Synthesis of salicylic acid from wintergreen oil by green chemistry overcomes its cytotoxicity in keratinocyte cells and teratogenicity in zebrafish embryos

Abstract

Salicylic acid topical is used to treat variety of skin conditions. However, salicylic acid in these products is generated through industrial synthesis and has been shown to negatively impact fetal development and cause congenital abnormalities. We hypothesized that teratogenic effects reported in salicylic acid can be prevented by naturally synthesizing salicylic acid from wintergreen oil using green chemistry method. For this purpose, we investigated the effects of natural salicylic acid (NSA) synthesized from wintergreen oil using green chemistry and synthetic salicylic acid (SSA) on keratinocyte cell (HaCaT) proliferation and zebrafish embryo development. NSA structures were analyzed by ¹H NMR, ¹³C NMR, and GC/MS methods. Percentage inhibition against HaCaT cell was determined by MTS assay. xCelligence system was used for cellular activities. Zebrafish embryos were exposed to NSA and SSA for 72 h post-fertilization. Lipid peroxidation, nitric oxide, sialic acid, glutathione-S-transferase, catalase, and superoxide dismutase were evaluated using biochemical methods. Expressions of nqO1, gfap, bdnf, vtg, egr, cyp1a, and igf2 were determined by RT-PCR as developmental indicators. MTS and RT-cell analysis showed increased cell viability by NSA, whereas SSA decreased cell viability. NSA beneficially affected zebrafish embryo development while SSA exerted deleterious effects through oxidant–antioxidant status, inflammation, and development. Results of our study showed for the first time that synthesis of salicylic acid from wintergreen oil by green chemistry overcomes its cytotoxicity in keratinocyte cells and teratogenicity in zebrafish embryos. This finding is important for drug research on safe topical applications during pregnancy, when preventing exposure to drug and chemical-derived teratogens is vital.

Graphical Abstract

Keywords:

• Salicylic acid
• wintergreen oil
• green chemistry
• zebrafish embryo toxicity
• cell proliferation

Author contributions

Conception/design of study: Gökhan Özokan and Ebru Emekli-Alturfan; data acquisition: Gökhan Özokan, Derya Cansız, Abdulkerim Bilginer, İsmail Ünal, and Merih Beler; data analysis/interpretation: Gökhan Özokan, Derya Cansız, Abdulkerim Bilginer, İsmail Ünal, and Merih Beler; drafting manuscript:: Gökhan Özokan and Ebru Emekli-Alturfan; critical revision of manuscript: A. Ata Alturfan and Ebru Emekli-Alturfan; supervision: Ebru Emekli-Alturfan.

Ethical approval

As the zebrafish embryos used were no older than 5 days old, no ethical approval was required for the protocols applied as stated by the Council of Europe (2010), EU Directive 2010/63/EU.

Consent form

All the authors have agreed for authorship, read and approved the manuscript, and given consent to participate.

Disclosure statement

The authors declare that they have no financial or other conflicts of interest.

Data availability statement

Data are available on reasonable request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.