1,3-Oxazin-6-one Derivatives and Bohemamine-Type Pyrrolizidine Alkaloids from a Marine-Derived Streptomyces spinoverrucosus

Abstract

Two new 1,3-oxazin-6-one derivatives (1 and 2) and six new bohemamine-type pyrrolizidine alkaloids (3–8) were isolated from the marine-derived Streptomyces spinoverrucosus strain SNB-048. Their structures including the absolute configurations were fully elucidated on the basis of spectroscopic analysis, ECD spectra, quantum chemical calculations, and chemical methods. Compounds 1 and 2 possess a γ-lactam moiety and a 1,3-oxazin-6-one system.

Marine natural products

“…SNB-048 (sand sample, Bahamian tidal at). 19 Additional research on another Bahamiancollected bacterial strain, Streptomyces spinoverrucosus SNB-032 by the same research group, yielded three new dimeric bohemamines, dibohemamines A-C 18-20 that were subsequently shown to be formed via a non-enzymatic process with formaldehyde, which was detected in the culture. 20 This mild dimerisation process was exploited to generate a series of semi-synthetic analogues for biological evaluation.…”

Expanding the chemical diversity of an endophytic fungusBulgaria inquinans, an ascomycete associated with mistletoe, through an OSMAC approach

“…43 The latter two compounds have been also reported from the marine-derived bacterium Streptomyces spinoverrucosus as spinoxazines A and B. 44 However, compared to the aforementioned natural products, the structures of 7 and 8 lack a keto function in the 1,3oxazine core, which is mostly attributed to synthetic compounds. 45,46 The trivial names bulgarixines A (7) and B (8) were assigned to these compounds.…”

The Biological and Chemical Diversity of Tetramic Acid Compounds from Marine-Derived Microorganisms

“…Palau'imide (206), with an N-acyl-4-methoxy-3-methyl-pyrrolin-2-one unit, was isolated from a marine Lyngbya sp. NIH309 collected in the Palau region and was cytotoxic to KB and LoVo cells (IC 50 = 1.4, and 0.36 µM) [156].…”

“…KORDI-3973 and displayed significant anti-angiogenesis activity [205]. Spinoxazine A (270), with a γ-lactam moiety and a 1,3-oxazin-6-one system, was obtained from marine-derived Streptomyces spinoverrucosus collected in the Bahamas and lacked bioactivity against four HTCLs and two bacterial strains [206].…”

“…Cont. Chemical structures of N-acylated tetramic acids(190)(191)(192)(193)(194)(195)(196)(197)(198)(199)(200)(201)(202)(203)(204)(205)(206)(207)(208)(209).…”