The study looked at how different solvents affect the amount of beneficial compounds in olive leaves. They used water, methanol/water, and methanol to extract these compounds. Methanol was best for getting oleuropein, while water was better for hydroxytyrosol, tyrosol, and verbascoside. Overall, methanol had the highest total phenolic content, followed by methanol/water, and then water. This means that polyphenolic compounds, which have health benefits, are best extracted using methanol solvents.