Phytochemical analysis and in vitro antibacterial screening of a bryophyte Pogonatum microstomum (R. Br. ex Schwägr.) Brid. extract against some pathogenic bacteria

Abstract Mosses, liverworts, and hornworts, collectively known as bryophytes, represent a significant group of plants, boasting around 28,000 species globally. Despite their abundance, the chemical composition of bryophytes remains largely unexplored, with existing research fragmented. These plants are believed to be a rich source of novel, secondary compounds, many exhibiting promising biological activity. This study aimed to analyze the phytochemical content of the moss Pogonatum microstomum (R. Br. ex Schwägr.) Brid. using various solvents (petroleum ether, ethanol, methanol, and water) and to assess its antibacterial properties against seven pathogenic bacteria. Preliminary analysis revealed the presence of a diverse range of phytochemicals, including flavonoids, glycosides, triterpenoids, phenols, steroids, coumarins, and tannins. The different solvent extracts displayed varying degrees of antibacterial activity against the tested bacteria, comparable to synthetic antibiotics. Notably, petroleum ether extracts exhibited the strongest antibacterial potential. In conclusion, extracts from P. microstomum show promise as antibacterial agents, particularly against P. aeruginosa, although the effectiveness depends on the solvent used and the specific plant part. V. cholerae and S. dysenteriae were resistant to all tested extracts. Interestingly, extracts from the capsule of the bryophyte showed superior antibacterial activity compared to leaf and rhizoid extracts, suggesting that the capsule could be a novel and valuable natural source of antimicrobial compounds. This is the first time the capsule of bryophytes is recognized for their potential as effective antimicrobial agents.