Silymarin—A Scintillating Phytoantioxidant: Clinical Applications and Bio-delivery Problems
Silymarin is a unique flavonoid complex—containing silybin, silydianin, and silychrisin—that is derived from the milk thistle plant. These unique phytochemicals from the milk thistle have been the subject of decades of research into their beneficial properties. Despite its extraordinary antioxidant capacity, the clinical usage of silymarin has remained restricted to amelioration of hepatic pathology. Perhaps its low bioavailability and uneven bio-distribution, owing to its poor aqueous solubility, are two main causes that have dampened the clinical applicability and scope of this preparation. However, considering its benefits and proven clinical evaluations, preparations for increased solubility and enhanced biodistribution have recently been developed. With newer methods like size restriction, nanoformulations, and co-precipitation strategies, benefits of silymarin can be reconsidered with a much better and potentially beneficial phytoantioxidnat. This chapter describes clinical applications of silymarin, problems faced in the early formulations, and presently used methods for enhancing the bioavailability and delivery. The chapter ends with future directions and prospective studies that can further expand the delivery and biodistribution of silymarin.