In vitro inhibitory effects of Limonium contortirameum and L. virgatum extracts from Sardinia on α-amylase, α-glucosidase and pancreatic lipase

Pancreatic triacylglycerol lipase (PL), alpha-amylase and alpha-glucosidase are interesting pharmacological targets for the management of dyslipidemia, atherosclerosis, and obesity-diabetes. Limonium spp (Plumbaginaceae) are endemic to Sardinia, Italy. Comparable with acarbose, aqueous extracts (AE) of L. contortirameum and L. virgatum, and their phytoconstituent gallic acid concentration gradients (mg/mL) were identified as in vitro potent (p<0.001, n=3) and efficacious dual inhibitors of alpha-amylase and alpha-glucosidase with respective IC50 (mg/mL) values of 0.6 +/- 0.1, 1.2 +/- 0.1 and 0.15 +/- 0.02. Equivalent to orlistat (PL IC50 of 0.114 +/- 0.004 microg/mL), L. contortirameum, L. virgatum AE and their phytoprinciple gallic acid inhibited PL substantially (p<0.001, n=3) in a dose-dependent manner in vitro with PL- IC50 (microg/mL) of 920.4 +/- 105.2, 593.1 +/- 56.8 and 8.4 +/- 0.9, respectively. LC-MS analysis of extracts revealed the presence of several phenolic compounds in their aglycon and glycoside forms. These are catechins, flavones, epigallocatechins and flavonols. Flavonoid- and polyphenol-rich L contortirameum and L. virgatum, modulating gastrointestinal carbohydrate and lipid digestion and absorption, may be advocated as candidates for obesity-diabetes prevention and phytotherapy.