Structural Classification

RNA is crucial for the regulation of numerous cellular processes and functions. With the in-depth study of disease mechanisms, processes such as RNA expression, splicing, translation, and stability regulation have become new targets for disease intervention. RNA has provided new therapeutic modalities for metabolic diseases, genetic disorders, and cancer patients, resulting in several innovative drugs.

MCE R&D team collected small molecules targeting RNA from the PDB, R-BIND, ROBIN, and internal database as the positive dataset, and non-targeting RNA small molecules from ROBIN as the negative dataset. Based on the GeminiMol pre-trained model, we encoded the molecules and calculated over 1700 molecular descriptors using Mordred as inputs for the model. Subsequently, we employed 13 deep learning models to learn from the data. All of which yielded good training results, with AUROCs greater than 0.75. Ultimately, we selected the Finetune model to screen HY-L901P, which exhibited the best classification performance, achieving an AUROC of 0.82 and a prediction accuracy of 0.76. We then applied filtering based on StaR rules (with at least two of the following properties: cLogP ≥ 1.5, Molar Refractivity ≥ 4, Relative Polar Surface Area ≤ 0.3) to obtain a library containing approximately 5,000 small molecule compounds targeting RNA. This library serves as a valuable tool for screening small molecules that interact with RNA.

Different functional groups confer unique chemical properties and reactivity characteristics to compounds. The presence of these functional groups not only affects the physical properties of the compounds, such as solubility and boiling point, but also determines their chemical reactivity and potential applications in chemical synthesis.

Covalent ligands rely on reactive groups (“warheads”), and new warheads are key to expanding the scope of covalent modalities. Through careful selection, we constructed a structural filter containing over 110 electrophilic groups. By analyzing the electrophilic fragments selected by the structural filter, we removed any molecules with trivial or undesirable structural features. Ultimately, we obtained 4,900 multifunctional covalent fragments.

Lysine is the second most common target residue used in the design of TCIs and related covalent ligands. Its appeal lies in its abundance in human proteins, which is approximately three times higher than that of cysteine (5.8% vs. 1.9%). This significantly increases the number of proteins suitable for covalent targeting, especially given that many human proteins lack ligandable cysteine residues. Moreover, it has been suggested that functional lysines have a lower probability of being replaced by mutation, as they often play a crucial role in catalysis by acting as bases or nucleophiles. Additionally, lysines are essential for maintaining the structural integrity of proteins and for regulating post-translational modifications (PTMs). Consequently, targeting lysine has garnered significant interest in recent years.

Through careful selection, we constructed a structural filter containing over 110 electrophilic groups. By analyzing the electrophilic fragments selected by the structural filter, we removed any molecules with trivial or undesirable structural features. Ultimately, we obtained 445 fragment molecules which can target lysine residue and can be used for fragment-based covalent drug discovery.

Covalent inhibitors are small molecules that can bind specifically to target proteins through covalent bonds and inhibit their biological functions. Although for a long time, covalent targeting has been playing a subordinate role in drug discovery, with an increasing number of reports on successful clinical applications of such drugs, the potential of these agents is now being acknowledged.

Covalent ligands rely on reactive groups (“warheads”), and new warheads are key to expanding the scope of covalent modalities. Through careful selection, we constructed a structural filter containing over 110 electrophilic groups. By analyzing the electrophilic fragments selected by the structural filter, we removed any molecules with trivial or undesirable structural features. Ultimately, we obtained 8,900 fragment molecules with covalent modification potential, which can target various reactive amino acid residues and can be used for fragment-based covalent drug discovery.

In the research of covalent inhibitors targeting serine and threonine, scientists have found that the nucleophilicity of these hydroxyl groups is significantly enhanced due to the influence of their surrounding environment. This results in higher activity during catalytic reactions. Aspirin, which targets the non-catalytic domain serine (Ser529 in human COX1) of cyclooxygenase, exerts its anti-inflammatory effect through covalent binding. β-lactam antibiotics, which targets the catalytic domain serine of penicillin-binding proteins, interferes with bacterial cell wall synthesis.

Through careful selection, we constructed a structural filter containing over 110 electrophilic groups. By analyzing the electrophilic fragments selected by the structural filter, we removed any molecules with trivial or undesirable structural features. Ultimately, we obtained 3,300 fragment molecules which can target serine and threonine residues and can be used for fragment-based covalent drug discovery.

