PHYTOCHEMICAL CHARACTERIZATION AND CYTOTOXIC EVALUATION OF THE AQUEOUS LEAF EXTRACT OF Piper mikanianum IN HepG2 CELLS

Resumo

INTRODUCTION: The Piperaceae family includes over 2,000 species distributed across eight genera, predominantly occurring in tropical and subtropical climates in both hemispheres. In Brazil, approximately 500 species of the Piper genus have been described, primarily in the Atlantic Forest. Traditionally, in southern and southeastern regions of the country, the species Piper mikanianum is widely used and, consequently, has been the subject of studies evaluating its chemical composition and biological activities. OBJECTIVE: To characterize the phytochemical profile and to evaluate the in vitro cytotoxicity of the aqueous extract from P. mikanianum leaves at different time points. MATERIALS AND METHODS: Leaves of P. mikanianum were dried at a temperature below 40oC, triturated, and extracted by infusion in water. Its phytochemical characterization was performed by ultra-performance liquid chromatography with a diode array detector (UPLC-DAD) following a previously established methodology. Briefly, the mobile phase consisted of acidified acetonitrile (phase A) and 0.1% formic acid (phase B) in a gradient system, using a CORTECS UPLC T3 column (2.1 x 100 mm, 1.6 µm).  Cytotoxicity was evaluated in HepG2 cells (human liver cancer cell line) using the MTT assay. Cells were exposed to different concentrations of the aqueous extract (0.25 – 6 mg/mL) for 24, 48, and 72 hours. RESULTS AND CONCLUSIONS: The aqueous extract from P. mikanianum leaves exhibited low in vitro toxicity in HEPG2 cells, maintaining mitochondrial activity above 85% at all tested concentrations and time points. Notably, at 48 h of exposure, specific concentrations induced a mild but consistent enhancement in cell viability, indicating a possible stimulatory or cytoprotective effect. Phytochemical characterization revealed the presence of vitexin, a flavonoid known for its antioxidant and anti-inflammatory activities. These results suggest that the aqueous extract from P. mikanianum leaves is biocompatible with HepG2 under the tested conditions and highlights its potential for future studies about its bioactive properties.