The structures of the novel 10-membered lactones, named decarestrictines A^A2(1/2), B (3), Ci/C2 (5/6) and D (7), are presented. The structures of these secondary metabolites, isolated from different Penicillium species, were established by spectroscopic analysis and confirmed by X-ray analysis of 7 and a derivative of 3 leading to the stereochemical information. The decarestrictines vary in the oxygenation pattern between C-3 and C-7 and show structural similarities to known lactones from other fungi.
In the course of our chemical screening program we detected a new naphthoquinone complex containing the naphthgeranines and the naphtherythrines2) produced by Streptomyces sp. (strain Tu 3556). This paper deals with the purification, structural elucidation and biological properties of the naphthgeranines A to E, which are similar to the recently described naphterpin3).After isolation from a soil sample collected in Nepal, the strain Tii 3556 was cultivated in 500ml flasks of 10liter fermenters at 27°C for 96hours or 120 hours using mannitol 2% and soybean meal 2% as a culture medium.Metabolites from the culture filtrate were adsorbed on Amberlite XAD-16 before being eluted with methanol from the resin. The mycelium was extracted with methanol. The combined solutions were concentrated under reduced pressure and the aqueous residues extracted with ethyl acetate. The isolation of the naphthgeranines from the resulting raw product was successful by using a silica gel column (flash chromatography) developed with a chloroform-methanol gradient of increasing polarity: Naphthgeranines A (95 : 5), B (9: 1), E (8 :2), C and D (7: 3). Further purification steps were carried out using silica gel (naphthgeranines A and B: chloroform-methanol (95 : 5 and 9 : 1, respectively), naphthgeranine C: chloroform -
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