Yinzhihuang Oral Liquid Ameliorates Hyperbilirubinemia Induced by δ-Aminolevulinic Acid and Novobiocin in Neonatal Rats.

Yinzhihuang oral liquid (YZH) is a traditional Chinese medicine that has been widely used in Asia to prevent and treat neonatal hyperbilirubinemia, but the published preclinical studies on its anti-hyperbilirubinemia effect are conducted in adult animals, partly due to the lack of preclinical neonatal hyperbilirubinemia animal models. In the present study, we tested six reagents to induce hyperbilirubinemia in neonatal rats, and established two appropriate neonatal hyperbilirubinemia rat models by subcutaneous injection of δ-Aminolevulinic acid (ALA, 200 mg/kg) or novobiocin (NOVO, 200 mg/kg). Oral treatment of YZH (80, 160 and 320 mg/kg) significantly decreased serum conjugated bilirubin levels in ALA-treated neonatal rats and serum unconjugated bilirubin levels in NOVO-treated neonatal rats, respectively. Additionally, pre-treatment of YZH also prevented the increase of serum bilirubin levels in both ALA- and NOVO-treated rats. Mechanistically, YZH significantly up-regulated the mRNA expression of genes involved in hepatic bilirubin disposition (organic anion-transporting polypeptide 1b2, Oatp1b2; multidrug resistance-associated protein 2, Mrp2) and bilirubin conjugation (UDP-glucuronosyltransferase 1a1, Ugt1a1). Additionally, YZH up-regulated the mRNA expression of cytochrome P450 1A1 (Cyp1a1), the target gene of aryl hydrocarbon receptor (AhR), and increased the nuclear protein levels of AhR in livers of neonatal rats. YZH and its two active ingredients, namely baicalin (BCL) and 4'-hydroxyacetophenone (4-HT), up-regulated the mRNA expression of AhR target genes (CYP1A1 and UGT1A1) and increased nuclear protein levels of AhR in HepG2 cells. In conclusion, the present study provides two neonatal hyperbilirubinemia animal models and evaluates the anti-hyperbilirubinemia effect and mechanisms of YZH in neonatal animals.

Biflavonoids from Juniperus oblonga inhibit organic anion transporter 3.

Organic anion transporters (OATs in humans, Oats in rodents) play an important role in the distribution and excretion of numerous endogenous metabolic products and exogenous organic anions, including a host of widely prescribed drugs. Their ligand recognition is also important for drug therapy and development. In this study, the n-butanol and dichloromethane soluble fractions of Juniperus oblonga were found to inhibit OAT3 in vitro and three biflavonoids were found to be responsible for this activity. One of these compounds, amentoflavone exhibited stronger inhibition than probenecid, a known strong inhibitor of OAT3. Biological characterization of amentoflavone in vivo also showed inhibition of Oat3. Preliminary observations of structure-activity relationships suggest that the biflavonoids are more potent inhibitors of this transporter than their corresponding monomer, and that methylation of even a single hydroxyl group results in a substantial decrease in activity. This greater potency of the biflavonoids may indicate the need for a more in-depth investigation of the distribution of biflavonoids in plants used as foodstuffs and herbal medicines, due to their potential for causing interactions with OAT3 substrate drugs.