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Carbohydrate digestive enzymes like α-amylase and α-glucosidase can be used to treat and manage diabetes. By inhibiting these enzymes, carbohydrate digestion slowed down, lowering the level of glucose entry into the bloodstream and preventing postprandial hyperglycemia. However, the effectiveness of current antidiabetic agents is limited due to their adverse effects. Therefore, the current study explored natural inhibitors from the methanol extract of rice to combat this issue. Through an integrated approach, four different rice cultivars were analysed and found that red rice methanol extract compounds stigmasterol and 1,2-benzenedicarboxylic acid interacted with α-amylase and α-glucosidase. Additionally, further research on stigmasterol directs the structure-activity relationship studies that aid in managing diabetic conditions. [ABSTRACT FROM AUTHOR]

Summary: Traditionally, cowpea (Vigna unguiculata) leaves are consumed by the sub‐Saharan population. Carotenoids and phenolic compounds in cowpea leaves possess great antioxidant properties; however, their bioaccessibility is affected by digestion. This study investigated the influence of in vitro digestion on carotenoids, antioxidant and antidiabetic capacity of three cowpea cultivars (VOP1, VOP3 and VOP4). Among the cowpea cultivars, VOP1 showed the highest 9‐cis‐β‐carotene (21.13%) bioaccessibility, VOP3 showed the highest all‐trans β‐carotene (32.11%) and α‐carotene (21.75%) bioaccessibilities and VOP4 showed the highest lutein (17.70%) and zeaxanthin (32.03%) bioaccessibilities. The ferric‐reducing antioxidant power, 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging (DPPH) activities, 2,2′‐azino‐bis‐3‐ethylbenzthiazoline‐6‐sulphonic acid), α‐amylase and α‐glucosidase inhibitory effects decreased in the small intestinal phase. The cowpea cultivars demonstrated a high ability to meet the recommended daily allowance for carotenoids. As a result, the findings of this study show that cowpea leaves have the potential to be used as functional ingredients. [ABSTRACT FROM AUTHOR]

The leaves of African pumpkins (Momordica balsamina L.) are a commonly consumed traditional vegetable. They are a good source of polyphenolic antioxidants and carotenoids, which are, however, affected by cooking or digestion. We investigated the effect of household cooking methods (stir-frying or boiling) on the changes in bioactive metabolites, antioxidant capacity, release and accessibility of β-carotene and also inhibition of inhibitory activity against α-amylase and α-glucosidase enzymes during in vitro digestion of African pumpkin leaves compared to the raw leaves. Compared to boiled or raw leaves, stir-frying improved the availability of bioactive metabolites at the gastrointestinal phase. Quercetin 3-galactoside and rhamnetin 3-O-glucoside (marker compounds) discriminated the stir-fried leaves from raw leaves and boiled leaves after digestion. Stir-frying improved the release and accessibility of β-carotene and enhanced the antioxidant activities compared to boiling. Dialysable fractions of stir-fried leaves exhibited the greatest inhibitory activity against α-amylase and α-glucosidase enzymes compared to the raw and boiled leaves, as well as acarbose. Stir-frying, therefore, is recommended for use in household cooking to benefit consumers by increasing the intake of phenolics and β-carotene.

This work proposes for the first time a model for reusing almond (Prunus dulcis cv. Casteltermini from Sicily, Southern Italy) skin to formulate a new functional blackberry (Rubus ulmifolius Schott) jam. For this purpose, blackberries were analysed fresh and as jam, traditionally prepared with a minimum fruit amount of 80%. Different percentages of almond skin (20, 15, and 10% w/w) were added to jam. The phytochemical profile of enriched jam was investigated by LC-ESI/LTQOrbitrap/MS analyses. Anthocyanins, hydrolysable tannins, and triterpenoids were identified in a blackberry extract, while proanthocyanidins, flavonoids, and oxylipins were identified in an almond extract. The n-hexane extract of P. dulcis skin, investigated by GC–MS, evidenced linoleic, palmitic, and oleic acids as the main abundant compounds. Samples were investigated for their antioxidant activity using DPPH, ABTS, β-carotene, and FRAP tests. The hypoglycaemic and hypolipidemic effects were studied by α-amylase, α-glucosidase, and lipase inhibitory assays. In order to evaluate the effect of thermal process on enriched jam bioactivity, pasteurisation was applied. An increase in activities for all samples was observed, in particular for jam enriched with 20% w/w of almond skin. Based on obtained data, and supported by sensory analysis, we propose enriched jam as a promising source of compounds useful for preventing diseases associated with oxidative stress.

