Metabolic Activation and Covalent Protein Binding of Berberrubine: Insight into the Underlying Mechanism Related to Its Hepatotoxicity.

INTRODUCTION: Berberrubine (BRB), an isoquinoline alkaloid, is a major constituent of medicinal plants Coptis chinensis Franch or Phellodendron chinense Schneid. BRB exhibits various pharmacological activities, whereas exposure to BRB may cause toxicity in experimental animals. METHODS: In this study, we thoroughly investigated the liver injury induced by BRB in mice and rats. To explore the underlying mechanism, a study of the metabolic activation of BRB was conducted. Furthermore, covalent modifications of cysteine residues of proteins were observed in liver homogenate samples of animals after exposure to BRB, by application of an exhaustive proteolytic digestion method. RESULTS: It was demonstrated that BRB-induced hepatotoxicities in a time- and dose-dependent manner, based on the biochemical parameters ALT and AST. H&E stained histopathological examination showed the occurrence of obvious edema in liver of mice after intraperitoneal (i.p.) administration of BRB at a single dose of 100 mg/kg. Slight hepatotoxicity was also observed in rats given the same doses of BRB after six weeks of gavage. As a result, four GSH adducts derived from reactive metabolites of BRB were detected in microsomal incubations with BRB fortified with GSH as a trapping agent. Moreover, four cys-based adducts derived from reaction of electrophilic metabolites of BBR with proteins were found in livers. CONCLUSION: These results suggested that the formation of protein adducts originating from metabolic activation of BRB could be a crucial factor of the mechanism of BRB-induced toxicities.

Electroactive polypyrrole-molybdenum disulfide nanocomposite for ultrasensitive detection of berberine in rat plasma.

Electroactive polypyrrole-molybdenum disulfide (MoP) nanocomposites were synthesized and used for modifying screen-printed carbon electrodes (SPCEs) for ultrasensitive detection of berberine, an anticancer drug, in rat plasma. The electroactive nanocomposites were fabricated by exfoliating MoS2 followed by pyrrole polymerization. The effect of polypyrrole in the MoP nanocomposite was evaluated by varying the pyrrole concentration during polymerization, and the resulting nanocomposites prepared with pyrrole concentrations of 10, 20, 30 µL were named as MoP-1, MoP-2, and MoP-3, respectively. The electrochemical characterization of the three MoP nanocomposite sensors revealed that MoP-2/SPCE exhibited the highest electroactivity. The detection of berberine by the three MoP-coated SPCEs revealed that MoP-2/SPCE exhibited the highest activity against berberine due to a two-electron transfer mechanism on the MoP-2/SPCE electrode surface. The detection limit of berberine using the MoP-2/SPCE sensor was found to be about 0.05 µM, which is remarkably lower than the reported detection limits. The interference study proved the selectivity of the MoP-2/SPCE sensor toward berberine in the presence of other bioactive molecules and metal ions. The designed MoP-2/SPCE sensor retained 92% of its initial activity after 15 days of storage at room temperature, with RSD values of about 2.95% and 3.68% for the repeatability and reproducibility studies. Finally, the detection limit of berberine in a rat plasma sample determined using the MoP-2/SPCE sensor was found to be about 5 µM.

Reno-protective effect of berberine.

OBJECTIVE: To assess the reno-protective effect of berberine on diclofenac-induced acute kidney injury in rats. METHODS: The experimental study was conducted at the College of Medicine, Mustansiriya University, Baghdad, Iraq, from January to March 2018, and comprised Sprague Dawley male rats which were divided into 3 equal groups. Group1 rats were treated with distilled water plus normal saline for 14 days, Group2 rats were treated with distilled water plus diclofenac for 14 days and Group3 rats were treated with berberine plus diclofenac for 14 days. Parameters measured were blood urea, serum creatinine, serum malondialdehyde, superoxide dismutase, glutathione reductase, neutrophil gelatinase associated lipocalin, kidney injury molecules-1, Interleukin-18and cystatin-c. Anthropometric measurements and estimated glomerular filtration rate were also noted. SPSS 20 was used for data analysis. RESULTS: Of the 30 rats, the three groups had 10(33.3%) each. Berberine reduced blood urea, serum creatinine, malondialdehyde, neutrophil gelatinase associated lipocalin, kidney injury molecules-1 and Interleukin-18 significantly compared to diclofenac-induced acute kidney injury (p<0.01 each). Berberine improved anti-oxidant capacity through significant elevation of superoxide dismutase and glutathione reductase sera levels (p<0.01 each). CONCLUSIONS: Berberine was found to be an effective agent in the attenuation of diclofenac-induced acute kidney injury through the modulation of pro-inflammatory and oxidative stress biomarkers.

Pharmacokinetic-Pharmacodynamic Modeling for Coptisine Challenge of Inflammation in LPS-Stimulated Rats.

Pro-inflammatory factors are important indicators for assessing inflammation severity and drug efficacy. Coptisine has been reported to inhibit LPS-induced TNF-α and NO production. In this study, we aim to build a pharmacokinetic-pharmacodynamic model to quantify the coptisine time course and potency of its anti-inflammatory effect in LPS-stimulated rats. The plasma and lung coptisine concentrations, plasma and lung TNF-α concentrations, plasma NO concentration, and lung iNOS expression were measured in LPS-stimulated rats after intravenous injection of three coptisine doses. The coptisine disposition kinetics were described by a two-compartment model. The coptisine distribution process from the plasma to the lung was described by first-order dynamics. The dynamics of plasma TNF-α generation and elimination followed zero-order kinetics and the Michaelis-Menten equation. A first-order kinetic model described the TNF-α diffusion process from the plasma to the lung. A precursor-pool indirect response model was used to describe the iNOS and NO generation induced by TNF-α. The inhibition rates of TNF-α production by coptisine (54.73%, 26.49%, and 13.25%) calculated from the simulation model were close to the decline rates of the plasma TNF-α AUC (57.27%, 40.33%, and 24.98%, respectively). Coptisine suppressed plasma TNF-α generation in a linear manner, resulting in a cascading reduction of iNOS and NO. The early term TNF-α response to stimulation is a key factor in the subsequent inflammatory cascade. In conclusion, this comprehensive PK-PD model provided a rational explanation for the interlocking relationship among TNF-α, iNOS and NO production triggered by LPS and a quantitative evaluation method for inhibition of TNF-α production by coptisine.

