In vitro α-amylase and pancreatic lipase inhibitory activity of Cornus mas L. and Cornus alba L. fruit extracts

Abstract

Less-common fruits from Cornus spp. (Cornaceae), also named dogwoods, have shown antidiabetic, antibacterial and anti-allergic properties and are thus considered a source of phytochemicals that are beneficial to human health. The study aimed to compare the chemical compositions of the aqueous and ethanolic extracts of lyophilized fresh-picked and commercially available dried fruits of Cornus mas (Cm, cornelian cherry) and Cornus alba (Ca) fruits using HPLC-DAD-MS/MS method. Simultaneously, the a -amylase and pancreatic lipase (PL) inhibitory activities of the prepared extracts were compared by in vitro fluorescence assay based on the kinetic hydrolysis of starch or oleate ester of 4-methylumbelliferone (MUO), respectively. Additionally, a bio-assay guided identification of compounds potentially responsible for the inhibition of pancreatic enzymes was performed. Iridoids (loganic acid, cornuside) and anthocyanins (pelargonidin 3- O -galactoside) were identified in the Cmfruit extracts. Flavonoids, such as quercetin and kaempferol derivatives, were detected in the Ca fruit extracts. The chromatographic separation of the constituents of Ca fruit provided a fraction containing phenolic acids derivatives, which inhibited PL activity by 69.9 ± 4.5% at a concentration of 7.5 μg·mL −1 . The IC 50 of hydroxytyrosol glucoside, isolated from the most active Ca fraction, was 0.99 ± 0.10 mg·mL −1 indicating other constituents responsible for the fraction activity. The most active subfraction from Cm fruit (7.5 μg·mL −1 ), which inhibited PL activity by 28.3 ± 1.5%, contained pelargonidin 3- O -galactoside. Loganic acid and cornuside in highly pure form did not inhibit lipase activity. The phytochemical constituents of Cm, and particularly of Ca fruit extracts, can inhibit pancreatic enzymes and thus might be considered effective preparations in the prevention and control of hyperlipidemia related diseases.

Inhibition of Digestive Enzymes and Antioxidant Activity of Extracts from Fruits of Cornus alba, Cornus sanguinea subsp. hungarica and Cornus florida–A Comparative Study

“…Firstly, the total phenols content was determined. Among all studied extracts, the highest content of phenolic compounds was found in the aqueous-ethanolic extract from the fruits of CA (39.60 ± 2.28 mg GAE/g of extract) as it was described in our previous study [13]. The content of phenolic compounds expressed as gallic acid equivalent in extract from fruits of CF was determined for the first time (24.30 ± 1.72 mg GAE/g).…”

“…Taking into consideration all the results obtained both in this and our previous study [13], it was concluded that the aqueous-ethanolic extract from fruits of CA was the most active one. In order to find the phytochemicals responsible for this activity, the isolation of compounds from acetone-methanol-water extract (3:1:1, v/v/v) was carried out.…”

“…The structure of compound D2.5 was found to be kaempferol 3-O-glucuronide 6"-methyl ester ([M-H] − m/z = 475) [19]. Last but not least, compound H1.1 (CA3) was identified as hydroxytyrosol glucoside ([M-H] − at m/z = 315) based on the data previously described [13,20]. The NMR spectra of identified compounds were provided in the Supplementary Materials.…”

“…Our previous study highlighted to some extent a role of flavonoids detected in the extracts from fruits of Cornus alba L. in the inhibition of digestive enzymes [13]. The compounds identified in the CA fruit extract were quercetin-3-O-glucuronide, kaempferol and quercetin 3-O-glucosides, as well as hydrolysable tannins, including 1,2,3,4,6-penta-O-galloylglucoside (PGG), and cornusiins A and B [13,14].…”

“…The content of these compounds in extract from fruits of CS (19.72 ± 1.86 g/mg) turned out to be significantly lower. The total content of phenolic compounds in the aqueous-ethanolic extract from the fruits of CA was previously determined [13].…”