Stimulation Effects of Exogenous Ascorbic Acid on Some Citrus Species Essential Oils

Abstract

This work investigates the influence of ascorbic acid (ASA) on the essential oil (EO) isolated from leaves and peels of two Citrus species {Citrus deliciosa (Ten.) and Citrus tangerine (Hort. ex Tanaka)}. Experiments were carried out in sandy soil at the Experimental Farm, National Research Centre (NRC), Egypt. Citrus trees were treated with different levels of ASA (0, 0.2, and 0.4 g/L). Essential oils of both Citrus species were isolated by hydrodistillation (HD) and then, analyzed by Gas chromatography and Gas chromatography-Mass spectrometry. The EO compositions were influenced by ASA treatments. For both species, EO (%) and the main constituents of leaves (linalool and thymol) or peels (limonene and γ-terpinene) EO increased. Various chemical groups (MCH, MCHO, SCH, SCHO, or DCHO) changed. ASA at 0.2 g/L resulted in the highest yield of EO percentages and major constituents for both species.

Key words:

• Citrus
• ascorbic acid
• essential oil
• linalool
• thymol
• limonene
• γ-terpinene