RESUMEN
Background: Green tea polyphenols (GTP) are known to have several health benefits. In spite of these benefits, its application as a therapeutic agent is limited due to some of its limitations such as stability, bioavailability, and biotransformation. To overcome these limitations, liposomal nanoparticles have been used as a carrier of the GTP. Objective: Encapsulation of GTP to the liposomal nanoparticles in order to achieve a sustained release of the GTP and to determine the drug release kinetics and the mechanism of the release. Materials and Methods: GTP encapsulated liposomal nanoparticles were prepared using phosphatidyl choline and cholesterol. The synthesized particles were characterized for their particle size and morphology. In vitro release studies were carried out, followed by drug release kinetics, and determining the mechanism of release. In vitro, antioxidant assay was determined following 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results: Atomic force microscope (AFM) and high resolution scanning electron microscope (HR SEM) images showed spherical particles of the size of 64.5 and 252 nm. An encapsulation efficiency as high as 77.7% was observed with GTP concentration of 5 mg.mL-1. In vitro release studies showed that the loading concentrations of GTP were independent to the cumulative percentage of the drug release. GTP release by varying the pH and temperature showed a direct correlation between the release parameter and the percentage of drug release. The higher the pH and temperature, the higher was the percentage of the drug release. The release data showed a good correlation with Zero order kinetics and the mechanism of the release being anomalous mode. Radical scavenging activity of the released GTP showed a potent scavenging activity. Conclusion: GTP encapsulated liposomal nanoparticles could be used as a delivery vehicle for achieving a sustained release.
RESUMEN
Growth regulation associated with dormancy is an essential element in plant's life cycle that leads to changes in expression of large number of genes. Forward and reverse suppression subtractive hybridization (SSH) libraries were developed to identify and characterize the genes associated with bud (banjhi) dormancy in tea (Camellia sinensis (L.) O. Kuntze). Efficiency of subtraction was confirmed by comparing the abundance of ß-actin gene. A total of 17 and 45 unique sequences were obtained from forward and reverse SSH library respectively. Many of the differentially regulated genes have unknown (41.1% and 26.7%) or hypothetical functions (11.7% and 2.2%) in forward and reverse SSH library respectively, while others have a role in cell growth and metabolism. Further, semi-quantitative RT-PCR was carried out for selected genes to validate the quality of ESTs from SSH library. Gene Ontology analysis identified a greater association of these ESTs in cellular metabolic pathways and their relevance to bud dormancy. Based on the EST data, the putative role of identified genes from tea is discussed in relation to dormancy, which includes various metabolic and signalling pathways. We demonstrated that SSH is an efficient tool for enriching up- and down-regulated genes related to bud dormancy in tea. This study represents an attempt to investigate banjhi dormancy in tea under field conditions, and the findings indicate that there is a potential to develop new approaches to modulate dormancy in this species.