Trimethoxycinnamates and Their Cholinesterase Inhibitory Activity

A series of twelve nature-inspired 3,4,5-trimethoxycinnamates were prepared and characterized. All compounds, including the starting 3,4,5-trimethoxycinnamic acid, were tested for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro; the selectivity index (SI) was also determined. 2-Fluororophenyl (2E)-3-(3,4,5-trimethoxyphenyl)-prop-2-enoate demonstrated the highest SI (1.71) in favor of BChE inhibition. 2-Chlorophenyl (2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoate showed the highest AChE-inhibiting (IC50 = 46.18 µM) as well as BChE-inhibiting (IC50 = 32.46 µM) activity with an SI of 1.42. The mechanism of action of the most potent compound was determined by the Lineweaver–Burk plot as a mixed type of inhibition. An in vitro cell viability assay confirmed the insignificant cytotoxicity of the discussed compounds on the two cell lines. Trends between structure, physicochemical properties and activity were discussed.

Enzymatic Synthesis, Structural Analysis, and Evaluation of Antibacterial Activity and α-Glucosidase Inhibition of Hesperidin Glycosides

This study was designed to investigate the structure of synthesized hesperidin glycosides (HGs) and evaluate their antibacterial and α-glucosidase inhibitory activities. The preliminary structure of HGs was confirmed by glucoamylase treatment and analyzed on thin layer chromatography (TLC). The LC-MS/MS profiles of HGs showed the important fragments at m/z ratios of 345.21 (added glucose to glucose of rutinose in HG1) and 687.28 (added maltose to glucose of rutinose in HG2), confirming that the structures of HG1 and HG2 were α-glucosyl hesperidin and α-maltosyl hesperidin, respectively. In addition, 1H and 13C-NMR of hesperidin derivatives were performed to identify their α-1,4-glycosidic bonds. The MIC and MBC studies showed that transglycosylated HG1 and HG2 had better antibacterial and bactericidal activities than hesperidin and diosmin, and were more active against Staphylococcus aureus than Escherichia coli. Hesperidin, HG1, HG2, and diosmin inhibited α-glucosidase with IC50 values of 2.75 ± 1.57, 2.48 ± 1.61, 2.36 ± 1.48, and 2.99 ± 1.23 mg/mL, respectively. The inhibition kinetics of HG2 shown by a Lineweaver–Burk plot confirmed HG2 was an α-glucosidase competitive inhibitor with an inhibitor constant, Ki, of 2.20 ± 0.10 mM. Thus, HGs have the potential to be developed into antibacterial drugs and treatments for treating α-glucosidase-associated type 2 diabetes.

Immobilization of Chaetomium erraticum dextranase (CED) by adsorption on carboxylated multi walled carbon nanotubes (c-MWCNT)

In this study, CED was immobilized onto c-MWCNT by adsorption. Optimization of immobilization conditions (immobilization buffer's pH and molarity, c-MWCNT amount, and immobilization time) was resulted in 100% immobilization yield and 114.13% activity yield. Further, characterization of FCED and ICED was also studied. After immobilization, the optimum pH shifted from 5.0 to 6.0, while the optimum temperature (55 °C) did not change. Furthermore, kinetic constants for FCED and ICED were also determined using the Lineweaver-Burk plot. The Km value for both FCED and ICED were 54.35 g / L, while Vmax values for FCED and ICED were 2.77 μmol reducing sugar / L.mg.min and 3.19 μmol reducing sugar / L.mg.min, respectively. Moreover, there was no reduction in the initial activity of ICED after 20 consecutive uses and 30 days of storage at optimal storage conditions. Finally, 17.15% and 17.53% of the dextran in 10% dextran solution (pH 6.0) were converted to reduced sugars (IMOs and Glucose) in 12 hours using FCED and ICED, respectively. Consequently, it can be concluded that ICED obtained in this study can be effectively used for industrial production of IMOs and for hydrolysis of dextran.

