Target: SARS‑CoV‑2 main protease (Mpro/3CLpro) – no IC₅₀/Ki/EC₅₀ values reported; docking binding free energy = −34.329 kcal/mol (Glide XP score) [2]
2-Methylanthraquinone does not have a defined biological or pharmacological target. As a chemical intermediate, it is not known to interact with specific receptors, enzymes, or cellular pathways in a therapeutic context. Some anthraquinone derivatives have biological activities (e.g., as laxatives or anticancer agents), but 2-methylanthraquinone itself is primarily an industrial chemical. Its biological effects are related to its chemical properties rather than specific molecular interactions. It may undergo metabolic activation to generate reactive species.

In vitro, 2-methylanthraquinone (tectoquinone) showed concentration-dependent mosquito larvicidal activity against fourth-instar larvae of Aedes aegypti and Aedes albopictus after 24 h exposure. The LC₅₀ values were 3.3 μg/mL for A. aegypti and 5.4 μg/mL for A. albopictus; the LC₉₀ values were 8.8 μg/mL for A. aegypti and 26.9 μg/mL for A. albopictus [1].
In structure-activity comparisons among anthraquinone congeners, 2-methylanthraquinone exhibited the strongest mosquito larvicidal activity. Anthraquinone, alizarin (1,2-dihydroxyanthraquinone), and 1-hydroxyanthraquinone showed no activity (LC₅₀ > 25 μg/mL). Anthraquinone-2-carboxylic acid had LC₅₀ values of 16.3 μg/mL (A. aegypti) and 17.9 μg/mL (A. albopictus); 2-hydroxymethylanthraquinone had LC₅₀ values of 15.4 μg/mL and 17.0 μg/mL, respectively. Emodin (3-methyl-1,6,8-trihydroxyanthraquinone) also showed strong activity (LC₅₀ 5.3 μg/mL against A. aegypti, 4.2 μg/mL against A. albopictus), but 2-methylanthraquinone was more potent than emodin against A. aegypti (3.3 vs. 5.3 μg/mL) [1].
2-Methylanthraquinone does not exhibit significant in vitro biological activity relevant to pharmacology. Some anthraquinone derivatives show enzyme inhibitory or DNA-intercalating activities, but 2-methylanthraquinone is not characterized as a pharmacologically active compound. Its primary applications are in industrial chemistry rather than biological research. In vitro studies have focused on its chemical properties and potential toxicity rather than pharmacological activity. It is not used in cell-based assays for studying signaling pathways or therapeutic endpoints.

In vivo, 2-methylanthraquinone (tectoquinone) was evaluated for mosquito larvicidal activity using fourth-instar larvae of Aedes aegypti and Aedes albopictus. The compound caused 50% and 90% mortality at the concentrations described (see In Vitro). No mortality was observed in the control groups (DMSO only). The positive control chlorpyrifos had LC₅₀ values of 1.1 μg/mL (A. aegypti) and 1.8 μg/mL (A. albopictus) [1].
2-Methylanthraquinone is not a therapeutic agent and does not have in vivo pharmacological activity. It is not administered to animals for therapeutic purposes. Its in vivo effects are primarily toxicological and relate to its use as an industrial chemical. Upon exposure, it may cause irritation to skin, eyes, and respiratory tract. Systemic effects may include effects on the liver and kidneys due to the compound's metabolism and potential for generating reactive oxygen species. It is not used in animal models for studying disease or therapeutic efficacy.

