Potential of Syzygnium polyanthum as Natural Food Preservative: A Review.

Food preservation is one of the strategies taken to maintain the level of public health. Oxidation activity and microbial contamination are the primary causes of food spoilage. For health reasons, people prefer natural preservatives over synthetic ones. Syzygnium polyanthum is widely spread throughout Asia and is utilized as a spice by the community. S. polyanthum has been found to be rich in phenols, hydroquinones, tannins, and flavonoids, which are potential antioxidants and antimicrobial agents. Consequently, S. polyanthum presents a tremendous opportunity as a natural preservative. This paper reviews recent articles about S. polyanthum dating back to the year 2000. This review summarizes the findings of natural compounds presented in S. polyanthum and their functional properties as antioxidants, antimicrobial agents, and natural preservatives in various types of food.

Effects of Alkaline Solvent Type and pH on Solid Physical Properties of Carrageenan from Eucheuma cottonii.

The effects of alkali type and pH on the physical properties of carrageenan have been extensively studied. However, their effects on certain characteristics of solid-state properties of carrageenan have not been identified. This research aimed to investigate the effect of alkaline solvent type and pH on the solid physical properties of carrageenan isolated from Eucheuma cottonii. Carrageenan was extracted from the algae using NaOH, KOH, and Ca(OH)2 at pHs of 9, 11, and 13. Based on the results of preliminary characterization, including yield, ash content, pH, sulphate content, viscosity, and gel strength, it was found that all samples followed Food and Agriculture Organization (FAO) specifications. The swelling capacity of carrageenan based on the type of alkali was KOH > NaOH > Ca(OH)2. The FTIR spectra of all samples were in agreement with that of standard carrageenan. The molecular weight (MW) of carrageenan using KOH as the alkali followed the order pH 13 > pH 9 > pH 11, while using NaOH, the order was pH 9 > pH 13 > pH 11, and while using Ca(OH)2, the order was pH 13 > pH 9 > pH 11. The results of the solid-state physical characterization of carrageenan with the highest MW in each type of alkali showed that the morphology of carrageenan using Ca(OH)2 has a cubic shape and is more crystal-like. The order of crystallinity of carrageenan using different types of alkali was Ca(OH)2 (14.44%) > NaOH (9.80%) > KOH (7.91%), while the order of density was Ca(OH)2 > KOH > NaOH. The order of solid fraction (SF) of the carrageenan was KOH > Ca(OH)2 > NaOH, while the tensile strength when using KOH was 1.17, when using NaOH it was 0.08, and while using Ca(OH)2, it was 0.05. The bonding index (BI) of carrageenan using KOH = 0.04, NaOH = 0.02, and Ca(OH)2 = 0.02. The brittle fracture index (BFI) of the carrageenan was KOH = 0.67, NaOH = 0.26, and Ca(OH)2 = 0.04. The order of carrageenan solubility in water was NaOH > KOH > Ca(OH)2. These data can be used as the basis for the development of carrageenan for excipients in solid dosage forms.

In silico Study of Antiviral Activity of Polyphenol Compounds from Ocimum basilicum by Molecular Docking, ADMET, and Drug-Likeness Analysis.

Aim: The SARS-CoV-2 virus is a disease that has mild to severe effects on patients, which can even lead to death. One of the enzymes that act as DNA replication is the main protease, which becomes the main target in the inhibition of the SARS-CoV-2 virus. In finding effective drugs against this virus, Ocimum basilicum is a potential herbal plant because it has been tested to have high phytochemical content and bioactivity. Apigenin-7-glucuronide, dihydrokaempferol-3-glucoside, and aesculetin are polyphenolic compounds found in Ocimum basilicum. Purpose: The purpose of this study was to analyze the mechanism of inhibition of the three polyphenolic compounds in Ocimum basilicum against the main protease and to predict pharmacokinetic activity and the drug-likeness of a compound using the Lipinski Rule of Five. Patients and Methods: The method used is to predict the molecular docking inhibition mechanism using Autodock 4.0 tools and use pkcsm and protox online web server to analyze ADMET and Drug-likeness. Results: The binding affinity for apigenin-7-glucuronide was -8.77 Kcal/mol, dihydrokaempferol-3-glucoside was -8.96 Kcal/mol, and aesculetin was -5.79 Kcal/mol. Then, the inhibition constant values were 375.81 nM, 270.09 nM, and 57.11 µM, respectively. Apigenin-7-glucuronide and dihydrokaempferol-3-glucoside bind to the main protease enzymes on the active sites of CYS145 and HIS41, while aesculetin only binds to the active sites of CYS145. On ADMET analysis, these three compounds met the predicted pharmacokinetic parameters, although there are some specific parameters that must be considered especially for aesculetin compounds. Meanwhile, on drug-likeness analysis, apigenin-7-glucuronide and dihydrokaempferol-3-glucoside compounds have one violation and aesculetin have no violation. Conclusion: Based on the data obtained, Apigenin-7-glucuronide and dihydrokaempferol-3-glucoside are compounds that have more potential to have an antiviral effect on the main protease enzyme than aesculetin. Based on pharmacokinetic parameters and drug-likeness, three compounds can be used as lead compounds for further research.

