The Discovery of Tyrosinase Enzyme Inhibitors Activity from Polyphenolic Compounds in Red Grape Seeds through In Silico Study

Tyrosinases are essential metal-containing enzymes in the biosynthesis of melanin, therefore responsible for pigmentation of the skin. The upregulation of tyrosinase enzyme activities leads to hyperpigmentation that will become a health problems and interfere psychosocially. Inhibition of tyrosinase enzyme activity, both competitive and non-competitive become widely developed for most anti hyperpigmentation agent. Natural antioxidants are one of the potential compounds for this purpose. Red grape seeds contain high levels of antioxidant compounds, such as procyanidin, prodelphinidin, and propelargonidin. In this research in silico studies, including molecular docking, molecular dynamics simulations, and toxicity predictions, were used to assess the activity of the three molecules of polyphenolic compounds on macromolecules of the tyrosinase enzyme. Molecular docking studies show that the compound propelargonidin has the highest affinity against the macromolecule of the tyrosinase enzyme, with a binding free energy value of −32.87 kJ/mol. These results were confirmed in molecular dynamics simulations that show strong interactions at the macromolecular active site of the tyrosinase enzyme. Toxicity prediction results show that the three polyphenolic compound molecules were classified in the High-Class Category, which shows that safety is not guaranteed, but is likely, not carcinogenic and nongenotoxic. Therefore, the compound propelargonidin is predicted to be able to interact strongly with the tyrosinase enzyme. The results in this research are useful for further study in the development of tyrosinase enzyme inhibitors.

Study of Sodium Chloride Production Using Gradual Evaporation of Seawater from Nggolonio Sea, East Nusa Tenggara

Sea water as a raw material resources for the kitchen salt production, besides containing NaCl, has also containing other dissolved salts such as hygroscopic calcium and magnesium salts. The high content of other salts cause industrial NaCl has a low quality. This aim research was to find out the effect of seawater evaporation on NaCl content changes. Seawater obtained from Nggolonto, Nagekeo, NTT, was used with an initial volume of 200 mL, then it was concentrated in varying of final volume, i.e. 20, 23, 25, 27 and 29 mL. The NaCl content was calculated based on total chloride ion content, corrected toward magnesium and calcium ions content and the presence of sulphate anion. In addition, the chloride and magnesium also calcium ions content was analyzed volumetrically, while the sulphate anion was determined spectrophotometrically. The research result showed that NaCl content increase significantly up to 27 mL of final volume and was constantly afterward. Furthermore, the highest of NaCl content obtained from final volume of 29 mL was 96.01%. Nevertheless, comparing to SNI 06-0303-1989, its content was still below the standard of 98.5%.

Effect of Calcination Temperature on the Synthesis of Silica from Bagasse

Bagasse is the solid waste derived from the sugar-making process. A large amount of silica in bagasse is a potential source of silica. In this study, extraction of silica from bagasse was carried out in the following steps: pretreatment of bagasse using HCl solution, followed by calcination at varying temperatures (700 oC, 800 oC, and 900 ℃) using a furnace. Furthermore, extraction using NaOH solution and precipitation using HCl. Silica characteristics were obtained using X-Ray Diffraction (XRD), Scanning Electron Microscopy-Electron Dispersive Spectrometry (SEM-EDS), and BET surface area. The results showed that calcination temperature affected the characteristics of the silica produced. The silica extracted at 700℃ produced an amorphous phase with a broad peak at an angle of 2θ = 20-24°. It contained the most considerable silica content and surface area, 42.46% and 796.89 cm2/g, respectively. The extracted silica had an average diameter of 5.67 mm and a pore volume of 1.184 cm3/g.

