Spectroscopic Studies on Dual Role of Natural Flavonoids in Detoxification of Lead Poisoning: Bench-to-Bedside Preclinical Trial

Abstract

Ubiquitousness in the target organs and associated oxidative stress are the most common manifestations of heavy-metal poisoning in living bodies. While chelation of toxic heavy metals is important as therapeutic strategy, scavenging of increased reactive oxygen species, reactive nitrogen species and free radicals are equally important. Here, we have studied the lead (Pb) chelating efficacy of a model flavonoid morin using steady-state and picosecond-resolved optical spectroscopy. The efficacy of morin in presence of other flavonoid (naringin) and polyphenol (ellagic acid) leading to synergistic combination has also been confirmed from the spectroscopic studies. Our studies further reveal that antioxidant activity (2,2-diphenyl-1-picrylhydrazyl assay) of the Pb–morin complex is sustainable compared to that of Pb-free morin. The metal–morin chelate is also found to be significantly soluble compared to that of morin in aqueous media. Heavy-metal chelation and sustainable antioxidant activity of the soluble chelate complex are found to accelerate the Pb-detoxification in the chemical bench (in vitro). Considering the synergistic effect of flavonoids in Pb-detoxification and their omnipresence in medicinal plants, we have prepared a mixture (SKP17LIV01) of flavonoids and polyphenols of plant origin. The mixture has been characterized using high-resolution liquid chromatography assisted mass spectrometry. The mixture (SKP17LIV01) containing 34 flavonoids and 76 other polyphenols have been used to investigate the Pb detoxification in mouse model. The biochemical and histopathological studies on the mouse model confirm the dual action in preclinical studies.

A Smart Nanotherapeutic Agent for in vitro and in vivo Reversal of Heavy‐Metal‐Induced Causality: Key Information from Optical Spectroscopy

“…Several studies have shown that serum aminotransferase activity as sensitive indicators of liver injury. Damage to the hepatic cells alters their membrane permeability, which leads to the leakage of enzymes from the cells . As described in Table , three weeks of Pb(II) exposure significantly enhanced the AST and ALT levels by 5.7‐fold and 5.2‐fold, respectively, compared to control ( p <0.001).…”

“…[Q] is the quencher concentration, K D denotes the SV quenching constant, k q the bimolecular quenching rate constant, τ 0 is the fluorescence lifetime of the fluorophore . The linearity in the SV plot (Figure C‐inset) indicates a single type of quenching, either static or dynamic . To, identify the nature of quenching, we repeated the experiments at three different temperatures (300 K, 310 K, and 320 K).…”

“…Various chemical assays have been developed to date that exactly mimic the pathophysiological conditions in the human body. However, the success of the chemical models for realistic assumptions are vastly dependent on the existence of an effective correlation between chemical and biological models . Therefore, we developed an animal (Pb 2+ ‐induced C57BL/6j mice) model which exactly mimics the pathogenicity of heavy metal overload disorders.…”

“…Being non‐redox in nature, most of the heavy metals lack pro‐oxidant catalytic activity, rather they covert to some indirect mechanisms (through destruction of sulfhydryl (−SH) containing enzymes essential for in vivo antioxidant defense) to exert pathogenesis through free radical mediated damage . Thus, regulating the free radical‐induced intracellular damage is equally essential in combating heavy metal overload diseases besides the elimination of the same from various organ systems . The conventionally used chelating agents for treatment of heavy metal overload disorders were introduced more than four decades ago (i. e., CaNa 2 EDTA‐1985; BAL‐1949; DMSA‐1978; DMPS‐1958), and they suffer from inherent toxic effects owing to non‐specificity and unwanted distribution throughout the body including several essential organs .…”

“…Unfortunately, to date, there is no commercially available therapeutic agent that can serve both the aforementioned purposes. In one of our previous studies, we developed one multi‐herb formulation for treatment of Pb(II)‐induced heavy metal toxicity. However, inadequate knowledge about in vivo synergistic or antagonistic behavior of the constituent phytochemicals, and lack of a standardized method to produce extract of similar composition and yield, limit its widespread use.…”