Bioenergetic and antioxidant effects of a fresh leaf extract from Cynara scolymus L.

Fresh leaf artichoke extracts contain high amounts of cynarin and related caffeoylquinic acids which possess high antioxidant activity. We have investigated mitochondrial stimulation and confirmed radical scavenging activity of cynarin, the lead compound of the special extract [15 – 30:1] from fresh leafs instead of dried material from Cynara cardunculus var. scolymus (L.) Benth., and its main bioactive metabolites caffeic acid, ferulic acid, dihydroferulic acid and their amide derivatives formed after administration of the fresh leaf artichoke extract to humans.

Neuroblastoma cells were incubated with 100 and 200µM cynarin or with their main metabolites at similar concentrations. All compounds increased mitochondrial respiration as assessed by NBT (Nitro Blue Tetrazolium) reduction by 3 to 6 fold. Activity of complex I (iron sulfur cluster N2) and complex IV (cytochrome-c-oxidase unit 5A) were equally stimulated after administration of cynarin and its derivatives to the same extend. Even under baseline conditions, NO formation was increased twofold, whereas the generation of superoxide anion radicals and peroxynitrite was reduced by almost 50% compared to vehicle treated control cells.

Cynarin exhibited potent hydroxyl radical scavenging activity (EC₅₀= 50µM), whereas caffeic, ferulic and dihydroferulic acid were even more potent (EC₅₀˜25µM). More importantly, the amide derivatives like melatonin and indolepropionamide, that have a unique bioavailability (Poeggeler et al., 2010; Poeggeler, 2013) due to their high amphiphilicity and therefore possess high bioactivity in vivo, were also quite potent (EC₅₀˜75µM).

References:

[1] Poeggeler B., Sambarmurti K., Siedlak S.L., Perry G., Smith M.A., Pappolla M.A.: A novel endogenous indole protects rodent mitochondria and extends rotifer lifespan. PLoS ONE 5 (4): e10206, 2010.

[2] Poeggeler B.: Die Heilkraft der Artischocke bei Verdauungsproblemen und Leberstoffwechselstörungen. Zeitschrift für Phytotherapie 34 (Suppl. 1): S25, P12, 2013.