Azhagesan Ananthaselvam, Chandrasekaran Natarajan
Centre for Nanobiotechnology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu 632014, India.
ACS Omega. 2025 Mar 11;10(11):10866-10877. doi: 10.1021/acsomega.4c07974. eCollection 2025 Mar 25.
The current in vitro study explores the exposure of the emerging pollutants polystyrene micro- and nanoplastics (PS-MNPs) within the digestive system and their interaction with key digestive enzymes such as α-amylase, pepsin, and pancreatin. The present research aims to elucidate the potential health implications of digestive enzymes by PS-MNPs based on the previously estimated mean of ingested microplastics (MPs) (0.714 g/day). The study deepens our understanding of the environmental pollutants' impact on human health by examining the interactions between polystyrene (PS) microplastics (PS MPs, 37-50 μm approx.) and PS nanoplastics (PS NPs, 100 nm) with digestive enzymes. The study analyzes the effects of micro- and nanosized plastics on enzyme activity using multiple spectroscopic techniques, revealing the molecular mechanisms of enzyme inhibition and structural changes caused by PS NPs, more than those by PS MPs. The fluorescence emission spectra indicated a static quenching mechanism across all the digestive enzymes at = 3.638, 4.615, and 1.855 (∼× 10 M·s), predominantly affecting tyrosine (Tyr) and tryptophan (Trp) residues. Resonance light scattering (RLS) spectra confirmed the formation of enzyme-PS NPs complexes, leading to aggregation. Fourier transform infrared (FT-IR) and circular dichroism (CD) spectrometry results showed a decrease in protein content and structural alterations in the enzymes, potentially affecting their function. The half inhibitory concentration (IC) values of PS NPs for salivary α-amylase (180 μg/mL), pepsin (580 μg/mL), and pancreatic protease (314 μg/mL) indicate uncompetitive inhibition, and that of pancreatic α-amylase (592 μg/mL) indicates mixed reversible inhibition of digestive enzymes. The study highlights the potential health risks associated with PS NPs exposure and gives a broader understanding of the interplay between environmental plastic pollutants and human health.
当前的体外研究探讨了新兴污染物聚苯乙烯微塑料和纳米塑料（PS-MNPs）在消化系统中的暴露情况，以及它们与关键消化酶（如α-淀粉酶、胃蛋白酶和胰酶）的相互作用。本研究旨在根据先前估计的摄入微塑料（MPs）的平均量（0.714克/天），阐明PS-MNPs对消化酶潜在的健康影响。该研究通过考察聚苯乙烯（PS）微塑料（约37 - 50微米的PS MPs）和PS纳米塑料（100纳米的PS NPs）与消化酶之间的相互作用，加深了我们对环境污染物对人类健康影响的理解。该研究使用多种光谱技术分析了微米级和纳米级塑料对酶活性的影响，揭示了PS NPs比PS MPs更能引起酶抑制和结构变化的分子机制。荧光发射光谱表明，在猝灭常数分别为3.638、4.615和1.855（约×10 M·s）时，所有消化酶均存在静态猝灭机制，主要影响酪氨酸（Tyr）和色氨酸（Trp）残基。共振光散射（RLS）光谱证实了酶 - PS NPs复合物的形成，导致聚集。傅里叶变换红外（FT-IR）光谱和圆二色性（CD）光谱结果显示，酶中的蛋白质含量降低且结构发生改变，这可能会影响其功能。PS NPs对唾液α-淀粉酶（180微克/毫升）、胃蛋白酶（580微克/毫升）和胰蛋白酶（314微克/毫升）的半数抑制浓度（IC）值表明存在非竞争性抑制，而对胰α-淀粉酶（592微克/毫升）的IC值表明对消化酶存在混合可逆抑制。该研究强调了与PS NPs暴露相关的潜在健康风险，并更广泛地理解了环境塑料污染物与人类健康之间的相互作用。
