Romani Annalisa, Simone Gabriele, Campo Margherita, Moncini Lorenzo, Bernini Roberta
Department of Statistics, Computing, Applications "Giuseppe Parenti" DiSIA, PHYTOLAB (Pharmaceutical, Cosmetic, Food supplement Technology and Analysis), University of Florence, Florence, Italy.
PIN scrl, "City of Prato" University Center-Educational and Scientific Services for the University of Florence, Prato, Italy.
PLoS One. 2021 Feb 22;16(2):e0247298. doi: 10.1371/journal.pone.0247298. eCollection 2021.
In the present study, the antifungal activities of two commercial tannins-rich dry fractions towards different filamentous fungi of agronomical and food interest were evaluated. In particular, a standardized fraction from sweet chestnut (Castanea sativa Mill.) wood by-products and a commercial green tea (Camellia sinensis L.) leaf extract were tested at different concentrations (0.1-5.0% and 0.2% w/v respectively). The Sweet Chestnut Wood fraction was produced in an industrial plant through an environmentally and economically sustainable process, involving hot-water extraction and a sequence of membrane filtration steps with different molecular cut-offs for fractionation and concentration of the active principles. The Sweet Chestnut Wood and Green Tea Leaf extracts were characterised via HPLC/DAD/MS quali-quantitative analysis. The first extract showed a polyphenolic content of 20.5% w/w, 100% hydrolysable tannins; the second one showed a polyphenolic content of 87.5% w/w, of which 96.2% epigallocatechin gallate and 3.8% epicatechin gallate. The antifungal activity of the Sweet Chestnut fraction in aqueous solutions was evaluated towards different filamentous fungi, in particular telluric phytopathogens (Fusarium oxysporum f. sp. radicis-lycopersici; Fusarium solani; Rhizoctonia solani; Sclerotium rolfsii) and post harvest pathogens (Botrytis cinerea, that can also attack field plants; Penicillium digitatum; Penicillium italicum), and compared to the activity of Green Tea Leaf extract solutions. The experimental results evidenced, for almost all tested fungi, inhibition of the mycelial growth rate in presence of tannins. The lowest inhibitions were observed for B. cinerea (7.5%, to 28.9%) and P. italicum (53.8% in 5.0% w/v Sweet Chestnut extract substrate). A proportional inhibitory effect to tannin concentration was observed for F. oxysporum f. sp. radicis-lycopersici and F. solani (from 33.7% to 56.6%), R. solani (from 29.7% to 68.8%) and P. digitatum (64.7% to 87.0%). The highest effect resulted for S. rolfsii, (5.0% to 100%).
在本研究中，评估了两种市售富含单宁的干燥馏分对具有农业和食品意义的不同丝状真菌的抗真菌活性。具体而言，测试了来自甜栗（Castanea sativa Mill.）木材副产品的标准化馏分和市售绿茶（Camellia sinensis L.）叶提取物在不同浓度下（分别为0.1 - 5.0%和0.2% w/v）的效果。甜栗木材馏分是在一家工厂通过环境和经济可持续的工艺生产的，该工艺包括热水提取以及一系列具有不同分子截留值的膜过滤步骤，用于活性成分的分离和浓缩。通过HPLC/DAD/MS定性定量分析对甜栗木材和绿茶叶提取物进行了表征。第一种提取物的多酚含量为20.5% w/w，全部为可水解单宁；第二种提取物的多酚含量为87.5% w/w，其中96.2%为表没食子儿茶素没食子酸酯，3.8%为表儿茶素没食子酸酯。评估了甜栗馏分在水溶液中对不同丝状真菌的抗真菌活性，特别是对土壤植物病原菌（尖孢镰刀菌番茄根腐专化型；茄腐镰刀菌；立枯丝核菌；齐整小核菌）和采后病原菌（灰葡萄孢，它也可侵害田间植物；指状青霉；意大利青霉）的活性，并与绿茶叶提取物溶液的活性进行了比较。实验结果表明，对于几乎所有测试真菌，在存在单宁的情况下菌丝生长速率均受到抑制。对灰葡萄孢（7.5%至28.9%）和意大利青霉（在5.0% w/v甜栗提取物培养基中为53.8%）观察到的抑制作用最低。对于尖孢镰刀菌番茄根腐专化型和茄腐镰刀菌（从33.7%至56.6%）、立枯丝核菌（从29.7%至68.8%）和指状青霉（64.7%至87.0%），观察到对单宁浓度的比例抑制作用。对齐整小核菌的抑制效果最高（5.0%至100%）。
