白色念珠球菌(Candida albicans)是寄宿於人體黏膜上皮組織的常在菌，會伺機性感染局部皮膚組織或擴散至全身造成念珠球菌症。白色念珠球菌具有雙型性及形成生物膜之特性，其中，生物膜對抗生素及宿主免疫細胞之攻擊的耐受性較高，因此，生物膜不易被清除。目前治療念珠球菌症的臨床藥物均會產生抗藥性及副作用，故欲尋找可抑制生物膜形成的藥物以治療念珠菌的感染。由先前研究可知，花椒精油具有抑制早期生物膜形成之作用，進一步分析花椒精油之成分發現Methyl cinnamate (MCN)為精油的主成分之一，因此，此實驗將探討MCN是否具有影響生物膜生成之能力及作用機制。實驗結果發現，MCN的抑菌活性並不佳，但可有效抑制白色念珠球菌型態的轉型作用。利用結晶紫染色及XTT 測定也顯示MCN對生物膜生成之抑制率可達80 %以上。此外，以腸道黏膜上皮細胞Caco-2作為白色念珠球菌的宿主，結果可見，MCN可明顯降低白色念珠球菌黏附於細胞之能力。在定量PCR分析結果發現，在菌絲發展重要的調控路徑中，包括cAMP-PKA路徑(cyr1、efg1、tec1)及MAPK路徑(cst20、hst7、cph1)，其基因表現量均受到MCN的抑制，而維持菌絲生長(hgc1、eed1、ece1)與黏附相關基因(hwp1、als3、eap1)的表現也有顯著的下降。由本研究結果顯示，MCN具有作為virulence inhibitor並防治白色念珠球菌的潛力。
Candida albicans (C. albicans) is a normal flora on human mucosal surfaces and it is an opportunistic pathogen that can cause local or systemic infection resulting in candidiasis. C. albicans is a dimorphism fungus that can switch between yeast and hyphae and it can also form biofilm, especially. The biofilm have higher tolerance to antimicrobiotics and can resistant to host immune cells attack. However, most of the problems in the clinical therapy of C. albicans infection are drug resistance and serious side effects, recently. Therefore, it is important to find a compound that can inhibit biofilm formation. Precious studies found that Zanthoxylum armaturm extract could inhibit early stage of biofilm development and Methyl cinnamate (MCN) is one of major composition in Zanthoxylum armaturm extract. The purpose of the study is to investigate whether MCN can inhibit biofilm formation and inhibition mechanisms. In the study, the result found that MCN could inhibit morphology switch, but it did not have better effect to inhibit C. albicans. In crystal violet stain and XTT assay, results showed that MCN could inhibit biofilm formation. Furthermore, MCN could significantly reduce C. albicans adhesion to Caco-2 cell. Finally, the mechanism analysis demonstrated that MCN inhibited the gene expression of cAMP-PKA (cyr1、efg1、tec1) and MAPK (cst20、hst7、cph1) pathway that could regulate C. albicans morphology switch. In additionally, the hyphae maintenance related genes (hgc1、eed1、ece1) and adhesion related genes (hwp1、als3、eap1) could significantly reduce expression by MCN. In conclusion, the results suggest that MCN have potential as a virulence inhibitor on C. albicans infection.
