Phytochemical Profiles and Antioxidant Activities in Six Species of Ramie Leaves

Abstract

Increased consumption of vegetables or plant food has been associated with decreased risk of developing major chronic diseases, such as cancers, diabetes, cardiovascular diseases, and age-related functional decline. Ramie leaves are rich in phenolics and flavonoids, which have been suggested for human health benefits. Phenolic contents, flavonoid contents, phenolic compounds, and anti-cancer properties in six species of ramie leaves were analyzed by Folin-reagent method, sodium borohydride/chloranil-based assay (SBC), HPLC method and antiproliferation, cytoxicity, respectively. Antioxidant activities were measured through peroxyl radical scavenging capacity (PSC) method, oxygen radical absorbance capacity (ORAC) method, and cellular antioxidant activity (CAA). Research indicated that Boehmeria penduliflora contained the highest total phenolic content (2313.7±27.28 mg GAE/100 g FW), and flavonoid content (1682.4±27.70 mg CAE/100 g FW). Boehmeria tricuspis showed the highest PSC value (9574.8±117.63 µM vit. C equiv./100 g FW), while Boehmeria penduliflora indicated the highest ORAC value (330.44±16.88 µmol Trolox equiv./g FW). The antioxidant activities were correlated with phenolic contents and flavonoid contents. Boehmeria tricuspis had the highest antiproliferative capacity with the lowest EC50 (4.11±0.19 mg/mL). The results for the analyzed ramie for CAA were significantly different from each other (p<0.05), Boehmeria tricuspis had the highest CAA value (133.63±7.10 µmol QE/100 g). Benzoic acid, 4-coumaric acid, caffeic acid, and ferulic acid were the dominant phenolic ingredients in the ramie leaves according to HPLC analysis. Our research is the first report to study the phytochemical profiles and antioxidant activities in different species of ramie leaves for their health benefit.

Phytochemical Content, Antidiabetic, Anticholinergic, and Antioxidant Activities of Endemic Lecokia cretica Extracts

“…They could be found as free and bound forms. In this study we evaluated only free phytochemicals, however, with the help of acid or base hydrolysis prior to HPLC process, bound phytochemicals could also be analyzed . Free phenolics are rapidly absorbed in early digestion.…”

“…Biodiversity 2019, 16, e1900341 www.cb.wiley.com (4 of 11) e1900341 © 2019 Wiley-VHCA AG, Zurich, Switzerland help of acid or base hydrolysis prior to HPLC process, bound phytochemicals could also be analyzed. [48] Free phenolics are rapidly absorbed in early digestion. Bound phenolics, on the other hand, are mainly found in the form of β-glycosides and remain intact in the stomach and small intestine.…”

Anti-cancer and antioxidant properties of phenolics isolated from<i> Toona sinensis</i> A Juss acetone leaf extract

“…PSC and ORAC assays incorporate fluorescent probe to monitor reaction. These methods are rapid, precise, reliable, reproducible, and sensitive; and can produce acceptable results comparable to common chemical assays [12]. The assays also take into account the bioavailability, uptake and metabolism of the extract [18].…”

“…Total phenolic content was determined as gallic acid equivalent using gallic acid standard curve [12], and the final value was expressed as milligram of gallic acid equivalent (GAE) per gram DW.…”

Aqueous extract of Orostachys japonicus A. Berger exerts immunostimulatory activity in RAW 264.7 macrophages

“…Total phenolic content in the extracts was determined using a modified Folin-Ciocalteu method (Chen et al, 2014). Briefly, 0.5 mL OJ extract was mixed with 5 mL Folin-Ciocalteu reagent (previously diluted with water at 1: 10 v/v) and 4 mL (75 g/L) of sodium carbonate (Na 2 CO 3 ).…”