The extract from O. europaea Madural’s leaves could be the most useful one for retaining a high-quality phenolic composition given the water content and TPC, making it a possible natural matrix for (1) cardioprotective therapies as a prophylactic and treatment agent, and (2) improving both the insulin sensitivity and (3) secretory capacity of pancreatic β-cells, thus mimicking metformin’s effects in patients with T2DM. This evidence concerns the gene INS and type 2 diabetes mellitus.