Lipids are a diverse and ubiquitous group of compounds which have many key biological functions, such as acting as structural components of cell membranes, serving as energy storage sources and participating in signaling pathways. Several studies suggest that bioactive lipids have effects on the treatment of some mental illnesses and metabolic syndrome. For example, DHA and EPA are important for monoaminergic neurotransmission, brain development and synaptic functioning, and are also correlated with a reduced risk of cancer and cardiovascular disease in clinical and animal studies.

MCE supplies a unique collection of 1,450 lipid and lipid derivative related compounds including triglycerides, phospholipids, sphingolipids, steroids and their structural analogues or derivatives. MCE lipid compound library can be used for research in bioactive lipids, and high throughput screening (HTS) and high content screening (HCS).

“BioDesign” approach incorporates key structural features of known pharmacologically relevant natural products (e.g. alkaloids and other secondary metabolites) into synthetically feasible medicinal chemistry scaffolds. In order to identify the privileged pharmacophores, ring systems and linkers, we have carried out statistical analysis of structural features of natural products, marketed drugs, and drug candidates.

Saturated, fused ring, spiro, and bridged systems with a tendency towards multiple chiral centers are highly privileged among natural products and marketed drugs yet these structures are very poorly represented in commercial libraries. This library addressed this market need by incorporating these privileged elements into the design of novel synthetic molecules with high molecular framework diversity, multiple stereogenic centers (≥2), and degree of saturation (Fsp3 > 0.5).

Bioactive small molecules are important sources of lead compounds and effective tools for drug screening. Because the target of active small molecules is clear, it is conducive to the study of mechanism. In addition, due to the large structural differences between the individual active molecules, it is easier to obtain a greater variety of lead compounds.

MCE integrates the Bioactive Compound Library (HY-L001) and Novel Bioactive Compound Library (HY-L111) to form the Bioactive Compound Library Max. Bioactive Compound Library Max contains novel active small molecules, molecules that have entered the clinical stage and the market, and small molecules that have been verified by cell experiments or biochemical experiments, which fundamentally expands the number of compound libraries in the library and improves the structural diversity, and is an effective tool to start drug screening and mechanism research.

MCE can provide a library of 22,901 mitophagy compounds, which can be used for drug development and mechanism research in cancer, immunity, infection and other hot research fields.

MCE Novel Bioactive Compound Library consists of 3,112 bioactive compounds with validated bioactivities tested by cell-based assays or biochemical assays. All compounds in this library are structurally novel and bioactivity diverse which makes it easier to discover new lead compounds. MCE Novel Bioactive Compound Library, as a supplement of MCE bioactive compound library (HY-L001), is a useful tool to screen new lead compounds.

Recently, significant advancements in tyrosine-targeting electrophiles have primarily occurred in the field of protein-protein interactions (PPIs), where cysteine residues are often underrepresented and novel chemistries are needed to address these interfaces. In this context, tyrosines are frequently more accessible compared to more buried binding sites. Moreover, they are commonly found at "hot spots," which are functional epitopes of PPIs, with 12.3% of the residues consisting of tyrosines. This prevalence is likely due to the hydrophobic nature of tyrosine, its ability to participate in aromatic π-interactions, and its capacity for hydrogen bonding. Beyond PPIs, some progress has also been made in covalent tyrosine targeting in other areas where more commonly addressed side chains are lacking. Even though tyrosine has a slightly lower pKa value compared to the protonated lysine side chain (approximately 10 vs. 10.5 for the unprotected amino acid side chains), significantly less progress has been made in the development of tyrosine-targeted covalent ligands compared to lysine. This is likely due to the reduced flexibility of the tyrosine side chain and the greater steric hindrance of its hydroxy group, which makes it more challenging to adopt suitable reaction geometries.

Through careful selection, we constructed a structural filter containing over 110 electrophilic groups. By analyzing the electrophilic fragments selected by the structural filter, we removed any molecules with trivial or undesirable structural features. Ultimately, we obtained 124 fragment molecules which can target tyrosine residue and can be used for fragment-based covalent drug discovery.

Natural products are an attractive source with varied structures that exhibit potent biological activities, and desirable pharmacological profiles. The core scaffold of a natural product can also provide a biologically validated framework upon which to display diverse functional groups. Inspired by bioactive natural products, natural product-like compounds, occupying the same chemical space, are ideally suited to explore and to facilitate understanding of biological pathways.

