Phytochemical analyses and bioactivities of various solvents extracts of Onychium japonicum (Thunb.) Kunze and its greenly synthesized silver nanoparticles

Bacterial resistance to antibacterial drugs has become a major health problem globally, thus natural products can be used as additional drugs to solve this problem. Hence, the present study is performed to examine bioactive chemicals, the antibacterial and anticancer activity of various solvent extracts and the antibacterial potential of greenly synthesized silver nanoparticles (AgNPs) of O. japonicum. The analysis of the data shows that different phytochemicals like phenols, coumarins, carotenoids, phlobatanins, terpenoids, saponins, glycosides, tannins, alkaloids, and flavonoids were present in O. japonicum. Higher quantities of phenols, sugar, and ascorbic acid were observed, while lower quantities of flavonoids, anthocyanins and proline were examined during spectrophotometry. Greenly synthesized nanoparticles show higher antibacterial activity against all selected bacterial strains. AgNPs show UV–vis absorbance peak at 428 nm, which indicates the synthesis of AgNPs. Face centered cubic structure of AgNPs was represented by three major sharp XRD peaks. Various peaks were observed at 3358, 2910, 1670, 1585, 1278, 1117, 1040, 803, 680 cm⁻¹ during FTIR analysis, pointing out the stretching vibrations of C-H, O-H, C[dbnd]O, C-O, C[dbnd]O, C-O, aromatic C-H and C-X bonds. According to SEM analysis, the synthesized AgNPs have an oval shape and the average size of AgNPs was calculated at 62 nm. The EDS graph also shows the presence of a single sharp peak indicating the presence of reduced AgNPs. All the organic solvent extracts of O. japonicum show prominent activity against S. aureus (N-hexane = 20.33 mm, chloroform = 16.66 mm, ethyl acetate = 15 mm, methyl alcohol = 14 mm) and K. pneumonia (N-hexane = 16.66 mm, chloroform = 14.33 mm), while lower inhibitory zones were observed against E. coli and P. aeruginosa. Cell proliferation assay, IC₅₀ analyses reveal that at a concentration of 1000 µg plant ethanolic extract was highly active against SGC and AGS cell lines. We concluded based on present results that O. japonicum has plenty of vital chemicals and could be used as a complement to conventionally be used antibiotics.