The Performance of Activated Carbon from Used Coffee Grounds Combined with Iron(III) Oxide under UV Light and Ultrasound for Phenol Degradation

Coffee consumption over the past four years has continued to increase the amount of used coffee grounds. Usually, the used coffee grounds are simply thrown away. In fact, it can still be used as other materials that are more efficient and environmentally friendly, such as activated carbon. Activated carbon can be utilized as an adsorbent to adsorb compounds that are carcinogenic and potentially last a long time in the environment, such as phenols. Phenol decomposition through chemical can be carried out by Advanced Oxidation Process (AOP) which utilize hydroxyl radicals. This method used a catalyst such as iron(III) oxide under ultraviolet light. Phenol decomposition can also be carried out using ultrasound. This study presents the performance of the combination of activated carbon-catalyst with ultrasound in phenol decomposition. The results showed that the mass of the composite influenced the 0.1 M phenol degradation by the activated carbon–iron(III) oxide assisted with ultraviolet light, ultrasound, and 0.01 M hydrogen peroxide. for 45 minutes. The best degradation of phenol was obtained when 0.5 g adsorbent was applied with the adsorption capacity of phenol was 704.37 mg/g. The concentration of hydrogen peroxide also affects the decomposition of phenol in solution. From the variation of the hydrogen peroxide solution used (0.01; 0.02; and 0.03 M), the optimal concentration in degrading phenol was 0.01 M with the adsorption capacity of phenol was 393.70 mg/g.

Determination of Heavy and Trace Metals in Honey Using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) in South Eastern Zone of Tigray Region, Northern Ethiopia

The present study aimed to determine concentration of heavy and trace metals (Fe, Cu, Mn, Zn, Co, Cd, Pb, As, and Hg) in honey by inductively coupled plasma optical emission spectrometry (ICP-OES). Samples passed through wet digestion methods following the optimum digestion condition by applying the reagents (30mL HNO3:30mL H2O2) at temperature of 270°C for 3 hours. The average concentrations of the metals are found in the range of 5.32-28.6 mg/kg for Fe, 0.24-0.749mg/kg for Cu, 0.627-4.401mg/kg Zn, 0.41-3.15mg/kg for Mn, 0.08-0.112 mg/kg for Co, 0.25-0.325mg/kg for Pb, 0.24-0.46mg/kg for As, ND-0.031mg/kg for Hg and 0.02-0.03mg/kg for Cd. This study shows that the honey in the studied area is a good sources of essential metals (Fe, Cu, Mn, Co and Zn) as they are found to be in the permissible limit. Moreover, the maximum concentration of the toxic metals determined in this work are below the level of toxicity as per the standard set by WHO/FAO.

Synthesis, Characterization, and Photocatalytic Activity of N-Doped TiO2/Zeolite-NaY for Methylene Blue Removal

Dye is an important compound in textile industry. The famous dye for coloring of textile is methylene blue. Methylene blue degradation has been difficult when carried out naturally by microorganisms. The advanced oxidative process is a promising method to degrade methylene blue using semiconductor material TiO2 and its modification. The modification catalyst of TiO2 such as TiO2-N, TiO2/zeolite-NaY and TiO2-N/zeolite-NaY. These materials were synthesized by mixing TiO2 and urea, then followed by impregnation of the mixture to zeolite-NaY as support material. The materials have been synthesized then characterized by XRD, and FTIR. Degradation of methylene blue on the synthesized materials was tested under UV light for 5, 20, 30, 40, and 50 minutes. The results showed that the diffractogram of TiO-N/zeolite-NaY and TiO2/zeolite-Y has a similar spesific peak with TiO2 and zeolite-NaY. It indicates that the impregnation process was sucessfully. TiO2/zeolite-NaY and TiO2-N/zeolite-NaY also showed the excellent activity for degrading methylene blue, which reached up to 99% for 3 hours of reaction.

