Phytochemicals Involved in Mitigating Silent Toxicity Induced by Heavy Metals.

Heavy metals (HMs) are natural elements present in the Earth's crust, characterised by a high atomic mass and a density more than five times higher than water. Despite their origin from natural sources, extensive usage and processing of raw materials and their presence as silent poisons in our daily products and diets have drastically altered their biochemical balance, making them a threat to the environment and human health. Particularly, the food chain polluted with toxic metals represents a crucial route of human exposure. Therefore, the impact of HMs on human health has become a matter of concern because of the severe chronic effects induced by their excessive levels in the human body. Chelation therapy is an approved valid treatment for HM poisoning; however, despite the efficacy demonstrated by chelating agents, various dramatic side effects may occur. Numerous data demonstrate that dietary components and phytoantioxidants play a significant role in preventing or reducing the damage induced by HMs. This review summarises the role of various phytochemicals, plant and herbal extracts or probiotics in promoting human health by mitigating the toxic effects of different HMs.

Influence of drug encapsulation within mixed micelles on the excited state dynamics and accessibility to ionic quenchers.

Photophysical techniques, specifically time-resolved fluorescence and laser flash photolysis, have proven to be noninvasive, straightforward, and valuable tools to demonstrate how drug encapsulation into biomimetic mixed micelles (MM) influences the dynamics of excited states and their accessibility to ionic quenchers. This concept has been illustrated by choosing a set of currently administered drugs containing a common naphthalene chromophore, namely, (S)-naproxen and its methyl ester, (R)-cinacalcet and (S)-propranolol. A remarkable increase of their triplet lifetimes is noticed when experiments are performed in MM, indicating efficient entrapment of the drugs in these supramolecular entities. Furthermore, a decrease of 1 order of magnitude in the quenching rate constant of the singlet and triplet excited states (by iodide or nitrite, respectively) is observed upon encapsulation into MM. This approach can in principle be extended to other microenvironments capable of incorporating photoactive compounds.

Bisbenzyltetrahydroisoquinolines, a new class of inhibitors of the mitochondrial respiratory chain complex I.

Four bisbenzyltetrahydroisoquinoline alkaloids (-)-medelline, (+)-antioquine, (+)-aromoline, and (+)-obamegine were isolated from the fruits of Xylopia columbiana. These compounds, the previously isolated alkaloids (+)-thaligrisine and (+)-isotetrandrine, as well as their O-acetylated derivatives were assayed on submitochondrial particles from beef heart as inhibitors of the mammalian respiratory chain. The results revealed that these alkaloids act as selective inhibitors of mitochondrial complex I in a 0.15 - 4.71 microM range. O-Acetylation, which increases their lipophilicity, considerably increased the inhibitory potency.