Micellar propolis nanoformulation of high antioxidant and hepatoprotective activity

ABSTRACT The present study reports a promising antioxidant protection by a recently developed micellar propolis formulation, against oxidative stress in in vitro and in vivo models of toxicity. The formulation, based on poplar propolis encapsulated in poly(ethylene oxide)-β-poly(propylene oxide)-β-poly(ethylene oxide) triblock copolymer (PEO26-PPO40-PEO26) micelles is characterized by small size (D h = 20 nm), enhances aqueous solubility and good colloidal stability. In vitro, propolis-loaded PEO26-PPO40-PEO26 micelles (20-100 µg/ml) significantly increased the cell viability of human hepatoma HepG2 cells, subjected to H2O2-induced cell injury (0.1 mM, 1 h). Antioxidant activity and protection of the micellar propolis were evaluated in a model of carbon tetrachloride-induced hepatotoxicity in rats (10% CCl4 solution, 1.25 ml/kg, p.o.) by measurement of non-enzyme (malondialdehyde and glutathione) and enzyme (catalase and superoxide dismutase) biomarkers of oxidative stress. Clinic observations, hematological, biochemical parameters and histological analysis were also performed. In vivo, micellar propolis (20 mg/kg b.w., p.o., 14 days) ameliorated CCl4-induced acute liver injury in rats. The oral administration of micellar propolis significantly prevented serum transaminase increases, as well as brought the levels of malondialdehyde, glutathione, and antioxidant enzymes catalase and superoxide dismutase toward the controls levels. Therefore, PEO26-PPO40-PEO26 micelles could be considered as a promising oral delivery system of propolis against oxidative stress injury in liver cells.

Amorpha fruticosa - A Noxious Invasive Alien Plant in Europe or a Medicinal Plant against Metabolic Disease?

Amorpha fruticosa L. (Fabaceae) is a shrub native to North America which has been cultivated mainly for its ornamental features, honey plant value and protective properties against soil erosion. It is registered amongst the most noxious invasive species in Europe. However, a growing body of scientific literature also points to the therapeutic potential of its chemical constituents. Due to the fact that A. fruticosa is an aggressive invasive species, it can provide an abundant and cheap resource of plant chemical constituents which can be utilized for therapeutic purposes. Additionally, exploitation of the biomass for medicinal use might contribute to relieving the destructive impact of this species on natural habitats. The aim of this review is to provide a comprehensive summary and systematize the state-of-the-art in the knowledge of the phytochemical composition and the potential of A. fruticosa in disease treatment and prevention, with especial emphasis on diabetes and metabolic syndrome. Also reviewed are aspects related to potential toxicity of A. fruticosa which has not yet been systematically evaluated in human subjects.

Antioxidant response and biocompatibility of curcumin-loaded triblock copolymeric micelles.

To evaluate the safety profile of cationic micelles, based on triblock copolymer poly(dimethylaminoethyl methacrylate)-poly(e-caprolactone)-poly(dimethylaminoethyl methacrylate) (PDMAEMA9- PCL70-PDMAEMA9), the effects of empty (PM) and curcumin loaded micelles (PM-Curc) on nonenzyme induced lipid peroxidation (LPO) in vitro, hemolytic activity and morphological changes in some organs after repeated intraperitoneal administration in vivo were studied. To induce LPO, rat liver microsomes were incubated with a solution of iron sulfate and ascorbinic acid (Fe2+/AA). The effect of empty PM (40 and 100 µg/ml), PM-Curc and free curcumin (both at 3.48 and 8.7 µg curcumin/ml) was assessed at 20 min incubation time. In the non-enzyme induced LPO model, the investigated substances at all concentrations significantly decreased the formation of malondialdehyde (MDA), compared to the Fe2+/AA induced LPO group. According to the results it can be concluded that curcumin alone and loaded in PM, exert significant antioxidant activity. In the biocompatibility safety studies, the mean hemolytic index for polymeric carrier was less than 2%, indicating it was non-hemolytic. The general appearance of the organ tissues from Wistar rats, treated in vivo with curcumin loaded PM was similar to that of controls, thus showing no apparent toxicity after repeated 14-days treatment.

In vitro and in vivo toxicity evaluation of cationic PDMAEMA-PCL-PDMAEMA micelles as a carrier of curcumin.

Polymeric micelles have attracted significant attention because of their potential application as promising drug-delivery systems. In the present study cationic micelles, based on triblock copolymer poly(dimethylaminoethyl methacrylate) - poly(e-caprolactone) - poly(dimethylaminoethyl methacrylate) were prepared and loaded with curcumin. In vitro cytotoxicity of empty and curcumin loaded polymer micelles was investigated on two cell culture models, human hepatoma cell line HEP G2 and freshly isolated rat hepatocytes, following their viability and lactate dehydrogenase (LDH) leakage. MTT dye reduction assay and LDH release study showed that empty cationic micelles did not cause significant changes in cell viability and membrane integrity at the concentration range from 10.0 to 80.0 µg/ml. Our special attention was focused on the effects of empty and curcumin loaded micelles on oxidative stress markers malondialdehyde (MDA) and reduced glutathione (GSH). The increase in the micelles concentration to 100 µg/ml was accompanied by GSH depletion and increased levels of MDA production in isolated rat hepatocytes. The in vivo toxicity of polymeric micelles was examined in male Wistar rats. The results showed that neither single (7.5 mg/kg, i.p.), nor repeated (3.5 mg/kg, i.p., 14 days) exposure to empty or curcumin loaded polymeric micelles induced any toxicity changes, e.g. hematopoietic and liver tissue damages.