Abstract
The beneficial properties of phenolic compounds from Olea europaea L. are well-known. An olive extract (OE) was prepared from unripe olives (Moraiolo cultivar). The study aimed to formulate OE into a microemulsion (ME) in oral dosage form. OE was extracted from olives with EtOH:H2O (80:20) and characterized by HPLC-DAD. ME composition was stated by a solubility and pseudo-ternary diagram. The ME was chemically and physically characterized, and its stability at 4 °C was analyzed for three months. The ability of the formulation to ameliorate the solubility and the intestinal permeability of OE was evaluated by a Parallel Artificial Membrane Permeability Assay (PAMPA) assay and Caco-2 cells. The total phenolic content of the extract was 39% w/w. The main constituent was oleuropein (31.0%), together with ligstroside (3.1%) and verbascoside (2.4%). The ME was prepared using Capryol 90 as the oily phase, and Cremophor EL and Transcutol (2:1) as surfactant and co-surfactant, respectively. ME droplet size was 14.03 ± 1.36 nm, PdI 0.20 ± 0.08, ζ-potential −1.16 ± 0.48. Stability of ME was confirmed for at least three months. The formulation was loaded with 35 mg/mL of OE, increasing the solubility of the extract by about four times. The enhanced permeability of OE was evaluated by PAMPA, as demonstrated by the Pe value (1.44 ± 0.83 × 10−6 cm/s for OE hydroalcoholic solution, 3.74 ± 0.34 × 10−6 cm/s for OE-ME). Caco-2 cell transport studies confirmed the same results: Papp was 16.14 ± 0.05 × 10−6 cm/s for OE solution and 26.99 ± 0.45 × 10−6 cm/s for OE-ME. ME proved to be a suitable formulation for oral delivery.
Highlights
The beneficial health properties associated to a regular consumption of extra virgin olive oil (EVOO) and other food products derived from the olive tree (Olea europaea L.) are well-known, mainly thanks to the presence of specific phenolic compounds
A microemulsion intended for preparation of oral dosage form and suitable for delivering an olive extract (OE)
The olive extract was obtained in the powder form from Tuscan olives of the Moraiolo cultivar harvested before any stone lignification and immediately lyophilized after freezing them with liquid nitrogen
Summary
The beneficial health properties associated to a regular consumption of extra virgin olive oil (EVOO) and other food products derived from the olive tree (Olea europaea L.) are well-known, mainly thanks to the presence of specific phenolic compounds. The main phenolic compound present in the olive fruits is the secoiridoid oleuropein, followed by other secoiridoids, namely ligstroside, nuzhenide (only present in seeds), and demethyloleuropein (which appears in late ripening stages), and by the phenylpropanoid derivative verbascoside [5,6,7,8]. Their concentration is affected by ripening stage and the part of the fruit [5,9,10,11]. During the green maturation, its level, as well as those of verbascoside and ligstroside, constantly decreases [5,12,13,14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
