In vitro effects of crude khat extracts on the growth, colonization, and glucosyltransferases of Streptococcus mutans
In vitro effects of crude khat extracts on the growth, colonization, and glucosyltransferases of Streptococcus mutans
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DOI：
10.1080/00016350510019838
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发表时间：
2005-06-01
影响因子：
2
通讯作者：
Skaug, N
中科院分区：
文献类型：
--
作者：
Al- Hebshi, NN;Nielsen, O;Skaug, N
数以百万计的也门人、东非人和西方国家的移民每天嚼阿拉伯茶，因为它有安非他明的作用。关于这种习惯对口腔微生物区系的可能影响，文献中几乎没有相关信息。本研究的目的是研究阿拉伯茶粗提物对变形链球菌生长和蔗糖依赖定植的影响，以及对其葡萄糖转移酶(GTF)活性和产量的影响。选用了3个阿拉伯茶品种。将冷冻干燥的阿拉伯茶粗提物以0-1%(w/v)的浓度用于不同的检测。用变形链球菌UA159在玻璃培养管中形成贴壁生物膜的能力来评估蔗糖依赖性定植的能力。浮游阶段的菌落形成单位(CFU)是细菌生长的衡量标准，而生物膜阶段的CFU则用于量化生物膜中的生存能力。通过将粗制的GTFS制剂与蔗糖孵育，并测定形成的水溶性和不溶性葡聚糖的数量来测试GTFS的活性。通过比较对照和含有阿拉伯茶的培养物提取物的蛋白质印迹中GTF条带的强度来检测GTFS的产生。阿拉伯茶提取物有效地抑制了生物膜的形成。最低生物膜抑制浓度(MBIC)因品种不同而不同(0.25-1%)。提取物还抑制了两种葡聚糖的合成，尤其是不溶性葡聚糖的合成(平均抑制率为85%，抑制率为1%)，不同品种之间差异显著。然而，阿拉伯茶促进了细菌的生长，在亚MBIC也促进了生物膜内的活力；品种间没有差异。结果表明，阿拉伯茶叶中含有能抑制变形链球菌某些致龋性的水溶性成分。
Millions of Yemenites, East Africans, and immigrants to Western countries chew khat daily for its amphetamine-like effects. There is little information in the literature concerning the possible effects of the habit on oral microbiota. Our objective was to study in vitro crude khat extract effects on Streptococcus mutans growth and sucrose-dependent colonization, and on its glucosyltransferase (GTF) activity and production. Three khat cultivars were used. Lyophilized crude aqueous khat extracts were applied to the different assays at concentrations of 0-1% (w/v). Sucrose-dependent colonization was assessed as the ability of Streptococcus mutans UA159 to form adherent biofilms in glass culture tubes. Colony forming units (CFUs) in the planktonic phase served as a measure of bacterial growth, while CFUs in the biofilm phase were used to quantify viability in the biofilms. GTFs activity was tested by incubating a crude GTFs preparation with sucrose and determining the amount of water-soluble and water-insoluble glucans formed. GTFs production was assayed by comparing intensities of GTF bands in Western blots of extracts from control and khat-containing cultures. The khat extracts effectively inhibited biofilm formation. The minimum biofilm inhibitory concentration (MBIC) varied among the cultivars (0.25-1%). The extracts also inhibited synthesis of both glucan types, particularly insoluble glucans (average 85% inhibition at 1%), with significant differences among the cultivars. However, khat increased bacterial growth and at sub-MBIC also viability within biofilms; there were no inter-cultivar differences. It is shown that khat leaves contain water-soluble constituents that inhibit some cariogenic properties of S. mutans in vitro.