Effect of Fruit Secondary Metabolites on Melanoma: A Systematic Review of In vitro Studies

Background: Melanoma is a highly aggressive form of skin cancer and is responsible for the majority of the deaths related to this pathology. Recently, different studies have identified naturally occurring compounds of fruits with chemopreventive action. This systematic review aims to investigate the protective role of fruit phytochemicals against melanoma skin cancer from in vitro studies. Methods: The articles were selected using the search terms string "skin neoplasms" OR “melanoma” AND “fruit” in the following databases: Pubmed/Medline, Bireme, Web of Science and ScienceDirect. Results: Out of an initial database search of 391 titles and/or abstracts, 115 full-text articles were eligible and after final evaluation 49 were selected for further assessment. Almost all analysed articles reveal that compounds of different classes (alkaloid, alkane, benzopyrone, cyclopenta[b]benzofuran, ester, flavonoid, tocotrienols, phenolic, phenylpropanoid, phloroglucinol derivative, terpenoids and betalain) possess anti-melanoma in vitro activity. The benzopyrone (α-mangostin) and stilbene (resveratrol) were effective in inhibiting melanoma cell metastasis, essential to stop the progression of malignant cells. Conclusion: Phytochemicals that possess anticancer properties are present in both, common and exotic fruits. Some of these novel compounds are considered as promising starting points for the discovery of effective new drugs.