A Nanotechnological Approach to Exploit and Enhance the Bioactivity of an Extract from Onopordum illyricum L. Leaves

Plant-derived products have been used for preventive and curative purposes from the ancient era to the present day. Several studies have demonstrated the efficacy of either multicomponent based extracts, enriched fractions, or isolated bioactives. However, they often display low solubility and bioavailability, chemical instability, poor absorption, and even toxicity, which restrict application in therapy. The use of drug delivery systems, especially nanocarriers, can overcome these physicochemical and pharmacokinetic limitations. In this study, an extract from Onopordum illyricum leaves was produced by maceration in 80% ethanol, characterized by liquid chromatography coupled to mass spectrometry, and formulated in phospholipid vesicles with the aim of exploiting and possibly enhancing its bioactivity for skin delivery. The results showed that phenolic compounds were abundantly present in the extract, especially hydroxycinnamic acid and flavonol derivatives. The extract-loaded vesicles showed small size (<100 nm), high entrapment efficiency (even >90% for most phenolic compounds), and good long-term stability. Moreover, the extract-loaded vesicles exhibited remarkable antioxidant activity, as demonstrated by colorimetric assays and by enhanced reduction of intracellular reactive oxygen species (ROS) levels in cultured skin cells. Hence, our findings support the key role of nanotechnological approaches to promote the potential of plant extracts and strengthen their application in therapy.