Antibacterial compound from the endophytic fungus Phomopsis longicolla isolated from the tropical red seaweed Bostrychia radicans

Abstract

Endophytic fungi isolated from the red seaweed Bostrychia radicans were studied to identify their molecularly diverse and biologically active natural chemical products. According to 28S ribosomal DNA-based identification, the strain named C81 was 98% identical to Phomopsis longicolla. This strain was cultivated in solid rice medium and produced three major metabolites identified as 18-deoxycytochalasin H (1), mycophenolic acid (2), and dicerandrol C (3). The chemical structures of these compounds were elucidated by 1D and 2D nuclear magnetic resonance as well as by mass spectrometry. Dicerandrol C had significant antimicrobial activity against Staphylococcus aureus (ATCC 6538) and Staphylococcus saprophyticus (ATCC 15305), with minimum inhibitory concentrations of 1 and 2 μg ml-1(1.33 and 2.66 μm), respectively. These results show the presence of promising metabolites and indicate that these natural products should be considered in the development of new antibiotics.

Syntheses of Dimeric Tetrahydroxanthones with Varied Linkages: Investigation of “Shapeshifting” Properties

“…7 The presence of a 4,4′ linkage was established by X-ray crystallography. The corresponding 2,2′-linked dimer dicerandrol C ( 6 ) 8 and 2,4′-linked dimer phomoxanthone B ( 7 ) have also been isolated from natural sources.…”

“…For example, the 4,4′-linked compound phomoxanthone A exhibits a strong cytotoxicity to L5178Y cancer cells (IC 50 = 0.3 µM), 7c whereas the 2,2′-linked congener dicerandrol C was found to be somewhat less potent (IC 50 = 2.8 µM). 8c For the secalonic acids, previous studies indicated that the linkage may undergo facile isomerization in polar solvents. 9 A similar transformation was observed for the monomeric tetrahydroxanthone parnafungins to generate a mixture of isomers A1 ( 8 )/A2 ( 9 )/B1 ( 10 )/B2 ( 11 ) from each pure isomer at room temperature (Figure 2).…”

Polyphenol-rich fraction from Ecklonia cava (a brown alga) processing by-product reduces LPS-induced inflammation in vitro and in vivo in a zebrafish model

“…Therefore, several species of seaweeds are used in cosmetics, food, and pharmaceuticals. Many studies have shown that seaweeds have diverse bioactivities such as antioxidant, anticoagulant, anti-inflammation, antibacterial, and anticancer activities (Heo et al 2003, Shin et al 2006, Kim et al 2007, Erbert et al 2012, Ko et al 2012. In particular, Ecklonia cava is a common edible brown algae that is plentiful in Jeju Island of Republic of Korea.…”

Natural Products from Marine Invertebrates and Microorganisms in Brazil between 2004 and 2017: Still the Challenges, More Rewards

“…Compound 42 displayed antimicrobial activity against S. aureus and S. saprophyticus with IC 50 at 1.33 and 2.66 µM, respectively. 44 Cultures of Aspergillus sp. isolated from the ascidian Eudistoma vannamei provided the known polyketides (R)-mellein (43, Figure 7), penicillic acid (44, Figure 7), cis-4-hydroxymellein (45, Figure 7) and trans-4-hydroxymellein (46, Figure 7).…”