Antioxidant Activity of an Aqueous Leaf Extract from Uncaria tomentosa and Its Major Alkaloids Mitraphylline and Isomitraphylline in Caenorhabditis elegans

Abstract

Uncaria tomentosa (Rubiaceae) has a recognized therapeutic potential against various diseases associated with oxidative stress. The aim of this research was to evaluate the antioxidant potential of an aqueous leaf extract (ALE) from U. tomentosa, and its major alkaloids mitraphylline and isomitraphylline. The antioxidant activity of ALE was investigated in vitro using standard assays (DPPH, ABTS and FRAP), while the in vivo activity and mode of action were studied using Caenorhabditis elegans as a model organism. The purified alkaloids did not exhibit antioxidant effects in vivo. ALE reduced the accumulation of reactive oxygen species (ROS) in wild-type worms, and was able to rescue the worms from a lethal dose of the pro-oxidant juglone. The ALE treatment led to a decreased expression of the oxidative stress response related genes sod-3, gst-4, and hsp-16.2. The treatment of mutant worms lacking the DAF-16 transcription factor with ALE resulted in a significant reduction of ROS levels. Contrarily, the extract had a pro-oxidant effect in the worms lacking the SKN-1 transcription factor. Our results suggest that the antioxidant activity of ALE in C. elegans is independent of its alkaloid content, and that SKN-1 is required for ALE-mediated stress resistance.

Characterization and Antioxidant Activity Determination of Neutral and Acidic Polysaccharides from Panax Ginseng C. A. Meyer

“…ROS production assay was performed based on the previously reported method [50,51]. After exposure to polysaccharides, approximately 1,000 worms were transferred to a transparent bottom black 96-well plate (Thermo Fisher Scientific, Rochester, NY, USA).…”

Uncaria tomentosa (Willd. ex Schult.) DC.: A Review on Chemical Constituents and Biological Activities

“…List of some of POA and TOA alkaloids along with their structures and biological activities are provided in Table 1. Mitraphyllin e C21H24N2O4 Anti-inflammatory, antioxidant activities [54,55] Isomitraphyl line C21H24N2O4 Antioxidant activity [55] Pteropodine C21H24N2O4 Immunomodulating properties [48] Isopteropodi ne C21H24N2O4 Antimicrobial activity [37] Tetracyclic oxindole alkaloid (TOA)…”

Two New Apotirucallane-Type Triterpenoids from the Pericarp of Toona sinensis and Their Ability to Reduce Oxidative Stress in Rat Glomerular Mesangial Cells Cultured under High-Glucose Conditions

“…In Vitro Antioxidant Activity of SOD, MDA, and ROS 3.6.1. SOD Superoxide dismutase is an important antioxidant enzyme defense in all organisms [30]. SOD levels were detected by Nanjing Jiancheng Bioengineering Institute assay kit.…”

“…SOD levels were detected by Nanjing Jiancheng Bioengineering Institute assay kit. GMCs were cultured in a 6-well plate at 3 × 10 5 cells/well and exposed to the compounds (10,30, and 50 µM) for 48 h. Absorbance was recorded at 450 nm using microplate reader. SOD activity is expressed as (U/mL), where each unit represents the amount of enzyme.…”

“…MDA was detected by Nanjing Jiancheng Bioengineering Institute assay kit [31,32]. GMCs were cultured in a 6-well plate at 3 × 10 5 cells/mL and exposed to the compounds (10,30, and 50 µM) for 48 h. Absorbance was recorded at 532 nm using microplate reader.…”