Rutin-loaded Phyto-Sterosomes as a potential approach for the treatment of hepatocellular carcinoma: In-vitro and in-vivo studies

beta-Sitosterol, isolated from Senecio fulgens, was used as a "heart-friendly" alternative to cholesterol to prepare a novel non-phospholipid liposomal nano-carrier "Phyto-Sterosomes". Different saturated fatty acids (Lauric, Stearic, and Palmitic acids) were used, in different ratios with beta-sitosterol (1:2 and 1:3), to prepare the Phyto-Sterosomes (P-STs) aiming to enhance the solubility and biological efficacy of the poorly soluble drug under study "Rutin". The in vitro release study performed for the formulations proved that the drug release followed a diffusion-dependent mechanism. Physicochemical investigations showed that P-ST6, composed of beta-sitosterol: lauric acid (3:1), was spherical and had the highest drug encapsulation efficiency (95.7%), smallest particle size (250.6 nm) with a homogenous distribution (PDI = 0.2) and a high zeta potential (-51.5 mV). It also attained the highest enhancement of drug release compared to the drug suspension (RE = 66.79% and 26.85%, resp.). Fluorescence spectroscopy and microscopy studies performed using the lipid soluble dye, Oil red O, proved its high affinity towards the selected nanovesicles. After one month of storage at various temperatures (4, 25 and 40 degrees C), P-ST6 demonstrated good physicochemical stability. Cell biology studies demonstrated that P-ST6 and unmedicated P-ST6 reduced the cell viability of HepG2 cell line in a significant and concentration-dependent manner, with an IC50 of 73.7 and 145 mu g/ml, respectively, using Sulforhodamine B assay. Both tested samples had marked anti-proliferative and tumor-suppressive effects by initiating cell cycle arrest as detected by flow-cytometry analysis. Pharmacokinetic study showed a significant increase in the bioavailability of the drug after a single oral administration of P-ST6 compared to the drug suspension. This study proves that the nano -encapsulation of Rutin in the innovated "heart-friendly" vesicular nanoformulation can be a promising thera-peutic platform.