Anti-Inflammatory Activity of an Indole Alkaloid Isolated from Bebuas (Premna serratifolia)

Premna serratifolia known as bebuas has long been used by Malay comunity for both food and traditional medicine. The most notable advantage of this plant is to heal woman after childbirth and to raise the notion that contains anti-inflammatory bioactive compounds. In this study, the hexane extract of bebuas was only contained steroids. Meanwhile the ethanol extract contained various secondary metabolites such as phenolics, alkaloids, flavonoids, steroids and saponins. The ethanol extract was further separated since the targeted compound isolate was an alkaloid. The isolate obtained was a yellow crystal which transformed to yellow oil after being exposed to air. The anti-inflammatory evaluation of the compound gave a result with a strong activity with ED50 = 4.06 mg/KgBW. Characterization by UV-Vis and FT-IR showed that the isolate’s spectra pattern had similarities with bufotenine. It revealed that the isolate shared the same basic skeleton with the bufotenine, especially the indole skeleton. Furthermore, it also shared the same physical form with bufotenine. These evidences strengthened the assumption that the isolate was an indole alkaloid.

Spectral Analysis and In vitro Biological Activity of Cu(II) Complex with Tridentate ONO Schiff Base Ligand

In this study, metal complex of Copper(II) with a Schiff base derived from 2,2-dihydroxyindane-1,3-dione and 2-aminoethanoic acid were synthesized. The product are characterized by spectral methods. The antimicrobial activity was tested on reference bacterial strains and the antioxidant capacity was analyzed by using the DPPH and FRAP methods. The spectral data indicates that the Schiff base coordinates the Copper(II) as a tridentate ONO donor ligand. The compounds showed weaker antimicrobial activity on certain tested microorganisms. In vitro testing of antioxidant activity showed a significant reducing ability of the complex, as well as inhibitory activity against DPPH radicals.

The Effect of Temperature Synthesis on the Plate-Like Particle of Bi4Ti3O12 Obtained by Single Molten NaCl Salt

Three-layer Aurivillius compound bismuth titanate (Bi4Ti3O12) is well known for having interesting properties such as ferroelectric and photocatalyst. Many researchers reported that the unique plate-like shaped particle affecting ferroelectric and photocatalyst properties. The molten salt synthesis is the common simple method to obtain that unique morphology. In this research, Bi4Ti3O12 was synthesized using single molten salt NaCl at various temperatures, which is 800, 850, 900, and 950 oC. X-Ray Diffraction data showed that all obtained Bi4Ti3O12 have a B2cb space group with no impurities detected. The Raman spectra shows the characteristic vibration modes of Bi4Ti3O12 at 62, 117, 228, 269, 332, 364, 536, 851 cm-1. The plate-like shaped particle was confirmed by SEM analysis. Based on SEM images, the size of the particle increased along with the synthesis temperature, which is due to the thermal effect on grain growth.

Utilization of Mendong Plants-Activated Charcoal as H2S and NO2 Gas Adsorbent: Preliminary Study

The study of exhaust H2S and NO2 gases using activated carbon has been conducted. In this study, activated carbon was prepared from mendong plant (Frimbistylis umbellaris), which was activated using zinc chloride (ZnCl2) with concentrations of 2.5; 5; 7.5; and 10 % w/v to determine the efficiency of H2S adsorption. Mendong charcoal was obtained from the process of using a modified tool. Activation was done by maceration using ZnCl2 activator (w/v) for 24 hours. The adsorption of H2S and NO2 was analyzed using UV-Vis spectrophotometry. Determinations of H2S gas carried out using the blue methylene’s method for 1 hour showed the highest effectiveness of mendong activated carbon was of that at the concentration of 2.5 % ZnCl2 w/v with 80% of H2S removal. Further, the mendong activated carbon with the concentration of 2.5% ZnCl2 w/v was used for NO2 adsorption. The adsorption of NO2 gas was conducted for 1 hour using Griess Saltzman’s method. The result showed that the largest concentration of NO2 gas was adsorbed when the HNO3 concentration was 1.5 M (0.057 µg/mL). The percentage of NO2 efficiency adsorbed was at 28%.