Search

Bioactive peptides play an important role in targeting cancer cells. Venom protein from Naja sumatrana can be explored as a source of bioactive peptides. This research aims to identify and study the molecular docking of bioactive peptides (BPs) from trypsin hydrolysate of N. sumatrana venom protein which was fractionated using an SPE C18 column. The venom of N. sumatrana was hydrolyzed with trypsin enzyme. The protein hydrolysate was then fractionated using an RP-SPE HyperSep Retain PEP column, and the peptide fractions were tested for their anticancer activity against MCF-7 breast cancer cells using the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Identification of peptides in the active fraction was carried out through high-resolution mass spectrometry. The identified peptides were molecularly docked with the EGFR receptor using AutoDock Vina. The results showed that the degree of hydrolysis was 74.7%. The 75% methanol fraction is the active fraction against MCF-7 cells, with an IC50 value of 4.80 μg/mL and a selectivity index of 5.00. Peptide-active anticancer fractions with the sequence of NSLLVK, SSLLVK and TVPVKR were successfully identified and exhibited high binding affinity values, good RMSD values, and the most suitable model for the epidermal growth factor receptor.

Vernonia amygdalina was reported to be used as a therapy for Diabetes Mellitus (DM). One of the mechanisms of therapy DM was to inhibit the action of the α-amylase enzyme. This study aimed to prove the presence of compounds that could inhibit the action of α-amylase. Vernonia amygdalina leaves were macerated with methanol and partitioned into n-hexane, dichloromethane (DCM), and ethyl acetate (EtOAc). Furthermore, they were tested for α-amylase inhibitory activity and analyzed using liquid chromatography-high resolutions mass spectrometry (LC-HRMS). Molecular docking and molecular dynamics simulation (MD simulation) examined unique compounds in the extract with good activity and chromatogram results. The EtOAc extracts showed potential as α-amylase inhibitors indicated by their IC50 values, namely 3.0 μg/mL. There are five unique compounds in the EtOAc extract predicted as 3-[(2Z)-3,7-dimethylocta-2,6-dien-1-yl]-2,4-dihydroxy-6-(2-phenylethyl)benzoic acid (compound 1), 2-hexylpentanedioic acid (compound 2), (2E,4E)-5-[1-hydroxy-2,6-dimethyl-4-oxo-6-({3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl] oxy}methyl)cyclohex-2-en-1-yl]-3-methylpenta-2,4-dienoic acid (compound 3), 3,5,5-trimethyl-4-(3-{[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-1-yl)oxy}butyl)cyclohex-2-en-1-one (compound 4), and 2-{[(6E)-2,10-dihydroxy-2,6,10-trimethyldodeca-6,11-dien-3-yl]oxy}-6-(hydroxymethyl)oxane-3, 4,5-triol (compound 5). The molecular docking analysis showed that compound 3 had better interaction energy (Ei) (-8.59 kcal/mol) and inhibition constant (Ki) values (0.503 μM) than acarbose. These data were supported by MD simulations based on the parameters of RMSD value, the radius of gyration, and protein-ligand interaction energy.

Context: Vernonia amygdalina has been reported as a potential antidiabetic agent. One of the mechanisms in diabetes mellitus treatment is the inhibition of the α-amylase enzyme’s action. Objective: This study is aimed to identify the presence of secondary metabolites in Vernonia amygdalina leaf extract, which has the potential as α-amylase inhibitors through phytochemical screening combined with metabolomic analysis. Materials and methods: Methanol extract from Vernonia amygdalina leaf was partitioned into n-hexane, dichloromethane (DCM), and ethyl acetate. From this process, methanol, hexane, DCM, and ethyl acetate extracts were obtained. These extracts were then being tested for phytochemical screening, α-amylase inhibition, and FTIR. Then FTIR data were used for metabolomic analysis (PCA and PLS). Results: The results of the α-amylase inhibition test showed that the ethyl acetate extract had the smallest IC50 average value, which was 3.00 μg/mL. Based on the phytochemical screening test results, the extract showed positive for the presence of compounds such as flavonoids, phenols, tannins, alkaloids, and saponins. From the PCA analysis (Bi-plot), the wavenumbers that were influential in the ethyl acetate extract were 1436 to 1681 and 3341 to 3348 cm−1. In theory, functional groups such as CH, CC, CO, NH, and OH appeared on the absorption. From the PLS analysis, these wavenumbers affected the activity. Conclusion: The most potential extract as an α-amylase inhibitor was the ethyl acetate extract. Based on phytochemical screening tests and metabolomic analysis, it was proven that this extract contained compounds as hypoglycemic agents.

