Department of Food and Animal Sciences, Alabama A & M University, Normal, Alabama, USA.
J Med Food. 2011 Sep;14(9):950-6. doi: 10.1089/jmf.2010.0200. Epub 2011 May 6.
The use of medicinal plants as natural antimicrobial agents is gaining popularity. Sorrel (Hibiscus sabdariffa) is widely used for the treatment of diseases. The objective of this study was to investigate the antimicrobial activity of sorrel on Escherichia coli O157:H7 isolates from food, veterinary, and clinical samples. Phenolics of the calyces were extracted from 10 g of ground, freeze-dried samples using 100 mL of 80% aqueous methanol. Concentrations of 10%, 5%, and 2.5% methanol extract of sorrel were investigated for its antimicrobial activity. Inhibition zones were indicated by a lack of microbial growth due to inhibitory concentrations of sorrel diffused into semisolid culture medium beneath the sorrel-impregnated disk. The results of this experiment showed that the most potent sorrel concentration was 10%, then 5%, and finally 2.5%. The overall mean zone of inhibition for the sorrel extract was 12.66 mm for 10%, 10.75 mm for 5%, and 8.9 mm for 2.5%. The highest inhibition zones (11.16 mm) were observed in veterinary samples, and the lowest (10.57 mm) in the food samples. There were significant (P<.05) differences among mean zones of inhibition found in the food, veterinary, and clinical sources. Based on the source of samples and concentration of sorrel extract, the lowest mean inhibition was 7.00±0.04 mm from clinical samples, and the highest was 15.37±0.61 mm from a food source. These findings indicated that sorrel was effective at all levels in inhibiting E. coli O157:H7; thus it possesses antimicrobial activity and hold great promise as an antimicrobial agent.
作为天然抗菌剂的药用植物的使用越来越受到欢迎。洛神花（洛神葵）被广泛用于治疗疾病。本研究的目的是研究洛神花对食品、兽医和临床样本中大肠杆菌 O157:H7 分离株的抗菌活性。使用 100ml80%甲醇从 10g 粉碎、冻干的样品中提取花萼中的酚类物质。研究了洛神花 10%、5%和 2.5%甲醇提取物的抗菌活性。由于扩散到半固体培养基下层的洛神花抑制浓度，抑菌圈表示没有微生物生长。实验结果表明，最有效的洛神花浓度为 10%，其次为 5%，最后为 2.5%。洛神花提取物的总体平均抑菌圈直径为 10%时为 12.66mm，5%时为 10.75mm，2.5%时为 8.9mm。兽医样本的抑菌圈最高（11.16mm），食品样本最低（10.57mm）。食品、兽医和临床来源的抑菌圈平均直径之间存在显著差异（P<.05）。根据样本来源和洛神花提取物浓度，临床样本的最低平均抑制率为 7.00±0.04mm，最高为 15.37±0.61mm，来自食品来源。这些发现表明，洛神花在抑制大肠杆菌 O157:H7 方面具有所有水平的有效性；因此，它具有抗菌活性，作为一种抗菌剂具有很大的应用前景。
