Inhibitory effect of 20(S)-protopanaxadiol on cytochrome P450: Potential of its pharmacokinetic interactions in vivo

Chemically Driven Clearance of Amyloid Aggregates by Polyfunctionalized Furo[2,3-b:4,5-b']dipyridine-Chalcone Hybrids to Ameliorate Memory in an Alzheimer Mouse Model

The aberrant assembly of amyloid-β (Aβ) is implicated in Alzheimer's disease (AD). Recent clinical outcomes of Aβ-targeted immunotherapy reinforce the notion that clearing Aβ burden is a potential therapeutic approach for AD. Herein, to develop drug candidates for chemically driven clearance of Aβ aggregates, we synthesized 51 novel polyfunctionalized furo[2,3-b:4,5-b']dipyridine-chalcone hybrid compounds. After conducting two types of cell-free anti-Aβ functional assays, Aβ aggregation prevention and Aβ aggregate clearance, we selected YIAD-0336, (E)-8-((1H-pyrrol-2-yl)methylene)-10-(4-chlorophenyl)-2,4-dimethyl-7,8-dihydropyrido[3',2':4,5]furo[3,2-b]quinolin-9(6H)-one, for further in vivo investigations. As YIAD-0336 exhibited a low blood-brain barrier penetration profile, it was injected along with aggregated Aβ directly into the intracerebroventricular region of ICR mice and ameliorated spatial memory in Y-maze tests. Next, YIAD-0336 was orally administered to 5XFAD transgenic mice with intravenous injections of mannitol, and YIAD-0336 significantly removed Aβ plaques from the brains of 5XFAD mice. Collectively, YIAD-0336 dissociated toxic aggregates in the mouse brain and hence alleviated cognitive deterioration. Our findings indicate that chemically driven clearance of Aβ aggregates is a promising therapeutic approach for AD.

Metabolism and drug interactions of Korean ginseng based on the pharmacokinetic properties of ginsenosides: Current status and future perspectives

Orally administered ginsenosides, the major active components of ginseng, have been shown to be biotransformed into a number of metabolites by gastric juice, digestive and bacterial enzymes in the gastrointestinal tract and also in the liver. Attention is brought to pharmacokinetic studies of ginseng that need further clarification to better understand the safety and possible active mechanism for clinical application. Experimental results demonstrated that ginsenoside metabolites play an important role in the pharmacokinetic properties such as drug metabolizing enzymes and drug transporters, thereby can be applied as a metabolic modulator. Very few are known on the possibility of the consistency of detected ginsenosides with real active metabolites if taken the recommended dose of ginseng, but they have been found to act on the pharmacokinetic key factors in any clinical trial, affecting oral bioavailability. Since ginseng is increasingly being taken in a manner more often associated with prescription medicines, ginseng and drug interactions have been also reviewed. Considering the extensive oral administration of ginseng, the aim of this review is to provide a comprehensive overview and perspectives of recent studies on the pharmacokinetic properties of ginsenosides such as deglycosylation, absorption, metabolizing enzymes and transporters, together with ginsenoside and drug interactions.

Development of KEAP1-targeting PROTAC and its antioxidant properties: In vitro and in vivo

Oxidative stress due to abnormal accumulation of reactive oxygen species (ROS) is an initiator of a large number of human diseases, and thus, the elimination and prevention of excessive ROS are important aspects of preventing the development of such diseases. Nuclear factor erythroid 2-related factor 2 (NRF2) is an essential transcription factor that defends against oxidative stress, and its function is negatively controlled by Kelch-like ECH-associated protein 1 (KEAP1). Therefore, activating NRF2 by inhibiting KEAP1 is viewed as a strategy for combating oxidative stress-related diseases. Here, we generated a cereblon (CRBN)-based proteolysis-targeting chimera (PROTAC), which we named SD2267, that induces the proteasomal degradation of KEAP1 and leads to NRF2 activation. As was intended, SD2267 bound to KEAP1, recruited CRBN, and induced the degradation of KEAP1. Furthermore, the KEAP1 degradation efficacy of SD2267 was diminished by MG132 (a proteasomal degradation inhibitor) but not by chloroquine (an autophagy inhibitor), which suggested that KEAP1 degradation by SD2267 was proteasomal degradation-dependent and autophagy-independent. Following KEAP1 degradation, SD2267 induced the nuclear translocation of NRF2, which led to the expression of NRF2 target genes and attenuated ROS accumulation induced by acetaminophen (APAP) in hepatocytes. Based on in vivo pharmacokinetic study, SD2267 was injected intraperitoneally at 1 or 3 mg/kg in APAP-induced liver injury mouse model. We observed that SD2267 degraded hepatic KEAP1 and attenuated APAP-induced liver damage. Summarizing, we described the synthesis of a KEAP1-targeting PROTAC (SD2267) and its efficacy and mode of action in vitro and in vivo. The results obtained suggest that SD2267 could be used to treat hepatic diseases related to oxidative stress.