Research on the isolation, toxicity test, antimalarial test, and identification of the active compound from the ethyl acetate fraction of Stylissa massa sponge from Oenggae waters, Rote Island, has been conducted. This study aimed to investigate the antimalarial activity of the ethyl acetate fraction of the Stylissa massa sponge. Isolation was carried out by the extraction method using a mixed solvent of methanol: dichloromethane of 3: 2 (v/v), then the extract was partitioned in a solvent mixture of ethyl acetate: water of 1: 2 (v/v). The ethyl acetate extract obtained was separated by column chromatography using the gradient polarity system method. The toxicity test of each fraction was carried out by the Brine Shrimp Lethality Test (BSLT) method, and the antimalarial test was carried out by the haematin polymerization inhibition method. Identification of compounds from the active fraction in the antimalarial test was carried out using Liquid Chromatography-Mass Spectrometry (LC-MS). The extraction yield was 1.14 g (0.23%) of the ethyl acetate extract in the form of a dark brownish-yellow oily solid. Separation by column chromatography resulted in 15 fractions. Toxicity test results showed the four most active fractions with LC50 values, which are very promising for new drug discovery. The IC50 value in the antimalarial activity test of the four fractions indicated that the Stylissa massa sponge ethyl acetate extract was more active than the standard chloroquine compound (115 μg/mL). The LC-MS analysis indicates that fraction 11 contains two compounds that have been reported, and 1 compound is unknown. In contrast, fraction 14 indicates that it contains three compounds that have been reported and one unknown compound.

In this study, the chloro-substituted hydroxyxanthones were prepared by cyclodehydration of acid derivatives and substituted phenol in the presence of Eaton reagent, followed by halogenations step to electrophilic substitution of chlorine in a moderate yield. The in vitro anticancer activity study on various cell lines revealed that the chloro functional group increases the anticancer activity of the hydroxyxanthone derivatives. The molecular docking study showed that there was a binding interaction between chloro-hydroxyxanthone and the amino acid residues such as Asp810, Cys809, Ile789, His790, and Leu644 of protein tyrosine kinase receptor (1T46.pdb).

The effect of pre-mixing by mechanical stirring before hydrothermal and hydrothermal time on the crystalline phases and morphology of titania has been studied. It was shown that nanotubes titania can be obtained after 5 h hydrothermal at 150 °C. The XRD patterns and Raman spectra of the produced powders showed the existence of anatase and titanate crystalline phases. At the longest stirring, TiO2 (B) was observed. High textural coefficient for [200] plane of anatase (TC200) confirmed oriented growth of one-dimensional anatase along [200]. All powders resulted at various stirring time were nanotubes, as confirmed by Transmission Electron Microscope (TEM). It was found that the longer the stirring, the higher the surface area of the nanotubes. All powders showed type-IV isotherm for nitrogen gas adsorption/desorption, indicating the existence of mesoporous materials. However, long hydrothermal induced the nanospheres formation, hence reducing the surface area. The band-gap of the resulted titania nanotubes were ranging from 3.11–3.16 eV. The photocatalytic performance toward the degradation of methylene blue of the titania nanotubes was higher (~50%) compared to the bulk TiO2 (~5%) under visible-light and was comparable under UV-light (~60%). These results pave a way of producing visible-sensitive TiO2 photocatalyst by altering the morphology.

A study of TiO2(rod)-SiO2 composites coated with polyaniline (PANI) has been performed. PANI was synthesized through in-situ polymerization of aniline at various concentration (0.0137, 0.0274, and 0.0411 M) on the composite under acidic condition. PANI was confirmed by the appearance of C=N, C=C vibrations and the redshift of the band-gap from 3.14 eV for the TiO2(rod)-SiO2 into 3.0 eV for the TSP01 composite. It is also shown that the polymerization does not change the crystal structure of TiO2(rod)-SiO2 as confirmed by the XRD pattern. The TEM image shows a mixed structure of SiO2 coated by TiO2(rod)-PANI layers and the oxides coated by PANI layers. Therefore, the surface area of the resulted TiO2(rod) and the composites did not change significantly. The T TiO2(rod)-SiO2-PANI composite give small improvement under visible irradiation from 20.25 to 25.59% (around 5% from the bulk of TiO2(rod)) and from 25.03 to 25.59% (around 2% from TiO2(rod)-SiO2 composite). The mixed structure of the composites, as well as the formation of excessive layers of PANI, are possibly the case for the low photoactivity. Further improvement to obtain a core-shell structure with a thin layer of PANI is still sought.