In Vitro Hepatotoxicity and Cytochrome P450 (CYP) Inhibitory Potential of a Selected Commercial Herbal Supplement Juice.

The surge in the consumption of commercial herbal supplement juice (CHSJ) is driven by the perception that natural products are inherently safe. However, many reach the market without rigorous toxicological evaluation, posing a hidden risk to public health. Despite their popularity, data regarding the hepatotoxic profiles of CHSJ and their interference with drug-metabolizing enzymes remain scarce. The present study addresses this critical knowledge gap by providing a multi-analytical toxicological characterization in vitro of a commercially available CHSJ, namely, Sample A marketed for women's reproductive health in Malaysia. This study evaluated the hepatotoxicity and cytochrome P450 (CYP) inhibitory potential of Sample A, using the in vitro HepG2 cell model. The phytochemical profile of Sample A was characterized via liquid chromatography-mass spectrometry (LC-MS). Cytotoxicity was assessed through the MTT assay, whereas oxidative stress was measured using the DCFH-DA ROS assay. Hepatotoxic effects were evaluated through alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity assays and H&E staining for morphological changes. Furthermore, the modulation of CYP1A2, CYP2C9, CYP2D6, and CYP3A4 was investigated at both the transcriptional level (RT-qPCR) and through functional activity using recombinant human CYP enzymes. Sample A exerts a concentration- and time-dependent cytotoxic effect on HepG2 cells, associated with uncompensated intracellular oxidative stress beginning at 2% v/v concentration. This early adaptive stress was biochemically characterized by elevated intracellular AST (1% v/v) and ALT (5% v/v) activities. This was then structurally validated by H&E staining showing prominent histopathological alterations in the treated HepG2 cells. Simultaneously, Sample A acts as potent, multitarget modulator of Phase I xenobiotic metabolism. It near-completely inhibited functional CYP3A4 activity at concentrations as low as 0.50% v/v, while reducing the transcriptional mRNA expression of CYP1A2 and CYP2C9 at 0.75% v/v. The findings demonstrate that this commercial formulation poses a dual threat of hepatotoxicity and xenobiotic metabolic interference. Sample A poses a risk of herb-induced liver injury and potentially significant herb-drug interactions. These insights underscore an urgent need for stricter regulatory oversight, standardized premarket evaluation, and enhanced public safety awareness regarding uncharacterized commercial polyherbal formulations.