Molecular insights in repurposing selective COX-2 inhibitor celecoxib against matrix metalloproteinases in potentiating delayed wound healing: a molecular docking and MMPB/SA based analysis of molecular dynamic simulations.

Matrix metalloproteinases (MMPs) are proteolytic enzymes that play a role in healing, including reducing inflammation, promoting fibroblast and keratinocyte migration, and modifying scar tissue. Due to their pleiotropic functions in the wound-healing process in diabetic wounds, MMPs constitute a significant cause of delayed wound closure. COX-2 inhibitors are proven to inhibit inflammation. The present study aims to repurpose celecoxib against MMP-2, MMP-8 and MMP-9 through in silico approaches, such as molecular docking, molecular dynamics, and MMPB/SA analysis. We considered five selective COX-2 inhibitors (celecoxib, etoricoxib, lumiracoxib, rofecoxib and valdecoxib) for our study against MMPs. Based on molecular docking study and hydrogen bonding pattern, celecoxib in complex with three MMPs was further analyzed using 1 µs (1000 ns) molecular dynamics simulation and MMPB/SA techniques. These studies identified that celecoxib exhibited significant binding affinity -8.8, -7.9 and -8.3 kcal/mol, respectively, against MMP-2, MMP-8 and MMP-9. Celecoxib formed hydrogen bonding and hydrophobic (π-π) interactions with crucial substrate pocket amino acids, which may be accountable for their inhibitory nature. The MMPB/SA studies showed that electrostatic and van der Waal energy terms favoured the total free binding energy component, while polar solvation terms were highly disfavored. The in silico analysis of the secondary structures showed that the celecoxib binding conformation maintains relatively stable along the simulation trajectories. These findings provide some key clues regarding the accommodation of celecoxib in the substrate binding S1' pocket and also provide structural insights and challenges in repurposing drugs as new MMP inhibitors with anti-inflammatory and anti-inflammatory wound-healing properties.Communicated by Ramaswamy H. Sarma.

A fragment-based exploration of diverse MMP-9 inhibitors through classification-dependent structural assessment.

Matrix metalloproteinases (MMPs) are belonging to the Zn2+-dependent metalloenzymes. These can degenerate the extracellular matrix (ECM) that is entailed with various biological processes. Among the MMP family members, MMP-9 is associated with several pathophysiological circumstances. Apart from wound healing, remodeling of bone, inflammatory mechanisms, and rheumatoid arthritis, MMP-9 has also significant roles in tumor invasion and metastasis. Therefore, MMP-9 has been in the spotlight of anticancer drug discovery programs for more than a decade. In this present study, classification-based QSAR techniques along with fragment-based data mining have been carried out on divergent MMP-9 inhibitors to point out the important structural attributes. This current study may be able to elucidate the importance of several pivotal molecular fragments such as sulfonamide, hydroxamate, i-butyl, and ethoxy functions for imparting potential MMP-9 inhibition. These observations are in correlation with the ligand-bound co-crystal structures of MMP-9. Therefore, these findings are beneficial for the design and discovery of effective MMP-9 inhibitors in the future.

Exploring natural anthraquinones as potential MMP2 inhibitors: A computational study.

OBJECTIVE: Matrix metalloproteinase-2 (MMP2) plays a significant role in cleaving extracellular matrix components, leading to many cancer cells' progression and invasion behavior. Therefore, MMP2 inhibition may hold promise for cancer treatment. Anthraquinones have shown antineoplastic effects, some of which have been used in clinical practice as anticancer drugs. This study used a computational drug discovery approach to assess the possible inhibitory effects of selected anthraquinones on MMP2. The results were then compared with that of Captopril, which was considered a standard drug. METHODS: This study used the AutoDock 4.0 tool to evaluate the binding affinity of 21 anthraquinones to the MMP2 catalytic domain. The most favorable scores based on the Gibbs free binding energy scores were given to the highest-ranked ligands. The Discovery Studio Visualizer tool illustrated interactions between MMP2 residues and top-ranked anthraquinones. RESULTS: A total of 12 anthraquinones were identified with ΔGbinding scores less than - 10 kcal/mol. Pulmatin (Chrysophanol-8-glucoside) was the most potent MMP2 inhibitor, with a ΔGbinding score of - 12.91 kcal/mol. This anthraquinone was able to restrict MMP2 activity within a picomolar range. CONCLUSION: MMP2 inhibition by anthraquinones, notably Pulmatin, may be a useful therapeutic approach for cancer treatment.