MCE provides a unique collection of 629 natural product-like compounds that are structurally like Steroids, Tannins, Flavonoids, Quinones, Isoquinolines, etc. This library is an important source of lead compounds for drug discovery.

The MCE 1K Drug Fragment Library consists of 1,168 drug fragments. These drug fragments are derived from 2,946 FDA-approved drug molecules, and fragments from one drug can appear in other drugs, so these fragments are somewhat correlated with good PK/PD properties. Fragment-based screening can reserve enough chemical space for subsequent structural optimization. This compound library is an essential tool for drug screening based on FBDD (Fragment-Based Drug Discovery).

Peptides are a group of biologically active substances that are involved in various cellular functions of organisms. Peptides are often used in functional analysis, vaccine research and especially in the field of drug research and development. At present, more than 80 peptide drugs have reached the market for a wide range of diseases, including diabetes, cancer, osteoporosis, multiple sclerosis, HIV infection and chronic pain.

MedChemExpress (MCE) offers a comprehensive collection of 1,663 peptides, including bioactive peptides, amino acid derivatives, and blocking peptides. MCE Peptide Library can be used for peptide library screening, peptide drug discovery, vaccine development, target verification, structural activity research, etc.

Fragment-based drug development (FBDD) is a strategy for drug discovery that can be applied both academically and commercially to enhance the identification of some non-drug targets. Fragment-based drug development has identified low molecular weight molecules (<300 Da) capable of binding to related macromolecules. These fragments can cover a wide chemical space and are easy to optimize later. Currently, several fragment-based drugs have entered clinical trials, of which two drugs, Vemurafenib and Venetoclax, have been approved for marketing.

Based on Tanimoto coefficient, MCE uses similarity algorithm to carefully select 2,302 high-structurally diverse 'RO3' compliant fragment molecules from large-scale fragment molecules, which can be applied to fragment based drug development.

Terpenoids, also known as isoprenoids, are the most numerous and structurally diverse natural products found in many plants. Terpenoids are divided into monoterpenes, sesquiterpenes, diterpenes, sesterpenes, and triterpenes depending on its carbon units. Several studies, in vitro, preclinical, and clinical have confirmed that this class of compounds displays a wide array of very important pharmacological properties in the fight against cancer, malaria, inflammation, and a variety of infectious diseases. Naturally occurring terpenoids provide new opportunities to discover new drugs with minimum side effects.

MCE designs a unique collection of 686 terpenoid compounds that all come from natural products. MCE Terpenoids Library is a useful tool for drug discovery that can be used for high throughput screening (HTS) and high content screening (HCS).

5-HT receptors, also called Serotonin receptors, are a group of G protein-coupled receptors (GPCRs) and ligand-gated ion channels (LGICs) found in the central and peripheral nervous systems. These receptors are now classified into seven families, 5-HT1–7, comprising a total of 14 structurally and pharmacologically distinct mammalian 5-HT receptor subtypes. The 5-HT receptors influence various biological and neurological processes such as aggression, anxiety, appetite, cognition, learning, memory, mood, nausea, sleep, andthermoregulation. The serotonin receptors are the target of a variety of pharmaceutical drugs, including many antidepressants, antipsychotics, anorectics, antiemetics, gastroprokinetic agents, antimigraine agents, hallucinogens, and entactogens.

MCE 5-HT Receptor Compound Library consists of 317 5-HT receptor inhibitors and activators, which can be used for neuropsychiatric disorders drugs discovery.

Natural products are characterized by enormous scaffold diversity and structural complexity, because of which, natural products do show a wide range of biological activities. Medicinal plants have been the major source of medicines over many centuries. About a quarter of all Food and Drug Administration (FDA) and/or the European Medical Agency (EMA) approved drugs are plant based, with well-known drugs such as Paclitaxel and Aspirin having been isolated from plants.

MCE provides a unique collection of 2,929 plant-sourced natural products. MCE Plant-Sourced Natural Product Library is a useful tool for drug discovery that can be used for high throughput screening (HTS) and high content screening (HCS).

Nucleoside and nucleotide analogues are synthetic, chemically modified compounds that have been developed to mimic their physiological counterparts in order to exploit cellular metabolism and subsequently be incorporated into DNA and RNA to inhibit cellular division and viral replication. In addition to their incorporation into nucleic acids, nucleoside and nucleotide analogues can interact with and inhibit essential enzymes such as human and viral polymerases (that is, DNA-dependent DNA polymerases, RNA-dependent DNA polymerases or RNA-dependent RNA polymerases), kinases, ribonucleotide reductase, DNA methyltransferases, purine and pyrimidine nucleoside phosphorylase and thymidylate synthase. These actions of nucleoside and nucleotide analogues have potential therapeutic benefits — for example, in the inhibition of cancer cell growth, the inhibition of viral replication as well as other indications.

