2-Phenoxyacetamide group has been identified as one of markers in the discovery and development of SARS-CoV-2 antiviral agent through its main protease (Mpro) inhibition pathway. This study aims to study a series of 2-phenoxyacetamide derivatives using in silico method toward SARS-CoV-2 Mpro as the protein target. The study was initiated by employing structure-based pharmacophore to virtually screen and to select the ligands, which have the best fit score (hits) along with the common pharmacophore features being matched. The result shows that from the 11 ligands designed, four ligands are selected as the hits by demonstrating fit score in the range of 56.20 to 65.53 to the pharmacophore model, employing hydrogen bond acceptor (HBA) and hydrophobic (H) as the common features. The hits were then docked into the binding site of the Mpro to see the binding mode of the corresponding hits as well as its affinity. The docking results free energy of binding (ΔGbind) of the hits are in agreement with the pharmacophore fit score, in the range of -6.83 to -7.20 kcal/ mol. To gain the information of the hits as a potential drug to be developed, the in silico study was further proceed by predicting the mutagenic potency, toxicity and pharmacokinetic profiles. Based on the efficiency percentage, all hits meet the criteria as drug candidates by showing 84-88% leading to a conclusion that 2-phenoxyacetamide derivatives are beneficial to be marked as the lead compound for SARS-CoV-2 Mpro inhibitor.
The H1N1 pandemic in 2009 and the H5N1 outbreak in 2005 have shocked the world as millions of people were infected and hundreds of thousands died due to the infections by the influenza virus. Oseltamivir, the most common drug to block the viral life cycle by inhibiting neuraminidase (NA) enzyme, has been less effective in some resistant cases due to the virus mutation. Presently, the binding of 10 chalcone derivatives towards H5N1 and H1N1 NAs in the non-catalytic and catalytic sites was studied using molecular docking. The in silico study was also conducted for its drug-like likeness such as Lipinski Rule, mutagenicity, toxicity and pharmacokinetic profiles. The result demonstrates that two chalcones (1c and 2b) have the potential for future NA inhibitor development. Compound 1c inhibits H5N1 NA and H1N1 NA with IC50 of 27.63 µM and 28.11 µM, respectively, whereas compound 2b inhibits NAs with IC50 of 87.54 µM and 73.17 µM for H5N1 and H1N1, respectively. The in silico drug-like likeness prediction reveals that 1c is 62% better than 2b (58%) in meeting the criteria. The results suggested that 1c and 2b have potencies to be developed as non-competitive inhibitors of neuraminidase for the future development of anti-influenza drugs.
Supplementary Information: The online version contains supplementary material available at 10.1186/s13765-021-00639-w.
This present study reports some natural products and one hydroxamic acid synthetic compound which were previously reported as matrix metalloproteinase-9 (MMP-9) inhibitors to be evaluated for their inhibition toward severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) 3-chymotrypsin-like protease (3CLpro). This enzyme is one of the proteins responsible for this coronaviral replication. Two herbal methanolic extracts i.e., Averrhoa carambola leaves and Ageratum conyzoides aerial part demonstrate >50% inhibition at 1000 µg/mL. Interestingly, apigenin, one of flavonoids, demonstrates 92% inhibition at 250 µg/mL (925 µM) as well as hydroxamic acid compound, N-isobutyl-N-(4-methoxyphenylsulfonyl)glycyl hydroxamic acid (NNGH), which shows 69% inhibition at 100 µM. The in vitro results are supported by the docking studies revealing that the binding mode of both compounds is mainly by interacting with GLU166 residue in the hydrophobic pocket of the 3CLpro. Pharmacophore mapping further supported the results by confirming that the in vitro activities of both compounds are due to their pharmacophore features employing hydrogen bond acceptor (HBA), hydrogen bond donor (HBD) and hydrophobic. Gas Chromatography-Mass Spectrometry (GC-MS) analysis reported chromene compounds in Ageratum conyzoides aerial part methanolic extract are potential to be this enzyme inhibitor candidate. These all results reflect their potencies to be SARS-CoV-2 inhibitors through 3CLpro inhibition mechanism.
Matrix metalloproteinase9 (MMP9) is known to be highly expressed during metastatic cancer where most known potential inhibitors failed in the clinical trials. This study aims to select local plants in our state, as anti-breast cancer agent with hemopexin-like domain of MMP9 (PEX9) as the selective protein target. In silico screening for PEX9 inhibitors was performed from our in house-natural compound database to identify the plants. The selected plants were extracted using methanol and then a step-by-step in vitro screening against MMP9 was performed from its crude extract, partitions until fractions using FRET-based assay. The partitions were obtained by performing liquid-liquid extraction on the methanol extract using n-hexane, ethylacetate, n-butanol, and water representing nonpolar to polar solvents. The fractions were made from the selected partition, which demonstrated the best inhibition percentage toward MMP9, using column chromatography. Of the 200 compounds screened, 20 compounds that scored the binding affinity -11.2 to -8.1 kcal/mol toward PEX9 were selected as top hits. The binding of these hits were thoroughly investigated and linked to the plants which they were reported to be isolated from. Six of the eight crude extracts demonstrated inhibition toward MMP9 with the IC50 24 to 823 µg/mL. The partitions (1 mg/mL) of Ageratum conyzoides aerial parts and Ixora coccinea leaves showed inhibition 94% and 96%, whereas their fractions showed IC50 43 and 116 µg/mL, respectively toward MMP9. Using MTT assay, the crude extract of Ageratum exhibited IC50 22 and 229 µg/mL against 4T1 and T47D cell proliferations, respectively with a high safety index concluding its potential anti-breast cancer from herbal.
In our previous work, the partitions (1 mg/mL) of Ageratum conyzoides (AC) aerial parts and Ixora coccinea (IC) leaves showed inhibitions of 94% and 96%, respectively, whereas their fractions showed IC50 43 and 116 µg/mL, respectively, toward Matrix Metalloproteinase9 (MMP9), an enzyme that catalyzes a proteolysis of extracellular matrix. In this present study, we performed IC50 determinations for AC n-hexane, IC n-hexane, and IC ethylacetate partitions, followed by the cytotoxicity study of individual partitions against MDA-MB-231, 4T1, T47D, MCF7, and Vero cell lines. Successive fractionations from AC n-hexane and IC ethylacetate partitions led to the isolation of two compounds, oxytetracycline (OTC) and dioctyl phthalate (DOP). The result showed that AC n-hexane, IC n-hexane, and IC ethylacetate partitions inhibit MMP9 with their respective IC50 as follows: 246.1 µg/mL, 5.66 µg/mL, and 2.75 × 10-2 µg/mL. Toward MDA-MB-231, 4T1, T47D, and MCF7, AC n-hexane demonstrated IC50 2.05, 265, 109.70, and 2.11 µg/mL, respectively, whereas IC ethylacetate showed IC50 1.92, 57.5, 371.5, and 2.01 µg/mL, respectively. The inhibitions toward MMP9 by OTC were indicated by its IC50 18.69 µM, whereas DOP was inactive. A molecular docking study suggested that OTC prefers to bind to PEX9 rather than its catalytic domain. Against 4T1, OTC showed inhibition with IC50 414.20 µM. In conclusion, this study furtherly supports the previous finding that AC and IC are two herbals with potential to be developed as triple-negative anti-breast cancer agents.