Figure 1.

Olive leaf extract preparation steps and characterisation. (A) Freshly harvested olive leaves (1) were freeze-dried and vacuum-sealed using a lyophiliser (2); upon use, olive leaves were ground with a homogeniser to obtain an uneven powder (3) which was immediately used for TPC extraction in PBS; the extract was centrifuged (4), the supernatant filtered (5) and finally stored at −20 °C before downstream applications. (B) OLE’s TPC was determined using the Folin–Ciocalteau reagent, whereas OLE’s main compounds were determined via UHPLC/UV-ESI-HRMS. (C) Molecular structure of OA and OC. This figure was created using the Servier Medical Art Commons Attribution 3.0 Unported Licence (http://smart.servier.com, accessed on 5 July 2023).