Catechin is a secondary metabolite of herbal source which belongs to a group of flavanoids that has diverse health benefits in mankind. They are basically polyphenolic compounds important for their antioxidant activities (Jin Ze Xu et al., 2004). The potential sources of catechin include apples, oranges, pears, black grapes, blackberries, cherries, raspberries, red wine and dark chocolate. Commercially, Acacia catechu being the richest source of catechin is widely used.
Flavanoids, a phytoconstituent present in catechin seem to have numerous therapeutic effects due to their inherent potential of various biochemical activities involved in inhibiting many enzymatic pathways and enzymes (Vanna Sanna Imtiaz et al., 2013), especially catechin possess anti-proliferative, antimicrobial, anti-inflammation, and antioxidant properties. It also improves blood flow and has potential benefits in cardiac health (Gupta R and Ramteke PW, 2011; Schroeter H et al., 2006; Fraga Cesar G and Oteiza Patricia I, 2011). Chemoprevention using herbal based products or plant secondary metabolites are essentially important in cost effective treatment of cancer therapy and mitigating the side effects of conventional cancer therapies. Bioavailability of the drug is a vital parameter for assessing the pharmacokinetics in vitro due to antioxidant activity and capacity to interact with cell signaling proteins and membrane proteins of Catechin (Kohri T et al., 2001). The in vivo absorption studies proved that high quantity of oral dosage of catechin is required which equals to 100 folds more than intravenous dosage (Tasnima K et al., 2013). There are only few clinical studies carried out on humans, the main reason being its very low bioavailability which might be due to rapid elimination from liver by biliary excretion (Agrawal AD, 2011) when administered in vivo (Zhu Min et al., 2000). Decreased bioavailability of catechin was found to be prominent in most of the in vivo research works, but the reason for such low bioavailability is still not clear.
Hence, the prevailing problems of low bioavailability, poor absorption and high first pass effect drives the need to develop strategies for optimizing the dosage of catechin for maximum therapeutic activity due to high absorption and higher bioavailability. It is therefore essential to make the molecule reach cells effectively and stay in cells for prolonged time to execute therapeutic activity.
Current research practices employs nanotechnology approaches to improve the solubility, bioavailability and bioefficacy as it allows the use of biodegradable, non-toxic nanoparticles having higher surface to volume ratio to attach or encapsulate natural plant products (McNeil SE, 2005). Nanophytomedicines prepared from active standardized extracts are used as nanophytomedicines for improved efficacy and bioavailability. Thus minimizing the side effects and toxicity of administered drugs (Alakh NS, 2013). Due to the advantages of nanophytomedicines and many potential health benefits of catechin (an active phytocompound), the pure and rich extract of catechin was investigated in the present study for effective management of the associated pharmacokinetic problems. The research intent was to investigate the role of nanotechnology with a pH-sensitive, biodegradable and non-toxic polymer Eudragit L 100 for efficient encapsulation and protection of the drug from an acidic degradation for sustained drug release from nanocapsules in the alkaline environment with an enhanced bioavailability and bio-efficiency of catechin.
Key words: Catechin rich extract, Nano-formulation, Antioxidant, in vitro bioavailability
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