The inhibitory effect of Noscapine derivatives as antioxidants on insulin fibrillation

Protein fibrillation is introduced as the main cause of some diseases such as Alzheimer and Parkinson in the last decades. Many scientists investigated the effect of small molecules on the inhibition or reduced formation of protein fibrillation and confirmed that polyphenol compounds inhibit the growth of fibrils by π – π interaction with aromatic residues. In this study we investigated the interaction of some novel Noscapine derivatives on insulin protein fibrillation. The study of insulin fibril formation as a model of protein fibrillation can lead to enhance our knowledge about the mechanisms of protein fibrillation and design of effective drugs to inhibit protein fibril formation. The 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS assay is used to determine the antioxidant efficiency of these compounds, in order to indicate that they have higher antioxidant activity in compare with Trolox as the analogue of vitamin E. Incubation of these compounds with insulin could inhibit protein fibrillation, parallel to their antioxidant activity. Spectroscopic methods such as Thioflavin T (ThT) fluorescence emission and Congo Red (CR) UV absorption used to measure the amount of protein fibrillation in the presence and absence of Noscapine derivatives. Two or three fold diminish of ThT fluorescence intensity in the presence of antioxidants compared to samples without antioxidants express high inhibitory effect of these compounds on protein fibril formation. Although reduced CR absorption of samples in the presence of Noscapine derivatives as antioxidant confirm the inhibitory effect of these compounds on protein fibril formation. In this paper we introduce Noscapine derivatives as compounds with a combination of antioxidant and anti-fibrillation properties of the protein.