Antimicrobial Cuparene-Type Sesquiterpenes, Enokipodins C and D, from a Mycelial Culture of Flammulina velutipes

Abstract

Two new cuparene-type sesquiterpenes, enokipodins C (1) and D (2), were isolated from culture medium of an edible mushroom, Flammulina velutipes, along with enokipodins A (3) and B (4). The structures of 1 and 2 were determined using spectroscopic methods (HRMS, (1)H and (13)C, and 2D NMR). The absolute configuration of enokipodin C was determined from the observed (1)H NMR chemical shifts and NOEs in NOESY experiments after conversion into the corresponding esters with the chiral reagent 2-(2'-methoxy-1'-naphthyl)-3,4-dichlorobenzoic acid. All the metabolites showed antimicrobial activity against a fungus, Cladosporium herbarum, and Gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus.

Glutathione S-Transferase, Acetylcholinesterase Inhibitory and Antibacterial Activities of Chemical Constituents of Barleria prionitis

“…Ceftriaxone (30 µg/disk) was used as positive control, and ethanol and ethyl acetate were used as negative controls. The antibacterial activity was determined by measuring the diameters of zones of inhibition around each paper disk [19]. Each experiment was performed in triplicate.…”

Enantioselective Total Synthesis of Enokipodins A–D, Antimicrobial Sesquiterpenes Produced by the Mushroom, Flammulina velutipes

“…24) The 1 H-NMR spectrum of A was exactly the same as that of an authentic sample prepared previously from natural enokipodin C by Ishikawa et al 13) to determine the absolute configuration of 1b. 1 H-and 13 C-NMR) for 1b and 2b were identical with those of natural enokipodins C and D, respectively.…”

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“…Four sesquiterpenes with antimicrobial activity were described. The enokipodins A, B, C, and D (4a-d), isolated from the mycelium of Flammulina velutipes, with activity against Bacillus subtilis, but only enokipodins A and C showed activity against Staphylococcus aureus [58]. Oxalic acid (3), an organic acid, isolated from the mycelium of Lentinus edodes, showed activity against Bacillus cereus, Staphylococcus aureus, and Streptococcus faecalis [59].…”