Characterization of Phloroglucinol‐enriched Fractions of Brazilian Hypericum Species and Evaluation of Their Effect on Human Keratinocytes Proliferation

In this study, a phytochemical and biological investigation on five South Brazilian Hypericum species (Hypericum caprifoliatum, Hypericum carinatum, Hypericum connatum, Hypericum myrianthum, and Hypericum polyanthemum) was carried out. The phloroglucinol‐enriched fractions (PEF) of the flowering aerial parts were analyzed by high‐performance liquid chromatography for the content of uliginosin A (1), japonicin A (2), uliginosin B (3), hyperbrasilol B (4), and the three benzopyrans, that is, 6‐isobutyryl‐5,7‐dimethoxy‐2,2‐dimethyl‐benzopyran (HP1) (5), 7‐hydroxy‐6‐isobutyryl‐5‐methoxy‐2,2‐dimethyl‐benzopyran (HP2) (6), and 5‐hydroxy‐6‐isobutyryl‐7‐methoxy‐2,2‐dimethyl‐benzopyran (HP3) (7). After chemical characterization, the PEF were assayed for cell proliferation on human keratinocyte cell line by MTT. The H. carinatum and H. polyanthemum PEF demonstrated better results with an increase in cell proliferation (138.7% and 120.6%, respectively). The cell counting and Ki‐67 assay with H. carinatum PEF confirmed the MTT results. The cell cycle distribution indicates an increase in the cells at S and G2/M phases, which is indicative of proliferation induction. In summary, the results indicate an induction of HaCaT proliferation by the treatment with H. carinatum PEF (at 10 and 15 µg/mL), suggesting a possible use as wound healing agent. Copyright © 2016 John Wiley & Sons, Ltd.