Bioactive Phenolics and Flavonoids, Antioxidants, Anti-Inflammatory, Enzyme-Inhibitory and Cytotoxic Activities of Aerial part of Trachyspermum roxburghianum (DC.) Craib.

Abstract

Trachyspermum roxburghianum (DC.) Craib is an edible plant found in Northern and Northeastern Thailand. This plant is used in household remedies to relieve carminative and digestive problems, hiccups, vomiting, bladder pain, etc. This study aims to assess the bioactive compounds, consisting of phenolics and flavonoids, and evaluate the biological activities of this plant. The aerial portion was macerated in EtOH1 to obtain EtOH1 crude extracts. Then, the EtOH1 was divided and separated by the solvents’ polarity to obtain Petr, EtOAc, and EtOH2 crude extracts. All crude extracts were assessed for their total phenolics and flavonoids and subsequentially evaluated for their antioxidants (using DPPH, ABTS and FRAP), enzymatic inhibitory effects (on tyrosinase and collagenase), anti-inflammatory activity (protein denaturation assay) and cytotoxicity (MTT assay). The results presented that a high amount of phenolics and flavonoids were observed in EtOH2 (56.57 mg GAE/g ext. and 22.75 mg QE/g ext.) followed by EtOAc (57.95 mg GAE/g ext. and 7.41 mg QE/g ext.), EtOH1 (47.14 mg GAE/g ext. and 4.23 mg QE/g ext.), and Petr (37.05 mg GAE/g ext. and 2.08 mg QE/g ext.), respectively. All crude extracts represented antioxidants in all assays; EtOAc presented a high level of antioxidants on ABTS (IC50 54.96 µg/mL) and DPPH (IC50 133.32 µg/mL), while EtOH2 revealed a high ability to reduce the Fe3+-TPTZ complex (155.85 Fe2+g ext.). Remarkably, for all crude extracts used for anti-collagenase enzyme activity, the percentage of inhibition ranged from 78.35 - 97.96 %. Besides, only Petr and EtOH2 showed the activity of the anti-protein denaturation (IC50 1.926 and 2.578 mg/mL). The cytotoxicity test showed that EtOH1, Petr, and EtOAc exhibited a concentration-dependent manner of inducing cell death in 24 and 48 h, while EtOH2 showed less toxicity to the cell line. This information would be valuable and pave the way for future study and application of this plant to other products. HIGHLIGHTS Trachyspermum roxburghianum (DC.) Craib from Northern Thailand High antioxidant and high anti-collagenase activities of Trachyspermum roxburghianum (DC.) Craib ethanolic extracts. GRAPHICAL ABSTRACT