New Derivatives of N-Hydroxybutanamide: Preparation, MMP Inhibition, Cytotoxicity, and Antitumor Activity.

Using a novel method of N-substituted succinimide ring opening, new N-hydroxybutanamide derivatives were synthesized. These compounds were evaluated for their ability to inhibit matrix metalloproteinases (MMPs) and their cytotoxicity. The iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide showed the inhibition of MMP-2, MMP-9, and MMP-14 with an IC50 of 1-1.5 µM. All the compounds exhibited low toxicity towards carcinoma cell lines HeLa and HepG2. The iodoaniline derivative was also slightly toxic to glioma cell lines A-172 and U-251 MG. Non-cancerous FetMSC and Vero cells were found to be the least sensitive to all the compounds. In vivo studies demonstrated that the iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide had low acute toxicity. In a mouse model of B16 melanoma, this compound showed both antitumor and antimetastatic effects, with a 61.5% inhibition of tumor growth and an 88.6% inhibition of metastasis. Our findings suggest that the iodoaniline derivative of N1-hydroxy-N4-phenylbutanediamide has potential as a lead structure for the development of new MMP inhibitors. Our new synthetic approach can be a cost-effective method for the synthesis of inhibitors of metalloenzymes with promising antitumor potential.

Assessing structural insights into in-house arylsulfonyl L-(+) glutamine MMP-2 inhibitors as promising anticancer agents through structure-based computational modelling approaches.

MMP-2 is potentially contributing to several cancer progressions including leukaemias. Therefore, considering MMP-2 as a promising target, novel anticancer compounds may be designed. Here, 32 in-house arylsulfonyl L-(+) glutamines were subjected to various structure-based computational modelling approaches to recognize crucial structural attributes along with the spatial orientation for higher MMP-2 inhibition. Again, the docking-based 2D-QSAR study revealed that the Coulomb energy conferred by Tyr142 and total interaction energy conferred by Ala84 was crucial for MMP-2 inhibition. Importantly, the docking-dependent CoMFA and CoMSIA study revealed the importance of favourable steric, electrostatic, and hydrophobic substituents at the terminal phenyl ring. The MD simulation study revealed a lower fluctuation in the RMSD, RMSF, and Rg values indicating stable binding interactions of MMP-2 and these molecules. Moreover, the residual hydrogen bond and their interaction analysis disclosed crucial amino acid residues responsible for forming potential hydrogen bonding for higher MMP-2 inhibition. The results can effectively aid in the design and discovery of promising small-molecule drug-like MMP-2 inhibitors with greater anticancer potential in the future.

Novel Matrix Metalloproteinase-9 (MMP-9) Inhibitors in Cancer Treatment.

Matrix metalloproteinases (MMPs) belong to a family of zinc-dependent proteolytic metalloenzymes. MMP-9, a member of the gelatinase B family, is characterized as one of the most intricate MMPs. The crucial involvement of MMP-9 in extracellular matrix (ECM) remodeling underscores its significant correlation with each stage of cancer pathogenesis and progression. The design and synthesis of MMP-9 inhibitors is a potentially attractive research area. Unfortunately, to date, there is no effective MMP-9 inhibitor that passes the clinical trials and is approved by the FDA. This review primarily focuses on exploring the diverse strategies employed in the design and advancement of MMP-9 inhibitors, along with their anticancer effects and selectivity. To illuminate the essential structural characteristics necessary for the future design of novel MMP-9 inhibitors, the current narrative review highlights several recently discovered MMP-9 inhibitors exhibiting notable selectivity and potency.

Computational design of matrix metalloprotenaise-9 (MMP-9) resistant to auto-cleavage.

