Dihydrophenanthrenes and other antifungal stilbenoids from Stemona cf. pierrei

• Published in: Phytochemistry (Oxford) Vol. 65; no. 1; pp. 99 - 106
• Main Authors: Kostecki, K, Engelmeier, D, Pacher, T, Hofer, O, Vajrodaya, S, Greger, H
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier 2004
• Subjects: Alternaria citri; Antifungal Agents - chemistry; Antifungal Agents - isolation & purification; Antifungal Agents - pharmacology; antifungal properties; Biochemistry & Molecular Biology; Biological and medical sciences; Biological Assay; Botrytis cinerea; Chemical constitution; Chemical control; chemical structure; Chromatography, Thin Layer; Cladosporium herbarum; Control; Dihydrophenanthrenes; dihydrostilbenes; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungi - drug effects; Fungi - genetics; Fungi - growth & development; Gibberella avenacea; Life Sciences & Biomedicine; Magnaporthe grisea; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; phenanthrene; Phenanthrenes - chemistry; Phenanthrenes - isolation & purification; Phenanthrenes - pharmacology; Phytopathology. Animal pests. Plant and forest protection; plant extracts; Plant physiology and development; Plant Sciences; racemosol; Science & Technology; spectral analysis; stemanthrene A; stemanthrene B; stemanthrene D; stemanthrenes; Stemona; Stemona cf. pierrei; Stemona pierrei; Stemonaceae; Stemonaceae - chemistry; Stilbenes - chemistry; Stilbenes - isolation & purification; Stilbenes - pharmacology; stilbenoids; stilbostemin G; stilbostemins; stilbostemin G; stilbenoids; JAPONICA; dihydrostilbenes; dihydrophenanthrenes; stemanthrenes A-C; NATURAL-PRODUCTS; Stemona cf. pierrei; 9,10-DIHYDROPHENANTHRENES; microdilution; stemonaceae; pyrrolo[1,2-a]azepines; SYNTHASE; antifungal; stemonine; stemona alkaloids; RACEMOSA; protostemonine; bioautography; ALKALOIDS; Stemanthrenes A-C; Monocotyledones; Dihydrophenanthrenes; Antifungal; Plant pathogen; Stemonaceae; Molecular structure; Dihydrostilbenes; Pyrrolo[1,2-a]azepines; Stemonine; Fungi; Alkaloid; Cladosporium herbarum; Stemona alkaloids; Angiospermae; Fungi Imperfecti; Thallophyta; Phenanthrene derivatives; Bioassay; Protostemonine; Pesticides; Microdilution; Stilbenoids; Stilbostemin G; Biological activity; Fungicide; Stilbene derivatives; Isolation; Spermatophyta; Bioautography
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2003.09.015

Three new dihydrophenanthrenes, stemanthrenes A-C, along with the new dihydrostilbene stilbostemin G were isolated and identified from the underground parts of Stemona cf. pierrei together with the known pinosylvin, 4'-methylpinosylvin, dihydropinosylvin, stilbostemins B, D, and E as well as the pyrrolo[1,2-a]azepine alkaloids protostemonine and stemonine. The structures of all new stilbenoids, elucidated by NMR analyses, showed a common substitution pattern for aromatic ring A and characteristic C-methylations for ring B. The trivial name racemosol, previously reported for S. collinsae, was renamed to stemanthrene D due to its priority for another compound. Bioautographic tests on TLC plates with Cladosporium herbarum displayed high antifungal activity for compounds with an unsubstituted aromatic ring A, e.g. pinosylvin, but only weak effects for the higher substituted stilbostemin G and stemanthrenes A-C. Similar results were obtained by germ tube inhibition of five microfungi using 2-fold serial broth dilutions determined by a microplate reader. Because of weak inhibition and chemical instability of stemanthrenes, no EC50 and EC90 values could be calculated.