Hydroquinone

Hydroquinone is a phenolic compound belonging to the hydroquinone class of reducing agents. It is used in organic synthesis, the preparation of antioxidants, as a polymerization inhibitor, and in analytical chemistry. By interfering with tyrosinase-related processes, hydroquinone reduces melanin formation and is used in research on skin pigmentation abnormalities such as hyperpigmentation and melasma. Hydroquinone exhibits strong redox activity and antioxidant properties.

Melan-a cells:4.21 μM, SYF cells:37.5 μM, P388/ADR cells:2.2 μg/mL (ED₅₀), A431 cells:23.3 μM

Method: Human squamous cell carcinoma A431 cells (1×10⁶ cells/mL) were treated with Hydroquinone (0–100 μM) for 24, 48, and 72 h, and cell viability was assessed using the MTT assay.
Result: Hydroquinone induced dose-dependent cell death in A431 cells at 48 h and 72 h, with an IC₅₀ of approximately 23.3 μM at 72 h ^[2].
Method: Mouse embryonic fibroblast SYF cells (1×10⁶ cells/mL) were treated with Hydroquinone (0–100 μM) for 24, 48, and 72 h, and cell viability was measured using the MTT assay.
Result: Hydroquinone caused dose-dependent cell death in SYF cells at 48 h and 72 h, with an IC₅₀ of approximately 37.5 μM at 72 h ^[2].
Method: Mouse melanoma B16F10 cells and human breast cancer MDA-MB-231 cells were treated with Hydroquinone (50 μM) for 48 h, and morphological changes were observed under a light microscope.
Result: Hydroquinone significantly induced cell shrinkage and death in both B16F10 and MDA-MB-231 cells ^[2].

Method: C57BL/6 mice were injected with B16F10 melanoma cells (1×10⁶ cells/mouse) via the tail vein to establish a pulmonary metastasis model. Mice were then intraperitoneally administered Hydroquinone (10 or 50 mg/kg) twice weekly for 18 days, and the number of melanoma metastatic foci in lung tissues was counted.
Result: Hydroquinone (10 and 50 mg/kg) dose-dependently and significantly reduced the number of melanoma metastatic foci in mouse lung tissues, without causing body weight loss, indicating no apparent in vivo toxicity ^[2].
Method: C57BL/6 mice were subcutaneously injected with Azoxymethane (AOM, 10 mg/kg) and given drinking water containing Dextran Sodium Sulfate (DSS, 1.2%) to induce a colon cancer model. Mice were then intraperitoneally administered Hydroquinone (10 mg/kg) twice weekly for 4 weeks. The number of colon tumors was counted, and histopathological changes were examined by H&E staining.
Result: Hydroquinone (10 mg/kg) effectively inhibited AOM/DSS-induced colon tumor formation, with a maximum reduction in tumor number of up to 50%, and significantly decreased colon tissue thickness ^[2].