Capturing of neurotoxins causing diabetes stress and nervous breakdown in the aqueous medium by naphthazarin esters

The fear of an increase in blood sugar can be very traumatic. Being diabetic either type I or type II leads to a disorder called diabetes distress having traits of stress, depression, and anxiety. Among risk factors of diabetes mellitus heavy and trace metal toxicity emerges as new risk factors reported in many studies. In this study we target toxic metals, viz., Ni²⁺, Zn²⁺, and Cu²⁺, involved in the pathogenesis of diabetes and diabetic stress with naphthazarin esters. The compounds C1-C3 isolated from the leaves and roots of Arnebia guttata were tested for their metal-binding ability in an aqueous medium in UV-Visible and nuclear magnetic resonance (NMR) studies. These probes are well-known naphthoquinones present in the Arnebia species. In the UV-Visible titrations of compounds C1-C3 with Na²⁺, K²⁺, Zn²⁺, Ca²⁺, Cu²⁺, Mg²⁺, Co²⁺, and Ni²⁺ ions, significant binding was observed with Ni²⁺, Cu²⁺, and Zn²⁺ ions in MeOH/H₂O. There occurs a beautiful formation of red-shifted bands between the 520 to 620 nm range with a synergistic increase in absorbance. Also, the disappearance of proton peaks in the ¹H NMR spectrum on addition of metal ions confirmed binding. Compounds C1-C3 isolated from A. guttata came out as potent Ni²⁺, Zn²⁺, and Cu²⁺ sensors that are reportedly involved in islet function and induction of diabetes.