Biva Israt J, Ndi Chi P, Griesser Hans J, Semple Susan J
Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia; Wound Management Innovation Cooperative Research Centre, Toowong, QLD 4066, Australia.
Quality Use of Medicines and Pharmacy Research Centre, Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Frome Road, Adelaide, SA 5000, Australia.
J Ethnopharmacol. 2016 Apr 22;182:1-9. doi: 10.1016/j.jep.2016.02.011. Epub 2016 Feb 10.
For traditional medicinal purposes Aboriginal Australians have utilised numerous plant species, Eremophila alternifolia is among the most prominent. Traditionally, fresh leaves, leaf-infusions and handmade leaf-pastes have been used as both external and internal preparations to provide relief from a variety of conditions. Preparations of the species have been used to treat various infections of skin, eyes and throat including the treatment of septic wounds. These usages suggest that the plant contains antibacterial compounds; however, to date they have not been isolated and identified.
The present study aimed to identify antibacterial compounds from this important traditionally recorded medicinal species.
Bioassay-guided fractionation was used to isolate compounds from the crude leaf-extract. Antibacterial activity of pure compounds was assessed through broth microdilution method by determining both minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). Structure elucidation was performed using spectroscopic techniques such as 1D and 2D nuclear magnetic resonance spectroscopy and high resolution mass spectrometry.
Four compounds have been isolated from the leaf-extract; they include previously known flavanones [pinobanksin (1), pinobanksin-3-acetate (2) and pinobanksin-3-cinnamate (3)] and a serrulatane diterpene, 8-hydroxyserrulat-14-en-19-oic acid (4). While compound 4 had been found in other Eremophilas, flavanones 2 and 3 are identified for the first time from the genus Eremophila. The flavanone 3 is the most promising antibacterial compound with significant activity (10-20µM) against strains of the Gram-positive bacterium Staphylococcus aureus including methicillin resistant and biofilm forming strains. No activity was observed for any isolated compounds against the Gram-negative bacterium Escherichia coli.
The antibacterial activity of the crude extract of E. alternifolia and of the isolated compounds against Gram-positive bacteria provides a Western scientific explanation of the therapeutic modality of this plant species in traditional Aboriginal medicinal practice.
澳大利亚原住民为了传统医学目的使用了多种植物物种，交替叶木犀榄是其中最突出的一种。传统上，新鲜叶子、叶浸剂和手工制作的叶糊剂被用作外用和内服用药，以缓解多种病症。该物种的制剂已被用于治疗皮肤、眼睛和喉咙的各种感染，包括治疗化脓性伤口。这些用法表明该植物含有抗菌化合物；然而，迄今为止它们尚未被分离和鉴定。
本研究旨在从这种重要的传统记载药用植物中鉴定抗菌化合物。
采用生物活性导向分离法从粗叶提取物中分离化合物。通过肉汤微量稀释法测定最低抑菌浓度（MICs）和最低杀菌浓度（MBCs），评估纯化合物的抗菌活性。使用一维和二维核磁共振光谱以及高分辨率质谱等光谱技术进行结构解析。
从叶提取物中分离出四种化合物；它们包括先前已知的黄烷酮[松属素（1）、松属素 - 3 - 乙酸酯（2）和松属素 - 3 - 肉桂酸酯（3）]以及一种锯齿烷二萜，8 - 羟基锯齿 - 14 - 烯 - 19 - 酸（四）。虽然化合物4已在其他木犀榄属植物中发现，但黄烷酮2和3是首次从木犀榄属中鉴定出来。黄烷酮3是最有前景的抗菌化合物，对革兰氏阳性菌金黄色葡萄球菌菌株具有显著活性（10 - 20μM），包括耐甲氧西林和形成生物膜的菌株。未观察到任何分离出的化合物对革兰氏阴性菌大肠杆菌有活性。
交替叶木犀榄粗提取物和分离出的化合物对革兰氏阳性菌的抗菌活性为该植物物种在澳大利亚原住民传统医学实践中的治疗方式提供了西方科学解释。
