https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Chemistry and Biology of Mycotoxins and Related Fungal Metabolites

Many fungi, lichens, and bacteria produce xanthones (derivatives of 9H-xanthen-9-one, “xanthone” from the Greek “xanthos”, for “yellow”) as secondary metabolites. Xanthones are typically polysubstituted and occur as either fully aromatized, dihydro-, tetrahydro-, or, more rarely, hexahydro-derivatives. This family of compounds appeals to medicinal chemists because of their pronounced biological activity within a notably broad spectrum of disease states, a result of their interaction with a correspondingly diverse range of target biomolecules. This has led to the description of xanthones as “privileged structures”.(1) Historically, the total synthesis of the natural products has mostly been limited to fully aromatized targets. Syntheses of the more challenging partially saturated xanthones have less frequently been reported, although the development in recent times of novel and reliable methods for the construction of the (polysubstituted) unsaturated xanthone core holds promise for future endeavors. In particular, the fascinating structural and biological properties of xanthone dimers and heterodimers may excite the synthetic or natural product chemist.

Xanthones from Fungi, Lichens, and Bacteria: The Natural Products and Their Synthesis

Xanthones from fungi, lichens, and bacteria : the natural products and their synthesis

This review describes examples of naturally occurring bioactive compounds obtained from fungal endophytes from various host plants The main topics addressed are sources, identification, biological

https://journals.sagepub.com/doi/pdf/10.1177/1934578X0900401114

Chemical and functional diversity of natural products from plant associated endophytic fungi.

Blennolides A-G (2-8), seven unusual chromanones, were isolated together with secalonic acid B (1) from Blennoria sp., an endophytic fungus from Carpobrotus edulis. This is the first reported isolation of the blennolides 2 and 3 (hemisecalonic acids B and E), the existence of which as the monomeric units of the dimeric secalonic acids had long been postulated. A compound of the proposed structure 4 (beta-diversonolic ester) will need to be revised, as its reported data do not fit those of the established structure of blennolide C (4). Other monomers, the blennolides D-F (5-7) seem to be derived from blennolides A (2) and B (3) by rearrangement of the hydroaromatic ring. The heterodimer 8, composed of the monomeric blennolide A (2) and the rearranged 11-dehydroxy derivative of blennolide E (6), extends the ergochrome family with an ergoxanthin type of skeleton. The structures of the new compounds were elucidated by detailed spectroscopic analysis and further confirmed by an X-ray diffraction study of a single crystal of 2. The absolute configurations were determined by TDDFT calculations of CD spectra, including the solid-state CD/TDDFT approach. Preliminary studies showed strong antifungal and antibacterial activities of these compounds against Microbotryum violaceum and Bacillus megaterium, respectively. They were also active against the alga Chlorella fusca and the bacterium Escherichia coli.

New Mono‐ and Dimeric Members of the Secalonic Acid Family: Blennolides A–G Isolated from the Fungus Blennoria sp.

Massarilactones E-G, new metabolites from the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima.

In addition to the known triclinic modification of the title compound, an ortho­rhom­bic modification is now described. In the crystal packing of the title compound, C10H10O3, the mol­ecules are linked via inter­molecular C–H⋯O hydrogen bonds into infinite chains which extend in the [100] direction and are stacked along [001].

Zia‐Ullah

Papers

New Mono‐ and Dimeric Members of the Secalonic Acid Family: Blennolides A–G Isolated from the Fungus Blennoria sp.

Massarilactones E-G, new metabolites from the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima.

An orthorhombic modification of (R)-(−)-8-hydroxy-3-methyl-3,4-dihydro-1H-2-benzopyran-1-one [(R)-(−)-mellein]

Zia‐Ullah

Papers

New Mono‐ and Dimeric Members of the Secalonic Acid Family: Blennolides A–G Isolated from the Fungus Blennoria sp.

Massarilactones E-G, new metabolites from the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima.

An ortho­rhom­bic modification of (R)-(−)-8-hydr­oxy-3-methyl-3,4-dihydro-1H-2-benzopyran-1-one [(R)-(−)-mellein]

An orthorhombic modification of (R)-(−)-8-hydroxy-3-methyl-3,4-dihydro-1H-2-benzopyran-1-one [(R)-(−)-mellein]