Dual-functional Brij-S20-modified nanocrystal formulation enhances the intestinal transport and oral bioavailability of berberine.

INTRODUCTION: Berberine (BBR) is a plant-derived benzylisoquinoline alkaloid and has been demonstrated to be a potential treatment for various chronic diseases. The poor water solubility and P-glycoprotein (Pgp)-mediated drug efflux are the main challenges for its further application in a clinical setting. MATERIALS AND METHODS: In this study, a Brij-S20 (BS20)-modified nanocrystal formulation (BBR-BS20-NCs) has been developed and investigated with the purpose of improving the intestinal absorption of BBR. The physicochemical properties of the developed BBR-BS20-NCs were characterized and the enhancement of the BBR-BS20-NCs on BBR absorption were investigated both in vitro and in vivo. RESULTS: The results indicated that BS20 could significantly enhance the intracellular uptake of BBR in MDCK-MDR1 cells via a short-term and reversible modulation on the Pgp function, accompanied by a marked increase in Pgp mRNA expression but without significant influence on the Pgp protein expression. Moreover, the morphology of the prepared BBR-BS20-NCs was observed to be prism-like, with a smooth surface and an average diameter of 148.0 ± 3.2 nm. Compared to raw BBR and physical mixture, BBR-BS20-NCs facilitated the dissolution rate and extent of release of BBR in aqueous solution, and further increased the absorption of BBR in MDCK-MDR1 monolayer by overcoming the Pgp-mediated secretory transport (Papp[BL-AP] values of 2.85 ± 0.04 × 10-6 cm/s, 2.21 ± 0.14 × 10-6 cm/s, and 2.00 ± 0.07 × 10-6 cm/s for pure BBR, physical mixture, and BBR-BS20-NCs, respectively). Significant improvements in the maximum concentration observed (Cmax) and area under drug concentration-time curve (AUC0-t) of BBR-BS20-NCs were obtained in pharmacokinetic studies compared to pure BBR, and the relative bioavailability of BBR-BS20-NCs to pure BBR was 404.1%. CONCLUSION: The developed BBR-BS20-NCs combine the advantages of nanocrystal formulation and functional excipient. The novel pharmaceutical design provides a new strategy to improve the oral bioavailability of those drugs with both poor water solubility and Pgp-mediated efflux.

Novel cremochylomicrons for improved oral bioavailability of the antineoplastic phytomedicine berberine chloride: Optimization and pharmacokinetics.

Berberine chloride (BER) is an antineoplastic phytomedicine that combat non-Hodgkin lymphoma. BER suffers from low oral bioavailability due to p-glycoprotein efflux and first-pass metabolism. Lymphatic drug targeting recently gained a profound attention due to circumventing hepatic first-pass metabolism and targeting lymph diseases. Therefore, novel BER-loaded cremochylomicrons were elaborated to mitigate BER drawbacks and enhance its lymphatic targeting and bioavailability. Optimized cremochylomicron was prepared with 2.5%w/v Cremophor El and 12.5% w/w berberine content. Promising in vitro characteristics (particle size = 175.6 nm and entrapment efficiency = 95.5%) were obtained. Lyophilized system showed high colloidal stability over 6 months. In addition in vivo pharmacokinetics study demonstrated significant enhancement (>2fold) in the rate and extent of absorption in cremochylomicron over free BER. Moreover, cremochylomicrons demonstrated in significant increase in mean residence time and volume of distribution with decreased intestinal drug clearance as a result of efflux inhibition. In another avenue, a significant reduction in BER absorption (43%) in presence of cycloheximide inhibitor was obtained confirming the lymphatic targeting ability of cremochylomicrons. In conclusion, berberine-loaded cremochylomicron could be considered as a promising nanoplatform for targeting lymphatic system and improving BER oral bioavailability with lower dose and side effects.

Enhancement by sodium caprate and sodium deoxycholate of the gastrointestinal absorption of berberine chloride in rats.

The aim of the investigation was to compare the effectiveness of two absorption enhancers, sodium caprate (C10) and sodium deoxycholate (SDC), in increasing the bioavailability of a poorly absorbed paracellar flux drug, berberine chloride, across the intestinal mucosae of rats in vivo, together with examination of their effects on mucosal damage. In addition, all four intestinal segments were collected after administration of the enhancers and sodium saline. The results of the bioavailability experiments showed the oral absorption of berberine chloride was poor and both C10 and SDC could significantly improve the very poor absorption of berberine chloride. After co-administration, the area under the plasma concentration-time curve of berberine chloride was increased 41.1-fold by C10 (100 mg/kg) and 35.3-fold by SDC (100 mg/kg) compared with that in the absence of C10 and SDC, respectively. Local toxicity experiment indicated that both enhancers caused no specific damage to the intact intestine. This study demonstrates that C10 and SDC could significantly promote the absorption of berberine chloride from the gastrointestinal tract with few toxic effects, which might be due mainly to relaxing the absorption limitation while inhibiting the efflux transporter of berberine chloride by the enhancers. Besides, this could lead to the development of new drug-enhancers.