Opaliferin, a New Polyketide from Cultures of Entomopathogenic Fungus Cordyceps sp. NBRC 106954

Abstract

Opaliferin, a polyketide with a unique partial structure in which a cyclopentanone and tetrahydrofuran were connected with an external double bond, was isolated from the insect pathogenic fungus Cordyceps sp. NBRC 106954. The structure and relative configuration of opaliferin were determined by spectroscopic analysis and X-ray crystallography. The absolute configuration was established by anomalous dispersion effects in X-ray diffraction measurements on the crystal of di(p-bromobenzoyl) ester of opaliferin. A plausible biosynthetic pathway for opaliferin is proposed.

Risks of Mycotoxins from Mycoinsecticides to Humans

“…Opaliferin, a polyketide with a unique partial structure in which a cyclopentanone and tetrahydrofuran were connected with an external double bond, was isolated from the insect pathogenic fungus Cordyceps sp. NBRC 106954 [ 93 ]. However, there is no information about the risks of these PK toxins to human health.…”

Total Synthesis of Ascospiroketal A Through a AgI‐Promoted Cyclization Cascade

“…[1] The relative stereochemistry within the tricyclic core of the ascospiroketals was established from analysis of NOESY experiments and confirmed that these compounds are anomeric spiroacetals. Structurally, these compounds represent the most complex members of a small family of tricyclic 5,5-spiroacetals [2] that includes the cephalosporolides, [3] penisporolides, [4] and opaliferin, [5] for which several potentially useful biological activities have been ascribed. Thus, the relative stereochemistry of the three remote stereocenters remained undefined.…”

“…Unfortunately, no information could be obtained regarding their absolute stereochemistry, the configurational relationship between the tricyclic core and side chain, or within the side chain itself. [3][4][5] Herein we describe the first total synthesis and full stereochemical assignment of ascospiroketal A (1) [6] through a highly efficient Ag I -promoted cyclization cascade that assembles the entire tricyclic core in one step from an acyclic precursor. Structurally, these compounds represent the most complex members of a small family of tricyclic 5,5-spiroacetals [2] that includes the cephalosporolides, [3] penisporolides, [4] and opaliferin, [5] for which several potentially useful biological activities have been ascribed.…”

Three New Pigment Protein Tyrosine Phosphatases Inhibitors from the Insect Parasite Fungus Cordyceps gracilioides: Terreusinone A, Pinophilin C and Cryptosporioptide A

“…Cordyceps is a genus of ascomycete fungi that includes about 400 species, which are parasitic mainly on insects and other arthropods [ 1 ]. Cordyceps are rich sources of novel biologically active substances with diverse structural architectures [ 2 ], such as the antimalarial erythrostominones [ 3 ], antimalarial cordypyridones [ 4 ], antitrypanosomal cardinalisamides A–C [ 5 ] and opaliferi [ 6 ]. Cordyceps gracilioides Kobayasi was a new species in China and the specimen was collected on a coleopteran from the National Natural Conservation of Guniujiang, Shitai County, Anhui Province in September 2000 [ 7 ].…”