Fighting free radicals with triterpenes.
Antioxidants as efficient free radical scavengers are currently on everyone's lips. IPB chemists as part of an international team have now determined the antioxidant potential of 15 selected triterpenes. Triterpenes are considered effective radical scavengers with outstanding anti-inflammatory activities. For their analyses, the scientists used various assays, including their reducing activity for copper ions and their ability to chelate iron ions. Most of the compounds tested showed tremendous antioxidant activities, but these were based on different modes of action. All triterpenes also had inhibitory effects on cholinesterases, amylases, glucosidases, and tyrosinases. In addition, the scientists subjected the 15 triterpenes to toxicological and pharmacokinetic analysis to assess absorption, distribution, metabolism and elimination (ADME analysis) of these compounds in the human organism.
Overall, the authors concluded that the investigated triterpenes show general inhibition of oxidative processes, as well as specific effects. Potentially semisynthetic modification may improve their specific action profile and the pharmacokinetic properties. In particular, those compounds with high basic activity could be used as lead structures for mild natural product-based (co-)treatment of early stage Alzheimer's disease and diabetes.
Free radicals are naturally generated in the process of cellular respiration. Since they are highly reactive and can oxidize all organic substances in their vicinity, thereby causing considerable damage to DNA and membranes, the organism must scavenge and neutralize these radicals. This is realized by an effective protective system, which includes antioxidant enzymes such as peroxidases and catalases, as well as various vitamins and further binding and buffering substances. If this balance between the formation of free radicals and their antioxidant-mediated inactivation is permanently disturbed, oxidative stress occurs, which leads to arteriosclerosis, diabetes and inflammatory neurodegenerative diseases.
Natural antioxidants, most of them obtained from plants, counteract oxidative stress and are therefore the focus of numerous studies investigating anti-inflammatory agents and their development into dietary supplements and drugs. In addition to polyphenols and flavonoids, triterpenes in particular show outstanding anti-inflammatory, bactericidal and anti-allergic activities.
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