In Vitro Tyrosinase Inhibitory Activity of Eleutherine bulbosa Bulb Extract and Characterization of Its Liposomal Delivery System

This study aimed to characterize the phytochemical profile of Eleutherine bulbosa bulb ethanolic crude extract, evaluate its anti-tyrosinase activity, and develop liposomal formulations to enhance skin delivery for topical skin-lightening applications. The extract contained total phenolics 89.88 ± 4.36 mg GAE/g crude extract, total flavonoids 7.99 ± 0.05 mg QE/g crude extract, and anthraquinones 114.12 ± 0.85 mg/g crude extract. The UHPLC-QTOF-MS analysis revealed the presence of naphthalenes, naphthoquinones, anthraquinones, coumarins, chalcone, myricetin, quercetin, epicatechin, catechin and their derivatives. Mangiferin, rhapontin and gingerol were also detected in E. bulbosa bulbs. The extract exhibited anti-tyrosinase activity (IC50 = 119.71 ± 3.76 µg/mL), comparable to that of alpha-arbutin (IC50 = 136.66 ± 12.49 µg/mL), although the difference was not statistically significant (p > 0.05). Liposomes loaded with E. bulbosa extract were prepared using the proliposome method and further fabricated by ultrasonication and microfluidics, achieving 86.16 ± 3.04% entrapment efficiency. The optimized liposomes (particle size 114.0 ± 1.23 nm, PDI 0.24 ± 0.04, zeta potential −38.3 ± 0.07 mV) demonstrated enhanced skin permeation versus non-liposomal extract using Strat-M™ membrane in Franz diffusion cells. These results demonstrate that E. bulbosa bulb extract is a promising candidate for further cosmeceutical research.