Publications by authors named "Kavita Ragini"

4 Publications

  • Page 1 of 1

Bisindole Alkaloids from a New Zealand Deep-Sea Marine Sponge .

Mar Drugs 2019 Dec 4;17(12). Epub 2019 Dec 4.

Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia.

Chemical investigation of the secondary metabolites of a rare New Zealand deep-sea sponge, , resulted in the isolation of twenty-one indole alkaloids, including two new bisindoles-()-coscinamide D (), ()-coscinamide D ()-and four compounds isolated for the first time as natural products-lamellomorphamides A (), B (), C () and D (). In addition, fifteen previously reported natural products were isolated, seven of which are seco analogs of hamacanthin alkaloids. The one sponge produces enantiomerically pure but opposite configurations of compounds that only differ in the number of bromines, suggesting enantiodivergent biosynthesis. In addition, four compounds were isolated as partial racemates, suggesting these compounds are biosynthesized via two independent routes.
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http://dx.doi.org/10.3390/md17120683DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950519PMC
December 2019

Crellasterones A and B: A-Norsterol Derivatives from the New Caledonian Sponge Crella incrustans.

Mar Drugs 2017 Jun 15;15(6). Epub 2017 Jun 15.

Department of Chemistry & Biomolecular Sciences, Macquarie University, Sydney NSW 2109, Australia.

Two new steroids, crellasterones A () and B (), together with the previously reported compound chalinasterol () and several nucleosides (-), were isolated from the sponge , collected in New Caledonia. The structures of the new compounds were established by extensive NMR and mass spectroscopic analysis and revealed unprecedented marine natural products with a ring-contracted A-norsterone nucleus and 2-hydroxycyclopentenone chromophore. The absolute configurations were derived from electronic circular dichroism (ECD) measurements in conjunction with high-level density functional theory (DFT) calculations.
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http://dx.doi.org/10.3390/md15060177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484127PMC
June 2017

Enantiodivergence in the Biosynthesis of Bromotyrosine Alkaloids from Sponges?

J Nat Prod 2017 01 13;80(1):215-219. Epub 2017 Jan 13.

Department of Chemistry and Biomolecular Sciences, Macquarie University , Sydney, NSW 2109, Australia.

The isolation of bromotyrosine alkaloids, some of which are enantiomers of previously isolated compounds, has highlighted a possible enantiodivergence in their biosynthesis. Two new (1, 2) and six known bromotyrosine alkaloids (4-9), and the enantiomer (10) of a known compound, have been isolated from a Western Australian marine sponge, Pseudoceratina cf. verrucosa. The compounds inhibited the growth of multidrug-resistant and methicillin-resistant Staphylococcus aureus with comparable activity to vancomycin. In addition, one possible artifact of extraction (3) containing an ethoxy group was isolated. From analysis of the known bromotyrosine alkaloids, a biogenesis is proposed that explains the formation of antipodal natural products within this family of sponges.
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http://dx.doi.org/10.1021/acs.jnatprod.6b01038DOI Listing
January 2017

Investigations of the marine flora and fauna of the Fiji Islands.

Nat Prod Rep 2012 Dec 14;29(12):1424-62. Epub 2012 Sep 14.

Centre for Drug Discovery and Conservation, Institute of Applied Sciences, The University of the South Pacific, Suva, Fiji.

Over the past 30 years, approximately 140 papers have been published on marine natural products chemistry and related research from the Fiji Islands. These came about from studies starting in the early 1980s by the research groups of Crews at the University of California Santa Cruz, Ireland at the University of Utah, Gerwick from the Scripps Institution of Oceanography, the University of California at San Diego and the more recent groups of Hay at the Georgia Institute of Technology (GIT) and Jaspars from the University of Aberdeen. This review covers both known and novel marine-derived natural products and their biological activities. The marine organisms reviewed include invertebrates, plants and microorganisms, highlighting the vast structural diversity of compounds isolated from these organisms. Increasingly during this period, natural products chemists at the University of the South Pacific have been partners in this research, leading in 2006 to the development of a Centre for Drug Discovery and Conservation (CDDC).
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http://dx.doi.org/10.1039/c2np20055dDOI Listing
December 2012
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