The Stability of Wild Thyme Extract-Loaded Phospholipid-Cholesterol Liposomal Particles

Abstract

Wild thyme contains biologically active compounds, particularly polyphenols (flavonoids and phenolic acids) that exert antitumor, antimicrobial, anti-inflammatory, antioxidant, immunomodulatory, analgesic, and spasmolytic activities. Nevertheless, the mentioned bioactive compounds have low stability, solubility, and bioavailability, thus their application is limited. Liposomal particles have been widely used for the encapsulation of bioactive components, due to their high structural integrity, stability during storage, and controlled release capability. In the present study, phospholipid-cholesterol liposomal particles, as the carrier for wild thyme extract, were developed. The stability of extract-loaded liposomes was monitored for 21 days by measuring vesicle size, polydispersity index (PDI), and zeta potential. The particle size and PDI of extract-loaded liposomes did not change drastically during 21 days of storage and amounted to ~450 nm and ~0.155, respectively. The zeta potential varied in the liposomes and started to decrease after 7 days of storage (from -21.0 mV to 20.3 mV, without a statistically significant difference), while the zeta potential value after 21 days was statistically significantly lower in comparison to the 1st day (19.3 mV). The beneficial effects of polyphenols on human health, as well as showed storage stability of the prepared liposomes highlight the use of the wild thyme extract-loaded phospholipid-cholesterol liposomal particles for potential application in food, pharmaceutical, and cosmetic industries.