Online Analysis of Xestodecalactones A−C, Novel Bioactive Metabolites from the Fungus Penicillium cf. montanense and Their Subsequent Isolation from the Sponge Xestospongia exigua

Abstract

Fungal isolates of Penicillium cf. montanense were obtained from the marine sponge Xestospongia exiguacollected from the Bali Sea, Indonesia. Culture filtrates of the fungi yielded three novel decalactone metabolites, xestodecalactones A, B, and C (1, 2a, and 2b), consisting of 10-membered macrolides with a fused 1,3-dihydroxybenzene ring. Online HPLC-NMR, ESI-MS/MS, and -CD spectra were acquired, and the structures of the new compounds were established and confirmed on the basis of offline NMR spectroscopic ((1)H, (13)C, COSY, ROESY, (1)H-detected direct and long-range (13)C-(1)H correlations) and mass spectrometric (EIMS) data. Quantum chemical calculations of the CD spectra proved to be difficult because of the conformational flexibility of the xestodecalactones. These compounds, of which 2a and 2b, due to the additional stereocenter at C-9, are diastereomeric compounds, are structurally related to a number of biologically active metabolites found in terrestrial fungal strains. Compound 2a was found to be active against the yeast Candida albicans.

Azaphilone and Isocoumarin Derivatives from the Endophytic Fungus Penicillium sclerotiorum PSU-A13

“…The second subfraction (368.8 mg) was further purified using the same procedure as fraction C22 to afford 5 (18.5 mg). Compound 7 (2.3 mg) was obtained from fraction C23 (52.3 mg) after purification by CC over silica gel followed by PTLC with 15% EtOAc-CH 2 [12][13][14][15] Crude extracts (200 mg/ml) were preliminarily tested against all the test microorganisms by a colorimetric broth microdilution test. The crude extract stock solutions (10 mg/ml) were diluted with Mueller-Hinton broth (MHB) for bacteria and RPMI for fungi to 400 mg/ml and 50 ml of each extract solution was pipetted into 3 wells of a 96 well plate.…”

“…The genus Penicillium has the efficiency to produce bioactive substances, for instance, antimicrobial isochromophilone VI, 1) antifungal xestodecalactone B, 2) and anti-human immunodeficiency virus (HIV) atrovenetinone methyl acetal. 3) Our previous investigation on two endophytic fungi isolated from Garcinia atroviridis resulted in the isolation of an antifungal pyrone against Microsporum gypseum SH-MU-4 and an antioxidant naphthol from P. paxilli PSU-A71 4) and the xylariaceous fungus PSU-A80, 5) respectively.…”

Nuclear Magnetic Resonance Spectroscopy for Structural Characterization of Bioactive Compounds

“…[63,64] (Figure 7.24). Since then, other bioactive compounds have been isolated and characterized ( 1 H, 13 C, COSY, ROESY, and one-bond and long-range heteronuclear correlations) from fungal isolates derived from marine sponges using this online stop-flow approach [65,66].…”

Bioprospecting of the Balinese marine sponges and nudibranchs

“…Although there have been several reports on chemical studies of marine sponges and sponge-associated fungi collected from West Bali [6][7], this is an early study carried out of specimens from East Bali including Tulamben. A single specimen of sponge Aplysinella strongylata and two nudibranch extracts including Hypselodoris infucata and Glossodoris hikuerensis were investigated.…”