Free and Bound Phenolic Profiles of Rosa roxburghii Tratt Leaves and Their Antioxidant and Inhibitory Effects on α-Glucosidase

Abstract

Rosa roxburghii Tratt (R. roxburghii) tea is a traditional Chinese beverage. This study aims to investigate and compare the phenolics in free and bound forms of two cultivars of R. roxburghii leaves, and their bioactivities. The total phenolic content of free and bound fractions was 72.71 and 17.75 mg GAE/g DW in Gui Nong No. 5 (GNN5) and 94.28 and 11.19 mg GAE/g DW in Seedless Cili (SC). A total of 37 phenolic compounds were characterized and quantified by UPLC-Q-Exactive Orbitrap/MS with ellagic acid, quercitrin, isoquercitrin, and quininic acid in free fraction, while gallic acid, ellagic acid, and hyperoside were main compounds in bound fraction. The free fraction with higher phenolic contents also showed excellent performances on antioxidant activities and α-glucosidase inhibitory potency than bound phenolics. Therefore, the results highlight that R. roxburghii leaves are a promising source enriched in phenolic constituents for functional beverages and nutritional foods.

Effect of free and bound polyphenols from Rosa roxburghii Tratt distiller's grains on moderating fecal microbiota

“…It could be that bound polyphenols linked to fiber in plants were difficult to release, whereas free polyphenols were soluble in water or polar solvents and were easily to liberate electrons or hydrogen atoms, contributing to the high free radical scavenging ability. Hence, free polyphenols were the primary antioxidant in fruits and vegetables in line with previous research ( Mithul Aravind et al, 2021 , Yang et al, 2022 ).…”

“…The free polyphenols from R. roxburghii DGs were extracted by the solvent extraction method with some modifications ( Yang et al, 2022 ). Firstly, the R. roxburghii DGs powder (2.0 g) was mixed with 20 mL of chilled 80% methanol (1% v/v formic acid).…”

Effects of shear emulsifying/ball milling/autoclave modification on structure, physicochemical properties, phenolic compounds, and antioxidant capacity of lotus (Nelumbo) leaves dietary fiber

“…Some phenolic components of lotus leaves were still retained in LDF extracted, and the retention rates of FP, BP and TP of lotus leaves powder were 30.74-64.53, 61.65-80.25, and 34.09-65.77%. The FP content of samples was 4.09-8.21 times that of their BP content, showing the phenolic components in lotus leaves were mainly FP, which was similar to date (Phoenix dactylifera L.) seeds (27) and rosa roxburghii tratt leaves (50).…”

The composition of phenolic compounds in Chinese olive (Canarium album L.) cultivars and their contribution to the anti-inflammatory properties of the cultivars

“…TFC was measured using the method introduced by Yang et al ( 14 ). Briefly, Sample extracts were dissolved by methanol, 25 μL of sample solution was mixed with 110 μL of 0.66 M NaNO 2 in 96-well plates and incubated for 5 min.…”

“…The gradient was formed as follows: 0–3 min 95–85% B, 3–11 min 85–70% B, 11–15 min 70–50% B, 15–21 min 50–10% B, 21–22 min 10–95% B. The flow rate was 150 μL/min with a sample injection volume of 2 μL, and the column temperature was equilibrated to 20°C ( 14 ). MS experiments were conducted in positive and negative scan ionization mode interfaces.…”