Olive leave extracts and components as an innovative approach for cancer therapy

Abstract

Olea europaea (Olive tree) bears the olive fruit, which belongs to the Oleaceae family, grows mainly in the Mediterranean region, and is widely consumed and studied. Recent studies have shown that extracts (OLE) from olive leaves have potent antioxidant and anti-cancer properties. The bioactive components in OLE enable the development of innovative approaches to cancer treatment. These components can have a suppressive effect on various cellular signaling pathways associated with the cancer process and increase the effectiveness and safety of chemotherapy agents targeting multiple signaling pathways in cancer treatment. However, phenolic compounds combined with chemotherapy drugs attract attention in creating new, more effective therapeutic approaches to be used in the treatment of aggressive cancers. Bioactive components have low solubility in water due to their lipophilic structure, and their therapeutic effectiveness is limited by rapid and widespread metabolism, poor systemic absorption, and bioavailability. For this reason, although bioactive components have demonstrated significant anti-cancer and treatment resistance effectiveness in pre-clinical studies, these components cannot demonstrate the expected effect in in-vivo applications due to the mentioned pharmaceutical incompatibilities. Recent studies show that it is possible to maximize therapeutic effects by encapsulating bioactive components within living systems through nanodrug delivery systems. Nanocarriers, with controlled and long-term release, enable biological substances to penetrate further into the target organs and reach the desired daily concentration, significantly increasing the molecules' effectiveness. In particular, local drug delivery creates an alternative treatment option and ensures the continuous release of the active compound at the desired site of action. To date, nanoparticles (NP) and nanofibers as nanocarrier systems have been used to develop cancer treatment strategies. NPs are considered a highly effective approach for intravenous delivery of flavonoids with good encapsulation potential of drugs or bioactive compounds and reduced toxicity. However, these carrier systems have some disadvantages, such as rapid burst release, drug leakage, limitations related to stability and shelf life, inability to provide continuous or controlled drug release, and multiple drug releases. Nanofibers produced by electrospinning are nanoscale biomaterials with a large specific surface area, high porosity, minimal barrier to mass transfer, controllable morphology, and good mechanical resistance. Nanofibers can be produced in various configurations, including monolayer, multilayer, core-shell, ribbon, network, and porous well. The problem of rapid dissolution of active compounds from nanofibers by burst release is overcome by core-shell electrospinning. Due to their biocompatibility and biodegradability, nanocarrier systems have become the focus of particular attention by researchers in drug delivery, tissue engineering, and cancer. Nanocarrier systems increase the drug's performance by drug accumulation on the tumor site, adjustability of the required dosage, and reduction of the side effects of the drug on nontarget tissues. As a result, this section examines the potential of bioactive compounds found in OLE, which are loaded into nanocarrier systems today, to create new, more effective treatment strategies with fewer side effects in cancer cells. This approach can potentially set new standards in cancer treatment and provide more effective and safe treatment options for cancer patients.