Nanomaterials have various unique properties and characteristics so that they can apply in many sectors. One of the most popular nanoparticles today is magnetite nanoparticles. Magnetite particles have several properties such as being super magnetic, having a high saturation field, chemical stability, biocompatibility, and low production costs. The purpose of this article is to review the synthesis of magnetite nanoparticles and their application to Glassy Carbon Electrode (GCE) modification. This modified GCE can applied as an electrochemical sensor to detect various organic and inorganic substances. In this study, type synthesis methods of magnetite nanoparticles which taken from kind literature well investigation include coprecipitation, sol-gel, microemulsion, hydrothermal, and thermal decomposition. The five routes have their respective advantages and disadvantages. Then the nano magnetite made can applied to modify the GCE as an electrochemical sensor that can detect uric acid, bacteria, and even metals dissolved in water.

Indonesia is a tropical country with biodiversity and a source of natural compounds such as terpenoids, phenolic, flavonoids, and alkaloid groups. The steroid is one of the large groups of terpenoid compounds with various structures and bioactivities. The steroid was also commonly found in the Meliaceae family. One species of this family is Lansium domesticum Corr. which has been studied to have various activities from isolated compounds (limonoids, sesquiterpenoids, onoceranoids, cycloartanoids, and steroids) as well as from their extracts such as antidiarrheal, antimalarial, antimicrobial, antiinsecticide, antifeedant and were used as traditional medicine such as eye drops and scorpion stings. The n -hexane fraction from the bark of L. domesticum Cor. cv. Kokosan produced steroid compounds whose structure is determined by IR, 1 H-NMR, 13 C-NMR, and DEPT spectroscopy methods and compared with the literature. It was concluded that the steroid isolated was (22 E )-stigmasta-5,22-dien-3ol and was first isolated from this genus. This compound was inactive against MCF-7 breast cancer cells with an IC 50 value of 832.14 µM.

Clean water is vital in the creation of energy and sustenance of life. However, the pollution of water and the absence of potable water are global problems resulting from agricultural and industrial activities. We have witnessed significant growth in the pollution of water by organic compounds like PAH. Experts have made an effort to establish favorable techniques for the treatment of PAH polluted water. These techniques are either thermal, biological, physical or chemical. Bioremediation, chemical oxidation, solid-phase extraction, coagulation, photocatalytic degradation and adsorption using graphenes, mesoporous silica and agricultural wastes are techniques that are already in use in the field treatment of PAHs while electrokinetic remediation and nanoremediation are still in their developmental stage. Several reviews on the treatment of sediments and soils contaminated with PAHs have been published, but only a few reviews center mainly on the removal of PAHs in water. Therefore, this review aims to provide information on the techniques used in the treatment of water contaminated with PAHs. Techniques that are already in use and those that are in their developmental stage were reviewed. The successes of these methods, limitations, constraints and field procedures were analyzed and this will help to inform decision making.

Styletella sp. is a type of sponge in the Halichondriidae family which is rich in secondary metabolite compounds that have various bioactivities that have the potential as drugs in the future, one of which is anticancer. This study aims to determine the types of secondary metabolites found in Stylotella sp. in Selayar Island and to determine the secondary metabolite bioactivity of MCF-7 breast cancer cells. The method used is extraction using acetone, fractionation and purification. The purity test was carried out by testing three eluent systems at TLC, namely chloroform:ethyl acetate (9:1), n-hexane: acetone (8:2), chloroform: acetone (9:1) eluent. Then qualitatively and characterized by FTIR spectrophotometer. The results showed that pure isolates contained alkaloid compounds. The MCF-7 cell activity test showed an IC50 value for acetone extract of 1452.38 g/mL which has potential anticancer activity and an IC50 value for pure isolate acetone extract of 14983.52 g/mL.

Nutmeg ( Myristica fragrans ) contains essential oils and can be applied in industrial scale because it has medicinal benefits such as stimulating the heart system, stomachache, rheumatism, muscle pain, toothache, eliminating toxins in the liver, flatulence, and antioxidant. The purpose of this study was to determine the antioxidant activity of the nutmeg mace graded extract. The research methods include plant determination, sample preparation, extraction by maceration method, phytochemical test, and antioxidant test using the DPPH method. The yield of Mace Nutmeg extract obtained was 30.3% n -hexane, 8.79% ethyl acetate, and 3.79% methanol and the IC 50 value of each mace nutmeg extract, namely the n -hexane extract was 56.22±1.15 ppm, 20.39±0.13 ppm ethyl acetate extract and 17.89±0.10 ppm methanol extract. From these results, it can be concluded that mace nutmeg extract has antioxidant activity with a strong category.

