Chemical Composition and Antibacterial Activity of Orange (Citrus sinensis) Essential Oils Obtained by Hydrodistillation and Solvent free Microwave Extraction

Essential oils (EOs) have gained much media attention in recent years because of their advantages in various fields, including food preservation, pharmaceuticals, herbal medicine, and natural therapies. Phenolic components which exhibit antimicrobial activity, along with some healthy substances, are present abundantly in essential oils, hence their use to prevent bacterial growth. Oranges are amongst the world's most popular fruits. Orange (Citrus sinensis) is widely recognized for its nutritious and medicinal properties. Since time immemorial, most parts of the orange plant from fruits, peels, flowers, leaves and juice are used as traditional medicine. Hydrodistillation (HD) and solvent free microwave extraction (SFME) were used to extract essential oils from orange fruit peels. The total volatile compound yield is obtained from 98-100% by HD and SFME. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the oils obtained from both method contained limonene (98.238% and 98.415, β-myrcene (1.169% and 1.172%) and α-pinene (0.548% and 0.413%). A small amount of sabinene (0.071%) and β- pinene (0.0032%) were only found in SFME-produced orange essential oil. The essential oils obtained from the two extraction methods were able to inhibit against Bacillus cereus.