Background: Anethum sowa L. is widely used as an important spice and traditional medicinal plants to treat various ailments. On the basis of scientific ethnobotanical information, this study was undertaken to evaluate the antioxidant, antimicrobial and cytotoxic activity of the crude extracts of Anethum sowa L. roots as well as to identify the classes of phytochemicals by chemical tests.
Methods: The antioxidant potential of the extracts was ascertained with the stable organic free radical (2, 2-diphenyl-1-picryl-hydrazyl). The agar well diffusion method was used to determine the susceptibility of bacterial and fungal strains of the crude extracts. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) were determined by the microdilution test. Cytotoxic activities were screened using brine shrimps (Artemia salina) lethality assay. Finally, phytochemicals were profiled using standard procedures.
Results: A preliminary phytochemical screening of the different crude extracts by methanol, ethyl acetate and chloroform showed the presence of secondary metabolites such as flavonoids, alkaloids, saponin, cardiac glycosides and tannins while cyanogenetic glycosides were not detected. The methanol, ethyl acetate and chloroform extracts displayed high antioxidant activity (IC50 = 13.08 ± 0.03, 33.48 ± 0.16 and 36.42 ± 0.41 μg/mL, respectively) in the DPPH assay comparable to that of the standard ascorbic acid and BHT (IC50 = 3.74 ± 0.05 and 11.84 ± 0.29 μg/mL). The cytotoxic activity of the crude ethyl acetate and chloroform extracts possessed excellent activity (LC50 = 5.03 ± 0.08, 5.23 ± 0.11 and 17.22 ± 0.14 μg/mL, respectively) against brine shrimp larvae after 24 h of treatment and compared with standard vincristine sulphate (LC50 = 0.46 ± 0.05 μg/mL). The extracts also showed good antimicrobial activity against both Gram-positive and Gram-negative bacteria when compared with two standard antibiotics ciprofloxacin and tetracycline.
Conclusion: These results showed that the Anethum sowa root extracts are the important source of the antioxidant, antimicrobial and cytotoxic agent. So, further research is necessary to isolate and characterize of different phytoconstituents for pharmaceutical drug lead molecules and also to verify its traditional uses.
Keywords: Anethum sowa L; Antioxidant; Cytotoxicity; Gram-negative bacteria; Gram-positive bacteria; Phytochemical screening.