Identification of phenolic secondary metabolites fromSchotia brachypetalaSond. (Fabaceae) and demonstration of their antioxidant activities inCaenorhabditis elegans

Abstract

BackgroundSchotia brachypetala Sond. (Fabaceae) is an endemic tree of Southern Africa whose phytochemistry and pharmacology were slightly studied. The present work aimed at profiling the major phenolics compounds present in the hydro-alcohol extract from S. brachypetala leaves (SBE) using LC/HRESI/MS/MS and NMR and prove their antioxidant capabilities using novel methods.MethodsIn vitro assays; DPPH, TEAC persulfate decolorizing kinetic and FRAP assays, and in vivo assays: Caenorhabditis elegans strains maintenance, Intracellular ROS in C. elegans, Survival assay, GFP expression and Subcellular DAF-16 localization were employed to evaluate the antioxidant activity.ResultsMore than forty polyphenols, including flavonoid glycosides, galloylated flavonoid glycosides, isoflavones, dihydrochalcones, procyanidins, anthocyanins, hydroxy benzoic acid derivatives, hydrolysable tannins, and traces of methylated and acetylated flavonoid derivatives were identified. Three compounds were isolated and identified from the genus Schotia for the first time, namely gallic acid, myricetin-3-O-α-L-1C4-rhamnoside and quercetin-3-O-L-1C4-rhamnoside. The total phenolics content of SBE was (376 mg CAE/g), followed by flavonoids (67.87 QE/g). In vitro antioxidant activity of SBE was evidenced by DPPH radical scavenging activity (IC50 of 9 µg/mL), FRAP ferric reducing activity (5,000 mol Fe2+ E/mg) and ABTS peroxide inhibiting activity (1,054 mM Trolox E/mg). The tested extract was able to protect the worms against juglone induced oxidative stress, an increased survival rate (up to 41%) was recorded, when compared with the control group (11%) and attenuate the reactive oxygen species (ROS) accumulation in dose-dependent and reached up to 72% for the highest tested concentration. SBE was also able to attenuate the levels of heat shock protein (HSP) expression in dose-dependent up to 60% in the 150 µg SBE/mL group. In DAF-16 Subcellular localization SBE treated worms showed nuclear localization pattern up to 78%, while it was only 5% in the untreated control group.DiscussionA pronounced antioxidant activity in vivo, which can be attributed to its ability to promote the nuclear translocation of DAF-16/FOXO, the main transcription factor regulating the expression of stress response genes. The remarkable antioxidant activity in vitro and in vivo correlates to SBE rich phenolic profile.

Senna singueana: Antioxidant, Hepatoprotective, Antiapoptotic Properties and Phytochemical Profiling of a Methanol Bark Extract

“…In vitro antioxidant activities of the bark extract were determined using two commonly assays DPPH (2,2-diphenyl-1-picrylhydrazyl radical) and FRAP [ 43 ] following the protocol described by [ 44 ]. In brief, DPPH scavenging capacity assay was done following the standard assay reported by Blois [ 45 ] with some modifications adapted to a 96-well microplate.…”

“…In addition, the total phenolic content was estimated by the Folin-Ciocalteu method as described before [ 44 ]. In brief, a stock solution (2.5 mg/mL of the lyophilized extract) was prepared.…”

“…All of them were obtained from the Caenorhabditis Genetic Center (CGC), University of Minnesota, Minneapolis, MN, USA. All assays followed a protocol as reported before [ 44 ]. In brief, to determine the survival rate of the worms under juglone induced oxidative stress, we treated the worms (N2 type) with two different doses (100 and 200 µg lypholized extract/mL), except the control group and they were kept at 20 °C in S-medium.…”

“…The nematodes were treated with two doses of the extract (100 and 200 µg extract/mL) at 20 °C for 24 h in S-medium. For the intracellular ROS content and DAF-16:GFP localization, fluorescence microscope (Keyence, BZ-9000, Osaka, Japan) was used to measure the fluorescence intensity and then the images were analyzed by Image J 1.48 software (National Institutes of Health, Bethesda, MD, USA) [ 44 ].…”

Selective Cytotoxic Effect of Dorycnium pentaphyllum Extract on Human Breast, Liver, and Lung Cancer Cells

“…(Demir et al, 2017a). In previous studies, Fabaceae family have been shown to be rich in phenolics, such as gallic acid, fumaric acid, chlorogenic acid, 4-hydroxybenzoic acid, caffeic acid, cinnamic acid, p-coumaric acid, catechin derivatives, quercetin, hesperidin, taxifolin, naringenin, myricetin, resveratrol, apigenin, and galangin (Sobeh et al, 2016;Bencherchar et al, 2017). There have been numerous reports of the selective cytotoxic effects of these phenolics on different cancer cells (Ravishankar et al, 2013;Anantharaju et al, 2016).…”