Bivalent Metal-Chelating Properties of Harzianic Acid Produced by <i>Trichoderma pleuroticola</i> Associated to the Gastropod <i>Melarhaphe neritoides</i>
Gaetano De Tommaso,
Maria Michela Salvatore,
Rosario Nicoletti,
Marina DellaGreca,
Francesco Vinale,
Assunta Bottiglieri,
Alessia Staropoli,
Francesco Salvatore,
Matteo Lorito,
Mauro Iuliano,
Anna Andolfi
Affiliations
Gaetano De Tommaso
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
Maria Michela Salvatore
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
Rosario Nicoletti
Council for Agricultural Research and Economics, Research Centre for Olive, Fruit and Citrus Crops, 81100 Caserta, Italy
Marina DellaGreca
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
Francesco Vinale
Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 Naples, Italy
Assunta Bottiglieri
Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
Alessia Staropoli
Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
Francesco Salvatore
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
Matteo Lorito
Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
Mauro Iuliano
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
Anna Andolfi
Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
Harzianic acid is a secondary metabolite of Trichoderma, structurally belonging to the dienyltetramic acid subgroup of the tetramic acids. Biological activities of harzianic acid are of great interest for its antimicrobial and plant growth-promoting activities, which might be related to its chelating properties. In the present work harzianic acid, isolated from cultures of a strain of Trichoderma pleuroticola associated to the gastropod Melarhaphe neritoides, was studied as a complexant agent of a number of biologically relevant transition metals (i.e., Zn2+, Fe2+, Cu2+, and Mn2+), using UV-VIS, potentiometry, MS and NMR techniques. Our findings show the coordination capacity of harzianic acid toward the above cations through the formation of neutral or charged complexes in a variable ratio depending on the metal and pH conditions.