Matrix metalloproteinase-9 (MMP-9) is an endopeptidase that remodels the extracellular matrix. MMP-9 has been implicated in several diseases including neurodegeneration, arthritis, cardiovascular diseases, fibrosis and several types of cancer, resulting in a high demand for MMP-9 inhibitors for therapeutic purposes. For such drug design efforts, large amounts of MMP-9 are required. Yet, the catalytic domain of MMP-9 (MMP-9Cat) is an intrinsically unstable enzyme that tends to auto-cleave within minutes, making it difficult to use in drug design experiments and other biophysical studies. We set our goal to design MMP-9Cat variant that is active but stable to auto-cleavage. For this purpose, we first identified potential auto-cleavage sites on MMP-9Cat using mass spectroscopy and then eliminated the auto-cleavage site by predicting mutations that minimize auto-cleavage potential without reducing enzyme stability. Four computationally designed MMP-9Cat variants were experimentally constructed and evaluated for auto-cleavage and enzyme activity. Our best variant, Des2, with 2 mutations, was as active as the wild-type enzyme but did not exhibit auto-cleavage after 7 days of incubation at 37°C. This MMP-9Cat variant, with an identical with MMP-9Cat WT active site, is an ideal candidate for drug design experiments targeting MMP-9 and enzyme crystallization experiments. The developed strategy for MMP-9CAT stabilization could be applied to redesign other proteases to improve their stability for various biotechnological applications.

Identification of N-Acyl Hydrazones as New Non-Zinc-Binding MMP-13 Inhibitors by Structure-Based Virtual Screening Studies and Chemical Optimization.

Matrix metalloproteinase 13 plays a central role in osteoarthritis (OA), as its overexpression induces an excessive breakdown of collagen that results in an imbalance between collagen synthesis and degradation in the joint, leading to progressive articular cartilage degradation. Therefore, MMP-13 has been proposed as a key therapeutic target for OA. Here we have developed a virtual screening workflow aimed at identifying selective non-zinc-binding MMP-13 inhibitors by targeting the deep S1' pocket of MMP-13. Three ligands were found to inhibit MMP-13 in the µM range, and one of these showed selectivity over other MMPs. A structure-based analysis guided the chemical optimization of the hit compound, leading to the obtaining of a new N-acyl hydrazone-based derivative with improved inhibitory activity and selectivity for the target enzyme.

Molecular Dynamics Simulations of Matrix Metalloproteinase 13 and the Analysis of the Specificity Loop and the S1'-Site.

The specificity loop of Matrix Metalloproteinases (MMPs) is known to regulate recognition of their substrates, and the S1'-site surrounded by the loop is a unique place to address the selectivity of ligands toward each MMP. Molecular dynamics (MD) simulations of apo-MMP-13 and its complex forms with various ligands were conducted to identify the role of the specificity loop for the ligand binding to MMP-13. The MD simulations showed the dual role of T247 as a hydrogen bond donor to the ligand, as well as a contributor to the formation of the van der Waal surface area, with T245 and K249 on the S1'-site. The hydrophobic surface area mediated by T247 blocks the access of water molecules to the S1'-site of MMP-13 and stabilizes the ligand in the site. The F252 residue is flexible in order to search for the optimum location in the S1'-site of the apo-MMP-13, but once a ligand binds to the S1'-site, it can form offset π-π or edge-to-π stacking interactions with the ligand. Lastly, H222 and Y244 provide the offset π-π and π-CH(Cß) interactions on each side of the phenyl ring of the ligand, and this sandwiched interaction could be critical for the ligand binding to MMP-13.

Exploration of structural alerts and fingerprints for novel anticancer therapeutics: a robust classification-QSAR dependent structural analysis of drug-like MMP-9 inhibitors.

Among various matrix metalloproteinases (MMPs), overexpression of MMP9 has been established as a key player in a variety of cancers. Therefore, MMP9 has emerged as a promising biomolecule that may be targeted to design potent inhibitors as novel anticancer therapeutics. In this study, a large database containing 1,123 drug-like MMP-9 inhibitors was considered for robust classification-dependent fragment-based QSAR study through SARpy, Bayesian classification, and recursive partitioning analyses and were validated by both internal and external validation techniques. In a nutshell, all these classification-dependent techniques revealed some common structural alerts and sub-structural fingerprints responsible for modulating MMP-9 inhibition. These observations are in agreement with the interactions obtained from the ligand-bound co-crystal structures of MMP-9 justifying the robustness of the current study. Finally, based on these crucial structural fragments, some new lead compounds were designed and further validated by the binding mode of interaction analysis. Therefore, these findings may be beneficial in designing novel and potential MMP-9 inhibitors in the future as a weapon to combat several cancers.