Enzyme Assay: No experimental enzyme assays were performed. The study used molecular docking with the GLIDE module of Schrodinger Maestro. The crystal structure of SARS‑CoV‑2 main protease (PDB ID: 6LU7) was retrieved. Protein preparation included adding hydrogen atoms, removing water molecules, building side chains and loops using the prime module, and optimization with the OPLS‑2005 force field. Ligands were prepared using the LigPrep module. A receptor grid was generated around the co‑crystal ligand with a diameter of 20 Å. Docking was performed in extra precision (XP) mode with scaling factor for van der Waals radii ≤0.15. The glide score function includes Coulomb, vdW, site, hydrogen bond, buryP, metal, rotB, and lipophilic terms. The best pose was selected based on glide score. For 2-Methylanthraquinone, the docking score (binding free energy) was −34.329 kcal/mol, with interactions mainly through hydrogen bonding with CYS‑145 and stacking interaction with HIS‑41 [2].
Molecular dynamics (MD) simulation was performed using the Desmond module for 50 ns under NTP conditions. The system included the protein‑ligand complex in a TIP3P water box with orthorhombic geometry, neutralized with 150 mM NaCl. The simulation was run after system relaxation. RMSD, RMSF, and protein‑ligand interactions were analyzed. The MD simulation showed that the 2-Methylanthraquinone‑Mpro complex had RMSD deviations not within acceptable range, indicating unstable interaction. Binding energies were calculated using MMGBSA from frames at 10 ns intervals; average binding energy was −37.21 ± 16 kcal/mol. The main interaction type was hydrophobic contacts [2].
Active site residues of SARS‑CoV‑2 Mpro were identified using the PLIP web server, including residues 143A GLY, 144A SER, 163A HIS, 164A HIS, 166A GLU [2].
In vitro assays for 2-methylanthraquinone are primarily conducted for safety assessment and regulatory compliance rather than pharmacological evaluation. Cytotoxicity assays using mammalian cell lines (e.g., HepG2, CHO, or 3T3 cells) involve exposing cells to various concentrations of the compound (typically 0.1-1000 μg/mL) for 24-48 hours, with cell viability assessed by MTT or neutral red uptake assays. For genotoxicity screening, the Ames test (bacterial reverse mutation assay) is performed using Salmonella typhimurium strains with and without metabolic activation, following OECD Test Guideline 471. The micronucleus test may be used to assess chromosomal damage.

Cell-based assays for 2-methylanthraquinone are typically conducted to assess its potential for cytotoxicity and genotoxicity rather than therapeutic activity. Human hepatocyte cell lines (e.g., HepG2) are exposed to the compound at various concentrations for 24-72 hours. Cell viability is measured using MTT, Alamar Blue, or neutral red uptake assays. Oxidative stress may be evaluated by measuring reactive oxygen species (ROS) production using fluorescent probes (DCFH-DA). DNA damage can be assessed using the comet assay. Inflammatory responses may be evaluated by measuring cytokine release via ELISA.

Mosquito larvicidal bioassay: Fourth-instar larvae of A. aegypti and A. albopictus (Kaohsiung strain, reared at 27 °C, 12:12 h photoperiod, 80±10% RH, fed with 10% yeast suspension) were used. Ten larvae were placed in 24.5 mL of degassed distilled water in a 30 mL cup. Then 500 μL of DMSO solution containing the test sample (2-methylanthraquinone) was added to achieve final concentrations of 100, 50, 25, 12.5, 6.25, 3.125, 1.56, 0.78, and 0.39 μg/mL. The control received 24.5 mL water and 500 μL DMSO. Each test was replicated four times. Larvicidal activity was evaluated 24 h after treatment. Larvae were considered dead if appendages did not move when prodded. Mortality percentages were corrected using Abbott's formula. LC₅₀ and LC₉₀ values (with 95% confidence limits) were calculated by probit analysis (Finney method) using log/probability paper. Chlorpyrifos was used as a positive control at concentrations of 6.25, 3.125, 1.56, 0.78, and 0.39 μg/mL [1].
In vivo animal studies for 2-methylanthraquinone are primarily toxicological and conducted according to regulatory guidelines for industrial chemicals. OECD Test Guideline 401 (Acute Oral Toxicity) involves administering the compound to rats by oral gavage at graded doses and monitoring for mortality and clinical signs over 14 days to determine the LD₅₀. For repeated-dose toxicity, rats are administered 2-methylanthraquinone by oral gavage for 28 or 90 days, with histopathological examination of organs, hematology, clinical chemistry, and urinalysis. Genotoxicity is assessed using the Ames test (OECD TG 471) and micronucleus test (OECD TG 474). Carcinogenicity studies may be conducted for long-term exposure assessment.

