The first record of biological activities and chemical constituents of different extracts and semi-purified fractions of Bidens aurea (Aiton) Sherff (Asteraceae)

Bidens aurea is a flowering plant known for its yellow or white flowers rich with various bioactive chemical compounds that possess or have proven high medicinal values, This research aimed to investigate the in vitro antioxidant and antimicrobial abilities of individual polar extracts and semi-purified fractions of Bidens aurea. In this study, three different extracts (cold water, hot water, and ethanol) and 6 isolated fractions of ethanolic extract (as the most potent sample) were assessed for their antiradical and antioxidant properties in comparison with ascorbic acid a natural standard with 2,2-diphenyl- 1-picrylhydrazyl (DPPH^•) and 2,2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) radical scavenging assays, in addition to, GC-MS/MS identification of fractions and biochemical compounds. The findings revealed that, both methods were correlated in which the ethanolic extract showed the highest antioxidant effect with 61.71 ± 0.22 and 87.29 ± 0.56% in comparison with ascorbic acid as the natural standard (95.12 ± 0.29 and 99.32 ± 0.08%) at 1000 µg/ml against DPPH and ABTS, respectively. The fraction no. 6 (ethanol 100%) recorded the highest antioxidant activity by 90.40 ± 0.13 and 94.34 ± 0.18% at 1000 µg/ml respectively followed by fraction no. 5 (ethyl acetate: ethanol 20:80) by 82.61 ± 0.19 and 87.00 ± 0.48% at 1000 µg/ml, respectively. The antimicrobial effect revealed that the ethanolic extract of Bidens aurea was effective against all tested microorganisms with growth inhibition zones (IZ) diameters ranging from 21 to 33 mm (mm). Also, the crude ethanolic extract recorded the highest antimicrobial potential against all tested microorganisms except Bacillus cereus when compared with the extract fractions and antimicrobial standards (Fluconazole and gentamycin). The GC-MS/MS analysed of different Bidens fractions revealed the presence of various phyto-components. Totally 26 constituents were identified in Bidens aurea from all the four analysed fractions. Ethyl acetate: ethanol (60:40) fraction has a recorded the highest number of (10) phyto-constituents, while Ethyl acetate: ethanol (20:80) fraction has lower number of (3) phytoconstituents. Based on these findings, the ethanolic extract and its fractions of Biden aurea exhibit promising antioxidant, antiradical, and antimicrobial activities, suggesting their potential for further investigation in biomedical application.