Background: Allium cepa L. var. Tropea is typically cultivated in Calabria (Italy) and it is certified as “Cipolla Rossa di Tropea Calabria-PGI” (Tropea red onion). The use of clinically available anti-obesity drugs such as Orlistat is being gradually dismissed due to their side-effects and this has encouraged the search for alternative inhibitors of intestinal lipases such as phytochemicals showing less side-effects. In this study we aimed to evaluate for the first time the anti-obesity potential of the hydroalcoholic extract from the dry outer scales of Tropea red onion by the assesment of its capacity to inhibit pancreatic lipase. Its possible mechanism of action was also studied with planar lipid membranes (PLMs) surrogate of intestinal membranes. Methods: Specialized metabolites in the extract were determined by GC–MS, HPLC-DAD, HPLC-UV-DAD and HPLC-HRMS analyses. Inhibition of pancreatic lipase was studied in vitro against crude lipase Type II from porcine pancreas. PLMs used in the electrophysiology measurements were made up of DOPS:DOPE:POPC. Results: The extract contained quercetin-4′-O-glucoside, quercetin and quercetin-3,4′-O-diglucoside as the most abundant phenolics. Among apolar constituents, γ-sitosterol, linoleic and stearic acids were dominant. The lipase inhibitory effect of the extract had an IC50 value equal to 0.77±0.03 mg/mL (positive control, IC50 = 0.018 mg/mL). The electrophysiological study demonstrated that the extract is able to incorporate into PLMs and to form transient channel-like events Conclusions: Taken altogether, the results allow us to suggest that the hydroalcoholic extract from the dry outer scales of Tropea red onion could prevent lipid ester hydrolysis and it has a protective effect against phospholipase as found for interfacially active compounds.

Phytochemical and biological characterization of dry outer scales extract from Tropea red onion (Allium cepa L. var. Tropea)–A promising inhibitor of pancreatic lipase

Marrelli M.;Russo C.;Argentieri M. P.;Meleleo D.;Mallamaci R.;Avato P.
;
2022-01-01

Abstract

Background: Allium cepa L. var. Tropea is typically cultivated in Calabria (Italy) and it is certified as “Cipolla Rossa di Tropea Calabria-PGI” (Tropea red onion). The use of clinically available anti-obesity drugs such as Orlistat is being gradually dismissed due to their side-effects and this has encouraged the search for alternative inhibitors of intestinal lipases such as phytochemicals showing less side-effects. In this study we aimed to evaluate for the first time the anti-obesity potential of the hydroalcoholic extract from the dry outer scales of Tropea red onion by the assesment of its capacity to inhibit pancreatic lipase. Its possible mechanism of action was also studied with planar lipid membranes (PLMs) surrogate of intestinal membranes. Methods: Specialized metabolites in the extract were determined by GC–MS, HPLC-DAD, HPLC-UV-DAD and HPLC-HRMS analyses. Inhibition of pancreatic lipase was studied in vitro against crude lipase Type II from porcine pancreas. PLMs used in the electrophysiology measurements were made up of DOPS:DOPE:POPC. Results: The extract contained quercetin-4′-O-glucoside, quercetin and quercetin-3,4′-O-diglucoside as the most abundant phenolics. Among apolar constituents, γ-sitosterol, linoleic and stearic acids were dominant. The lipase inhibitory effect of the extract had an IC50 value equal to 0.77±0.03 mg/mL (positive control, IC50 = 0.018 mg/mL). The electrophysiological study demonstrated that the extract is able to incorporate into PLMs and to form transient channel-like events Conclusions: Taken altogether, the results allow us to suggest that the hydroalcoholic extract from the dry outer scales of Tropea red onion could prevent lipid ester hydrolysis and it has a protective effect against phospholipase as found for interfacially active compounds.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/390371
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