Involvement of CYP3A4 and MDR1 in altered metabolism and transport of indinavir in 1,25(OH)2D3-treated Caco-2 cells

Altered drug concentrations may induce unexpected toxicity or treatment failure; thus, understanding the factors that alter the pharmacokinetic profiles of drugs is crucial for optimal disease treatment. Vitamin D receptor (VDR), a nuclear receptor, regulates the expression of cytochrome P450 3A4 (CYP3A4) and multidrug resistance protein 1 (MDR1), which are crucial determinants of drug pharmacokinetics. In this study, we investigated the effects of 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃], a VDR ligand, on the metabolism, transport, and pharmacokinetics of indinavir, a dual substrate of CYP3A4 and MDR1. 1,25(OH)₂D₃ treatment for three days upregulated the expression levels of CYP3A4 and MDR1 in Caco-2 cells and consequently led to an increase in the level of a metabolite formed via CYP3A4 (indinavir M6) and the efflux ratio of indinavir in transport study. The increase in the metabolic reaction was also confirmed through a metabolism assay performed using the lysate of 1,25(OH)₂D₃-treated Caco-2 cells. In the Ussing chamber study conducted with the rat intestine, 1,25(OH)₂D₃ treatment did not alter the transport of indinavir into the basolateral side but increased indinavir M6 formation. Similarly, plasma levels of the metabolite increased in 1,25(OH)₂D₃-treated rats; however, systemic exposure to indinavir led to insignificant alterations. Considering the overlapping substrate specificities for CYP3A4 and MDR1 and their significant roles in drug pharmacokinetics, VDR may play an important role in drug interactions of CYP3A4 and MDR1 substrates for accessing more effective and safe disease treatments.

Analysis of metabolites and metabolism-mediated biological activity assessment of ginsenosides on microfluidic co-culture system

In vivo, the complex process of drugs metabolism alters the change in drug composition and determines the final pharmacological properties of oral drugs. Ginsenosides are primary constituents of ginseng, whose pharmacological activities are greatly affected by liver metabolism. However, the predictive power of existing in vitro models is poor due to their inability to mimic the complexity of drug metabolism in vivo. The advance of organs-on-chip-based microfluidics system could provide a new in vitro drug screening platform by recapitulating the metabolic process and pharmacological activity of natural product. In this study, an improved microfluidic device was employed to establish an in vitro co-culture model by culturing multiple cell types in compartmentalized microchambers. Different cell lines were seeded on the device to examine the metabolites of ginsenosides from the hepatocytes in top layer and its resulting efficacy on the tumors in bottom layer. Metabolism dependent drug efficacy of Capecitabine in this system demonstrated the model is validated and controllable. High concentrations of CK, Rh2 (S), and Rg3 (S) ginsenosides showed significant inhibitory effects on two types of tumor cells. In addition, apoptosis detection showed that Rg3 (S) through liver metabolism promoted early apoptosis of tumor cells and displayed better anticancer activity than prodrug. The detected ginsenoside metabolites indicated that some protopanaxadiol saponins were converted into other anticancer aglycones in varying degrees due to orderly de-sugar and oxidation. Ginsenosides exhibited different efficacy on target cells by impacting their viabilities, indicating hepatic metabolism plays an important role in determining ginsenosides efficacy. In conclusion, this microfluidic co-culture system is simple, scalable, and possibly widely applicable in evaluating anticancer activity and metabolism of drug during the early developmental phases of natural product.