“…Not only do numerous studies confirm that olive leaves are able to decline blood pressure, improve blood flow in the coronary arteries [ 20 , 21 ], regulate arrhythmia, and prevent intestinal smooth muscle spasms [ 22 ], but their antimicrobial potential against bacteria, fungi, and mycoplasma has also been highlighted [ 23 , 24 , 25 , 26 , 27 ]. Like olive oil, the therapeutic benefits of O. europaea L. folium have been credited to low-molecular-weight polyphenols such as oleuropein (up to 60–90 mg/g dry leaf weight), hydroxytyrosol, tyrosol, and vitamin E isomers of tocopherol, elenolic acid derivatives, caffeic acid, p -coumaric acid, and vanillic acid, as well as flavonoids—luteolin, diosmetin, rutin, luteolin-7-glucoside, apigenin-7-glucoside, and diosmetin-7-glucoside [ 28 , 29 ]. The relevance of the whole olive leaf and its extract has been quickly rising in both pharmaceutical and food industries, not only as a functional food but also as a material used in food additives for preservation [ 30 , 31 ].…”