The chemical constituents and biological activities of the terrestrial Aspergillus flavipes MM2 isolated from Egyptian rice hulls are reported. Seven bioactive compounds were obtained, of which one sterol: ergosterol (1), four butyrolactones: butyrolactone I (2), aspulvinone H (3), butyrolactone-V (6) and 4,4'-diydroxypulvinone (7), along with 6-methylsalicylic acid (4) and the cyclopentenone analogue; terrien (5). Structures of the isolated compounds were deduced by intensive studies of their 1D & 2D NMR, MS data and comparison with related structures. The strain extract and the isolated compounds (1-7) were biologically studied against number of microbial strains, and brine shrimp for cytotoxicity. In this article, the taxonomical characterization of A. flavipes MM2 along with its upscale fermentation, isolation and structural assignment of the obtained bioactive metabolites, and evaluate their antimicrobial and cytotoxic activities were described.
19 August 2024 in European Journal of Clinical Microbiology & Infectious Diseases
Bacteria have their own language through which they communicate with one another like all higher organisms. So, many researchers are working hard to identify and comprehend the components of this bacterial communication, known as quorum sensing (QS). In quorum sensing, bacteria use signaling molecules called autoinducers (AIs) to exchange information. Many natural compounds and extraction techniques have been intensively studied to disrupt bacterial signaling and examine their effectiveness for bacterial pathogenesis control. Quorum sensing inhibitors can interfere with QS and block the action of AI signaling molecules. Recent research indicates that quorum sensing inhibitors (QSIs) and quorum quenching enzymes (QQEs) show great promise in reducing the pathogenicity of bacteria and inhibiting biofilm synthesis. In addition, the effectiveness of QQEs and QSIs in experimental animal models was demonstrated. These are taken into account in the development of innovative medical devices, such as dressings and catheters, to prevent bacterial infections. The present review highlights this aspect with a prospective vision for its development and application.
The anticancer activity of terretonin N (1) and butyrolactone I (2), obtained from the thermophilic fungus Aspergillus terreus TM8, was intensively studied against prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines. According to this study, both compounds showed potent cytotoxicity towards ovarian adenocarcinoma cells (SKOV3) with IC50 1.2 and 0.6 μg/mL, respectively. With respect to metastatic prostate cells (PC-3), the two compounds 1 and 2 showed a significantly promising cytotoxicity effect with IC50 of 7.4 and 4.5 μg/mL, respectively. The tested fungal metabolites showed higher rates of early and late apoptosis with little or no necrotic apoptotic pathway in all treated prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines, respectively. The results reported in this study confirmed the promising biological properties of terretonin N (1) and butyrolactone I (2) as anticancer agents via the induction of cellular apoptosis. However, further studies are needed to elucidate the molecular mechanism by which cellular apoptosis is induced in cancer cells.
Investigation of bioactive secondary metabolites from terrestrial Aspergillus oryzae sp. MMAO1 using M2 medium afforded a new diketopiperazine alkaloid, 7,9-dihydroxy-3-(1H-indol-3-ylmethyl)-8-methoxy-2,3,11,11a-tetrahydro-6H-pyrazino[1,2-b]isoquinoline-1,4-dione (1a), containing the unusual amino acid l-6,8-dihydroxy-7-methoxyphenylalanine. This was co-isolated with ditryptophenaline (2), cyclo-(Tryp,Tyr) (4), cyclo-(Pro,Val), α-cyclopiazonic acid (3), kojic acid and uridine. Re-cultivation of the fungal strain on Dox medium led to the production of bisdethio(bismethylthio)gliotoxin (5), pseurotin A (6) along with linoleic acid, α-cyclopiazonic acid (3) and kojic acid. The chemical structure of the new diketopiperazine alkaloid including the relative configuration was determined by 1D and 2D NMR spectroscopy and HR-ESI-MS spectrometry, and by comparison with the related literature. The new alkaloid (1a) showed no antimicrobial activity or cytotoxicity against brine shrimps.