有机栽培龙脑百里香精油对白色念珠菌体外抑菌活性的研究

【背景】白色念珠菌(Candidaalbicans)属于条件致病性真菌，可引起严重的黏膜真菌感染及全身系统性真菌感染，是导致患者高发病率和高死亡率的主要菌群之一。【目的】探究百里香精油对白色念珠菌的抑菌活性及抑制机理。【方法】测定5种百里香精油对白色念珠菌的抑菌圈直径，分析具有高抑菌活性的精油成分。在此基础上，通过扫描电子显微镜(scanning electron microscope, SEM)观察精油对白色念珠菌菌体细胞形态的影响。测定碱性磷酸酶(alkaline phosphatase, AKP)含量、胞外溶液电导率并进行碘化丙啶(propidium iodide, PI)染色分析，探究精油对白色念珠菌生物膜的形成与黏附及磷脂酶活性的影响，并通过实时荧光定量PCR法分析与白色念珠菌生物膜形成相关基因(凝集素样序列基因ALS4，从酵母型向菌丝型细胞的形态转变基因HWP1、磷脂酶基因PLB1)的表达水平，探究该精油对白色念珠菌的抑菌机制。【结果】筛选出了对白色念珠菌高度敏感的有机栽培龙脑百里香精油(Thymus vulgaris CT borneol essential oil, T...

In vitro inhibitory activity of organic Thymus vulgaris CT borneol essential oil against Candida albicans

[Background] Candida albicans is a conditional pathogenic fungus capable of causing severe mucosal and systemic fungal infections and one of the major fungi leading to high morbidity and mortality in patients. [Objective] To study the inhibitory activity and mechanism of thyme essential oil against C. albicans. [Methods] The inhibitory zone diameters of 5 thyme essential oils against C. albicans were determined, and the components of the essential oils with high inhibitory activity were identified. Scanning electron microscope (SEM) was employed to observe the effect of essential oils on the morphology of C. albicans. The alkaline phosphatase (AKP) content and extracellular solution conductivity were determined, and propyl iodide (PI) staining was performed, on the basis of which the effects of essential oil on the biofilm formation and adhesion and the phospholipase activity of C. albicans were determined. In addition, real-time fluorescence quantitative PCR was conducted for the lectin-like sequence gene ALS4 involved in the biofilm formation, HWP1 involved in the switch from yeast growth to hyphal growth, and the phospholipase gene PLB1 to reveal the inhibitory mechanism of this essential oil on C. albicans. [Results] The Organic Thymus vulgaris CT borneol essential oil (TBEO) with the strongest inhibitory effect on C. albicans was selected, which showed the inhibition zone diameter was (36.0±4.8) mm. The main components of TBEO were α-terpineol (43.43%), camphene (8.97%), caryophyllene (7.70%), carvacrol (5.81%), and linalool (5.19%), which accounted for about 70% of the total TBEO. The results of SEM showed that TBEO caused concave surface and distorted cells of C. albicans. TBEO increased the permeability of the cell membrane and cell wall of C. albicans, causing the leakage of intracellular substances. TBEO inhibited the biofilm formation and exerted a scavenging effect on the formed biofilm of C. albicans. TBEO reduced mycelium formation, affected adhesion, and decreased phospholipase activity. Real-time fluorescence quantitative PCR results showed that TBEO significantly down-regulated the expression levels of HWP1, ALS4, and PLB1. [Conclusion] TBEO exerts an inhibitory effect on C. albicans. This study provides a theoretical basis for the application of TBEO in the prevention and control of C. albicans infection.