Rheumatoid arthritis is an auto-immune disease that causes chronic inflammation occurs of the joints. Rheumatoid arthritis is characterized by the the overproduction of proinflammation cytokines such as TNF-α and IL-1. The phenolic compounds mainly anthocyanin and elagitanin have TNF-α inhibition activity that induces cyclooxygenase-2 expressions that cause inflammation. Phytochemical screening showed that ethanol extract of red ginger contains alkaloids, phenolics, flavonoids, tannins, terpenoid, and steroids while ethanol extract of secang wood contains alkaloids, phenolics, flavonoids, tannins, and terpenoid. This research aims to identify the secondary metabolite qualitatively and total phenolic compunds on red ginger and secang wood with Folin-Ciocalteu method. Total phenolic compounds are defined as the Gallic Acid Equivalent (GAE). The results showed that the total phenolic compunds of red ginger and sappan wood were 21.90 mg GAE/g extract and 27.65 mg GAE/g extract, respectively. The phenolic compounds in red ginger and secang wood have the potential as antiarthritic.

In developing countries, malaria remains a disease that can spread easily and caused death. Malaria is an infectious disease caused by Plasmodium sp involving female anopheles masquitos during its transmission. Arcangelisia flava L. Merr has been investigated earlier that it can inhibited P. falciparum growth. Method of antimalarial activity based on inhibition of heme polymerization can confirm one of the mechanism of antimalarial drugs. The aim of this research to study further antimalarial activity and IC50 based on inhibition of heme polymerization and determine the chemical constituent from water extract of A. flava L. Merr. This research was conducted through several steps, namely 1) water extraction, 2) column chromatography (SiO2 ; (i) CH2Cl2-MeOH=10:1~1:1 (ii) n-hexane: EA=1:1; CH2Cl2-MeOH=10:1~1:1), 3) antimalarial assay, 4) identification of chemical constituent using FTIR and GC-MS. Results of this research are water extract of A. flava L. Merr has IC50 601 ppm and identification of chemical constituent using FTIR and GC-MS was assumed as stigmastan.

Epitopes are essential peptides for immune system stimulation, such as governing helper T lymphocyte (HTL) activation via antigen presentation and recognition. Current predictive models for epitope selection mainly rely on the antigen presentation, although HTLs only recognize 50% of the presented peptides. Thus, we developed a HTL epitope predictor which involves the antigen recognition step. The predictor is specific for epitopes presented by Human Leukocyte Allele (HLA)-DRB1*01:01, which is protective against developing multiple sclerosis and association with autoimmune diseases. As the data set, we used binding register of immunogenic and non-immunogenic HTL peptides related to HLA-DRB1*01:01. The binding registers were obtained from consensus results of two current HLA-binder predictors. Amino acid descriptors were extracted from the binding registers and subjected to random forest algorithm. A threshold optimization were applied to overcome data set imbalance class. In addition, descriptors were screened by using a recursive feature elimination to enhance the model performance. The obtained model shows that the hydrophobicity, steric, and electrostatic properties of epitopes, mainly at center of binding registers, are important for the TCR recognition as well as the HTL epitopes predictive model. The model complements current HLA-DRB1*01:01-binder prediction methods to screen immunogenic HTL epitopes.

α-Hydroxyisovaleric acid (Ac-Hiv) and α-acetyloxyisovaleric acid (Ac-Hiv) have been successfully synthesized through a diazotisation of amino acid using sodium nitrite with the catalyst of sulfuric acid and acetic acid, respectively. In the synthesis of Hiv, Zubia et al. (2005) mentioned that 3 equivalents of sodium nitrite for the reaction gave the hydroxy acid with a good yield. However, Cohen-Arazi et al. (2008) described that 6 equivalents of sodium nitrite resulted the highest yield. In present study, a variation of equivalents of sodium nitrite (3, 4, 5, 6 eq.) were trialed for the same method of synthesis. Through several experiments, we found that 6 equivalents of sodium nitrite were the best portion among all. This finding was applied into the synthesis of protected Hiv (Ac-Hiv) that was previously reported by Maharani et al. (2017) giving 63% yield when 3 equivalent of sodium nitrite was employed. By increasing the equivalent of sodium nitrite into 6 equivalents, the Ac-Hiv can be synthesized with an improved yield (71%).

Comparison between the references and the quantification of biuret standard curves can be performed using statistical methods. The objective of this study was to select a method of protein quantification of the biuret-spectrophotometric based on the similar standard curve of the compound. The study used experimental methods in the laboratory and references from a comparative scheme of mean that has categories of statistics called academic and practical terms. Two standard curves were tested with the reference data. The academic way was performed with a comparison of 11.779-12.401% confidence, and the quantification of the results of the protein mean of 8.211% and 10.17% showed no significant difference. The practical methods were carried out with the original reference data of 10.8-12.8%, and the result of the test confidence values of 9.163-11.180% and 7.596-8.826% showed different accuracy results. The quantifications of the protein biuret method displayed different results on how to compare according to academic and practical ways. The quantification method using the Biuret-spectrophotometric practical way shows accuracy by a certain standard curve compared with the original values of references.