Designed Loop Extension Followed by Combinatorial Screening Confers High Specificity to a Broad Matrix MetalloproteinaseInhibitor.

Matrix metalloproteinases (MMPs) are key drivers of various diseases, including cancer. Development of probes and drugs capable of selectively inhibiting the individual members of the large MMP family remains a persistent challenge. The inhibitory N-terminal domain of tissue inhibitor of metalloproteinases-2 (N-TIMP2), a natural broad MMP inhibitor, can provide a scaffold for protein engineering to create more selective MMP inhibitors. Here, we pursued a unique approach harnessing both computational design and combinatorial screening to confer high binding specificity toward a target MMP in preference to an anti-target MMP. We designed a loop extension of N-TIMP2 to allow new interactions with the non-conserved MMP surface and generated an efficient focused library for yeast surface display, which was then screened for high binding to the target MMP-14 and low binding to anti-target MMP-3. Deep sequencing analysis identified the most promising variants, which were expressed, purified, and tested for selectivity of inhibition. Our best N-TIMP2 variant exhibited 29 pM binding affinity to MMP-14 and 2.4 µM affinity to MMP-3, revealing 7500-fold greater specificity than WT N-TIMP2. High-confidence structural models were obtained by including NGS data in the AlphaFold multiple sequence alignment. The modeling together with experimental mutagenesis validated our design predictions, demonstrating that the loop extension packs tightly against non-conserved residues on MMP-14 and clashes with MMP-3. This study demonstrates how introduction of loop extensions in a manner guided by target protein conservation data and loop design can offer an attractive strategy to achieve specificity in design of protein ligands.

Identification of small molecule inhibitors against MMP-14 via High-Throughput screening.

Matrix metalloproteinases (MMPs) are involved in various cellular events in physiology and pathophysiology through endopeptidases activity. The expression levels and activities of most MMPs remain minimal in the normal conditions, whereas some MMPs are significantly activated in pathological conditions such as cancer and neovascularization. Hence, MMPs are considered as both diagnostic markers and potential targets for therapeutic agents. Twenty-three known human MMPs share a similar active site structure with a zinc-binding motif, resulting in lack of specificity. Therefore, the enhancement of target specificity is a primary goal for the development of specific MMP inhibitors. MMP-14 regulates VEGFA/VEGFR2-system through cleavage of the non-functional VEGFR1 in vascular angiogenesis. In this study, we developed a fluorescence-based enzymatic assay using a specific MMP-14 substrate generated from VEGFR1 cleavage site. This well optimized assay was used as a primary screen method to identify MMP-14 specific inhibitors from 1,200 Prestwick FDA-approved drug library. Of ten initial hits, two compounds showed IC50 values below 30 µM, which were further validated by direct binding analysis using surface plasmon resonance (SPR). Clioquinol and chloroxine, both of which contain a quinoline structure, were identified as MMP-14 inhibitors. Five analogs were tested, four of which were found to be completely devoid of inhibitory activity. Clioquinol exhibited selectivity towards MMP-14, as it showed no inhibitory activity towards four other MMPs.

A review of MMP-2 structures and binding mode analysis of its inhibitors to strategize structure-based drug design.

The protease enzyme, matrix metalloproteinase-2 (MMP-2) has been a target of choice for the drug development due to its multi-façade involvement in numerous diseased conditions including cancer. To find a selective MMP-2 inhibitor several computational strategies are employed in its design and discovery. In these strategies, protein structure of MMP-2 is an inevitable part to formulate effective structure-based drug design (SBDD) of selective MMP-2 inhibitors. In the present communication, several crystal structures of MMP-2 have been analyzed with different statistical parameters and their implementations in SBDD of inhibitors are scrutinized. In addition, binding mode analyses of various classes of inhibitors are discussed to pinpoint the effective design of selective inhibitors by maximizing its interaction with the MMP-2 enzyme binding site. This may provide a crucial insight for exploring the numerous possibilities for SBDD of MMP-2 inhibitors to accelerate anticancer drug discovery efforts.

Development of a putative Zn2+-chelating but highly selective MMP-13 inhibitor.

