extract of the fruit of Durio zibethinus (D. zibethinus) on human leukemia (HL-60) cells. The methanolic extract of D. zibethinus fruits exhibited its anticancer effect on HL-60 cells by inducing DNA damage and apoptosis. The DNA damage was confirmed by comet and DNA fragmentation assays. The methanolic extract of D. zibethinus fruits has been shown to cause cell cycle arrest in HL-60 cells during the S phase and G2/M phase. Additionally, the methanolic extract caused induction of the apoptotic pathway in the HL-60 cell line. This was confirmed by increased expression in pro-apoptotic proteins, viz., Bax protein expression, and a substantial reduction (p < 0.001) in anti-apoptotic proteins, viz., Bcl-2 and Bcl-xL expressions. Therefore, this study confirms that the methanolic extract of D. zibethinus exerts its anticancer effects on the HL-60 cell line, causing cell cycle arrest and induction of apoptosis by an intrinsic mechanism.

Secreted phospholipases A₂ are snake-venom proteins with many biological activities, notably anti-tumor activity. Phospholipases from the same snake type but different geographical locations have shown similar biochemical and biological activities with minor differences in protein sequences. Thus, the discovery of a new phospholipase A₂ with unique characteristics identified in a previously studied venom could suggest the origins of these differences. Here, a new Group II secreted phospholipase A₂ (Cc-PLA₂-II) from the snake venom of Saudi Cerastes cerastes gasperetti was isolated and characterized. The purified enzyme had a molecular weight of 13.945 kDa and showed high specific activity on emulsified phosphatidylcholine of 1560 U/mg at pH 9.5 and 50 °C with strict calcium dependence. Interestingly, stability in extreme pH and high temperatures was observed after enzyme incubation at several pH levels and temperatures. Moreover, a significant dose-dependent cytotoxic anti-tumor effect against six human cancer cell lines was observed with concentrations of Cc-PLA₂ ranging from 2.5 to 8 µM. No cytotoxic effect on normal human umbilical-vein endothelial cells was noted. These results suggest that Cc-PLA₂-II potentially has angiogenic activity of besides cytotoxicity as part of its anti-tumor mechanism. This study justifies the inclusion of this enzyme in many applications for anticancer drug development.