Procedure
1: Selecting the 7 olive tree varieties (Kaissy, Jlott, Sorani, dan mawi, khodeiri, instanbuli and nabali) for experiment
2: extract the leaves from the variety of the different trees and dry it in a ventilated oven for 72 hours at a temperature of 40degrees celcius
3: grind the leaves to collect the powder
4: store powder at -20degrees celsius until extraction
5: use chemicals - 1- oleuropein obtained from sigma chromatographic grade double distilled water 2- hplc grade acetonitrile 3- analytical grade formic acid
6: prepare standards solution consisting of stock solution 100mg/ml oleuropein/methanol
7: extract leaves by macerating 5g of dried powder materials with 50g methanol for 2 hours at room temperature using a magnetic stirrer
7: filter the extracts and drying through evaporation under 40degrees celcius
8: dissolves residue in 50ml of HPLC grade Merck methanol
9: pass solution through 0.45um filter and inject 20ul into HPLC