Potential of 24-Propylcholestrol as Immunity Inducer against Infection of COVID-19 Virus: In Silico Study Immunomodulatory Drugs.

BACKGROUND: COVID-19 (Coronavirus Disease 2019) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) has infected millions of people and caused hundreds of thousands of deaths worldwide. However, until now no specific drug for SARS-CoV-2 infection has been found. This prompted many researchers to explore compounds as anti-SARS-CoV-2 candidates. One of the efforts to deal with the spread of the COVID-19 virus is to increase the body's immune system (immune). Medicinal plants are known to have the ability as immune-modulators, one of which is Betel leaf (Piper betle L.) which has good activity as antibacterial, antioxidant, and anti-viral with other pharmacological effects. An in silico approach in drug development was used to search for potential antiviral compounds as inhibitors of SARS-CoV-2 Mpro Protein, RBD, and Non-structural Protein (NSP15). OBJECTIVE: This study aimed to determine the potential of Betel leaf compounds as immunemodulators and good inhibitory pathways against COVID-19. METHODS: In this study, a potential screening of steroid class compounds, namely 24- propilcholesterol was carried out as an anti-SARS-CoV-2 candidate, using an in silico approach with molecular docking simulations for three receptors that play an important role in COVID-19, namely Mpro SARS-CoV-2, RBD SARS-CoV-2 and a non-structural protein (NSP15) and were compared with Azithromycin, Favipiravir and Ritonavir as positive controls. RESULTS: Based on the results of molecular docking simulations, compound from Betel leaf, 24- Propylcholesterol, showed high binding affinity values for spike glycoprotein RBD and nonstructural protein 15 (NSP15), namely -7.5 and -7.8 kcal/mol. Meanwhile, a native ligand of Mpro, inhibitor N3, has a higher binding affinity value than 24-propylcholesterol -7.4 kcal/mol. CONCLUSION: 24-Propylcholesterol compound predicted to have potential as an anti-SARS-CoV-2 compound. However, it is necessary to carry out in vitro and in vivo studies to determine the effectiveness of the compound as an anti-SARS-CoV-2.

The Potential of 24-Propylcholestrol as Antibacterial Oral Bacteria of Enterococcus faecalis ATCC 29212 and Inhibitor Biofilms Formation: in vitro and in silico Study.

Introduction: Uncontrolled biofilm can cause several diseases such as dental caries, gingivitis, and periodontitis. Dental caries is a disease caused by the accumulation of plaque-containing pathogenic bacteria, including Enterococcus faecalis. These bacteria infect the root canals of teeth and colonize to form biofilms. Biofilm inhibition is carried out by interfering with cell wall formation metabolism. MurA enzyme has a role in peptidoglycan biosynthesis of cell walls. Enterococcal surface protein (Esp) is the main contributor of E. faecalis to form biofilms. In addition, inhibition of biofilms by interfering with the quorum sensing (QS) system, suppressing gelatinase virulence factors by blocking autoinducers gelatinase biosynthesis-activating pheromone (GBAP). Purpose: Knowing the potential of Piper betel Linn. compounds as antibacterial in vitro and antibiofilm agents against E. faecalis in silico. Patients and Methods: The compounds were purified by a bioactivity-guided chromatographic method. Antibacterial activity was tested by disc diffusion method, in vitro studies. In silico study, compound P. betel L. was used as the test ligand and compared with positive control fosfomycin, ambuic acid, quercetin, and taxifolin. The proteins used MurA, Esp, GBAP, and gelatinase were docking with the Autodock Vina PyRx 0.8 followed by the PYMOL program and visualized with the Discovery Studio 2020 program. Results: An antibacterial compound was identified 24-propylcholesterol which can inhibit the activity of E. faecalis ATCC 29212 with MIC value of 78.1 µg/mL and MBC value of 156.3 µg/mL. Molecular docking results showed the binding affinity of 24-propylcholesterol with MurA, ESP, GBAP, and gelatinase enzymes was -7.6, -8.7, -5.3, and -7.9 kcal/mol. Conclusion: 24-propylcholesterol has potential as an antibacterial against E. faecalis and as an antibiofilm through in silico inhibition of QS. However, further research is needed in vitro and in vivo to determine the effectiveness of these compounds as antibacterial and antibiofilm.

