Abstract:
Nowadays, unprecedented health challenges are urging novel solutions to address antimicrobial resistance as multidrug-resistant strains of bacteria, yeasts and moulds are emerging. Such microorganisms can cause food and feed spoilage, food poisoning and even more severe diseases, resulting in human death. In order to overcome this phenomenon, it is essential to identify novel antimicrobials that are naturally occurring, biologically effective and increasingly safe for human use. The development of gemmotherapy extracts (GTEs) using plant parts such as buds and young shoots has emerged as a novel approach to treat/prevent human conditions due to their associated antidiabetic, anti-inflammatory and/or antimicrobial properties that all require careful evaluations. Seven GTEs obtained from plant species like the olive (Olea europaea L.), almond (Prunus amygdalus L.), black mulberry (Morus nigra L.), walnut (Juglans regia L.), blackberry (Rubus fruticosus L.), blackcurrant (Ribes nigrum L.) and bilberry (Vaccinium myrtillus L.) were tested for their antimicrobial efficiency via agar diffusion and microbroth dilution methods. The antimicrobial activity was assessed for eight bacterial (Bacillus cereus, Staphylococcus aureus, Salmonella enterica subsp. enterica, Proteus vulgaris, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Listeria monocytogenes), five moulds (Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus, Penicillium citrinum, Penicillium expansum) and one yeast strain (Saccharomyces cerevisiae). The agar diffusion method revealed the blackberry GTE as the most effective since it inhibited the growth of three bacterial, four moulds and one yeast species, having considered the total number of affected microorganism species. Next to the blackberry, the olive GTE appeared to be the second most efficient, suppressing five bacterial strains but no moulds or yeasts. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were then determined for each GTE and the microorganisms tested. Noticeably, the olive GTE appeared to feature the strongest bacteriostatic and bactericidal outcome, displaying specificity for S. aureus, E. faecalis and L. monocytogenes. The other GTEs, such as blueberry, walnut, black mulberry and almond (the list indicates relative strength), were more effective at suppressing microbial growth than inducing microbial death. However, some species specificities were also evident, while the blackcurrant GTE had no significant antimicrobial activity. Having seen the antimicrobial properties of the analysed GTEs, especially the olive and black mulberry GTEs, these could be envisioned as potential antimicrobials that might enhance antibiotic therapies efficiency, while the blackberry GTE would act as an antifungal agent. Some of the GTE mixtures analysed have shown interesting antimicrobial synergies, and all the antimicrobial effects observed argue for extending these studies to include pathological microorganisms.
摘要:
如今,前所未有的健康挑战正在敦促新的解决方案,以解决作为多重耐药菌株的抗菌素耐药性,酵母和霉菌正在出现。这种微生物会导致食物和饲料变质,食物中毒甚至更严重的疾病,导致人类死亡。为了克服这种现象,鉴定天然存在的新型抗菌药物至关重要,生物有效,对人类使用越来越安全。使用植物部分(如芽和嫩芽)的gemmotherapy提取物(GTE)的开发已成为治疗/预防人类疾病的新方法,因为它们相关的抗糖尿病药,抗炎和/或抗菌特性都需要仔细评估。从橄榄(OleaeuropaeaL.)等植物物种中获得的七个GTE,杏仁(李子),黑桑树(黑桑树),核桃(核桃),黑莓(RubusfruticosusL.),通过琼脂扩散和微肉汤稀释方法测试了黑醋栗(RibesnigrumL.)和越橘(VacciniummyrtillusL.)的抗菌效率。对八种细菌(蜡状芽孢杆菌,金黄色葡萄球菌,肠沙门氏菌亚种。enterica,普通变形杆菌,粪肠球菌,大肠杆菌,铜绿假单胞菌和单核细胞增生李斯特菌),五个霉菌(黄曲霉,黑曲霉,曲霉,柑橘青霉,扩展青霉)和一种酵母菌株(酿酒酵母)。琼脂扩散法显示黑莓GTE是最有效的,因为它抑制了三种细菌的生长,四种霉菌和一种酵母,考虑了受影响的微生物种类的总数。在黑莓旁边,橄榄GTE似乎是第二有效的,抑制五种细菌菌株,但没有霉菌或酵母。然后确定每种GTE和测试的微生物的最小抑制浓度(MIC)和最小杀菌浓度(MBC)。值得注意的是,橄榄GTE似乎具有最强的抑菌和杀菌效果,显示对金黄色葡萄球菌的特异性,粪肠球菌和单核细胞增生李斯特菌。其他GTE,比如蓝莓,核桃,黑桑树和杏仁(列表显示相对强度),在抑制微生物生长方面比诱导微生物死亡更有效。然而,一些物种特异性也很明显,而黑醋栗GTE没有显著的抗菌活性。在看到所分析的GTE的抗菌特性后,尤其是橄榄和黑桑树GTE,这些可以被设想为可能提高抗生素治疗效率的潜在抗菌药物,而黑莓GTE将作为抗真菌剂。分析的一些GTE混合物显示出有趣的抗菌协同作用,观察到的所有抗菌作用都主张将这些研究扩展到包括病理微生物。