Jornal de Nanomedicina e Nanotecnologia

Abstrato

Nanoencapsulation of Natural Products for Chemoprevention

Imtiaz A. Siddiqui, Yogeshwer Shukla and Hasan Mukhtar

Chemoprevention by utilization of natural products has emerged as an important strategy that has the potential to prevent the occurrence of cancer mainly by slowing the process of carcinogenesis. Laboratory data supported by several epidemiological and some clinical studies have validated that bioactive food components produce a broad spectrum of activities that ultimately culminate in prolonging the development time for cancer outcome. With an armamentarium of over 1500 such compounds great hope for cancer control rest on chemoprevention. Despite remarkable effectiveness in preclinical settings, its applicability to human has met with limited success mainly due to inefficient systemic delivery and poor bioavailability of promising chemopreventive agents. Thus, novel strategies are needed to enhance the bioavailability and reduced perceived toxicity associated with the long-term use of potentially useful bioactive food components. We introduced a novel concept of 'nanochemoprevention' where nanotechnology was exploited to augment the outcome of chemoprevention. In our study, we reported significant dose-advantage of polylactic acid-polyethylene glycol (PLA-PEG) encapsulated EGCG, a major polyphenol from green tea (nanoEGCG) over non-encapsulated (native) EGCG. Nano- EGCG exhibited over ten-fold dose advantage for exerting its proapoptotic and anti-angiogenic effects in human prostate cancer cells. It is increasingly appreciated that nanoparticle technology could be easily utilized for cancer because of the fact that most of the biological processes occur at nanoscale. Our concept of nanochemoprevention opened a new era in the field of cancer chemoprevention by natural products. Several laboratories worldwide are now focusing their attention on the subject and emerging data is accumulating for use of many agents using diverse nanoparticles. Some other naturally occurring dietary agents which have been tested for chemoprevention following nanoencapsulation are curcumin, resveratrol and taxol. All of these data at present is limited to use in cell culture or xenograft model. Extending this research to in vivo evaluation in well-defined animal bioassay system should be the next step.