Screening of the Antimelanoma Activity of Monoterpenes-In Vitro Experiments on Four Human Melanoma Lines.

(1) Malignant melanoma is the most aggressive type of malignant tumor caused by a dysfunction of melanocytes. Despite progress in the treatment of melanoma, further research and search for new potential drugs are necessary to optimize the therapy. (2) The aim of this study was to evaluate the antiproliferative activity of eight selected monoterpenes by MTT and LDH assays on four malignant melanoma cell lines. (3) Myrcene, rhodinol and nerol did not show any significant anticancer effect on melanoma cell lines, but citral, carvacrol, citronellol, thymol and geraniol showed a significant anti-viability effect. Our studies have shown that the most effective terpene among those tested in inhibiting melanoma cell viability was carvacrol, with the lowest IC50 in the range of 0.05 ± 0.00 to 0.06 ± 0.01 mM. Moreover, it did not negatively affect normal human keratinocyte cells. (4) Metastatic melanoma is very difficult to treat, and some terpenes have the ability to sensitize cells to other chemicals; so, it is worth investigating their antimelanoma potential, as terpenes could become an adjuvant to traditional treatment.