Molecular modeling for potential cathepsin L inhibitor identification as new anti-photoaging agents from tropical medicinal plants.

Ultraviolet exposure can cause photoaging toward the human skin which is begun by the inflammation on the exposure area, also resulting in activation of a degradative enzyme cathepsin L. This enzyme is one of the interesting novel therapeutic targets for antiaging agents. Three plants, named Kleinhovia hospita, Aleurites moluccana, and Centella asiatica, are well-known in the tropical region as anti-inflammatory herbs. The aims of this study were to predict the antiaging activity of the 31 compounds from these plants via inhibition of cathepsin L. All compounds were minimized their energies and then used in molecular docking. After that, molecular dynamics (MD) simulation was employed for the 5 candidate ligands and the positive control; schinol. Interaction analysis results of the pre-MD and post-MD simulation structures were obtained. Furthermore, a toxicity test was performed using ADMET Predictor 7.1. Based on the molecular docking and the MD simulation results, kleinhospitine A, ß-amyrin, and castiliferol exhibited lower binding free energy than schinol (-27.0925, -28.6813, -26.0037 kcal/mol) and also had interactions with the S´ region binding site. The toxicity test indicated that ß-amyrin is the most potential candidate since it exhibited the lowest binding energy and the high safety level.

A Search for Cyclin-Dependent Kinase 4/6 Inhibitors by Pharmacophore-Based Virtual Screening, Molecular Docking, and Molecular Dynamic Simulations.

The G1 phase of cell cycle progression is regulated by Cyclin-Dependent Kinase 4 (CDK4) as well as Cyclin-Dependent Kinase 6 (CDK6), and the acivities of these enzymes are regulated by the catalytic subunit, cyclin D. Cell cycle control through selective pharmacological inhibition of CDK4/6 has proven to be beneficial in the treatment of estrogen receptor-positive (ER-positive) breast cancer, particularly improving the progression-free survival of patients. Thus, targeting specific inhibition on CDK4/6 is bound to increase therapeutic efficiency. This study aimed to obtain CDK4/6 inhibitors through a pharmacophore-based virtual screening of the ZINC15 purchasable compound database using the in silico method. The pharmacophore model was designed based on the FDA-approved cdk4/6 inhibitor structures, and molecular docking was performed to further screen the hit compounds obtained. A total of eight compounds were selected based on docking results and interactions with CDK4 and CDK6, using palbociclib as the reference drug. According to the results, the compounds of ZINC585292724 and ZINC585291674 were the best compounds based on free binding energy, as well as hydrogen bond stability, and, therefore, exhibit potential as starting points in the development of CDK4/6 inhibitors.

Xylan from Pineapple Stem Waste: a Potential Biopolymer for Colonic Targeting of Anti-inflammatory Agent Mesalamine.

We have successfully conjugated mesalamine (5-aminosalicylic acid, 5-ASA) with xylan, a biopolymer isolated from pineapple stem waste, to form xylan-5-ASA conjugate. The biopolymer was used to provide colon-targeting properties for 5-ASA, a golden standard anti-inflammatory agent commonly used for ulcerative colitis treatment. A series of data from FTIR spectroscopy, UV-Vis spectrophotometry, and HPLC confirmed the xylan-5-ASA conjugate formation. To ensure successful colon targeting properties, in vitro and in vivo drug release studies after oral administration of xylan-5-ASA conjugate to Wistar rats were performed. Xylan-5-ASA conjugate was able to retain 5-ASA release in the upper gastrointestinal tract fluid simulation but rapidly released 5-ASA in the rat colon fluid simulation. In vivo release profile shows a very low peak plasma concentration, reached at 6 h after xylan-5-ASA conjugate administration. The delayed release and the lower bioavailability of 5-ASA from xylan-5-ASA conjugate administration compared to free 5-ASA administration confirmed the successful local colon delivery of 5-ASA using xylan-5-ASA conjugate. The administration of xylan-5-ASA conjugate also exhibited greater efficacy in recovering 2,4,6-trinitrobenzene sulfonic acid-induced colon ulcer compared to free 5-ASA administration. Taken together, xylan isolated from pineapple stem waste is promising to obtain colon targeting property for 5-ASA.

The novel selective inhibitors of cyclin-dependent kinase 4/6: in vitro and in silico study.

