Pharmacokinetics of vitexin-4″-O-glucoside in rats after intravenous application

Huang-Lian Jie-Du decoction: a review on phytochemical, pharmacological and pharmacokinetic investigations

Huang-Lian Jie-Du decoction (HLJDD), a famous traditional Chinese prescription constituted by Rhizoma Coptidis, Radix Scutellariae, Cortex Phellodendri and Fructus Gradeniae, has notable characteristics of dissipating heat and detoxification, interfering with tumors, hepatic diseases, metabolic disorders, inflammatory or allergic processes, cerebral diseases and microbial infections. Based on the wide clinical applications, accumulating investigations about HLJDD focused on several aspects: (1) chemical analysis to explore the underlying substrates responsible for the therapeutic effects; (2) further determination of pharmacological actions and the possible mechanisms of the whole prescription and of those representative ingredients to provide scientific evidence for traditional clinical applications and to demonstrate the intriguing molecular targets for specific pathological processes; (3) pharmacokinetic feature studies of single or all components of HLJDD to reveal the chemical basis and synergistic actions contributing to the pharmacological and clinically therapeutic effects. In this review, we summarized the main achievements of phytochemical, pharmacological and pharmacokinetic profiles of HLJDD and its herbal or pharmacologically active chemicals, as well as our understanding which further reveals the significance of HLJDD clinically.

Assessment of baicalin in mouse blood by monoclonal antibody-based icELISA

An indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibaodies (MAb) was recently developed. This new method displays high sensitivity and accuracy, and is especially suitable for pharmacokinetic studies in small laboratory animals. This study aimed to develop an icELISA procedure for baicalin (BAL) quantitation in blood. We successfully developed the icELISA and applied in pharmacokinetic assays of Gegen Qinlian Decoction in mice. A linear correlation was obtained for BAL concentrations in the range from 34.69 to 2220.00 µg/L. The regression equation was y = 1.5557 - 0.4028log(C) with a correlation coefficient of 0.9936. Precision and accuracy of the icELISA method were evaluated by the variations between replicates from well to well (intra-assay) and plate to plate (inter-assay). The values obtained for these parameters were within the normal range (<15%). The recovery rates ranged from 98.93 to 126.78%, meeting the requirements for biological samples. Stability studies showed that BAL sample solutions were intact for 1 h, enough time for UV detection. However, long-term storage and especially freeze-thaw procedures were detrimental to BAL. The pharmacokinetic parameters derived from mouse experiments were as follows: area under the curves from time 0 to 48 h, 1876.15 ± 1108.14 mg h/L; mean maximum blood concentrations, 101.09 ± 31.53 mg/L; time of maximum concentration, 3.58 ± 2.88 h; mean residence time, 79.30 ± 61.21 h.

Effects of vitexin-2"-O-rhamnoside and vitexin-4"-O-glucoside on growth and oxidative stress-induced cell apoptosis of human adipose-derived stem cells

OBJECTIVES

Vitexin-2"-O-rhamnoside (VOR) and vitexin-4"-O-glucoside (VOG) are the two main flavonoid glycosides of the leaves of Cratagus pinnatifida Bge. var. major N. E. Br. that has been widely used for the treatment of cardiovascular system diseases. In this study, we simultaneously investigated the influence of VOR and VOG on human adipose-derived stem cells (hADSCs) injury induced by hydrogen peroxide (H2 O2 ) to further characterize their anti-oxidative and anti-apoptotic activity.

METHODS

hADSCs were isolated, cultured in vitro and pretreated with 62.5 μm VOR or 120 μm VOG for 24 h and then exposed to 500 μm H2 O2 for an additional 4 h.

KEY FINDINGS

Pretreatment of hADSCs with VOR and VOG was demonstrated to significantly ameliorate the toxicity and apoptosis effects, such as morphological distortion, nuclear condensation, decreased intracellular caspase-3 activity and percentage of cells in apoptosis/necrosis by using morphological assay, immunocytochemistry and flow cytometric evaluation. In addition, VOR and VOG caused no cytotoxic effect on hADSCs at concentrations up to 250 and 480 μm, respectively.

CONCLUSIONS

Our results indicated that both VOR and VOG contribute to the protection against H2 O2 -mediated oxidative stress damage and could be safely used for a wide range of concentrations.

Hepatic and gastrointestinal first-pass effects of vitexin-4″-O-glucoside in rats

Objectives

This paper was to clarify the reasons of low bioavailability of vitexin-4″-O-glucoside (VOG) in rats via hepatic combined with gastrointestinal first-pass effect.

Methods

Observed the hepatic first-pass effect through the comparison of area under the plasma concentration-time curve from zero to infinity (AUC0→∞) of VOG in arterial plasma after femoral and portal vein administration (10 mg/kg), similarly, evaluated the gastrointestinal first-pass effect after portal vein (10 mg/kg) and gastrointestinal administration (20 mg/kg). For the study on regulatory mechanisms of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp) on the bioavailability of VOG, the solution of verapamil hydrochloride (60 mg/kg) was instilled into intestine at 10 min before the infusion of VOG.

Key findings

The bioavailability of VOG after intraportal, intestinal as well as gastric administration was 45.1%, 8.1% and 9.8%, respectively. The value of AUC0→∞ for verapamil group was approximately 1.4-fold higher than that for normal saline group, meaning that perhaps CYP3A participated in the metabolism of VOG or P-gp transported VOG outside.

Conclusions

The hepatic and intestinal first-pass effect were considered to mostly contribute to the low bioavailability of VOG in rats, and the gastric first-pass effect should be neglected. Also, the contribution of CYP3A to metabolism and P-gp mediated efflux have played a significant role in low bioavailability of VOG.