Salicylic acid is a natural phenolic plant defense hormone and a medicinal molecule with keratolytic activity. Salicylic acid can activate systemic acquired resistance through the NPR1 receptor and upregulate PR defense gene expression to enhance plant disease resistance, while reducing inflammatory responses by inhibiting NF-κB and COX activities. Salicylic acid can be used in studies related to plant immune regulation, acne, and anti-inflammatory research[1-4].
In vitro, Salicylic acid (50–100μM) was applied to human SEB-1 sebocytes for 24–48h, or 3%–16% Salicylic acid was applied to human SEB-1 and SZ95 sebocytes. Salicylic acid downregulated the AMPK/SREBP1 pathway to reduce lipid synthesis, inhibited NF-κB pathway activity, decreased proinflammatory cytokine expression, and alleviated inflammatory responses[5]. Salicylic acid (0.08–1μg/ml) was applied to human MKN-45 gastric cancer cells, Gumbus lymphoma cells, and SK-N-MC Ewing sarcoma cells for 2.5h. Salicylic acid activated intercellular ROS signaling and the caspase9- and caspase3-dependent mitochondrial pathway, inducing tumor cell apoptosis[6].
In vivo, Salicylic acid (2.75mg/kg) combined with lead acetate (15mg Pb2+/kg) was administered by oral gavage to 5-week-old Kunming male mice for 7 days. Salicylic acid elevated SOD and CAT antioxidant enzyme activities, increased reduced glutathione levels and the GSH/GSSG ratio, reduced MDA-represented lipid peroxidation levels, and improved Pb2+-induced body weight gain inhibition[7]. Salicylic acid (5.5mg/kg; every 3 days) was administered by oral gavage to Hg⁰-exposed female albino mice for 15 days. Salicylic acid effectively counteracted Hg⁰-induced growth inhibition, maintained brain and lung SOD and POD activities as well as reduced GSH levels and GSH/GSSG ratios, and suppressed H₂O₂ and MDA accumulation[8].
References:
[1] Janda T, Szalai G, Pál M. Salicylic Acid Signalling in Plants. Int J Mol Sci. 2020 Apr 10;21(7):2655.
[2] Pokotylo I, Kravets V, Ruelland E. Salicylic Acid Binding Proteins (SABPs): The Hidden Forefront of Salicylic Acid Signalling. Int J Mol Sci. 2019 Sep 6;20(18):4377.
[3] Lebwohl M. The role of salicylic acid in the treatment of psoriasis. Int J Dermatol. 1999 Jan;38(1):16-24.
[4] Suzuki T, Ota H, Namba Y, et al. Salicylic Acid as a Photosensitizer for Thymidine Dimerization Induced by UV. Chem Pharm Bull (Tokyo). 2019;67(2):130-134.
[5] Lu J, Cong T, Wen X, et al. Salicylic acid treats acne vulgaris by suppressing AMPK/SREBP1 pathway in sebocytes. Exp Dermatol. 2019 Jul;28(7):786-794.
[6] Scheit K, Bauer G. Direct and indirect inactivation of tumor cell protective catalase by salicylic acid and anthocyanidins reactivates intercellular ROS signaling and allows for synergistic effects. Carcinogenesis. 2015 Mar;36(3):400-11.
[7] Xu Q, Xu X, Zhang Y, et al. Salicylic acid-involved in lead tolerance associated with the maintenance of reducing conditions in mice. Bull Environ Contam Toxicol. 2009 Jul;83(1):67-70.
[8] Ma C, Xie D, Huang L, et al. Protective effect of salicylic acid on Hg(0) intoxication in mice. Inhal Toxicol. 2013 Jun;25(7):398-404.