Abstract

This study covers chemical profiling of leaf essential oil of Plectranthus scutellarioides (L.) R.Br along with the first report on its antibacterial activity. The extraction was performed by microwave assisted hydrodistillation where the yield of essential oil was 0.18%. A total of 28 constituents were separated and identified by gas chromatography mass spectrometry. The constituents that occurred in abundance were spathulenol (24.57%), D-germacrene (14.53%), bicyclogermacrene (11.24%), nonacosane (9.74%) and morillol (4.95%). The antibacterial evaluation of essential oil was carried out against 8 different gram negative and positive strains including multidrug-resistant ones with agar well diffusion method and macrodilution method and was found to be active against all strains. The strongest activity (MIC) was found against multidrug resistant strains of Escherichia coli (0.625 mg/mL) and methicillin resistant Staphylococcus aureus (2.5 mg/mL) that shows the potential of this essential oil.

摘要

本研究涵盖了Plectranthus scutellarioides叶子精油的化学分析(L.) R.Br 及其抗菌活性的第一份报告。萃取采用微波辅助加氢蒸馏，精油收率为0.18%。气相色谱-质谱共分离鉴定了28种成分。大量出现的成分是spathulenol (24.57%)、D-germacrene (14.53%)、bicyclogermacrene (11.24%)、nonacosane (9.74%) 和 morillol (4.95%)。采用琼脂井扩散法和宏观稀释法对8种不同的革兰氏阴性和阳性菌株包括多重耐药菌株进行了精油的抗菌评价，发现对所有菌株均有效。对大肠杆菌的多重耐药菌株具有最强的活性 (MIC)(0.625 mg/mL) 和耐甲氧西林金黄色葡萄球菌(2.5 mg/mL)，显示出这种精油的潜力。