Laboratory of Applied Microbiology, Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
J Ethnopharmacol. 2011 Apr 12;134(3):865-71. doi: 10.1016/j.jep.2011.01.028. Epub 2011 Feb 1.
The study aimed to test the activity of Terminalia catappa L. against bacterial quorum sensing (QS) in order to provide a potential scientific basis for the traditional use of leaf extracts of this plant as an antiseptic.
The anti-QS activity of the methanolic leaf extract of Terminalia catappa was detected through the inhibition of the QS-controlled violacein pigment production in Chromobacterium violaceum. Fractions resulting from size-exclusion chromatography were assayed. The most active fraction was characterized through qualitative phytochemical detection methods. The effect of this fraction on known QS-controlled phenotypes in test strains was assessed.
The fraction with the highest activity (labeled as TCF12) was characterized to be tannin-rich. It specifically inhibited QS-controlled violacein production in Chromobacterium violaceum with 50% reduction achieved at 62.5 μg mL(-1) without significantly affecting growth up to about 962 μg mL(-1). The assessment of its effects on LasA activity of Pseudomonas aeruginosa ATCC 10145 found that the production of this virulence determinant is reduced in a concentration dependent manner with about 50% reduction at 62.5 μg mL(-1). Furthermore, it was found that TCF12 was able to inhibit the maturation of biofilms of Pseudomonas aeruginosa, a phenotype that has also been known to be QS-regulated.
Therefore, tannin-rich components of Terminalia catappa leaves are able to inhibit certain phenotypic expression of QS in the test strains used.
本研究旨在测试诃子（Terminalia catappa L.）的活性对细菌群体感应（QS）的影响，为该植物叶提取物作为防腐剂的传统用途提供潜在的科学依据。
通过抑制荧光假单胞菌（Chromobacterium violaceum）中 QS 控制的紫罗酮色素产生，检测诃子甲醇叶提取物的抗 QS 活性。对体积排阻色谱得到的馏分进行了检测。通过定性植物化学检测方法对最活跃的馏分进行了表征。评估了该馏分对测试菌株中已知 QS 控制表型的影响。
活性最高的馏分（标记为 TCF12）富含单宁。它特异性地抑制了 Chromobacterium violaceum 中 QS 控制的紫罗酮产生，在 62.5 μg mL(-1)时达到 50%的减少，而在约 962 μg mL(-1)时对生长没有显著影响。评估其对铜绿假单胞菌（Pseudomonas aeruginosa ATCC 10145）LasA 活性的影响发现，该毒力决定因素的产生呈浓度依赖性减少，在 62.5 μg mL(-1)时减少约 50%。此外，发现 TCF12 能够抑制铜绿假单胞菌生物膜的成熟，这一表型也被认为是 QS 调控的。
因此，诃子叶中的单宁类成分能够抑制测试菌株中某些 QS 表型的表达。