ADME/Pharmacokinetics: ADME properties were predicted using the SwissADME web tool. 2-Methylanthraquinone obeys all existing drug‑likeness rules including Lipinski’s rule of five (MW ≤500, MLOGP ≤4.15, N or O ≤10, NH or OH ≤5). It is suitable for oral bioavailability. Calculated parameters: lipophilicity (LOGP) = −0.7 to +5.0; molecular weight ~150‑500 g/mol; polarity (TPSA) = 20 Å to 130 Å; Log S (solubility) = 6; fraction Csp3 = 1; number of rotatable bonds = 9. The compound is highly absorbed in the GI tract and is blood‑brain barrier permeant [2].
Target prediction using Swiss Target Prediction indicated that protease is the main target class for 2-Methylanthraquinone, followed by ligand‑gated ion channels and kinases [2].
2-Methylanthraquinone does not have established pharmacokinetic properties in the context of therapeutic use. As a lipophilic compound (log P ~3.5-4.0), it would be expected to be absorbed through the gastrointestinal tract and distributed to tissues. Metabolism likely occurs via cytochrome P450-mediated oxidation and reduction of the quinone moiety, generating reactive oxygen species and potentially reactive metabolites. Excretion is primarily via bile and feces. However, specific pharmacokinetic data for this compound are limited as it is not a therapeutic agent.

Toxicity/Toxicokinetics: Toxicity was evaluated using the pkCSM web server. 2-Methylanthraquinone has no AMES toxicity. The predicted maximum tolerated dose in humans is 0.122 mg/kg/day. Oral acute toxicity (LD₅₀) in rats is 2.11 mol/kg. Oral chronic toxicity (LOAEL) in rats is 2.128 mg/kg_bw/day. The compound has no hepatotoxicity and no skin sensitization. It is not a hERG I or hERG II inhibitor. Predicted T. pyriformis toxicity is 1.302 log μg/L, and Minnow toxicity is 0.86 log mM [2].
2-Methylanthraquinone is classified as an industrial chemical with potential toxicity upon exposure. It may cause skin, eye, and respiratory tract irritation. Some anthraquinone derivatives have been associated with carcinogenicity in animal studies, and appropriate precautions should be taken. The compound should be handled with proper safety equipment, including gloves, goggles, and respiratory protection as needed. It is not intended for human or veterinary therapeutic use. Proper disposal procedures should be followed in accordance with local regulations for chemical waste.

[1]. Larvicidal activity of tectoquinone isolated from red heartwood-type Cryptomeria japonica against two mosquito species. Bioresour Technol. 2008 Jun;99(9):3617-22.

[2]. Molecular modeling study of tectoquinone and acteoside from Tectona grandis linn: a new SARS-CoV-2 main protease inhibitor against COVID-19. J Biomol Struct Dyn. 2022 Mar;40(4):1764-1775.

2-Methylanthraquinone is an anthraquinone that is a derivative of 9,10-anthraquinone, in which the hydrogen at the 2-position is replaced by a methyl group. It is functionally related to 9,10-anthraquinone. 2-Methylanthraquinone has been reported in the tea plant (Camellia sinensis), the snakegrass (Rhinacanthus nasutus), and other organisms with relevant data.

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Additional Info: 2-Methylanthraquinone (tectoquinone) is a phytoconstituent from Tectona grandis (teak) with known fungicidal and larvicidal properties. In this in silico study, it showed binding affinity to SARS‑CoV‑2 main protease with a docking score of −34.329 kcal/mol, interacting with CYS‑145 and HIS‑41. However, MD simulation over 50 ns indicated that the tectoquinone‑Mpro complex was not stable (RMSD deviations outside acceptable range). Nevertheless, the compound obeys Lipinski’s rule of five and has favorable ADME and low predicted toxicity. The study suggests it as a potential lead for COVID‑19 drug development after further validation [2].
2-Methylanthraquinone (CAS# 84-54-8) is an organic compound belonging to the anthraquinone family, consisting of an anthraquinone core with a methyl substituent at the 2-position. It is primarily used as an intermediate in the synthesis of dyes, pigments, and other organic compounds. It is also used in the production of hydrogen peroxide via the anthraquinone process. It is not a pharmaceutical agent and does not have therapeutic applications. It is not approved for human or veterinary use. This compound is for research and industrial use only. Standard safety precautions should be followed when handling this chemical.

C15H10O2

222.2387

222.068

84-54-8

6773

Off-white to yellow solid powder

1.3±0.1 g/cm3

407.8±35.0 °C at 760 mmHg

170-173 °C(lit.)

152.7±22.9 °C

0.0±1.0 mmHg at 25°C

1.644

3.84

0

2

0

17

347

0

NJWGQARXZDRHCD-UHFFFAOYSA-N

InChI=1S/C15H10O2/c1-9-6-7-12-13(8-9)15(17)11-5-3-2-4-10(11)14(12)16/h2-8H,1H3

2-methylanthracene-9,10-dione

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)