Structural and inhibitory effects of fulvic and humic acids against tyrosinase

Abstract

Inhibition of tyrosinase activity can control fruit browning and preserve the flavor and nutritional value of food. The impacts of fulvic acid (FA) and humic acid (HA) on tyrosinase activity were investigated utilizing circular dichroism (CD) and fluorescence spectroscopy, molecular docking (MD), and molecular dynamics simulations. HA and FA demonstrated a mixed type of inhibition with K i 2.02 and 5.2 μM, respectively. The thermodynamic parameters displayed that the hydrogen bond and hydrophobic force play a major role in the FA-tyrosinase and HA-tyrosinase interaction, respectively.Fluorescence experiments demonstrated changes in tyrosinase tertiary structures.HA could not destroy the tyrosinase secondary structure significantly, however, FA has a significant influence on the tyrosinase secondary structure. The molecular dynamics findings demonstrated the minimal fluctuations and the lowest flexibility in the complex amino acids in the HA-tyrosinase and FA-tyrosinase interaction. Altogether, HA and FA could be utilized in food industries as an accessible natural source for tyrosinase inhibition. Practical applicationsRecently, the investigation of tyrosinase inhibitors from the biosphere for hindrance of undesired browning in the food industry has increased considerably. Mushroom tyrosinase is a suitable model for kinetic research owing to its availability as well as close conformational similarity to tyrosinase in a mammal. Natural sources and their effective compounds could have wonderful potential on tyrosinase activity and structure, thus, in this study, the interactions between tyrosinase and fulvic acid (FA) and Humic acid (HA) were investigated. Previously, it has been shown that HA and FA have antioxidant properties and they can improve the quality of food via retarding lipid oxidation. Altogether, further investigations are warranted to draw firm conclusions, HA and FA could be utilized in food industries not only as antioxidant agents but also as an accessible natural source for tyrosinase inhibition.

Therapeutic Efficiency of Humic Acids in Intoxications

“…The most important role in melanin synthesis is played by tyrosinase (TYR) and tyrosine-related proteins (TYRP1 and TYRP2). TYR is a bifunctional and glycosylated copper-containing metalloenzyme with dinuclear copper ions widely distributed in prokaryotes, plants, and mammals [97]. Despite the well-known catalytic activity of tyrosinase, it is the only melanin-forming enzyme in humans [98,99].…”

“…Despite the well-known catalytic activity of tyrosinase, it is the only melanin-forming enzyme in humans [98,99]. The study of Taherkhani et al [97] followed the inhibitory effects of FAs and HAs acids against TYR. Detection of the kinetic parameters for TYR after the addition of HAs and FAs into mixtures of tyrosine and L-DOPA unveiled a dose-dependent inhibitory action of humic compounds against the enzyme.…”

Fulvic acid modification with phenolic precursors towards controllable solubility performance

“…They are strong antioxidants, include complex organic phenols and polyelectrolytes that enable the benecial ingestion of nutrients in our food and support plants growth. [11][12][13] The complex and heterogeneous FA structure contains molecules with many different functional groups among which the carboxylic and phenolic groups stand out as the most prominent in terms of both quantity and biological activity. 13 These groups, characterized by their unique chemical structures and reactivity, play crucial roles in numerous biological processes.…”

A Fluorescence Biosensor for Tyrosinase Activity Analysis Based on Silicon-Doped Carbon Quantum Dots

“…As a result, TYR serves as a significant biomarker in clinical diagnosis of melanoma cancer [8] . Moreover, TYR also exerts a substantial influence on the nutritional value of food [9] . Therefore, achieving accurate and real-time monitoring of TYR activity becomes indispensable for clinical diagnosis, disease treatment, and nutritional analysis of food.…”