One of the main regulators in the cell cycle is cyclin-dependent kinase 4 and 6 (CDK4/6). FDA has approved CDK4/6 inhibitors for the treatment of patients with metastatic breast cancer. However, the development of selective agents remains problematic due to the conservation of their ATP binding sites. In the previous in silico study, ZINC585292724, ZINC585292587, ZINC585291674, and ZINC585291474 have been identified as potential inhibitors. Therefore, the present study aimed to analyze the selectivity and inhibitory activity of the four compounds against CDK4/6 in vitro as well as determine the potential for their further development in silico. The in vitro results showed that the four compounds had good selectivity towards both kinases, due to their similar structure. In agreement with the in silico results, ZINC585291674 produced the best inhibitory activity against CDK4 and CDK6, with IC50 of 184.14 nM and 111.78 nM, respectively. Their ADMET profile were also similar to reference compound of Palbociclib. Based on this, ZINC585291674 can be used as a lead compound for further inhibitor development.

Toxicity evaluation of zinc oxide nanoparticles green synthesized using papaya extract in zebrafish.

In green synthesis of zinc oxide nanoparticles (ZnO NPs), the use of papaya extract as a capping and reducing agent shows promise for potential applications of these particles in biomedicine. However, toxicity evaluation is necessary to ensure the safety of humans and the environment. The zebrafish model is used to assess toxicity with embryo developmental observation as it is a rapid, simple method for screening of toxicity. The objective of the present study was to assess the toxicological characteristics of ZnO NPs produced from papaya extract using a zebrafish model. The preparation of plant extracts from papaya using two solvents (water and methanol) and characterization of bioactive compounds in the extracts were reported. ZnO NPs were synthesized from both plant extracts and characterized with scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Toxicity evaluation was conducted on zebrafish embryos for 96 h. ZnO NPs synthesized from aqueous and methanol extracts had mean crystallite diameters of 13 and 12 nm, respectively. Mortality, hatching rate and malformation of zebrafish embryos were assessed at different concentrations of ZnO NPs. Both NPs showed high mortality rates at high concentrations, with 100 (aqueous) and 20 mg/l (methanol extract) being lethal for all embryos. Concentrations <10 mg/l for both synthesized ZnO NPs had similar results to the negative control, indicating a safe dosage for embryos. The hatching rate and malformation were also affected, with higher concentrations of NPs causing a delayed hatching rate and malformation in pericardial and yolk sac edema. Whole embryo mRNA expression of immune-associated genes, including IL-1 and -10 and TNF-α, was upregulated following lethal concentration 50 (LC50) ZnO NP exposure. ZnO NPs synthesized from papaya extract (both in aqueous and methanol environments) had a dose- and time-dependent embryonic toxicity effect. Hence, the present study demonstrated initial toxicity screening of ZnO NPs synthesized from plant extract.

Alpha-mangostin, piperine and beta-sitosterol as hepatitis C antivirus (HCV): In silico and in vitro studies.

Hepatitis C is still a serious liver case of health. Up to now the development of anti-Hepatitis C Virus (HCV) drugs is challenging, especially the development of natural material compounds as anti-HCV. In the present study, we evaluated the probability of α-mangostin, piperine, and ß-sitosterol as anti-HCV with the in silico and in vitro approaches. Molecular docking was performed between nonstructural protein 5B (NS5B, PDB ID 3FQL) with α-mangostin, piperine, and ß-sitosterol by Autodock Tools® and BIOVIA Discovery Studio®. Subsequently, molecular dynamics simulations were conducted for 200 ns, evaluating the dynamic interaction between the ligands and the viral protein NS5B. Furthermore, compound characterization at the hepatocarcinoma cell line was employed. α-Mangostin with NS5B complex demonstrated the most negative binding free energy value based on MM-PBSA calculation with a value of -9.13 kcal/mol. In vitro test showed that IC50 of α -mangostin was 2.70 ± 0.92 µM, IC50 of piperine was 52.18 ± 3.21 µM, IC50 of ß-sitosterol was >100 µM. α-Mangostin can serve as a valuable lead compound for further development of the anti-HCV.

Analytical Method Development for Determining Formaldehyde in Cream Cosmetics Using Hyphenated Gas Chromatography.

