Ein bicyclischer Abkömmling von (−)-longifolen ausHelminthosporium sativum undH. victoriae

Sativene Sesquiterpenoids from the Plant Endophytic Fungus Bipolaris victoriae S27 and Their Potential as Plant-Growth Regulators

Thirteen new sativene sesquiterpenoids (1 and 3-14), one new natural product (2), and 16 known compounds (15-30) were isolated from the endophytic fungus Bipolaris victoriae S27. Their structures were elucidated by extensive spectroscopic analysis, NMR and ECD calculations, and X-ray crystal diffractions. Compound 1 represented the first example of sativene sesquiterpenoids with a 6/5/3/5-caged tetracyclic ring system. All obtained compounds were evaluated for their plant-growth regulatory activity. The results showed that 1, 3, 4, 6, 8, 11, 12, 17, 19, 26, and 27 could suppress the growth of Arabidopsis thaliana, while 2, 5, 13, 15, 18, and 25 showed promoting effects. Among them, compound 3 showed the most potent plant-growth inhibitory activity, which is obviously superior to that of the marked herbicide glyphosate.

Sesquiterpenoids and Xanthones from the Kiwifruit-Associated Fungus Bipolaris sp. and Their Anti-Pathogenic Microorganism Activity

Nine previously undescribed sesquiterpenoids, bipolarisorokins A-I (1-9); two new xanthones, bipolarithones A and B (10 and 11); two novel sativene-xanthone adducts, bipolarithones C and D (12 and 13); as well as five known compounds (14-18) were characterized from the kiwifruit-associated fungus Bipolaris sp. Their structures were elucidated by extensive spectroscopic methods, electronic circular dichroism (ECD), 13C NMR calculations, DP4+ probability analyses, and single crystal X-ray diffractions. Many compounds exhibited anti-pathogenic microorganism activity against the bacterium Pseudomonas syringae pv. actinidiae and four pathogenic microorganisms.

Synthesis of Functionally Substituted Bicyclo[4.2.1]nona-2,4-dienes and Bicyclo[4.2.1]nona-2,4,7-trienes by Cobalt(I)-catalyzed [6π + 2π] Cycloaddition of 2-Tropylcyclohexanone

The [6π + 2π] cycloaddition of 2-tropylcyclohexanone to allenes and alkynes was accomplished for the first time using the three-component catalytic system Co(acac)2(dppe)/Zn/ZnI2, thus giving previously unknown functionally substituted bicyclo[4.2.1]nona-2,4-dienes and bicyclo[4.2.1]nona-2,4,7-trienes in high yields (70-89%). The structures of the synthesized carbocycles were reliably proved using modern spectral methods and X-ray diffraction. The in vitro cytotoxic activity of the obtained bicyclo[4.2.1]nona-2,4-dienes and bicyclo[4.2.1]nona-2,4,7-trienes against the Jurkat, K562, and U937 tumor cell lines has been studied.

Bipolenins K-N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

Chemical investigation of the barley and wheat fungal pathogen Bipolaris sorokiniana BRIP10943 yielded four new sativene-type sesquiterpenoid natural products, bipolenins K-N (1-4), together with seven related known analogues (5-11), and a sesterterpenoid (12). Their structures were determined by detailed analysis of spectroscopic data, supported by TDDFT calculations and comparison with previously reported analogues. These compounds were evaluated for their phytotoxic activity against wheat seedlings and wheat seed germination. The putative biosynthetic relationships between the isolated sesquiterpenoids were also explored.

Anti-phytopathogenic sesquiterpenoid-xanthone adducts from potato endophytic fungus Bipolaris eleusines

A bioguided separation on the cultures of the potato endophytic fungus Bipolaris eleusines led to the isolation of two anti-phytopathogenic (Alternaria solani) sesquiterpenoid-xanthone adducts, namely bipolins I and J (1 and 2). Their structures were established via extensive spectroscopic analysis. Compounds 1 and 2 exhibit potent inhibitory activity against A. solani with MIC values of 8 and 16 μg mL-1, respectively.

Neuraminidase inhibitory terpenes from endophytic Cochliobolus sp

The chemical study of endophytic fungus of Cochliobolus led to the isolation of 10 terpenes (1-10), including one new compound named isocochlioquinone B (1). Their structures were elucidated on the basis of spectroscopic methods, including 2D NMR techniques. Compounds 5-7 showed significant neuraminidase inhibitory activity with IC(50) values of 0.79-1.75 μM.

Terpenes from marine-derived fungi

Terpenes from marine-derived fungi show a pronounced degree of structural diversity, and due to their interesting biological and pharmacological properties many of them have aroused interest from synthetic chemists and the pharmaceutical industry alike. The aim of this paper is to give an overview of the structural diversity of terpenes from marine-derived fungi, highlighting individual examples of chemical structures and placing them in a context of other terpenes of fungal origin. Wherever possible, information regarding the biological activity is presented.

Highly regio- and stereocontrolled formation of functionalized tricyclo[4.2.1.0(2,8)]non-3-enes

The electrophilic activations of bicyclo[4.2.1]nonatrienes by 4-isopropyl-1,2,4-triazolinedione, N-iodosuccinimide, or an epoxidation/acidic ring-opening sequence is reported. The subsequent in situ trappings by water, alcohols, or benzoic acids led to original tricyclo[4.2.1.0(2,8)]non-3-enes with high regio- and stereoselectivities. The synthetic potentiality of these synthons is illustrated by the straightforward access to a fused cyclopropane featuring six consecutive controlled stereocenters.

Rare sesquiterpenes from the algicolous fungus Drechslera dematioidea

From the inner tissue of the marine red alga Liagora viscida the fungus Drechslera dematioidea was isolated. After mass cultivation, the fungus was investigated for its secondary metabolite content, and 10 new sesquiterpenoids [isosativenetriol (1), drechslerines A (2) and B (3), 9-hydroxyhelminthosporol (5), drechslerines C-G (6-10), and sativene epoxide (12)] were isolated. Compounds 8 and 10 exhibited antiplasmodial activity against Plasmodium falciparum strains K1 and NF54. The known compounds helminthosporol (4), cis-sativenediol (11), isocochlioquinone A (14), isocochlioquinone C (15), and cochlioquinone B (16) were also isolated. All structures were elucidated using spectroscopic methods, mainly 1D and 2D NMR and MS.