ABSTRACT
A novel nucleoside phytotoxin, albucidin (1), was isolated from the culture broth of Streptomyces albus subsp. chlorinus NRRL B-24108 using bioassay directed fractionation. The structure of the new natural product, albucidin, was determined by NMR and MS; however, the compound has been reported earlier in the literature following synthetic modification of oxetanocin. This is the first report of herbicidal activity for compounds of this structural type. Albucidin shows high levels of broad spectrum activity following post-emergence applications as well as moderate levels of pre-emergence activity. Accordingly, albucidin could be an important new lead for herbicide discovery.
Subject(s)
Herbicides/isolation & purification , Nucleosides/isolation & purification , Streptomyces/chemistry , Acetylation , Chromatography, High Pressure Liquid , Culture Media , Fermentation , Herbicides/chemistry , Magnetic Resonance Spectroscopy , Nucleosides/chemistry , Nucleosides/toxicity , Plant Development , Plants/drug effects , Spectrometry, Mass, Electrospray Ionization , Streptomyces/classification , Streptomyces/ultrastructureABSTRACT
Bioactivity-directed separation of a foliage extract from the New Zealand shrub Pseudowintera axillaris led to a compound with fungicidal activity against the plant pathogen Phytophthora infestans. This was identified as a new sesquiterpene dialdehyde cinnamate named paxidal. Two 6-hydroxy derivatives were present at lower levels in the extract. A further nine derivatives were synthesized from these natural products for a structure-activity study against a range of important food crop pathogens. The cinnamate group was important for fungicidal effects, and protection of the dialdehyde as a dimethyl acetal gave more potent, broader spectrum activity.
Subject(s)
Cinnamates/analysis , Fungicides, Industrial/analysis , Pseudowintera/chemistry , Sesquiterpenes/analysis , Cinnamates/chemistry , Cinnamates/pharmacology , Fungicides, Industrial/pharmacology , Models, Molecular , New Zealand , Phytophthora/drug effects , Plant Extracts/pharmacology , Plant Leaves/chemistry , Sesquiterpenes/chemistry , Sesquiterpenes/pharmacologyABSTRACT
A new member of the tartrolone series of macrodiolides, tartrolone C (1), was isolated from a Streptomyces species on the basis of its insecticidal activity. Metacycloprodigiosin (2) and undecylprodigiosin (3) were also isolated on the same basis. The structure of all compounds was established by spectroscopic data (NMR, MS, and UV).