MCE offers a unique collection of 550 nucleotide compounds including nucleotide, nucleoside and their structural analogues. MCE Nucleotide Compound Library is a useful tool to discover anti-cancer and antiviral drugs for high throughput screening (HTS) and high content screening (HCS).

Natural product have great diversity and structural complexity of scaffolds. And the number of their drugs represents a large number of sources of new pharmacological entities, so natural products are of great significance in drug discovery. The Dictionary of Natural Products (DNP) shows that natural products mainly come from plants, animals and microorganisms, and animal sources are the second important source of natural products. Animal derived natural products exist to varying degrees in almost all forms of animals, generally secondary metabolite extracted from organisms.

MCE provides a unique collection of 1,096 animal-sourced natural products. MCE Animal-Sourced Natural Product Library is a useful tool for drug discovery that can be used for high throughput screening (HTS) and high content screening (HCS).

With features of enormous scaffold diversity and structural complexity, natural products (NPs) are the main sources of lead compounds and new drugs and play a highly significant role in the drug discovery and development process, especially for cancer and infectious diseases. A large number of natural products have been proven to have potential anti-tumor effects, mainly from plants, animals, Marine organisms and microorganisms. At present, derived than 60% of anti-tumor drugs come from natural sources, and they are widely used in breast, prostate and colon cancers.

MCE offers a unique collection of 1,710 natural products with validated anti-cancer activity. MCE anti-cancer natural product library is a useful tool for anti-tumor drugs screening and other related research.

The incidence and significance of central nervous system diseases are increasing at an alarming rate all over the world. Although substantial research efforts have been applied to develop new CNS-active drugs, only a few CNS disorders are addressed satisfactorily, while the remaining ones pose significant clinical challenges. Blood-brain barrier (BBB) permeability is one of the most important limiting factors in the design and development of novel CNS-targeted pharmaceuticals for the treatment of neurological disorders.

Carefully selected from the HTS Compound Collection to meet the parameters optimized for high BBB-permeability, our CNS Focused Screening Library comprising over 30,300 structurally-diverse and potentially CNS-active screening compounds. This original Screening Compound Library is aimed at supporting CNS drug design projects and HTS efforts in search for novel neurotherapeutics.

Protein phosphorylation is a key post-translational modification underlying the regulation of many cellular processes. Phosphatases and kinases contribute to the regulation of protein phosphorylation homeostasis in the cell. This reversible regulation of protein phosphorylation is critical for the proper control of a wide range of cellular activities, including cell cycle, proliferation and differentiation, metabolism, cell-cell interactions, etc.

Protein phosphatases have evolved in separate families that are structurally and mechanistically distinct. Based on substrate specificity and functional diversity, protein phosphatases are classified into two superfamilies: Protein serine/threonine phosphatases and Protein tyrosine phosphatases. Ser/Thr phosphatases are metalloenzymes belonging to two major gene families termed PPP (phosphoprotein phosphatase) and PPM (metal-dependent protein phosphatases), whereas protein tyrosine phosphatases (PTPs) belong to distinct classes of enzymes that utilize a phospho-cysteine enzyme intermediate as a part of their catalytic action.

MCE supplies a unique collection of 117 phosphatase inhibitors that mainly targeting protein tyrosine phosphatases (PTPs) and serine/threonine-specific protein phosphatases. MCE Phosphatase Inhibitor Library is a useful tool for phosphatase drug discovery and related research.

Heterocyclic compounds are cyclic organic compounds which contain at least one hetero atom, the most common heteroatoms are nitrogen, oxygen ,and sulfur. Heterocycles are common in biology, featuring a wide range of structures from enzyme co-factors to amino acids and proteins. On the one hand, heterocycles are common structural units in approved drugs and in medicinal chemistry targets in the drug discovery process. In addition, heterocycles have been found as a key structure in medical chemistry and also they are frequently found in large percent of biomolecules such as vitamins, natural products ,and biologically active compounds including antifungal, anti-inflammatory, antibacterial, antioxidant, antiallergic, anti-HIV, antidiabetic, anticancer activity.