Formaldehyde has been reported to be a potential human carcinogen due to its toxicity. However, formaldehyde releaser substances are still widely used as a preservative in cosmetics. Researchers have developed various methods for determining formaldehyde. One of the problems involved in the standard method is that of obtaining a derivatization agent, especially for routine analysis in the National Agency of Drug and Food, Indonesia. Therefore, this study aimed to develop a new method using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The significant modifications involved optimizations of five series of concentrations of p-toluenesulfonic (PTS) acid in ethanol (acidified ethanol), used as the derivatization agent, and the conditions of time and temperature of the reaction to yield the highest peak area. In addition, sample analysis was also carried out using the 2,4-dinitrophenylhydrazine (DNPH) method with high-performance liquid chromatography (HPLC) to compare the quantification results. The validated method showed intraday and interday precision, an accuracy (% RSD) of less than 3.7%, confidence interval 95.0-105.0%, a limit of detection and quantitation of 0.0099 and 0.0329 µg/mL (for DNPH by HPLC-DAD), 0.0158 and 0.0528 µg/mL (for PTS by SHS-GC-MS), and 1.1287 and 3.7625 µg/mL (for PTS liquid by GC-FID), respectively. These results have met the requirements for a validated analytical method and could be applied for routine analysis.

Regulation of mitogen-activated protein kinase signaling pathway and proinflammatory cytokines by ursolic acid in murine macrophages infected with Mycobacterium avium.

Mycobacterium avium, one of the closest relatives of Mycobacterium tuberculosis (MTB), offers an advantage in studying MTB because of its tuberculosis-like effect in humans and host immune tolerance. This study examined the antimycobacterial action of ursolic acid and its regulation in macrophages during infection. Colonyforming units of the bacteria were determined in the cell lysate of macrophages and in the supernatant. The effect of ursolic acid on macrophages during infection was determined by analyzing the phosphorylation of the mitogen-activated protein kinase signaling pathway and the concentrations of tumor necrosis factor-α, interleukin-1ß, interleukin-6, and nitrite. The colony-forming units analysis demonstrated that ursolic acid reduced the presence of Mycobacterium avium both intracellularly (in macrophages) and extracellularly. It decreased the levels of tumor necrosis factor- α and interleukin-6 but increased the concentrations of interleukin-1ß and nitrite during infection. It also inhibited the phosphorylation of ERK1/2 but phosphorylated the C-Jun N-terminal kinase signaling pathway. The antimycobacterial effect of ursolic acid correlated with its ability to regulate the activation of macrophages. This dual ability made the ursolic acid-related elimination of the mycobacteria more effective.

Antifibrotic Activity and In Ovo Toxicity Study of Liver-Targeted Curcumin-Gold Nanoparticle.

Conjugation of curcumin and gold with green chemistry is an approach to improve the effectiveness of curcumin as anti-fibrosis. In this work, curcumin and gold were conjugated to deliver curcumin to the liver. Curcumin-gold nanoparticles (cAuNPs) were prepared by varying curcumin pH and concentration. The successful of cAuNPs formation were identified by using UV-visible and FTIR spectrophotometers. The particle size and morphology were analyzed using particle size analyzer and cryo-TEM respectively. In vitro antioxidant assay was performed to determine the curcumin activity after conjugation. Physical and chemical stabilities of cAuNPs were studied for one month at 5 °C, 25 °C, and 40 °C. Furthermore, the cAuNPs activity to modulate early marker of fibrosis was tested on NIH/3T3 cells. The optimum condition for cAuNPs synthesis was by using 1.5 mM curcumin at pH 9.3. As compared to free curcumin, cAuNPs showed higher antioxidant activity and maintained the nanosize after stored for one month. In line with the antioxidant activity, cAuNPs 0.25⁻1 µg/mL reduced the collagen production by NIH/3T3 cells. More importantly, cAuNPs did not demonstrate any effect on the development of chicken embryo. Taken together, the attachment of gold to curcumin in the form of cAuNPs is promising for curcumin targeting to treat hepatic fibrosis.

In Silico Study to Develop a Lectin-Like Protein from Mushroom Agaricus bisporus for Pharmaceutical Application.

A lectin-like protein of unknown function designated as LSMT was recently discovered in the edible mushroom Agaricus bisporus. The protein shares high structural similarity to HA-33 from Clostridium botulinum (HA33) and Ricin-B-like lectin from the mushroom Clitocybe nebularis (CNL), which have been developed as drug carrier and anti-cancer, respectively. These homologous proteins display the ability to penetrate the intestinal epithelial cell monolayer, and are beneficial for oral administration. As the characteristics of LSMT are unknown, a structural study in silico was performed to assess its potential pharmaceutical application. The study suggested potential binding to target ligands such as HA-33 and CNL although the nature, specificity, capacity, mode, and strength may differ. Further molecular docking experiments suggest that interactions between the LSMT and tested ligands may take place. This finding indicates the possible use of the LSMT protein, initiating new research on its use for pharmaceutical purposes.