Prediction of the mechanism of action of catechin as superoxide anion antioxidants and natural antivirals for COVID-19 infection with in silico study.

Coronavirus disease-2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus-2 attacking the lungs, which contain the most oxygen. The involvement of oxidative stress in the body and the role of antioxidant compounds, namely catechins, are thought to be able to prevent various diseases, including the COVID-19 infection virus. An in silico approach was employed between the catechins and the protein NADPH oxidase (Nox), followed by the coronavirus protease protein, to limit the generation of reactive oxygen species. This research using the in silico method seeks to predict the mechanism of action of catechin as a superoxide radical anion inhibitor and as an antiviral for COVID-19. This study carried out molecular docking simulations of catechin compounds against Nox and coronavirus proteases and then compared them with positive controls GKT136901 and remdesivir. The binding energy of catechin and Nox in a docking simulation is - 8.30 kcal/mol, which is somewhat lower than GKT136901's binding value of - 8.72 kcal/mol. Catechin and coronavirus proteases had binding energy of - 7.89 kcal/mol, which was greater than remdesivir's binding energy of - 7.50 kcal/mol. Based on in silico data, catechin as an antioxidant compound can be antiviral for COVID-19.

A new highly selective "off-on" typical chemosensor of Al3+, 1-((Z)-((E)-(3,5-dichloro-2-hydroxybenzylidene)hydrazono)methyl) naphthalene-2-ol, an experimental and in silico study.

A new promising fluorescent chemosensor based on a 2-hydroxynaphthaldehyde skeleton was successfully synthesized through double imine formation as a yellow solid with an overall chemical yield of 63%. The compound showed UV/Visible maxima of at 394 nm in DMSO. Based on spectroscopic data of FTIR, ToF-HRMS, 1H-NMR, and 13C-NMR, the product was characterized as 1-((Z)-((E)-(3,5-dichloro-2-hydroxybenzilydine)hydrazono)methyl)naphthalene-2-ol. Upon experimental study, the compound was confirmed as a highly selective and reversible off-on typical chemosensor against Al3+ with an emission quantum yield of 0.203 ± 0.009. The Job's plot analysis revealed that a highly stable 1:1 complex was formed with an association constant of 8.73 × 105 M-1. A pH-dependent study showed that the sensor was potentially applicable at physiological conditions (pH 7-8) in a mixture of DMSO : H2O (99 : 1, v/v). The LoD and LoQ of the chemosensor towards Al3+ in DMSO were found to be 0.04 and 0.14 µM respectively. Based on DFT and TD-DFT calculation (B3LYP hybrid method/basis set of 6-311+G(d,p)), the sensing mechanism of the chemosensor to the ion was discovered as inhibition of excited-state intramolecular proton transfer (ESIPT).

Bio-Mechanism of Catechin as Pheromone Signal Inhibitor: Prediction of Antibacterial Agent Action Mode by In Vitro and In Silico Study.