MCE offers a unique collection of 5,727 heterocyclic compounds which can be used for drug discovery for high throughput screening (HTS) and high content screening (HCS). MCE heterocyclic compound library is critical for drug discovery and development.

Fragment-based drug discovery (FBDD) is well suited for discovering both drug leads and chemical probes of protein function. 3-dimensionality (3D) diversity is pivotal because the molecular shape is one of the most important factors in molecular recognition by a biomolecule. There is a developing appreciation that 3D fragments could offer opportunities that are not provided by 2D fragments.

MCE 3D Diverse Fragment Library consists of 5,400 non-flat fragment-like molecules (average Fsp3 value 0.58). More than 4,700 fragment compounds contain at least one chiral center in the structure. The key concepts that underlie the library design were 3D shape, structural diversity, reactive functionality and fragment-like. This 3D Diverse Fragment Library brings higher fragment hit optimization and increases the likelihood to find innovative hits in FBDD.

Aging is a complex biological process characterized by functional decline of tissues and organs, structural degeneration, and reduced adaptability and resistance, all of which contribute to an increase in morbidity and mortality caused by multiple chronic diseases, such as Alzheimer's disease, cancer, and diabetes. Many theories, which fall into two main categories: programmed and error theories, have been proposed to explain the process of aging, but neither of them appears to be fully satisfactory. The programmed theories imply that aging relies on specific gene regulation, and the error theories emphasize the internal and environmental damages accumulated to living organisms. The damage theories proposed the nine hallmarks that were generally considered to contribute to the aging process: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication.

MCE Anti-Aging Compound Library contains 4,646 compounds, mainly targeting Sirtuin, mTOR, IGF-1R, AMPK, p53, Telomerase, Mitophagy, Mitochondrial Metabolism, COX, Cytochrome P450, Oxidase, etc. This library is a useful tool for anti-aging research.

Traditional Chinese medicine provides abundant natural resources for medicinal compounds, which are often considered effective and safe for drug discovery. Traditional Chinese medicine is based on the principle of "multiple components, multiple targets, and multiple pathways", and naturally has multiple pharmacological effects. As herbal medicine, the secondary plant metabolites in Chinese herbal medicine play an important role in alleviating many diseases in Traditional medicine and folk use. Therefore, the identification of traditional Chinese medicine derived compounds is also an important process in drug development and a necessary factor in dissecting the overall mechanism of action of traditional Chinese medicine. FDA listed compounds have completed extensive preclinical and clinical studies, exhibiting good biological activity, safety, and bioavailability.

MCE designs a unique collection of 332 FDA-approved traditional Chinese medicine active compounds, including flavonoids, polyphenols, alkaloids, terpenoids, and other structural types. It is a good tool for drug reuse and screening drugs from traditional Chinese medicine sources.

Drug-induced liver injury (DILI; also known as drug-induced hepatotoxicity) is caused by medications (prescription or OTC), herbal and dietary supplements (HDS), or other xenobiotics that result in abnormalities in liver tests or in hepatic dysfunction that cannot be explained by other causes. Drugs are an important cause of liver injury. Drug-induced hepatic injury is the most common reason cited for withdrawal of an approved drug.

DILI is thought to occur via several different mechanisms. Among these are direct impairment of the structural (e.g., mitochondrial dysfunction) and functional integrity of the liver; production of a metabolite that alters hepatocellular structure and function; production of a reactive drug metabolite that binds to hepatic proteins to produce new antigenic drug-protein adducts, which are targeted by hosts’ defenses (the hapten hypothesis); and initiation of a systemic hypersensitivity response (i.e., drug allergy) that damages the liver.

MCE Drug-induced Liver Injury (DILI) Compound Library contains a unique collection of 1,444 hepatotoxicity causing compounds and is a powerful tool to research DILI and other drug toxicities. This library can be used to understand the mechanisms of DILI, identify biomarkers for early DILI prediction, and allow timely recognition during drug development, thus finally achieving successful DILI prevention and assessment in the pre-marketing phase.

Cyclic peptides are polypeptide chains taking cyclic ring structure, which exhibit diverse biological activities, such as antibacterial activity, immunosuppressive activity and anti-tumor activity. Cyclic peptides, with the features of good binding affinity, target selectivity and low toxicity, show great success as therapeutics. Multiple cyclic peptides are currently in clinical use, for examples, gramicidin and tyrocidine with bactericidal activity, cyclosporin A with immunosuppressive activity, and vancomycin with antibacterial activity. Furthermore, cyclic peptides usually have the sufficient size and a balanced conformational flexibility/rigidity for binding to flat protein-protein interaction (PPI) interfaces, which have potential to develop PPI drugs.

