Oleanane saponins from Bellis sylvestris Cyr. and evaluation of their phytotoxicity on Aegilops geniculata Roth

Six oleanane saponins were isolated for the first time from leaves of Bellis sylvestris Cyr., the southern daisy. Their structures were established by the extensive use of 2D-NMR experiments, including COSY, TOCSY, NOESY, HSQC, HMBC, CIGAR, H2BC, and HSQC-TOCSY, along with Q-TOF HRMS2 analysis. All of the compounds are constituted by bayogenin as aglycone, and characterized by the presence of an oligosaccharide moiety, consisting of two to four sugar unities esterified at the C-28 carboxyl carbon. One of the isolated compounds is a bisdesmoside containing an additional sugar moiety at the C-3 carbon. The phytotoxic activity assayed against Aegilops geniculata Roth., a coexisting test species, has been evaluated revealing that all the compounds, at the highest concentrations, showed strong phytotoxicity against the leaf development. (c) 2012 Elsevier Ltd. All rights reserved.