Department of Environmental Engineering, Faculty of Natural Resources and Environment, University of Birjand, Birjand, Iran.
Industrial Fungi Biotechnology Research Department, Research Institute for Industrial Biotechnology, Academic Center for Education, Culture and Research (ACECR)-Khorasan Razavi Branch, Mashhad, Iran.
Int J Med Mushrooms. 2023;25(6):21-30. doi: 10.1615/IntJMedMushrooms.2023048172.
Medicinal mushrooms belonging to Lentinus spp. exhibit significant antibacterial activities, but little attention has been paid to their efficacy against the food-borne pathogen, Bacillus cereus. The present study for the first time quantitatively evaluated the antibacterial activity of different extracts from fruiting bodies of a well-authenticated Iranian native strain of medicinal mushroom, Lentinus tigrinus, against Gram-positive spore-forming bacterium B. cereus. The findings revealed that the acetone extract inhibited the growth of B. cereus at concentrations as low as 31.25 μg/ML, while it had no effect against Escherichia coli and Staphylococcus aureus even at 10,000 μg/ML. The rest of the bacteria were also susceptible to the acetone extract at concentrations greater than 5 mg/ML. Antibacterial activities of the methanol-ethyl acetate extract and the hot water extract were significantly weaker than that of the acetone extract, which contained high amounts of total phenols (5.83 ± 0.08 mg GAE/g, dw), while Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of functional groups, such as hydroxyl, carbonyl, amide, and amine. Further studies by scanning electron microscopy (SEM) confirmed obvious changes in the morphology of B. cereus in response to the acetone extract of L. tigrinus. This study may suggest that L. tigrinus could be a good natural source for isolating and purifying antibacterial compounds against B. cereus.
药用蘑菇属于香菇属，具有显著的抗菌活性，但人们对其对抗食源性病原体蜡样芽孢杆菌的功效关注甚少。本研究首次定量评估了从伊朗本土药用蘑菇香菇的子实体不同提取物对革兰氏阳性芽孢形成菌蜡样芽孢杆菌的抗菌活性。研究结果表明，丙酮提取物在低至 31.25μg/ml 的浓度下就能抑制蜡样芽孢杆菌的生长，而即使在 10000μg/ml 的浓度下，对大肠杆菌和金黄色葡萄球菌也没有影响。其余细菌在大于 5mg/ml 的浓度下也对丙酮提取物敏感。甲醇-乙酸乙酯提取物和热水提取物的抗菌活性明显弱于丙酮提取物，丙酮提取物中含有大量的总酚（5.83±0.08mgGAE/g，dw），而傅里叶变换红外光谱（FT-IR）证实了存在羟基、羰基、酰胺和胺等功能基团。扫描电子显微镜（SEM）的进一步研究证实了蜡样芽孢杆菌对香菇丙酮提取物的形态发生了明显变化。本研究表明，香菇可能是分离和纯化抗蜡样芽孢杆菌抗菌化合物的良好天然来源。
