Two-Dimensional PCA Highlights the Differentiated Antitumor and Antimicrobial Activity of Methanolic and Aqueous Extracts of Laurus nobilis L. from Different Origins

Maria Inês Dias, João C. M. Barreira, Ricardo C. Calhelha, Maria-João R. P. Queiroz, M. Beatriz P. P. Oliveira, Marina Soković, Isabel C. F. R. Ferreira

Natural matrices are important sources of new antitumor and antimicrobial compounds. Species such as Laurus nobilis L. (laurel) might be used for this purpose, considering its medicinal properties. Herein, in vitro activity against human tumor cell lines, bacteria, and fungi was evaluated in enriched phenolic extracts. Specifically, methanol and aqueous extracts of wild and cultivated samples of L. nobilis were compared considering different phenolic groups. Principal component analysis (PCA) was applied to understand how each extract acts differentially against specific bacteria, fungi, and selected human tumor cell lines. In general, the extract type induced the highest differences in bioactivity of laurel samples. However, from the PCA biplot, it became clear that wild laurel samples were higher inhibitors of tumor cell lines (HeLa, MCF7, NCI-H460, and HCT15). HepG2 had the same response to laurel from wild and cultivated origin. It was also observed that methanolic extracts tended to have higher antimicrobial activity, except against A. niger, A. fumigatus, and P. verrucosum. The differences in bioactivity might be related to the higher phenolic contents in methanolic extracts. These results allow selecting the extract type and/or origin with highest antibacterial, antifungal, and antitumor activity.