Maslinic acid is a pentacyclic triterpene widely distributed in the plant kingdom and found in several edible vegetables and fruits, being table olives a rich source of this compound. Maslinic acid is being recognized as a nutraceutical due to its lack of harmful effects and numerous health-protecting properties. Maslinic acid is a pentacyclic triterpene occur naturally in many herbs and plant foods. It is found in the protective wax-like coating of the leaves and fruit of Olea europaea and is one of the ingredients in olive oil. 

Bioavailability

The bioavailability of this compound was studied after a single oral administration (50?mg/kg) to rats, and it was absorbed by the intestine and reached the blood, where it was found 10?min after the oral administration and could still be detected in plasma after 60?min. However, no study has examined its levels in humans after administration.

Biological activities

Maslinic acid exerts a wide range of biological activities including antitumor, antidiabetic, anti-obesity, antioxidant, anti-inflammatory, cardioprotective, neuroprotective and antimicrobial. In vitro anti-diabetic effects of maslinic acid are exhibited by increasing glycogen content and inhibiting glycogen phosphorylase activity in HepG2 cells. It was shown to induce the phosphorylation level of IRβ-subunit, Akt, and GSK3β with specific activation of Akt. 

In vivo maslinic acid treatment of mice fed with a high-fat diet reduced the model-associated adiposity and insulin resistance, and increased the accumulated hepatic glycogen content. In hyperglycemia mice, the elevation of blood glucose level caused by adrenaline or glucose was antagonized by maslinic acid significantly.Diabetic rats pretreated with high-dose maslinic acid had lower blood glucose levels, reduced infarct volumes and improved neurological scores. 

Less glutamate overflow was also observed in maslinic acid -treated rats after 2 hours of ischemia followed by 24 and 72 hours of reperfusion. In addition, maslinic acid treatment enhanced the glial glutamate transporter GLT-1 expression at the protein and mRNA levels. 

Direct beneficial effect in cerebral ischemic injury in rats may be correlated with the promotion of glutamate clearance by NF-κB-mediated GLT-1 up-regulation. Through NF-kappa B and MAPK/AP-1 signaling pathways maslinic acid suppresses RANKL-induced osteoclastogenesis as well.