Identification of two meridianins from the crude extract of the tunicate Aplidium meridianum by tandem mass spectrometry

Abstract

As part of the development of an analytical technique for the detection of meridianins and related compounds in biological fluids, a crude extract of the tunicate Aplidium meridianum was analysed using neutral loss tandem mass spectrometry. The 41 u neutral loss-EI(+) mass spectrum showed molecular ions corresponding to two previously undetected alkaloids. We report herein the isolation and structure elucidation of these alkaloids, meridianins F and G.

†Dedicated to the memory of Dr Alicia M. Seldes, Founder and Leader of the research group on Marine Natural Products at the Department of Organic Chemistry, FCEN-UBA.

Keywords:

• Meridianins
• Marine natural products
• Indole alkaloids
• Tandem mass spectrometry
• Constant neutral loss

Acknowledgments

We thank Lic. Enrique Marschoff (Instituto Antártico Argentino), Dr Daniel Nahabedian and Dr Javier Calcagno (Departamento de Ciencias Biológicas, FCEN, Universidad de Buenos Aires) for sample collection, and the scientific team and crew of the BIP Dr Holmberg for their collaboration. We are indebted to Drs Elisa Bal de Kier Joffé and Lydia Puricelli (Instituto de Oncología “Angel Roffo”, Buenos Aires) for the bioassays, and the technical assistance of Mrs Alicia Rivelli is greatly appreciated. We are also indebted to LANAIS–EMAR (CONICET–FCEN, UBA) for mass spectra and UMYMFOR (CONICET–FCEN, UBA) for NMR spectra. We thank Dr Michael Grayson (Center for Biomedical and Bioorganic Mass Spectrometry, Washington University, St Louis, Mo. USA) for additional tandem mass spectrometry experiments. L.H.F. acknowledges a research fellowship from CONICET. M.F.R.B. acknowledges a research fellowship from ANPCyT. This research was partially supported by grants from Universidad de Buenos Aires (grant X-122), CONICET and ANPCyT (PICT 98-06-03614).

Notes

†Dedicated to the memory of Dr Alicia M. Seldes, Founder and Leader of the research group on Marine Natural Products at the Department of Organic Chemistry, FCEN-UBA.