Extraction and comparison of oleuropein content in different cultivars of olive (Olea europaea L.) at Fars and Rudbar

Phenolic compounds are one of the most important factors in olive، which has been considered greatly. Phenols have pharmacological characteristics and contain natural antioxidants in olive. Oleuropein is one of the most abundant and important phenolic compounds in fruits and leaves of olive، which causes the bitter taste of olive. Oleuropein is a heterosidic ester of elenolic acid and 3،4-dihydroxy phenyl ethanol. It is worth mentioning that the use of this compound has a significant role in health. In this study، the amount of existing compounds in different cultivars of olive (Olea europaea L.) was studied during harvesting season in two regions of Rudbar and Kazeroun، and oleuropein was extracted with methanol and its amount was determined by High Performance Liquid Chromatography (HPLC). According to the conducted researches، it was found that the highest composition rate of fruit oleuropein was recorded for yellow olive in Fars (34. 31 mg/g) and for Fyshmy olive in Rudbar (30. 25 mg/g). However، the lowest composition rate of fruit oleuropein was recorded for Mishen olive in Fars (9. 55 mg/g) and for Lechyo olive in Rudbar (10. 23 mg/g). Based on the provided data، it can be concluded that more edibility of Rudbar olives may be due to the lower level of oleuropein compound، resulting in less bitterness. Notably، the medicinal usage of different types of Fars olives is due to the higher level of oleuropein compounds.