Combined effect of soil applied iron and sulfur fertilisers on monoterpene content and antioxidant activity of Satureja hortensis L. Extract

Chemical-composition/antioxidant-activity of Satureja hortensis L. extract is influenced by many factors including nutrient elements. A factorial completely randomized design greenhouse experiment was conducted to study the effect of three levels of soil-applied iron,Fe (0,8 and 16mg kg-1 soil as ethylene-di-amine-die-hydroxyl-acetic-acid,Fe-EDDHA) and three levels of sulfur,S (0,50 and 100mg kg-1 soil as elemental-S) on monoterpene production and antioxidant activity of Satureja hortensis L. The maximum (377.75 mg/L) and minimum (720.406 mg/L) antioxidant activity were obtained with 8mg Fe+100mg S treatment and control,respectively. The main oil constituents in control were γ-terpinene(67%),α-terpinene(11%),myrcene (4%),α-thujene (4%),p-cymene (4%),α-pinene (3%) and carvacrol (2%). The maximum content of α-thujene,α-pinene,myrcene and α-terpinene was obtained with 8mg Fe+50mg S application whereas the control was suitable for obtaining γ-terpinene. Carvacrol was mainly produced with addition of 16mg Fe+100mg S. Furthermore,the α-thujene,α-pinene,myrcene and α-terpinene contents increased with application of 8mg Fe+50mg S. The α-terpinene,myrcene,α-thujene and α-pinene increased by 13,27,21 and 43% compared to control,respectively when 8mg Fe+50mg S was applied. The entire component of monoterpenoid fraction with the major constituent of γ-terpinene,α-terpinene,myrcene,α-thujene,p-cymene,α-pinene and carvacrol that constitutes 99.9% of essential oil showed a same trend whereas identified sesquiterpenes and sesquiterpenoid components were relatively low (0.1%). The low molecular weight of γ-terpinene decreased as 8mg Fe+50mg S was applied. In general,it could be concluded that application of 8mg Fe+50mg S kg-1 was the most suitable treatment for obtaining higher amounts of α-terpinene,myrcene,α-thujene and α-pinene whereas addition of 16mg Fe+100mg S kg-1 was preferable for obtaining carvacrol. Copyright © 2015. Universiti Putra Malaysia Press.