Anti-Bacterial Activities of Essential Oils from Mah-Khwuaen (Zanthoxylum limonella Alston)

Abstract

Mah-Khwuaen (Zanthoxylum limonella Alston) is a spice that has been used for enhancing the flavor of local food in northern Thailand. The spice is also known as a traditional herb with medicinal properties. Antibacterial activity of essential oils from Mah-Khwuaen has been reported. However, the activities of essential oils extracted from each part of Mah-Khwuaen have not been fully investigated. In this research, three parts of Mah-Khwuaen fruits, which consisted of seed coats, seeds and whole fruits (seed coats and seeds) were used for essential oils extraction by hydrodistillation method. Evaluation of the minimum inhibitory concentration (MIC) showed that the MIC of 6.64 mg/mL was required to inactivate Staphylococcus aureus and Escherichia coli when the oils from seed coats were tested. On the other hand, the MIC value of Mah-Khwuaen fruits oils against Bacillus cereus was 26.56 mg/mL. The results of the minimum bactericidal concentration (MBC) revealed that seed coats oils exhibited the highest anti-bacterial activity against Escherichia coli at 6.64 mg/mL, followed by Staphylococcus aureus and Bacillus cereus (26.56 and 13.28 mg/mL), respectively. The chemical compositions of Mah-Khwuaen were analyzed by GC-MS. The result showed that the major compound of Mah-Khwuaen seed coats, seeds and whole fruits are limonene, with the contents at 46.0 %, 69.9 % and 42.8 %, respectively