Investigation of in vitro Biological Activity from Extracts of Ruellia tuberosa.

<b>Background and Objective:</b> <i>Ruellia tuberosa</i> is a common plant in the Mekong Delta and is widely used in many Vietnamese folk remedies. This study was conducted to investigate the potential use of roots, stems, leaves of <i>Ruellia tuberosa</i> as antioxidant, antimicrobial, α-amylase and α-glucosidase inhibitors. <b>Materials and Methods:</b> The extracts were tested for their ability to inhibit the enzymes α-amylase and α-glucosidase associated with diabetes. The antioxidant activities of the extracts were evaluated using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2-Azino-Bis-(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS), ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC) and reducing power (RP) assays. The antibacterial activity of extracts from <i>Ruellia tuberosa</i> was evaluated by the agar well diffusion method. <b>Results:</b> The root extract of <i>Ruellia tuberosa</i> has more polyphenols (32.49±0.72 mg GAE/g extract) and flavonoids (15.48±1.32 mg QE/g extract) than the other parts. Simultaneously, the root extract of <i>Ruellia tuberosa</i> has antioxidant activity (IC₅₀ values range from 117.67±2.82 to 569.20±7.68 μg/mL), inhibiting amylase (IC₅₀ = 266.72±10.58 μg/mL) and glucosidase (IC₅₀ = 147.13±3.58 μg/mL) enzymes more effectively than the other parts. Research results also show that extracts from <i>Ruellia tuberosa</i> are capable of inhibiting <i>Staphylococcus aureus</i>, <i>Escherichia coli</i> and <i>Pseudomonas aeruginosa</i> bacteria with minimum inhibitory concentrations ranging from 1280 to 10240 mg/mL. <b>Conclusion:</b> These results highlighted the potential using of <i>Ruellia tuberosa</i> extracts as natural antioxidant, antimicrobial, α-amylase and α-glucosidase inhibitors agents.