Proteolytic enzyme arbitrated antagonization of helminthiasis by Cinnamomum cappara leaf extract in Pheretima posthuma

Background There have been several studies carried out to irradiate Helminthiasis however very little research have been carried out where in the enzymatic activity of plants are exploited to antagonize infections. Here we are analyzing the anthelmintic activity of Cinnamomum cappara leaf extract against Pheretima posthuma complimented by proteolytic action. Results The fresh leaves of Cinnamomum cappara was collected from local areas of Thrissur during December 2019. Plants were identified and authenticated by morphological and molecular characterization. The enzymatic action was analyzed by plotting Lineweaver–Burk plot which suggested that the extract possess the Km 185.77 μM for casein as substrate and obeyed Michaelis–Menten kinetics with typical hyperbolic relation with enzyme and increasing concentration of substrate. The effect of extract upon study subject was in directly proportional with concentration of antagonist where higher activities were obtained in high concentrations. The anatomical and histological studies suggested that the activity of extract was due to the degradation of muscular bundle of subject that resulted in the leakage of ceolomic fluid. Conclusions Cinnamomum cappara leaf extract possessed high degree of protease intervened anthelmintic activity against Pheretima posthuma. As the study subject show immense morphological and physiological resemblance with all other helminthic parasites, this results shall be adopted to further clinical and pharmacological applications.

Three Novel Biphenanthrene Derivatives and a New Phenylpropanoid Ester from Aerides multiflora and Their α-Glucosidase Inhibitory Activity

A phytochemical investigation on the whole plants of Aerides multiflora revealed the presence of three new biphenanthrene derivatives named aerimultins A–C (1–3) and a new natural phenylpropanoid ester dihydrosinapyl dihydroferulate (4), together with six known compounds (5–10). The structures of the new compounds were elucidated by analysis of their spectroscopic data. All of the isolates were evaluated for their α-glucosidase inhibitory activity. Aerimultin C (3) showed the most potent activity. The other compounds, except for compound 4, also exhibited stronger activity than the positive control acarbose. Compound 3 showed non-competitive inhibition of the enzyme as determined from a Lineweaver–Burk plot. This study is the first phytochemical and biological investigation of A. multiflora.

Deviation of Trypsin Activity Using Peptide Conformational Imprints

In this study, a methodology utilizing peptide conformational imprints (PCIs) as a tool to specifically immobilize porcine pancreatic alpha-trypsin (PPT) at a targeted position is demonstrated. Owing to the fabrication of segment-mediated PCIs on the magnetic particles (PCIMPs), elegant cavities complementary to the PPT structure are constructed. Based on the sequence on targeted PPT, the individual region of the enzyme is trapped with different template-derived PCIMPs to show certain types of inhibition. Upon hydrolysis, N-benzoyl-L-arginine ethyl ester (BAEE) is employed to assess the hydrolytic activity of PCIMPs bound to the trypsin using high-performance liquid chromatography (HPLC) analysis. Further, the kinetic data of four different PCIMPs are compared. As a result, the PCIMPs presented non-competitive inhibition toward trypsin, according to the Lineweaver-Burk plot. Further, the kinetic analysis confirmed that the best parameters of PPT/PCIMPs 233–245+G were Vmax = 1.47 × 10−3 mM s−1, Km = 0.42 mM, kcat = 1.16 s−1, and kcat/Km = 2.79 mM−1 s−1. As PPT is bound tightly to the correct position, its catalytic activities could be sustained. Additionally, our findings stated that the immobilized PPT could maintain stable activity even after four successive cycles.

Lipase from Rhizopus oryzae R1: in-depth characterization, immobilization, and evaluation in biodiesel production