MCE offers a unique collection of 91 cyclic peptides, all of which have good bioactivities. MCE Cyclic Peptide Library is a powerful tool for drug discovery and PPI inhibitor screening.

Antibody-Drug Conjugates (ADCs), a new class of treatment for cancer, are composed with a monoclonal antibody, a linker and a cytotoxic agent also referred to as a payload. To date, several ADCs have received market approval and more than 60 ADCs are currently in clinical trials. ADCs are one of the fastest growing classes of oncology drugs worldwide.

The payload or cytotoxic agent is the most important unit in the ADC. ADC has the capability to kill cancer cell depending on the potency of the payload. MCE provides 105 highly potent cytotoxins that contain auristatin derivatives, maytansinoids, calicheamicin, duocarmycin, pyrrolobenzodiazepines (PBDs), etc.

Animal disease models are used in a variety of settings in basic research, such as studies on mechanisms of disease progression and evaluation new drugs. Animal models can be broadly classified into five categories: 1) experimental, 2) spontaneous, 3) negative, 4) orphan, 5) genetically engineered. Experimental models, which are induced artificially in the laboratory, are most common. Some small molecular compounds are usually used as inducers for animal models, such as Ceruletide for inflammatory model, Azoxymethane for tumor model. These inducers are useful tool in building animal models.

MCE offers a unique collection of 51 animal model inducers, involving inflammatory model, tumor model, nervous disease model, etc. MCE Animal Disease Model library is a powerful tool for the establishment of animal disease models.

A drug metabolite is a byproduct of the body breaking down, or “metabolizing” a drug into a different substance. Most drugs undergo chemical alteration by various bodily systems as a way to create compounds that are more easily excreted from the body. Drugs can be metabolized by oxidation, reduction, hydrolysis, hydration, conjugation, condensation, or isomerization. Drug metabolism can produce metabolites with physicochemical and pharmacological properties that differ substantially from those of the parent drug, and consequently have important implications for both drug safety and efficacy.

MCE offers a unique collection of 231 drug metabolites which is a useful tool for drug safety and efficacy study and drug repurposing.

The lack of availability of appropriate medicines for children is an extensive and urgent problem. A variety of obstacles hinder children's drug development, including the limited commercial interest, lack of suitable infrastructure and competence for conducting paediatric clinical trials, difficulties in trial design, ethical worries and many others. Because of these factors, unlicensed and off-label prescribing is very common in children which may lead to safety concern.

MCE offers a unique collection of 684 children’s medicines, all of which have been approved or studied in clinical trials for children diseases. MCE children’s drug library is a useful tool for drug repurposing to discover new children’s indications.

Chemical probes are simply reagents with high potency, selectivity and cell-permeability which play important roles in both fundamental and applied biological research. In their most common application, chemical probes can establish the tractability of a specific target. They are used to interrogate the relationship between a target and its phenotype (biological tractability) as well as an ability to modulate that phenotype using a small molecule. Otherwise, chemical probes also have had a major impact in enabling and accelerating discoveries along the path to pioneer medicines. They have helped to improve the understanding of targets and pathways and have created opportunities for proprietary drug discovery efforts to an extent that would not have been possible otherwise.

MCE provides a unique collection of 268 chemical probes with high potency (at least 100 nM potency), selectivity (at least 10-fold selectivity against any other target) and cell-permeability (at least 10 μM potency). MCE Chemical probe library is a useful tool for target identification and mechanism research.

Food additives are substances added to food to maintain or improve its safety, freshness, taste, texture, or appearance. All food additives used in food undergo a safety assessment, which includes rigorous testing, before they are approved, so all food additives are generally recognized as safe substances.

MCE supplies 447 approved food additives which are safe substances and can be used for drug discovery and other research.

Flavor is an expression of smell and taste that is achieved through a variety of chemical processes triggered by molecules. Food flavor is an important attribute of food quality and in some cases determines consumers' food preferences. In addition to playing a key role in taste and smell, flavor molecules can also be involved in regulating metabolism and have an impact on health. In daily life, flavor molecules have absolute application value in food and spices. In scientific research, the study of flavor molecules is helpful to reveal the relationship between food intake and taste perception. Research on the combination behavior of flavor and food components can explore the retention, release and perception of flavor molecules. Most importantly, while exploring multi-sensory flavor perception, the food industry can fully mobilize the enthusiasm of researching new strategies for delicious and healthy food design.

