There are some potential use for olive leaf extract as anti oxidant, anti bacterial or anti viral effect but there is no scientific study to prove it, there is one recent study for treating hypertension: bsusalit e, agus n, effendi i, et al.
Olive (olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captopril
. Phytomedicine. 2011 feb 15;18(4):251-8.