Cytotoxicity Evaluation of Chalcones and Flavanones from the Leaves of Corema album (L.) D. Don

In a preliminary screening of phytochemical compounds from Andalusian vascular plants, the ethyl acetate extract obtained from the leaves of Corema album (L.) D. Don (Ericaceae) was selected due to its cytotoxic activity. Eight phenolic compounds were isolated from this extract: four chalcones (2′,4′-dihydroxydihydrochalcone, 2′,4′-dihydroxychalcone, 2′,4′-dihydroxy-6′-methoxydihydrochalcone, 2′-methoxy-4′-hydroxydihydrochalcone) and four flavanones (pinocembrin, 6-methylpinocembrin, 6,8-dimethylpinocembrin and 7-O-prenylpinocembrin). Their structures were elucidated using 1H NMR and 13C NMR data, including 2D NMR, as well as mass spectrometry. These compounds were evaluated using the MTT cytotoxicity assay against human colorectal adenocarcinoma (HT-29) and renal adenocarcinoma (ACHN) cell lines. The chalcone 2′,4′-dihydroxychalcone exhibited greater cytotoxicity than the corresponding 2′,4′-dihydroxydihydrochalcone in both cell lines. The IC50 values (µM ± SEM) were 13.31 ± 0.48 and 9.43 ± 0.34 for the chalcone, and 62.23 ± 1.06 and 54.68 ± 1.62 for the dihydrochalcone, respectively. The introduction of methyl groups at positions 6 and 8 of pinocembrin increased cytotoxicity in the ACHN cell line. The IC50 values (µM ± SEM) were 91.28 ± 3.03 for pinocembrin, 64.36 ± 0.53 for 6-methylpinocembrin, and 28.74 ± 0.35 for 6,8-dimethylpinocembrin. These results highlight the leaves of C. album as a promising source of chalcones and flavanones with pharmacological interest.