Fluorescence study of curcumin and β-glucan binding interaction: investigation of its potential as a quantitative method for β-glucan

β-glucan from mushrooms gained popularity because of its immuneboosting and anti-tumor effect but its quantitative study was still limited. Currently, available methods have been facing longer analysis time, expensive and unsustainable dyes were involved. In this study, an alternative environmentally friendly fluorescence dye was introduced which is curcumin for the determination of β-glucan. Binding occurred by pH-driven method and significant fluorescence enhancement was studied. The influencing factors like temperature, salting effect, pH, the ratio of the fluorophore, and excitation and emission wavelength were optimized to get stable binding interaction. Curdlan was used as a standard for studying linear dynamic range. The consequences will be compared with the existing traditional method of Aniline blue and Calcofluor fluorescence assay. The technique presents a linearity range of 0 to 20 ppm when using 4 ppm curcumin concentration and 20-60 ppm with the 10 ppm curcumin concentration. LOD/LOQ was 0.28/0.92 ppm and 1.5/5 ppm for each curcumin concentration. The method achieved 93-108% recovery with %RSD < 2. Lentinus squarrosulus (Herd Khon Khao) and Lentinula edodes (shiitake) mushrooms were used as a sample and β-glucan from these mushrooms was extracted using hot water, alkaline, and microwave extraction.

蘑菇来源的β-葡聚糖（β-glucan）因免疫增强与抗肿瘤活性而广受关注，但其定量研究仍相对匮乏。当前现有检测方法普遍存在分析耗时较长、所用染料成本高昂且不可持续等问题。本研究引入一种环保型荧光染料姜黄素（curcumin）用于β-葡聚糖的定量检测，采用pH驱动法实现结合作用，并对其显著的荧光增强效应展开研究。本研究对温度、盐效应、pH值、荧光团配比以及激发波长与发射波长等影响因素进行优化，以获得稳定的结合相互作用。本研究以短梗霉多糖（Curdlan）为标准品，考察方法的线性动态范围。将本方法的检测结果与传统的苯胺蓝（Aniline blue）及卡尔科弗卢尔（Calcofluor）荧光分析法进行对比。当姜黄素浓度为4 ppm时，该方法的线性范围为0~20 ppm；当姜黄素浓度为10 ppm时，线性范围为20~60 ppm。两种姜黄素浓度下对应的检出限（Limit of Detection, LOD）/定量限（Limit of Quantitation, LOQ）分别为0.28/0.92 ppm与1.5/5 ppm。该方法的回收率为93%~108%，相对标准偏差（Relative Standard Deviation, RSD）小于2%。本研究以鳞皮扇菇（Lentinus squarrosulus, Herd Khon Khao）及香菇（Lentinula edodes, shiitake）为实验样品，分别采用热水提取法、碱提法与微波提取法对其中的β-葡聚糖进行提取。