Antitumor Perspectives of Oleuropein and Its Metabolite Hydroxytyrosol: Recent Updates

Abstract

Olive fruit is a significant and promising source of potential bioactive compounds such as oleuropein and hydroxytyrosol. Oleuropein is the ester of elenolic acid and 3,4-dihydroxyphenyl ethanol (HT). It is the main glycoside in olives, the degradation of which results in the formation of hydroxytyrosol in olive oil. Both plays a significant role in the reduction of coronary heart diseases and a certain type of cancers. Both olive oil phenols have an effective role counter to cell proliferation, cell growth, migration, invasion, and angiogenesis. They down regulate the expression of BCL-2 and COX-2 proteins, and reduced DNA damage. Hydroxytyrosol and oleuropein inhibited the multiple stages in colon carcinogenesis; initiation, promotion, and metastasis. They also provide protection against various human cancers including colorectal, skin, breast, thyroid, digestive, lung, brain, blood, and cervical. This review article discusses the anticancer perspectives and mechanisms of oleuropein and hydroxytyrosol in cell cultures and animal and human studies.

Potential Protective Role Exerted by Secoiridoids from Olea europaea L. in Cancer, Cardiovascular, Neurodegenerative, Aging-Related, and Immunoinflammatory Diseases

“…For example, OL, which is apolar, is able to diffuse through the lipid bilayer of the epithelial cell membrane. However, also, the more polar HTy appears to be absorbed via a passive bidirectional diffusion mechanism [52,53].…”

Hydroxytyrosol stimulates neurogenesis in aged dentate gyrus by enhancing stem and progenitor cell proliferation and neuron survival

“…21,22 The multiple biological properties of HTyr are well known, especially the antioxidant, anticancer, anti-inflammatory, and neuroprotective effects. [23][24][25][26] In fact, HTyr reduces oxidative stress in brain slices undergoing such stress, that is, lipid peroxidation, peroxynitrite formation, and production of inflammatory mediators (prostaglandin E2 and interleukin 1beta) 27 ; similarly, HTyr protects in vitro from oxidative stress, by rescuing either PC12 cells or SH-SY5Y neuroblastoma cells from 6-hydroxydopamine-induced damage, from L-DOPA toxicity or preventing hydrogen peroxide-induced death. [28][29][30] Moreover, HTyr is able to cross the blood-brain barrier 31,32 and its treatment in a mouse model of Alzheimer's disease (TgCRND8 mice) caused a significant reduction of the amyloid-β plaque number in hippocampal areas.…”

Simultaneous Purification and Separation of Syringoside and Oleuropein from Syringa oblata Lindl. Extract Using Macroporous Resin

“…Oleuropein (Figure 1) is an important phenolic substance obtained from olive leaves and fruits. e biological and pharmacological activities of oleuropein include antioxidant activity [8], antimicrobial activity [9], anti-inflammatory and analgesic activities [10], cancer prevention and treatment [11,12], and cardioprotective and neuroprotective effects [13]. Oleuropein can also be used to prevent skin damage and skin cancer caused by UVB radiation [14,15]; therefore, it has been widely applied in the field of cosmetics.…”