Thermal Degradation Kinetics and pH-Rate Profiles of Iriflophenone 3,5-C-β-d-diglucoside, Iriflophenone 3-C-β-d-Glucoside and Mangiferin in Aquilaria crassna Leaf Extract.

Eakkaluk Wongwad,Boonchoo Sritularak,Wudtichai Wisuitiprot,Neti Waranuch,Kornkanok Ingkaninan

doi:10.3390/molecules25214898

Eakkaluk Wongwad, Boonchoo Sritularak + Show 3 more

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https://doi.org/10.3390/molecules25214898

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Abstract

The health benefits of the Aquilaria crassna Pierre ex Lecomte leaf extract (AE) make it very useful as an ingredient in food and pharmaceutical products. Iriflophenone 3,5-C-β-d-diglucoside (1), iriflophenone 3-C-β-d-glucoside (2) and mangiferin (3) are bioactive compounds of AE. We assessed the stability of AE by investigating the thermal degradation kinetics and shelf-life (t90%) of compounds 1, 2 and 3 using Arrhenius plot models and studied their pH-rate profiles. The results demonstrate that 1 and 2 were degraded, following a first-order kinetic reaction. The degradation of 3 followed first-order reaction kinetics when present in a solution and second-order reaction kinetics in the dried powder form of the extract. According to the first-order kinetic model, the predicted shelf-life (t90%) of the extract at 25 °C in dried form for compound 1 was 989 days with activation energy 129.86 kJ·mol−1, and for 2 it was 248 days with activation energy 110.57 kJ·mol−1, while in the extract solution, the predicted shelf-life of compounds 1–3 was 189, 13 and 75 days with activation energies 86.83, 51.49 and 65.28 kJ·mol−1, respectively. In addition, the pH-rate profiles of 1–3 indicated that they were stable in neutral to acidic environments.

Highlights

Extracts from natural origins are thermally unstable, leading to their bioactive compounds, such as phenolic compounds, tending to degrade over time
The thermal degradation kinetic model was used in our study for assessing the stability of Aquilaria crassna aqueous leaf extract (AE)
These results indicate that dried AE is more thermally stable than the solution form

Summary

Introduction

Extracts from natural origins are thermally unstable, leading to their bioactive compounds, such as phenolic compounds, tending to degrade over time. The thermal degradation kinetic is a commonly used model to describe how chemical compounds degrade. This model can help in controlling and predicting the quality over time of the plant extracts and changes affecting shelf-life. This method had been applied to several stability studies, including studies of the degradation of the polyphenols, benzophenones and xanthonoids in the plant material of honeybush. The extracts of sour cherry (Prunus cerasus) [3] In these prior studies, it was found that the degradation rate constants were influenced the most by temperature; warmer temperatures resulted in greater degradation. The thermal degradation kinetic model was used in our study for assessing the stability of Aquilaria crassna aqueous leaf extract (AE)

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Conclusion