Based on the FlavorDB database, collects and organizes 426 flavor molecules, which can be used in taste perception and other related studies.

Mitochondrial autophagy refers to the selective encapsulation and degradation of damaged mitochondria by cells through the autophagy mechanism, thereby maintaining mitochondrial and cellular homeostasis. The concept of mitochondrial autophagy has received extensive attention since it was proposed. Current studies have shown that the mechanisms of mitochondrial autophagy can generally be divided into two categories: Ubiquitin-dependent pathways and Ub-independent pathways. In addition, mitochondrial autophagy is a research hotspot related to the pathogenesis of neurodegenerative diseases, cardiovascular diseases, cancer, metabolic diseases and other clinical diseases. Therefore, high-throughput screening based on mitochondrial autophagy can effectively screen out compounds that are closely related to the occurrence of diseases and analyze their mechanisms.

MCE can provide a library of 577 mitophagy compounds, which can be used for drug development and mechanism research in cancer, immunity, infection and other hot research fields.

Methylation is an epigenetic modification mechanism that involves adding methyl groups to molecules such as DNA and histones, which can alter gene expression without changing the DNA sequence. This process is catalyzed by enzymes such as DNA methyltransferases (DNMTs) and histone methyltransferases (HMTs), and can be reversed by demethylases. The balance of methylation and demethylation is crucial for maintaining cellular function and genomic stability. Abnormal regulation of methylation may lead to a variety of diseases, including cancer, neurological disorders, and developmental abnormalities. A deep understanding of the molecular mechanisms of methylation metabolism is essential for developing therapeutic strategies for diseases associated with methylation dysregulation.

MCE contains 241 compounds targeting methylation/demethylation enzymes, which is of significant value for studying the pathways of methylation metabolism and exploring their mechanisms of action in diseases.

Pesticide is a single substance or mixture that can be used to prevent, mitigate, iminate pests or as a plant conditioner, defoliant or desiccant. In recent years, scientists have proposed the concept of "Molecules to Ecosystems", bringing the concept of molecular biology to understand the impact of pesticides, degradation and relationship with the environment or organisms. MCE integrates effective compounds approved as pesticides by agencies such as the Environmental Protection Agency (EPA) and some insecticidal compounds with potential for agricultural applications.

MCE can provide a library of 286 pesticide compounds that are tool compounds for relevant research.

Antibody inhibitors are compounds with the same activity as the original therapeutic antibodies, which can be used as positive controls for drug efficacy evaluation and other studies. Antibody inhibitors can also assist in verifying the functional activity of the target protein. These antibody inhibitors are active in vivo and can achieve certain physiological functions by blocking or neutralizing target proteins, such as CD20, HER2, EGFR, VEGFR, TNF-α, etc. In drug screening, antibody inhibitor-based screening can be carried out to identify active compounds targeting target proteins and target diseases.

MCE can provide 927 antibody inhibitors that can be used for drug development in cancer, immunity, infection and other hot research areas.

Vitamins are a category of trace organic compounds essential for maintaining normal physiological functions in living organisms. They are classified into fat-soluble and water-soluble vitamins. Fat-soluble vitamins play a role in maintaining vision, bone health, reproductive functions, and blood coagulation. Water-soluble vitamins are involved in energy metabolism, nervous system function, and cellular repair processes. Most vitamins cannot be synthesized by the organism and must be obtained through diet. In recent years, vitamins and their derivatives have become increasingly important in the field of drug development due to their extensive physiological activities. Additionally, vitamins and their derivatives can be used to construct research platforms for vitamin metabolism, which helps to delve into the metabolic pathways and dynamic changes of vitamins within the body and aids in identifying new biomarkers for certain diseases.

MCE included 141 vitamins and their derivatives, including Vitamin A, Vitamin B, Vitamin D, etc., which is a good tool for studying vitamin metabolism.

