Antioxidant, Cytotoxic, Thrombolytic and Antimicrobial Activity of Zanthoxylum rhetsa Root Bark with Two Isolated Quinolone Alkaloids

The background of this study was to investigate the antioxidant, cytotoxic, thrombolytic and antimicrobial activity of the petroleum ether (PE), carbon tetrachloride (CTC), chloroform (CF) and aqueous (AQ) soluble fractions of crude methanolic Zanthoxylum rhetsa root bark with two isolated quinolone alkaloids, 8-methoxy-n-methylflindersine (1) and zanthodioline (2). Structures were characterized by 1D NMR analyses. Antioxidant activity was assessed by using DPPH assay and antimicrobial activity was screened by disc diffusion method. An in vitro thrombolytic model was used to evaluate the clot lysis effect of different extracts of root bark of Z. rhetsa along with streptokinase as a positive control and distilled water as a negative control and the cytotoxic activity of different extracts of Z. rhetsa root bark was evaluated by Brine Shrimp Lethality Bioassay. AQ fraction exhibited strongest antioxidant, cytotoxic and thrombolytic activity among four fractions. The CTC and CF soluble fractions exhibited significant antioxidant, cytotoxic and thrombolytic activity. CTC and AQ fractions gave highest anti-bacterial activity against Vibrio cholera and Klebsiella pneumonia respectively. Compound 1 showed significant activity at a concentration of 100 μgm/disc against Sarcina lutea, Staphylococcus aureus and Salmonella paratyphi-A, Shigella dysenteriae, Shigella boydii and Shigella sonnei with high antioxidant activity. The antioxidant, thrombolytic and antimicrobial activity of 8-methoxy-n-methylflindersine and zanthodioline are the first record from root bark of this plant.