Quinolizidines alkaloids: Petrosin and xestospongins from the sponge
KEISHAM SARJIT SINGHa,*, BABULAL DASb and CHANDRAKANT G NAIKa
aBioorganic Chemistry Laboratory, National Institute of Oceanography (CSIR), Goa 403 004, India
bDepartment of Chemistry, Indian Institute of Technology (IIT), Guwahati 781 039, India
MS received 10 May 2010; revised 27 April 2011; accepted 13 June 2011
Abstract. A bisquinolizidine alkaloid, petrosin (1) and a series of bis-1-oxaquinolizidine, xestospongins
(2–9), were obtained from the ethyl acetate extract of the sponge Oceanapia sp. Petrosin was obtained along
with xestospongin- C, D, E, F, G, H, I and J having di-hetroatom rings, from the ethyl acetate extract of the
sponge. The compounds exhibited moderate to high activities against some microorganisms and clinical isolates.
The structures of the alkaloids were elucidated by NMR and ESIMS spectroscopic data. The structure of
petrosin was confirmed by an X-ray diffraction study.
Graphical Abstract. Bisquinolizidine alkaloids, petrosin (1) and a series of bis-1-oxaquinolizidine
alkaloids, xestospongins (2–9), have been obtained from the ethyl acetate
extract of the marine sponge Oceanapia sp. collected from the southern coast
of India. The structures of the compounds were determined by NMR and
mass spectroscopic data. The structure of petrosin was confirmed by X-ray
Keywords. Alkaloid; bisquinolizidine; Oceanapia; sponge; crystallography.