Starting from an already known MMP-13 inhibitor, 1, we pursued an SAR-approach focusing on optimizing interactions close to the Zn2+ binding site of the enzyme. We found the oxetane containing compound 32 (MMP-13 IC50 = 42 nM), which exhibited complete inhibition of collagenolysis in in vitro studies and an excellent selectivity profile among the MMP family. Interestingly, docking studies propose that the oxetane ring in 32 is oriented towards the Zn2+ ion for chelating the metal ion. Chelating properties of MMP13-inhibitors are often connected with non-selectivity within the enzyme family. Compound 32 demonstrates a rare example where the selectivity can be explained via combinatorial effects of interactions within the S1' loop and a chelating effect of the oxetane moiety. Furthermore, in vivo pharmacokinetic studies were performed demonstrating a concentration of 1.97 µM of 32 within the synovial fluid of the rat knee joint, which makes the compound a promising lead compound for further optimization and development for osteoarthritis.

Discovery of Highly Potent and Selective Matrix Metalloproteinase-7 Inhibitors by Hybridizing the S1' Subsite Binder with Short Peptides.

Matrix metalloproteinase-7 (MMP-7) has emerged as a protein playing important roles in both physiological and pathophysiological processes. Despite the growing interest in MMP-7 as a potential therapeutic target for diseases including cancer and fibrosis, potent and selective MMP-7 inhibitors have yet to be identified. Compound 1, previously reported by Edman and co-workers, binds to the S1' subsite of MMP-7, exhibiting moderate inhibitory activity and selectivity. To achieve both higher inhibitory activity and selectivity, we conceived hybridizing 1 with short peptides. The initially designed compound 6, which was a hybrid molecule between 1 and a tripeptide (Ala-Leu-Met) derived from an MMP-2-inhibitory peptide (APP-IP), showed enhanced MMP-7-inhibitory activity. Subsequent optimization of the peptide moiety led to the development of compound 18 with remarkable potency for MMP-7 and selectivity over other MMP subtypes.

Discovery of Phenolic Matrix Metalloproteinase Inhibitors by Peptide Microarray for Osteosarcoma Treatment.

Because of the abnormal upregulation of matrix metalloproteinase (MMP) activities in tumors, MMP inhibitors (MMPIs) are validated anticancer drug candidates. We identified several MMPIs including mangiferin as an MMP-9 inhibitor with a half maximal inhibitory concentration (IC50) value of 250 nM, isosilybin as an MMP-13 inhibitor with an IC50 value of 250 nM, and isoliquiritigenin as a broad-spectrum MMPI (with IC50 values of 16 nM for MMP-1, 10 nM for MMP-2, 81 nM for MMP-3, 8 nM for MMP-7, 10 nM for MMP-9, and 14 nM for MMP-13) through studying the interactions of 6 MMPs secreted by U-2OS cells with 51 phenolic natural products on the peptide microarray platform. In addition, the inhibitory mechanisms of as-discovered MMPIs were evaluated by a molecular docking simulation. The antitumor efficiencies of MMPIs were demonstrated by both a cell scratch test and growth suppression of mouse-born OS tumors. The results of the cell scratch test suggested that isoliquiritigenin significantly inhibited the migration of U-2OS cells. In addition, administration of isoliquiritigenin significantly reduced the tumor size (by about 80%) and prolonged the survival time (by more than 70 days). This study suggests that the discovery of MMPIs from phenolic natural products is a meaningful way to screen anticancer agents.

Selective Inhibitors of Medium-Size S1' Pocket Matrix Metalloproteinases: A Stepping Stone of Future Drug Discovery.

Among various matrix metalloproteinases (MMPs), MMPs having medium-size S1' pockets are established as promising biomolecular targets for executing crucial roles in cancer, cardiovascular diseases, and neurodegenerative diseases. However, no such MMP inhibitors (MMPIs) are available to date as drug candidates despite a lot of continuous research work for more than three decades. Due to a high degree of structural resemblance among these MMPs, designing selective MMPIs is quite challenging. However, the variability and uniqueness of the S1' pockets of these MMPs make them promising targets for designing selective MMPIs. In this perspective, the overall structural aspects of medium-size S1' pocket MMPs including the unique binding patterns of enzyme-inhibitor interactions have been discussed in detail to acquire knowledge regarding selective inhibitor designing. This overall knowledge will surely be a curtain raiser for the designing of selective MMPIs as drug candidates in the future.

Screening a Panel of Topical Ophthalmic Medications against MMP-2 and MMP-9 to Investigate Their Potential in Keratoconus Management.