The occurrence of diseases is often associated with multiple targets and pathways, and the factors of disease formation are complex and diverse, so the development of more powerful drugs is needed. According to statistics, 21% of the FDA-approved drugs in 2015-2017 were multi-target compounds. Multi-target compounds refer to a drug targeting multiple disease-related targets or multiple subtypes of a target. Multi-target compounds can be applied to drug screening or targeted ligand design. Because the targets of such compounds are diverse and clear, they have the characteristics of saving time and drug cost during the mechanism research of new drug research and development. In addition, due to the diversity of drug targets, multiple strategies can be applied to pharmacological studies.

MCE supplies a unique collection of 4,449 multi-target compounds that targets two or more different targets or different subtypes of the same target. MCE Multi-Target Compound Library can be used for target protein ligand screening or drug development.

PROTACs (Proteolysis-targeting chimeras) is a class of molecules that utilize ubiquitin-proteasome system (UPS) to ubiquitinate and degrade target proteins. The PROTACs molecule consists of two ligands joined by a linker. The one-to-one interaction between PROTACs and target proteins determines the high efficiency of PROTACs, making it a potential molecule for targeted protein degradation (TPD) therapy.

MCE supplies a unique collection of 296 PROTACs that effectively degrade target proteins with more powerful screening capability. MCE PROTAC Library is a useful tool for signal pathway research, protein degradation therapy research, drug discovery and drug repurposing, etc.

Bioactive compounds are a general term for a class of substances that can cause certain biological effects in the body, which are the main source of small molecule drugs. These compounds generally penetrate cell membranes, act on specific target proteins in cells, regulate intracellular signaling pathways, and cause some changes in cell phenotype.

MCE owns a unique collection of 25,361 compounds with confirmed biological activities and clear targets. These compounds include natural products, innovative compounds, approved compounds, and clinical compounds. This library is a useful tool for signal pathway research, drug discovery and drug repurposing, etc.

Bioactive Compound Library Plus, with more powerful screening capability, further complements Bioactive Compound Library (HY-L001) by adding some compounds with low solubility or solution stability (Part B) and some novel, rare or exclusive compounds (Part C) to this library. Overall, bioactive compound library plus (HY-L001P) includes tree parts: Part A, Part B and Part C. Compounds in Part A are equal to the products in HY-L001, which can be supplied in solution or solid form. Compounds in Part B and C are only supplied in solid form.

Neurotransmitters are chemical messengers that allows a neuron's electrical signal to pass to a postsynaptic neuron or effect target. Neurotransmitters include amino acids, monoamines, and peptides, while other neurotransmitters are composed of metabolites such as nitric oxide and carbon monoxide. The function of neurotransmitters is closely related to the disease of life, helping to regulate the body's heartbeat, blood pressure, breathing, sleep, aging and muscle activity. Therefore, research based on neurotransmitters can help to increase human understanding of diseases.

MCE collects and organizes 54 neurotransmitters and is a tool library for drug screening and mechanism research.

Miao medicine is an important part of Chinese medicine, which carries the profound cultural heritage and rich life wisdom of the Hmongb people. Miao people live in a concentrated community in the mountainous area of the southwest border of China, which has a unique natural environment. Complex and diverse geology, lush natural vegetation, rich animal and plant species, a large number of mineral resources which provide a wide range of species sources for miao ethnicity medicine. On the other hand, due to the characteristics of the living environment of the Hmongb people, Miao medicine has demonstrated its unique therapeutic effect in the treatment of some endemic diseases, infectious diseases, insect, snake and beast bites, rheumatism and other diseases. With the development of modern science and technology, the research and application of seedling medicine are also deepening. Through the systematic study of the chemical composition and pharmacological action of the seedling medicine, it can provide a new idea and method for modern medicine.

MCE included 1,667 natural products from traditional miao ethnicity medicine, including animal, plant and mineral sources.

Exosomes are small membrane vesicles of endocytic origin that are secreted by most cells in culture. Exosomes contain nucleic acids, proteins, lipids, amino acids, and metabolites, etc. Their diverse constituents can reflect their cell of origin. Exosomes are associated with immune responses, viral pathogenicity, pregnancy, cardiovascular diseases, central nervous system-related diseases, and cancer progression. Proteins, metabolites, and nucleic acids delivered by exosomes into recipient cells effectively alter their biological response. Such exosome-mediated responses can be disease promoting or restraining.

The biology of exosomes in disease is still emerging, and the number of studies addressing their utility in the diagnosis and treatment of various pathologies has increased substantially. MCE supplies a unique collection of 46 compounds with the activity of inhibiting or stimulating exsomes secretion/biosynthesis. MCE Exosomes Compound Library is a useful tool for exsomes research.