A facile and simple synthesis of a cytotoxic tocotrienol-based nanoemulsion against MCF-7 and A549 cancer cell lines

Tocotrienol is a subfamily of natural vitamin E with multiple biological activities, including antioxidants, antiproliferative, proapoptotic, antiangiogenic, and anti-inflammatory properties. Despite numerous biological activities, the application of tocotrienol is hampered by its poor solubility, resulting in low bioavailability, and in turn, limits its therapeutic effectivity. To address these limitations, the present study focuses on the development of tocotrienol nanoemulsion, followed by an in vitro anticancer evaluation of the formula. The tocotrienol nanoemulsion was prepared by a combination of high-speed homogenization with ultrasonication, using food-grade canola oil and Tween 80 as oil phases and surfactants, respectively. The formulated nanoemulsion observed an encapsulation efficiency of 90.26% with particle size and zeta potential of 145 +/- 0.06 nm and -25.27 +/- 0.01 mV, respectively. The FTIR spectra show no interference between the active compounds and the excipients, indicating that tocotrienol was successfully loaded into the nanoemulsion. Besides, the tocotrienol nanoemulsions demonstrated higher antioxidant ABTS (2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity than the free form of tocotrienol at the same concentration (p < 0.05). In the in vitro cytotoxicity studies, there was a decrease in cell viability observed against MCF-7 breast and A549 lung cancer cell lines for tocotrienol nanoemulsion. Overall, it suggests that nanoemulsion-based natural component delivery systems have substantial implications in developing and designing encapsulated biologically active systems. The potent cytotoxicity of tocotrienol-loaded nanoemulsion under aqueous phases provides insight into the development of nanoemulsion systems for enhancing the bioavailability and activity of tocotrienol as well as other lipophilic compounds in water systems, particularly for anticancer therapeutic.