Salivary alpha amylase enzyme as a stress parameter: Establishment and comparison of laboratory methods

Abstract

Aim: Salivary alpha ( alpha )-amylase enzyme is a biomarker used to measure sympathetic nervous system activity. This study aimed to establish three existing methods for measuring salivary alpha- amylase enzyme activity in the laboratory and to compare these methods in terms of their usability. Materials and Methods: alpha- amylase enzyme activity can be measured in ready-made kits by three methods: Starch-Iodine, 2-chloro-4-nitrophenyl maltotrioside (CNPG3) and dinitrosalicylic acid (DNS) methods. In this context, standard curves were created in the laboratory for manual study of these methods and their advantages and disadvantages were presented. The usability of these methods was tested. Results: The starch-iodine and CNPG3 methods were successfully established. However, although a standard curve was successfully established for the DNS method, this assay was not suitable for the studies as the samples were not readable and had many disadvantages. The test sensitivities and working ranges were appropriate for the starch-iodine and CNPG3 tests, requiring 4,000-fold dilution for the starch-iodine test and 5-fold dilution for the CNPG3 test. A weak but statistically significant positive correlation was observed between the two tests (R2=0.048 for linear regression; p<0.05, R2=0.106 for quadratic regression; p<0.01). Conclusion: The CNPG3 and starch-iodine methods were feasible, cost-effective, accessible, and time-efficient. The starch-iodine method is a cheaper but the CNPG3 method is also a practical test with fewer steps. In this respect, it has been decided that the CNPG3 method is the most effective method in studies based on salivary alpha- amylase enzyme method.