Ghorbanian Mehdi, Razzaghi-Abyaneh Mehdi, Allameh Abdolamir, Shams-Ghahfarokhi Masoomeh, Qorbani Mahdi
Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Mycoses. 2008 Jan;51(1):35-9. doi: 10.1111/j.1439-0507.2007.01440.x.
Aflatoxins are secondary metabolites that are produced by toxigenic strains of some Aspergillus species on foods. Neem plant is a known inhibitor of aflatoxin production. We studied the effects of different concentrations of aqueous neem leaf extract on fungal growth and aflatoxin production by Aspergillus parasiticus (NRRL 2999) at different incubation times. The toxigenic fungus was cultured on sucrose low salts medium in the presence of various concentrations of extracts (0.2, 0.8, 3.12, 12.5 and 50% v/v). After shaking incubation of cultures for 2, 4, 6, 8, 10 and 12 days at 28 degrees C, the fungal mycelia was collected and processed for determination of dry weight. Mycelia and culture media were assayed by TLC method to detect aflatoxin B(1) (AFB(1)). The extracts did not have any obvious effect on fungal growth. AFB(1) production in the control samples increased to the maximum level on the 8th day. The inhibition of aflatoxin synthesis by plant extracts was found to be time- and dose-dependent. The maximum inhibitory effect was 80-90% in the presence of 50% concentration that when compared with control samples was significant (P < 0.05). AFB(1) secretion/production ratio in all of control and treated samples, other than 2nd day, approximately stayed and neem had no effect on it.
黄曲霉毒素是某些曲霉菌产毒菌株在食物上产生的次生代谢产物。印楝是一种已知的黄曲霉毒素产生抑制剂。我们研究了不同浓度的印楝叶水提取物在不同培养时间对寄生曲霉（NRRL 2999）真菌生长和黄曲霉毒素产生的影响。将产毒真菌在蔗糖低盐培养基上培养，培养基中含有不同浓度的提取物（0.2、0.8、3.12、12.5和50% v/v）。在28℃下将培养物振荡培养2、4、6、8、10和12天后，收集真菌菌丝体并进行处理以测定干重。通过薄层色谱法对菌丝体和培养基进行检测以检测黄曲霉毒素B1（AFB1）。提取物对真菌生长没有明显影响。对照样品中的AFB1产量在第8天增加到最高水平。发现植物提取物对黄曲霉毒素合成的抑制作用具有时间和剂量依赖性。在50%浓度存在下，最大抑制作用为80 - 90%，与对照样品相比具有显著性（P < 0.05）。除第2天外，所有对照和处理样品中的AFB1分泌/产生率大致保持不变，印楝对其没有影响。