Keratoconus (KC) is a serious disease that can affect people of any race or nationality, although the exact etiology and pathogenic mechanism are still unknown. In this study, thirty-two FDA-approved ophthalmic drugs were exposed to virtual screening using docking studies against both the MMP-2 and MMP-9 proteins to find the most promising inhibitors as a proposed computational mechanism to treat keratoconus. Matrix metalloproteinases (MMPs) are zinc-dependent proteases, and MMP inhibitors (MMPIs) are usually designed to interact with zinc ion in the catalytic (CAT) domain, thus interfering with enzymatic activity. In our research work, the FDA-approved ophthalmic medications will be investigated as MMPIs, to explore if they can be repurposed for KC treatment. The obtained findings of the docking study suggest that atenolol and ampicillin are able to accommodate into the active sites of MMP-2 and MMP-9. Additionally, both exhibited binding modes similar to inhibitors used as references, with an ability to bind to the zinc of the CAT. Molecular dynamic simulations and the MM-GBSA binding free-energy calculations revealed their stable binding over the course of 50 ns. An additional pharmacophoric study was carried out on MMP-9 (PDB ID: 1GKC) using the co-crystallized ligand as a reference for the future design and screening of the MMP-9 inhibitors. These promising results open the door to further biological research to confirm such theoretical results.

Discovery of Aryloxyphenyl-Heptapeptide Hybrids as Potent and Selective Matrix Metalloproteinase-2 Inhibitors for the Treatment of Idiopathic Pulmonary Fibrosis.

Matrix metalloproteinase-2 (MMP2) is a zinc-dependent endopeptidase that plays important roles in the degradation of extracellular matrix proteins. MMP2 is considered to be an attractive target for the treatment of various diseases such as cancer, arthritis, and fibrosis. In this study, we have developed a novel class of MMP2-selective inhibitors by hybridizing the peptide that binds to a zinc ion and S2-S5 pockets with small molecules that bind to the S1' pocket. Structural modifications based on X-ray crystallography revealed that the introduction of 2,4-diaminobutanoic acid (Dab) at position 4 dramatically enhanced MMP2 selectivity by forming an electrostatic interaction with Glu130. After improving the metabolic and chemical stability, TP0556351 (9) was identified. It exhibited potent MMP2 inhibitory activity (IC50 = 0.20 nM) and extremely high selectivity. It suppressed the accumulation of collagen in a bleomycin-induced idiopathic pulmonary fibrosis model in mice, demonstrating the efficacy of MMP2-selective inhibitors for fibrosis.

Identification of Novel Natural Product Inhibitors against Matrix Metalloproteinase 9 Using Quantum Mechanical Fragment Molecular Orbital-Based Virtual Screening Methods.

Matrix metalloproteinases (MMPs) are calcium-dependent zinc-containing endopeptidases involved in multiple cellular processes. Among the MMP isoforms, MMP-9 regulates cancer invasion, rheumatoid arthritis, and osteoarthritis by degrading extracellular matrix proteins present in the tumor microenvironment and cartilage and promoting angiogenesis. Here, we identified two potent natural product inhibitors of the non-catalytic hemopexin domain of MMP-9 using a novel quantum mechanical fragment molecular orbital (FMO)-based virtual screening workflow. The workflow integrates qualitative pharmacophore modeling, quantitative binding affinity prediction, and a raw material search of natural product inhibitors with the BMDMS-NP library. In binding affinity prediction, we made a scoring function with the FMO method and applied the function to two protein targets (acetylcholinesterase and fibroblast growth factor 1 receptor) from DUD-E benchmark sets. In the two targets, the FMO method outperformed the Glide docking score and MM/PBSA methods. By applying this workflow to MMP-9, we proposed two potent natural product inhibitors (laetanine 9 and genkwanin 10) that interact with hotspot residues of the hemopexin domain of MMP-9. Laetanine 9 and genkwanin 10 bind to MMP-9 with a dissociation constant (KD) of 21.6 and 0.614 µM, respectively. Overall, we present laetanine 9 and genkwanin 10 for MMP-9 and demonstrate that the novel FMO-based workflow with a quantum mechanical approach is promising to discover potent natural product inhibitors of MMP-9, satisfying the pharmacophore model and good binding affinity.