Iriflophenone-3-C-β-d Glucopyranoside from Dryopteris ramosa (Hope) C. Chr. with Promising Future as Natural Antibiotic for Gastrointestinal Tract Infections

Ethnopharmacological approaches provide clues for the search of bioactive compounds. Dryopteris ramosa (Hope) C. Chr. (plant family: Dryopteridaceae) is an ethnomedicinal plant of the Galliyat region of Pakistan. The aqueous fraction (AqF) of D. ramosa is being used by inhabitants of the Galliyat region of Pakistan to treat their gastrointestinal tract ailments, especially those caused by bacteria. The aims of the present study were as follows: (i) to justify the ethnomedicinal uses of the AqF of D. ramosa; (ii) to isolate a bioactive compound from the AqF of D. ramosa; and (iii) to evaluate the antibacterial and cytotoxic potential of the isolated compound. Column chromatography (CC) techniques were used for the isolation studies. Spectroscopic techniques (UV-Vis, MS, 1&2D NMR) were used for structural elucidation. The agar-well diffusion method was used to evaluate the antibacterial potential of i3C beta DGP against five bacterial strains, and compare it with the known antibiotic Cefixime. The brine shrimp lethality test (BSLT) was used for cytotoxic studies. The AqF of D. ramosa afforded iriflophenone-3-C-beta-D glucopyranoside (i3C beta DGP) when subjected to LH20 Sephadex, followed by MPLC silica gel(60), and purified by preparative TLC. The i3C beta DGP showed a strong potential (MIC = 31.1 +/- 7.2, 62.5 +/- 7.2, and 62.5 +/- 7.2 mu g/mL) against Klebsiella pneumoniae, Staphylococcus aureus, and Escherichia coli, respectively. On the other hand, the least antibacterial potential was shown by i3C beta DGP (MIC = 125 +/- 7.2 mu g/mL), against Bacillus subtilis, in comparison to Cefixime (MIC = 62.5 +/- 7.2 mu g/mL). The cytotoxicity of i3C beta DGP was significantly low (LD50 = 10.037 +/- 2.8 mu g/mL) against Artemia salina nauplii. This study not only justified the ethnomedicinal use of D. ramosa, but also highlighted the importance of ethnomedicinal knowledge. Further studies on AqF and other fractions of D. ramosa are in progress.

Automated summary

Ethnopharmacological approaches are valuable for identifying bioactive compounds. Dryopteris ramosa is used as an ethnomedicinal plant in Pakistan for gastrointestinal tract ailments. This study successfully isolated and evaluated a bioactive compound from D. ramosa AqF, showing strong antibacterial potential and low cytotoxicity.