Short Lecture 10 “Oxone induced oxidation of Oleocanthal and Oleacein tuned to chemoselective conversion to semisynthetic analogues and evaluation of their biological potential”

The most notable secoiridoids of Olive Oil, Oleocanthal and Oleacein gather intense scientific interest due to their potent biological activities [1]. Recently, their 3-carboxylic forms, named Oleocanthalic and Oleaceinic acids, have been isolated as minor components of OO [2]. This fact has triggered the exploration of various semisynthetic approaches for better understanding of the mechanism of action as well as the discovery of new bioactive compounds. In this context, their semisynthetic preparation was investigated for suitable reaction conditions in order to access these analogues effortlessly. Thus, a reaction using Selenium dioxide and Hydrogen peroxide has been developed to oxidize selectively the aldehyde at position 3 [3]. In a next step, the study of the bis-oxidation of the aldelydic analoques led to the application of Oxone as oxidative reagent. Interestingly, in low oxone consentration the reaction led exclusively to 3-carboxylic analogues while in high oxone concentration, Bayer Villiger mechanism is activated promoting the further oxidation in position 1 and the recovery of corresponding 9-ketonic forms (Oleocanthanonic and Oleaceinonic acids). The reaction mechanism was verified by identifying the intermediate analogues using 1-D and 2-D NMR analysis.

The antioxidant and antigenotoxic properties of the semisynthetic analogues were studied in comparison to initial secoiridoids. The results revealed that Oleocanthanonic acid demonstrated remarkable activity in contrast with the inactive Oleocanthal and Oleocanthalic acid. On the other hand, both Oleacein and its derivatives presented outstanding antioxidant and antigenotoxic activity.

Fig. 1 

The authors declare no conflict of interest; Funding: DDIOL (ERDF & Greek National Funds, ID: T2EDK-02423)

• References

• 1 Visioli F, Bernardini E. Extra Virgin Olive Oilʼs Polyphenols: Biological Activities. Curr Pharm Des 2011; 17: 786-804
• 2 Angelis A, Antoniadi L, Stathopoulos P. et al. Oleocanthalic and Oleaceinic acids: new compounds from Extra Virgin Olive Oil (EVOO). Phytochem Lett 2018; 26: 190-194
• 3 Antoniadi L, Angelis A, Stathopoulos P. et al. Oxidized Forms of Olive Oil Secoiridoids: Semisynthesis, Identification and Correlation with Quality Parameters. Planta Med 2022.

Publication History

Article published online:
12 December 2022