Profiling of Biologically Active Metabolites of Spergula fallax L. Using High-resolution UPLC-QTOF-MS

Medicinal plants are recognized to have a wide range of important biological activities, Spergula fallax L. is a well-known plant while phytochemical and biological activities screening of the species are rare.

This study aims to evaluate the antioxidant, anticáncer, antimicrobial, and antiviral activities of the methanol extract (ME) of the aerial parts of Spergula fallax L. and its successive fractions; n-hexane (HF), ethyl acetate (EAF), and n-butanol (BF) fractions and identify their biologically active metabolites.

Ultra-performance liquid chromatography (UPLC) coupled to quadrupole high-resolution time-of-flight mass spectrometry (QTOF-MS) was utilized to establish the metabolic profile of Sergula fallax L. Total phenol and flavonoids content were determined colorimetrically using Folin Ciocalteu and aluminum chloride reagents, respectively. 1,2-diphenyl-1-picrylhydrazyl (DPPH) was utilized for estimation of antioxidant activity, cytotoxic activity was determined on Hep-G2, HCT- 116, and MCF-7 cell lines, and agar diffusion method was used for screening of antimicrobial activity while cytopathic effect inhibition assay was utilized for antiviral assay.

Twenty-eight metabolites were identified, flavonoids were predominated (26), it was characterized by the presence of four main aglycones (Apigenin, luteolin, quercetin and kaempferol) with their O and/or C-glycosides based on its MS fragments. ME and EAF significantly scavenged DPPH in a dose-dependent manner with IC₅₀ 16.99 and 18.74 μg.mL^-1, respectively. Among the tested samples, only ME and EAF showed significant cytotoxic activity against the tested cell lines with IC₅₀ ranging from 5.541- 9.509 μg.mL^-1. All tested samples significantly inhibited the growth of the tested bacterial strains with inhibition zone diameters ranging from 11.2- 26.4 mm and showed a wide range of antiviral activity.

Generally, S. fallax is potentially bioactive as evident by antioxidant, cytotoxic, antibacterial, and antiviral assays. These activities are correlated with its identified metabolites. The results proved that S. fallax has promising medicinal activities and would be examined in future clinical trials for herbal therapy.