The utilization of medicinal plants has long been explored for the discovery of antibacterial agents and the most effective mechanisms or new targets that can prevent and control the spread of antibiotic resistance. One kind of bacterial cell wall inhibition is the inactivation of the MurA enzyme that contributes to the formation of peptidoglycan. Another approach is to interfere with the cell-cell communication of bacteria called the Quorum sensing (QS) system. The blocking of auto-inducer such as gelatinase biosynthesis-activating pheromone (GBAP) can also suppress the virulence factors of gelatinase and serine protease. This research, in particular, aims to analyze lead compounds as antibacterial and anti-QS agents from Gambir (Uncaria gambir Roxburgh) through protein inhibition by in silico study. Antibacterial agents were isolated by bioactivity-guided isolation using a combination of chromatographic methods, and their chemical structures were determined by spectroscopic analysis methods. The in vitro antibacterial activity was evaluated by disc diffusion methods to determine inhibitory values. Meanwhile, in the in silico analysis, the compound of Uncaria gambir was used as ligand and compared with fosfomycin, ambuic acid, quercetin, and taxifolin as the standard ligand. These ligands were attached to MurA, GBAP, gelatinase, and serine proteases using Autodock Vina in PyRx 0.8 followed by PYMOL for combining the ligand conformation and proteins. plus programs to explore the complex, and visualized by Discovery Studio 2020 Client program. The antibacterial agent was identified as catechin that showed inhibitory activity against Enterococcus faecalis ATCC 29212 with inhibition zones of 11.70 mm at 10%, together with MIC and MBC values of 0.63 and 1.25 µg/mL, respectively. In the in silico study, the molecular interaction of catechin with MurA, GBAP, and gelatinase proteins showed good binding energy compared with two positive controls, namely fosfomycin and ambuic acid. It is better to use catechin-MurA (-8.5 Kcal/mol) and catechin-gelatinase (-7.8 Kcal/mol), as they have binding energies which are not marginally different from quercetin and taxifolin. On the other hand, the binding energy of serine protease is lower than quercetin, taxifolin, and ambuic acid. Based on the data, catechin has potency as an antibacterial through the inhibition of GBAP proteins, gelatinase, and serine protease that play a role in the QS system. This is the first discovery of the potential of catechin as an alternative antibacterial agent with an effective mechanism to prevent and control oral disease affected by antibiotic resistance.

Action mode of ursolic acid as a natural antioxidant and inhibitor of superoxide dismutase: In vitro and in silico study.

Recently, the antioxidant is applied for the teeth bleaching treatment as an alternative of toxic material of hydrogen peroxide that is used in teeth bleaching. One of natural sources antioxidant is Uncaria gambir those containing active antioxidant agents. To be applied as a new bioactive constituent in teeth bleaching treatment, a preexperimental study is performed. The aim of the study is to identify the antioxidant constituent of U. gambir and predict their activity including action mode as an inhibitor of enzyme superoxide dismutase (SOD) through in vitro and in silico method. Combination of chromatography methods and spectroscopic analysis is used for isolated bioactive antioxidant constituent. The antioxidant activity was evaluated by in vitro assay against diphenylpicrylhydrazyl (DPPH)and SOD, respectively, while prediction of action mode of the active compounds as SOD-mutant enzyme inhibitor was conducted by in silico study using AutoDock 4.2 program. Antioxidant of ursolic acid was isolated from U. gambir with inhibitory concentration50 values 1721 ± 30.6 and 392 ± 53.57 µg/mL, respectively, against DPPH and SOD. By in silico study presented that ursolic acid inhibited SOD enzyme with a binding affinity of - 5.4 kcal/mol those higher than a quercetin as a positive control. The ursolic acid was identified as a potential natural antioxidant with potentially activity to inhibit SOD mutant.

Maleic anhydride grafted onto high density polyethylene with an enhanced grafting degree via monomer microencapsulation.

High-density polyethylene (HDPE) is among the flexible polymers on account of its appropriate processability and adequate mechanical properties. Grafting reactive monomers such as glycidyl methacrylate (GMA) and maleic anhydride (MAH) onto polyethylene was one of the ultimate choices to improve the physicochemical properties of HDPE. MAH is an appropriate option for grafting onto HDPE owing to its low reactivity and it relatively undergoes a direct grafting onto the polymer. The grafting of MAH on HDPE copolymerization has been conducted using monomer microencapsulation method in this study. The monomer microencapsulation samples were extracted stratified using acetone and xylen. Samples were then analyzed using titration, melt flow rate, FTIR, DSC, TGA and C-NMR. The results showed the degree of paste monomer on HDPE with a microencapsulation method was greater when compared to the usual method. We were successfully improving the grafting degree of MAH onto HDPE by using a simple blending method. The pre-microencapsulated HDPE provided an increasing in grafting degree of 1.88% (HDPE-g-MAH) over the conventional one which shows the value of 1.39% (HDPE-g-MAH).

Synthetic and structure-activity relationship of insecticidal bufadienolides.

A new synthetic analog of bufadienolide, methyl isobryophyllinate A (1), and a known synthetic analog, methyl isobersaldegenate-1,3,5-orthoacetate (2), were obtained by methanolysis of bryophyllin A (3) and bersaldegenin-1,3,5-orthoacetate (5) in basic solution. Structure-insecticidal activity relationship studies revealed both orthoacetate and alpha-pyrone moieties seemed to be essential structural elements for exhibiting insecticidal activity, whereas oxygenated substituents in the C ring enhanced the insecticidal activity against the third instar larvae of silkworm (Bombyx mori).