Deriving a Health-Based Guidance Value for 9,10-Anthraquinone via integrating PBTK modeling-based reverse dosimetry and In Vitro bioassays

Anthraquinones, both naturally occurring and synthetic, are widely distributed in the environment. Recent years, human exposure to 9,10-anthraquinone (9,10-AQ) through contaminated food has been raising significant health concerns due to its potential toxicity upon chronic exposure. Among these, 9,10-AQ has been studied in traditional toxicology, with few of established Points of Departure (PoDs) and Health-Based Guidance Values (HBGV). However, toxicological data for other anthraquinones remain severely limited. Traditional animal experiments are resource-intensive and time-consuming, restricting the feasibility of deriving PoDs and HBGVs for a larger set of compounds and exposures, especially for risk assessment purposes. To address these challenges, New Approach Methodologies (NAMs) were employed and validated by using 9,10-AQ as a reference and representative compound in current study. Hepatocyte hypertrophy via lipid metabolism pathway induced by 9,10-AQ was predicted with applying network toxicology, which was validated using HepG2 cell (0.625-10 μM, for 48 h) combined with high-content imaging showing lipid accumulation induced by 9,10-AQ. The physiologically based toxicokinetic (PBTK) model for rat of 9,10-AQ was developed using in vitro and in silicodata, which was further extrapolated to humans PBTK model, enabling the translation of in vitro concentration-response relationships into in vivo dose-response predictions through PBTK modeling-based reverse dosimetry. From this, a PoD value was derived and converted to a HBGV of 0.0105 mg/kg BW, accounting for uncertainty factors of 100. The NAMs-based HBGV of 9,10-AQ matched well with values derived from animal studies, providing a proof-of-principle of using in vitro-in silicoapproach to predict hepatic lipid metabolic disorder in humans and indicating a good performance of the NAMs. This approach has the potential to be extended to other anthraquinones and derivatives, offering more accurate and reliable human-relevant value (i.e. PoDs, HBGVs), to support Next Generation Risk Assessment (NGRA) of 9,10-AQ and related compounds.