ABSTRACT
Nanoemulsification of nutrients could improve bioavailability by enhancing intestinal uptake. We investigated the antioxidant and hypolipidemic effects of nanoemulsified green tea extract (NGTE). Antioxidant effect was measured by 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and dichlorofluorescein diacetate (DCFH-DA) assay. C57BL/6 mice were fed a control high-fat diet, green tea extract (GTE), or NGTE diet for 4 weeks. In composition analysis, GTE and NGTE contained similar total catechin concentrations. The antioxidative effect of GTE was comparable with that of NGTE. In the ABTS assay, GTE had a marked effect, although NGTE was more effective than GTE in the DCFH-DA assay. In the mouse feeding experiment, total and low-density lipoprotein (LDL) cholesterol concentrations were significantly reduced after NGTE treatment in comparison with GTE treatment in high-fat-fed C57BL/6J mice over the course of 4 weeks. The hypocholesterolemic effects were greater in the NGTE group compared with the GTE group (24% vs. 15.4% LDL cholesterol reduction compared with the control). Expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase was significantly down-regulated. Protein expression of LDL receptor was significantly increased in the livers of both the GTE- and NGTE-treated groups (+234.1%, P<.01 and +274.7%, P<.001), with a greater effect in the NGTE than in the GTE group. Cholesterol 7α-hydroxylase gene expression was similarly increased in both the GTE and NGTE groups. These results suggest that nanoemulsification significantly increased hypocholesterolemic effects of GTE in vivo due to increased bioavailability.
Subject(s)
Anticholesteremic Agents/pharmacology , Camellia sinensis/chemistry , Plant Extracts/pharmacology , Animals , Antioxidants/pharmacology , Cholesterol 7-alpha-Hydroxylase/genetics , Cholesterol, LDL/blood , Diet, High-Fat , Down-Regulation , Emulsions , Gene Expression Regulation/drug effects , Hydroxymethylglutaryl CoA Reductases/genetics , Lipids/blood , Male , Mice , Mice, Inbred C57BL , Nanotechnology/methods , Plant Extracts/chemistry , Sterol Regulatory Element Binding Protein 2/geneticsABSTRACT
BACKGROUND: Biodegradable polymers have increasingly been recognized for various biological applications in recent years. Here we examined the immunostimulatory activities of the novel poly(aspartic acid) conjugated with L-lysine (PLA). METHODS: PLA was synthesized by conjugating L-lysine to aspartic acid polymer. PLA-nanoliposomes (PLA-NLs) were prepared from PLA using a microfluidizer. The immunostimulatory activities of PLA-NLs were examined in mouse bone marrow-derived dendritic cells (BM-DCs). RESULTS: PLA-NLs increased the number of BM-DCs when added to cultures of GM-CSF-induced DC generation on day 4 after the initiation of cultures. Examination of the phenotypic properties showed that BM-DCs generated in the presence of PLA-NLs are more mature in terms of the expression of MHC class II molecules and major co-stimulatory molecules than BM-DCs generated in the absence of PLA-NLs. In addition, the BM-DCs exhibited enhanced capability to produce cytokines, such as IL-6, IL-12, TNF-α and IL-1ß. Allogeneic mixed lymphocyte reactions also confirmed that the BMDCs were more stimulatory on allogeneic T cells. PLA- NL also induced further growth of immature BM-DCs that were harvested on day 8. CONCLUSION: These results show that PLA-NLs induce the generation and functional activities of BM-DCs, and suggest that PLA-NLs could be immunostimulating agents that target DCs.