Highlights • C. phelypaea roots/flowers water extracts have high antioxidant activity. • C. phelypaea roots/flowers water extracts have high enzymatic inhibitory properties. • Tubuloside A, echinacoside and acteoside were among the most abundant compounds. • Tubuloside A may be a competitive inhibitor of α-glucosidase and tyrosinase. • C. phelypaea should be explored for pharmaceutical and biomedical applications. Abstract In this study, ethyl acetate, acetone, ethanol and water extracts from flowers, stems and roots of Cistanche phelypaea (L.) Cout were appraised for radical scavenging activity (RSA) towards 1,1-diphenyl-2-picrylhydrazyl,2,2-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) and superoxide free radicals, and for metal chelating activities on iron and copper ions. The water extracts had the highest antioxidant activity, especially those from roots and flowers, and were further appraised for in vitro inhibition of enzymes implicated on the onset of human ailments, namely acetyl- (AChE) and butyrylcholinesterase (BuChE) for Alzheimer's disease, α-glucosidase and α-amylase for diabetes, and tyrosinase for skin hyperpigmentation disorders. The extracts had a higher activity towards BuChE, and the roots extract had the highest capacity to inhibit tyrosinase. Samples showed a low capacity to inhibit carbohydrate hydrolysing enzymes, except for the root extract with a good inhibition on glucosidase. Samples were then characterized by NMR (1D and 2D): the main metabolites identified in the flowers extract were iridoid glycosides, in particular gluroside and bartsioside. In stems, phenylehanoid glycosides (PhGs) and iridoids were detected, especially acteoside. In roots were detected essentially PhGs, mainly echinacoside and tubuloside A. Docking studies were performed on the identified compounds. A favorable binding energy of tubuloside A to tyrosinase was calculated, and indicated this compound as a possible competitive inhibitor of α-glucosidase and tyrosinase. Our results suggest that C. phelypeae is a promising source of biologically-active compounds with health promoting properties for pharmaceutical and biomedical applications. [ABSTRACT FROM AUTHOR]

Purslane (Portulaca oleracea L.) is a member of the family Portulacaceae. Due to its many health benefits, it is listed in a World Health Organization database. The aim of this work is to investigate the purslane extracts for their chemical profile and bioactivity. In this study, two different solvents (MeOH/H2O and EtOH) were applied to fresh and dried leaves. The extracts were analysed using HPLC-DAD. Phenolic acids (caffeic acid, p-coumaric acid and ferulic acid) and flavonoids (apigenin, kaempferol, luteolin, quercetin, isorhamnetin, kaempferol-3-O-glucoside and rutin) were identified in all samples. Quercetin and p-coumaric acid were the most abundant compounds. Total antioxidant activity was measured by using the ABTS and DPPH tests, and the ferric reducing antioxidant power (FRAP) assay. Hypoglycaemic properties were investigated via the inhibition of carbohydrate-hydrolysing enzymes, α-amylase and α-glucosidase. Fresh hydroalcoholic purslane extract exhibited the highest radical scavenging potential in both ABTS and DPPH test (IC50 values of 52.86 and 66.98 µg/mL, respectively), whereas dried hydroalcoholic purslane extract showed the highest α-glucosidase inhibitory potential (IC50 value of 45.05 µg/mL). Collectively these data show the health properties of this widely consumed salad plant. [ABSTRACT FROM AUTHOR]

