Antioxidant property and α $$ \boldsymbol{\upalpha} $$ -glucosidase, α $$ \boldsymbol{\upalpha} $$ -amylase and lipase inhibiting activities of Flacourtia inermis fruits: characterization of malic acid as an inhibitor of the enzymes

Abstract

Flacourtia inermis Roxb. (Flacourtiaceae), is a moderate sized tree cultivated in Sri Lanka for its fruits known as Lovi. The current study was undertaken to study the biological activity of extracts of the fruits in an attempt to increase the value of the under exploited fruit crops. Fruits of F. inermis were found to be rich in phenolics and anthocyanins. Polyphenol content of the fruits was determined to be 1.28 g gallic acid equivalents per 100 g of fresh fruit and anthocyanin content was estimated as 108 mg cyanidin-3-glucoside equivalents per 100 g of fresh fruits. The EtOAc extract showed moderate antioxidant activity in the DPPH radical scavenging assay with IC 50 value of 66.2 ppm. The EtOAc and MeOH extracts of the fruits also exhibited inhibitory activities toward α-glucosidase, α-amylase and lipase enzymes with IC 50 values ranging from 549 to 710 ppm, 1021 to 1949 ppm and 1290 to 2096 ppm, respectively. The active principle for the enzyme inhibition was isolated through activity-guided fractionation and was characterized as (S)-malic acid. The results of this study indicate that F. inermis fruits have the potential to be used in health foods and in nutritional supplements.

In vitro studies on the effect of watercress juice on digestive enzymes relevant to type 2 diabetes and obesity and antioxidant activity

“…Other bioactive compounds in WJ may contribute to these inhibitory activities. Roseoside, pinoresinol and their glycosides are known to be a-glucosidase inhibitory agents (Kwon et al, 2014;Yang, Liang, Xie, & Wei, 2016), while malic acid has been characterized as the active principle for inhibition of a-glucosidase, a-amylase and lipase from Flacourtia inermis Roxb fruits (Alakolanga et al, 2015).…”

“…Therefore, inhibition of α‐glucosidase and α‐amylase by dietary polyphenols or isolated phenolic compounds from plant derived foods may offer an alternative natural approach for control and management of glycaemia in T2D (Arulselvan et al, ). Phenolic compounds are also known to interfere with pancreatic lipase activity (Alakolanga, Kumar, Jayasinghe, & Fujimoto, ; Kim et al, ; Mahmood, ), thus limiting fat absorption in the intestinal lumen.…”

Phytopharmacological Strategies in the Management of Type 2 Diabetes Mellitus

“…Polyphenol-rich extracts of six common bean cultivars (Phaseolus vulgaris) showed inhibitory activity against alpha-amylase (IC 50 values ranged from 69 ± 1.9 to 126 ± 3.2 µg/mL and from 107.01 ± 4.5 to 184.20 ± 5.7 µg/mL before and after cooking), alpha-glucosidase (IC 50 values ranged from 39.3 ± 4.4 to 74.13 ± 6.9 µg/mL and from 51 ± 7.7 to 122.1 ± 5.2 µg/mL before and after cooking) and pancreatic lipase (IC 50 values ranged from 63.11 ± 7.5 to 103.2 ± 5.9 µg/mL and from 92 ± 6.3 to 128.5 ± 7.4 µg/mL before and after cooking) [38]. Ethanol and methanol extracts from Lovi (Botoko plum) from Flacourtia inermis, found in Sri Lanka exhibited inhibitory activity against alpha-glucosidase (IC 50 from 549 to 710 ppm), alpha-amylase (IC 50 from 1021 to 1949 ppm) and lipase (IC 50 from 1290 to 2096 ppm), where (S)-malic acid was characterized as the active principle for this inhibition effect [40]. Additionally, this fruit has great polyphenol (1.28 g gallic acid equivalents per 100 g of fresh fruit) and anthocyanin (108 mg cyaniding-3-glucoside equivalents per 100 g fresh fruit) content [40].…”

Antioxidant and antidiabetic properties of tartary buckwheat rice flavonoids after in vitro digestion

“…Antioxidants are known to reduce the complications of diabetes induced by oxidative stress by delaying glucose absorption. This is achieved by inhibiting carbohydrate hydrolyzing enzymes such as α-amylase and α-glucosidase (Yu et al, 2012;Alakolanga et al, 2015). α-Amylase, a primary enzyme mostly found in the saliva, is capable of decomposing starch into absorbable molecules (Kim et al, 2014).…”