Background Rhizopus species is among the most well-known lipase producers, and its enzyme is suitable for use in many industrial applications. Our research focuses on the production of lipase utilizing waste besides evaluating its applications. Results An extracellular lipase was partially purified from the culture broth of Rhizopus oryzae R1 isolate to apparent homogeneity using ammonium sulfate precipitation followed by desalting via dialysis. The partially purified enzyme was non-specific lipase and the utmost activity was recorded at pH 6, 40 °C with high stability for 30 min. The constants Km and Vmax, calculated from the Lineweaver-Burk plot, are 0.3 mg/mL and 208.3 U/mL, respectively. Monovalent metal ions such as Na+ (1 and 5 mM) and K+ (5 mM) were promoters of the lipase to enhance its activity with 110, 105.5, and 106.5%, respectively. Chitosan was used as a perfect support for immobilization via both adsorption and cross-linking in which the latter method attained immobilization efficiency of 99.1% and reusability of 12 cycles. The partially purified enzyme proved its ability in forming methyl oleate (biodiesel) through the esterification of oleic acid and transesterification of olive oil. Conclusion The partially purified and immobilized lipase from Rhizopus oryzae R1 approved excellent efficiency, reusability, and a remarkable role in detergents and biodiesel production.

Comparison of Antioxidant and α-Glucosidase Inhibitory Activities in Different Cultivars of Five Mango (Mangifera Indica L.) Leaf Extracts

The objectives of study were to evaluate and compare the antioxidant, total phenolic, total flavonoid, mangiferin content and antidiabetic activities of five young mango cultivars leaf extract, namely, ‘Apple’, ‘Nam Dok Mai’, ‘Bao’, ‘OkRong’ and ‘Kiew Savoey’. Antioxidant effect was investigated by DPPH, ABTS radical scavenging activity, and ferric reducing power (FRAP) assays. Inhibitory on α-glucosidase activity and type of enzyme inhibition were evaluated by using Lineweaver Burk plot analysis. Mangiferin, major active compound, was quantified by HPTLC method. Furthermore, the hypoglycemic effect was determined using streptozotocin (STZ) –nicotinamide (NA) -induced type 2 diabetic mice. Young mango cv. ‘Apple’ leaf extract demonstrated the strongest antioxidant activity in all assays. Moreover, it contains highest amounts of total phenolic and mangiferin to the values of 311 mg GAE/g extract and 197 mg/g extract, respectively. It possessed potent α-glucosidase inhibitory activity with IC50 value of 0.50 µg/mL. Lineweaver-Burk plot analysis demonstrated a non-competitive inhibition of αglucosidase activity with the inhibition constant (Ki) of 2.98 µg/mL. Coadministration of young mango cv. ‘Apple’ leaf extract at dose of 1,000 mg/kg significantly reduced the total blood glucose level by 13.43% in STZ-NA-induced type 2 diabetic mice when compared with control diabetic mice in oral glucose tolerance test (OGTT) model. Inhibition of glucose absorption may be one of the possible mechanism of its hypoglycemic effect. In conclusion, young mango cv. ‘Apple’ leaf extract possesses the strongest antioxidant and antidiabetic activities which has a potential to develop as nutraceutical products.

Enhanced Kinetic Performance of CLEA-Lipase Extracted from Skim Latex of Hevea brasiliensis upon Immobilization on Magnetic Iron Nanoparticles

In this research, lipase recovered from the skim latex of Hevea brasiliensis was immobilized via cross-linked enzyme aggregates (CLEA) technology, while supported by magnetic nanoparticles (MNPs), for properties enhancement. Hybrid immobilization may have affected the kinetic performances of the biocatalysts. The kinetic performance of both MNP supported and unsupported CLEA-lipase, were evaluated based on the Michaelis-Menten model using p-nitrophenyl palmitate as the substrate. Three different linearization model equations were used to compute the kinetic properties, v_max and K_m, and a hyperbolic regression was conducted with computer software. Based on the best fitted model, v_max of MNP-CLEA-lipase, obtained from the Lineweaver-Burk plot (R2=0.9823), was 0.0023 µmol/min.mL, which is higher than CLEA-lipase (0.0015 µmol/min.mL), indicating it needs much higher substrate concentration to saturate the enzymatic sites to reach its maximum velocity. K_m for MNP-CLEA-lipase was 0.4400 µmol, compared to 0.5188 µmol for CLEA-lipase, inferring that it has a higher affinity towards substrates, whereby its rate will approach v_max with lower substrate concentration. Overall, this research demonstrated that wasteful by-products such as skim latex can be converted to useful value-added biocatalyst. A better understanding of the kinetic parameters of this newly produced MNP immobilized biocatalyst is necessary for its further development.