Isolation, chemical characterisation and biological activity ofacylphloroglucinols from petroleum ether extract of Hypericum barbatumJacq. 1775

Abstract

Within this doctoral thesis, eighteen new compounds, polycyclic polyprenylated acylphloroglucinols, were isolated from petrol ether extract of Hypericum barbatum plant. The compounds are named hyperibarbins A–R. For hyperibarbins A–D, cytotoxicity towards carcinogenic cells and antibacterial activity were evaluated. All four compounds exhibited intermediate activity towards tumor cells in vitro. Although inactive towards Gram negative bacteria, examined compounds have expressed extraordinary bacteriostatic activity towards Gram positive bacterial strains. Hyperibarbins C, E, N and K were, since having endoperoxide bridge in their structures, tested for antiprotozoal activity, but shown intermediate activity towards the examined parasite strains. All goals set for this doctoral thesis at the beginning have been fully met, with isolation of new compounds, described andcompletely chemically characterized for the first time.

U okviru ove doktorske disertacije izolovano je osamnaest novih jedinjenja, policikličnih poliprenilovanih acilfloroglucinola, iz petroletarskog ekstrakta biljke Hypericum barbatum. Imena jedinjenja su hiperibarbini A–R. Za hiperibarbine A–D, ispitana je citotoksičnost prema kancerogenim ćelijama i antibakterijska aktivnost. Sva četiri jedinjenja su ispoljila srednju aktivnost prema tumorskim ćelijama in vitro. Iako neaktivni prema Gram negativnim bakterijama, ispitana jedinjenja su ispoljila izuzetnu bakteriostatsku aktivnost prema sojevima Gram pozitivnih bakterija. Hiperibarbini C, E, N i K su, zbog posedovanja endoperoksidnog prstena u svojoj strukturi, testirana na antiprotozoalnu aktivnost, ali su pokazali srednju aktivnost prema ispitanim sojevima parazita. Svi ciljevi postavljeni na početku izrade ove doktorske disertacije su do kraja ispunjeni, sa izolacijom novih, prvi put opisanih i u potpunosti hemijski okarakterisanih jedinjenja.