Qualitative and quantitative analysis of the proautophagic activity of Citrus flavonoids from Bergamot Polyphenol Fraction

Abstract

Bergamot Polyphenol Fraction (BPF®) is a natural mixture of Citrus flavonoids extracted from processed bergamot fruits. It has been shown to counteract cardiovascular risk factors and to prevent liver steatosis in rats and patients. Hepatic effects of BPF correlate with its ability to stimulate liver autophagy. Six aglyconic flavonoids have been identified in the proautophagic fraction of the hydrolysis product of BPF (A-BPF): naringenin, hesperetin, eridictyol, diosmetin, apigenin and luteolin. We report here the output parameters of high resolution mass spectrometry analysis of these flavonoids and chemical structures of their parent compounds. The second set of data shows the proautophagic activity of BPF flavonoids in a hepatic cell line HepG2 analyzed by a flow cytometry approach. The method is based on the red to green fluorescence intensity ratio analysis of DsRed -LC3- GFP, which is stably expressed in HepG2 cells. Proportional analysis of ATG indexes allowed us to address a relative contribution of individual compounds to the proautophagic activity of the A-BPF mixture and evaluate if the effect was additive. Qualitative analysis of ATG indexes compared the effects of flavonoids at equal concentrations in the presence and absence of palmitic acid and chloroquine. The Excel files reporting the analysis of flow cytometry data are available in the public repository.

Bergamot Polyphenols Boost Therapeutic Effects of the Diet on Non-Alcoholic Steatohepatitis (NASH) Induced by “Junk Food”: Evidence for Anti-Inflammatory Activity

“…Our previous work showed that the supplementation of hypercaloric diet with an extract of natural Citrus polyphenols from bergamot (BPF) prevents NAFLD through the stimulation of autophagy in the liver [ 12 ], which was further confirmed by in vitro studies [ 19 , 20 ]. The main aim of the present study was to examine the effect of BPF supplementation to normocaloric diet on CAF diet-induced advanced NAFLD in therapeutic regime.…”

“…Indeed, dietary polyphenols, a large and heterogeneous group of phytochemicals in herbs and plant-based foods, have been associated with lower risk of NAFLD [ 16 , 17 ]. In particular, Citrus flavonoids have been shown to exert several positive health effects on glucose and lipid metabolism in experimental models [ 12 , 16 , 18 , 19 , 20 , 21 , 22 ] and humans [ 23 , 24 , 25 ].…”

“…Bergamot has attracted considerable attention due to its peculiar composition and high content of flavonoids, some of which are also found in other Citrus species [ 18 , 27 ]. BPF is a highly concentrated extract of glycosylated flavanones (naringin, neoeriocitrin and hesperidin) and flavones (diosmetin, apigenin and luteolin glycosides) from bergamot fruit juice [ 19 , 20 , 28 ]. BPF phyto-complex contains around 40% of flavonoids, but also sugars, salts and other natural compounds with a possible detoxifying activity [ 19 , 20 ].…”

“…BPF is a highly concentrated extract of glycosylated flavanones (naringin, neoeriocitrin and hesperidin) and flavones (diosmetin, apigenin and luteolin glycosides) from bergamot fruit juice [ 19 , 20 , 28 ]. BPF phyto-complex contains around 40% of flavonoids, but also sugars, salts and other natural compounds with a possible detoxifying activity [ 19 , 20 ]. A particular feature of certain flavonoid glycosides, abundant in bergamot juice and in BPF, such as bruteridin and melitidin, is the presence of covalently linked 3-hydroxy-3-methylglutaryl (HMG) moiety [ 28 , 29 ].…”

“…These studies also demonstrated strong reduction of blood TGL levels and mild effects on glucose levels in individuals taking BPF [ 23 , 24 , 30 ]. These effects might depend on the ability of BPF flavonoids to stimulate AMPK, which should also explain proautophagic proprieties of these compounds in models of hepatic steatosis in vitro and in vivo [ 12 , 19 , 20 ]. Finally, BPF may also have anti-inflammatory activity, since bergamot juice extract have been shown to reduce inflammation in animal models of ischemia/reperfusion and inflammatory bowel disease [ 31 , 32 ].…”