Polyphenols constitute a family of natural substances distributed widely in plant kingdom. These are produced as secondary metabolites by plants and so far 8000 representatives of this family have been identified. Recently, there is an increased interest in the polyphenols because of the evidence of their role in prevention of degenerative diseases such as neurodegenerative diseases, cancer, and cardiovascular diseases. Although a large number of drugs are available in the market for treatment of these diseases, however, the emphasis these days is on the exploitation of natural principles derived from plants. Most polyphenols show low in vivo bioavailability thus limiting their application for oral drug delivery. This low bioavailability could be associated with low aqueous solubility, first pass effect, metabolism in GIT, or irreversible binding to cellular DNA and proteins. Therefore, there is a need to devise strategies to improve oral bioavailability of polyphenols. Various approaches like nanosizing, self-microemulsifying drug delivery systems (SMEDDS), microencapsulation, complexation, and solid dispersion can be used to increase the bioavailability. This paper will highlight the various methods that have been employed till date for the solubility enhancement of various polyphenols so that a suitable drug delivery system can be formulated. 1. Introduction Naturally occurring active moieties have been used in therapy since ages. Currently 80% of the world’s population uses plant derived principles either directly or indirectly [1]. Certain examples of plant derived products employed as therapeutic agents are tannins, alkaloids, polyphenols, polysaccharides, essential oils, various extracts, and exudates. Lately, much research has been envisaged on polyphenols due to two main reasons. Firstly, these possess high spectrum of biological activities including antioxidant, anti-inflammatory, antibacterial, and antiviral and secondly, they are present in abundance in diet [2]. Polyphenols are found in many components of the human food including peanuts, dark chocolate, green and black tea, and turmeric. Extensive research in the past years and collected data shed light on certain physiological properties of plant polyphenols. These can slow the progression of certain cancers, neurodegenerative diseases, and diabetes and can reduce the risks of cardiovascular disease, thus highlighting the importance of the use of plant polyphenols as potential chemopreventive and anticancer agents in humans [3]. Many medicinal plants constitute polyphenols as active
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