[Display omitted] • A metabolomic and chemometric analysis indicated fruit clustering based on 21 metabolites. • Delphinidin 3-galactoside levels were highest in Transvaal milkplum. • Quercetin 3-galactoside was highest in Water berries. • Sand apricot vine and Sour plum inhibited the carbohydrate hydrolyzing enzymes. • Xanthohumol and 3-O-p-coumaroylquinic acid have been identified as bioactive compounds. Using UPLC-QTOF/MS, metabolites were identified in 10 indigenous fruits from South Africa. Metabolomic-chemometric analysis showed chlorogenic acid scored highest for the discrimination of three different fruit clusters. Heat maps showed patterns and groupings based on the metabolite concentrations. The highest concentrations of quercetin 3-O-α- l -arabinopyranoside (401.09 mg/kg), delphinidin 3-galactoside (57.80 mg/kg), procyanidin B-type dimer (527.07 mg/kg) and epicatechin (1349.46 mg/kg), was in Englerophytum magalismontanum (Transvaal milkplum). Syzygium cordatum (Water berry) had the highest concentrations of quercetin 3-galactoside and methyl gallate 3-O-beta- d -glucopyranoside, Ficus capensis (Cape fig) the most 3-CQA and 5-CQA, and Parinari curatellifolia (Mobola plum) had the highest FRAP (9.5 mmol TEAC/g) and DPPH (14.2 IC 50 µg/mL) scavenging activities. When compared to eight other indigenous fruits, Ximenia caffra (Sour plum), and Landolphia kirkii (Sand apricot vine), showed the highest inhibition of carbohydrate hydrolysing enzymes. Correlation analysis identified candidates responsible for each biological activity in these fruits, proving their utility as functional ingredients. [ABSTRACT FROM AUTHOR]

The leaves of African pumpkins (Momordica balsamina L.) are a commonly consumed traditional vegetable. They are a good source of polyphenolic antioxidants and carotenoids, which are, however, affected by cooking or digestion. We investigated the effect of household cooking methods (stir-frying or boiling) on the changes in bioactive metabolites, antioxidant capacity, release and accessibility of β-carotene and also inhibition of inhibitory activity against α-amylase and α-glucosidase enzymes during in vitro digestion of African pumpkin leaves compared to the raw leaves. Compared to boiled or raw leaves, stir-frying improved the availability of bioactive metabolites at the gastrointestinal phase. Quercetin 3-galactoside and rhamnetin 3-O-glucoside (marker compounds) discriminated the stir-fried leaves from raw leaves and boiled leaves after digestion. Stir-frying improved the release and accessibility of β-carotene and enhanced the antioxidant activities compared to boiling. Dialysable fractions of stir-fried leaves exhibited the greatest inhibitory activity against α-amylase and α-glucosidase enzymes compared to the raw and boiled leaves, as well as acarbose. Stir-frying, therefore, is recommended for use in household cooking to benefit consumers by increasing the intake of phenolics and β-carotene. [ABSTRACT FROM AUTHOR]

This work proposes for the first time a model for reusing almond (Prunus dulcis cv. Casteltermini from Sicily, Southern Italy) skin to formulate a new functional blackberry (Rubus ulmifolius Schott) jam. For this purpose, blackberries were analysed fresh and as jam, traditionally prepared with a minimum fruit amount of 80%. Different percentages of almond skin (20, 15, and 10% w/w) were added to jam. The phytochemical profile of enriched jam was investigated by LC-ESI/LTQOrbitrap/MS analyses. Anthocyanins, hydrolysable tannins, and triterpenoids were identified in a blackberry extract, while proanthocyanidins, flavonoids, and oxylipins were identified in an almond extract. The n-hexane extract of P. dulcis skin, investigated by GC–MS, evidenced linoleic, palmitic, and oleic acids as the main abundant compounds. Samples were investigated for their antioxidant activity using DPPH, ABTS, β-carotene, and FRAP tests. The hypoglycaemic and hypolipidemic effects were studied by α-amylase, α-glucosidase, and lipase inhibitory assays. In order to evaluate the effect of thermal process on enriched jam bioactivity, pasteurisation was applied. An increase in activities for all samples was observed, in particular for jam enriched with 20% w/w of almond skin. Based on obtained data, and supported by sensory analysis, we propose enriched jam as a promising source of compounds useful for preventing diseases associated with oxidative stress. [ABSTRACT FROM AUTHOR]