Identification of volatile compounds (VCs) in the leaves collected from 'Gemlik', 'Halhalı' and 'Sarı Hasebi' olive tree varieties

Abstract

There is a considerably interest on some fruits and leaves extracts such as olive leaf, due to their beneficial health effects. Olive leaf has been consumed as tea for many years. However, the studies on volatile compounds (VCs) of leaves are scarce. Therefore, this study was aimed to evaluate of VCs in the leaves collected from 'Gemlik', 'Halhalı' and 'Sarı Hasebi' olive trees varieties grown in Hatay province. The VCs were analyzed by gas chromatography-mass spectrometry (GC-MS) using solid phase micro-extraction (SPME). The 97 out of 127 VCs identified were found common in all the olive leaves. Terpenes, aldehydes, alcohols and ketones were identified in the olive leaves as major VCs groups, which accounted for about 36-60%, 20-28%, 6-14% and 4-8% of total VCs identified in leaves, respectively. The relative proportions of these chemical groups showed considerably differences among olive leaves. ?-Cubebene was found as major VC followed by transcaryophyllene, cycloisosativene, benzaldehyde. These compounds accounted for 56-75% of total VCs identified in the olive leaves. While 'Halhalı' olive leaf had highest (p<0.01) levels of ?-cubebene (31.79%), cycloisosativene (7.69%) and ?-muurolene (4.05%), 'Sarı Hasebi' had trans-caryophyllene (23.16%), trans-4,8-dimethyl-1,3,7-nonatriene (4.65%), ?humulene (3.64%) and 'Gemlik' had benzeneethanol (6.93%), nonanal (5.07%), and benzaldehyde (2.17%) at the highest levels. This study has showed that olive leaves from each variety are a good terpene source that makes them important in terms of beneficial effects on health.

There is a considerably interest on some fruits and leaves extracts such as olive leaf, due to their beneficial health effects. Olive leaf has been consumed as tea for many years. However, the studies on volatile compounds (VCs) of leaves are scarce. Therefore, this study was aimed to evaluate of VCs in the leaves collected from 'Gemlik', 'Halhalı' and 'Sarı Hasebi' olive trees varieties grown in Hatay province. The VCs were analyzed by gas chromatography-mass spectrometry (GC-MS) using solid phase micro-extraction (SPME). The 97 out of 127 VCs identified were found common in all the olive leaves. Terpenes, aldehydes, alcohols and ketones were identified in the olive leaves as major VCs groups, which accounted for about 36-60%, 20-28%, 6-14% and 4-8% of total VCs identified in leaves, respectively. The relative proportions of these chemical groups showed considerably differences among olive leaves. ?-Cubebene was found as major VC followed by transcaryophyllene, cycloisosativene, benzaldehyde. These compounds accounted for 56-75% of total VCs identified in the olive leaves. While 'Halhalı' olive leaf had highest (p<0.01) levels of ?-cubebene (31.79%), cycloisosativene (7.69%) and ?-muurolene (4.05%), 'Sarı Hasebi' had trans-caryophyllene (23.16%), trans-4,8-dimethyl-1,3,7-nonatriene (4.65%), ?humulene (3.64%) and 'Gemlik' had benzeneethanol (6.93%), nonanal (5.07%), and benzaldehyde (2.17%) at the highest levels. This study has showed that olive leaves from each variety are a good terpene source that makes them important in terms of beneficial effects on health.