Secondary metabolites of Phlebopus species from Northern Thailand

Abstract

Submerged cultures of the edible mushrooms Phlebopus portentosus and Phlebopus spongiosus were screened for their secondary metabolites by HPLC-UV/Vis and HR-LC-ESI-MS. Two new compounds, 9′-hydroxyphenyl pulvinone (1), containing an unusual pulvinone structure, and phlebopyron (2), together with the seven known pigments, atromentic acid (3), xerocomic acid (4), variegatic acid (5), methyl atromentate (6), methyl isoxerocomate (7), methyl variegatate (8), and variegatorubin (9) were isolated from the cultures. Their structures were assigned on the basis of extensive 1D/2D NMR spectroscopic analyses, as well as HR-ESI-MS, and HR-ESI-MS/MS measurements. Furthermore, the isolated compounds were evaluated for their antimicrobial and cytotoxic properties. 9′-hydroxyphenyl pulvinone (1), xerocomic acid (4), and methyl variegatate (8) exhibited weak to moderate cytotoxic activities against several tumor cell lines. The present paper provides a comprehensive characterization of pigments from the class of pulvinic acids that are present in the basidiomes of many edible bolete species.

Pulvinic Acid Derivative Pigments in Lanmaoa asiatica and L. macrocarpa

“…Seven pigments have been detected in these species including atromentic acid, xerocomic acid, variegatic acid, methyl atromentate, methyl isoxerocomate, methyl variegatate and variegatorubin. Under different culture conditions, production of xerocomic acid and variegatic acid are abundant and stable in the pure cultures of the two mushrooms [18] . The bluing reaction in these non‐Boletaceae species are also due to the hydroxylated pulvinic acid derivatives, and in addition there are three more compounds of their methylated derivatives which have not been reported in the Boletaceae.…”

“…Xerocomic acid and isoxerocomic acid also have the same theoretical molecular mass, but only trace amount of (iso)xerocomic acid(s) was detected, deterring further purification and characterization. In previous studies, xerocomic acid always coexists with variegatic acid in a given species; [15,17–19] isoxerocomic acid is the precursor of xerocomorubin, and they are reported to coexist [20] . Based on the above results, we determined that the bluing‐reaction‐related pigments contained in L. asiatica and L. macrocarpa were atromentic acid, xerocomic acid (and/or isoxerocomic acid), variegatic acid, xerocomorubin, and variegatorubin.…”

“…Under different culture conditions, production of xerocomic acid and variegatic acid are abundant and stable in the pure cultures of the two mushrooms. [18] The bluing reaction in these non-Boletaceae species are also due to the hydroxylated pulvinic acid derivatives, and in addition there are three more compounds of their methylated derivatives which have not been reported in the Boletaceae. "Cyanescent Gyroporus" refers to several species of Gyroporaceae previously lumped together as G. cyanescens with bluing reactions caused by the oxidation of gyrocyanin to a blue cyclopentane derivative.…”

Cultivation of Edible Tropical Bolete, Phlebopus spongiosus, in Thailand and Yield Improvement by High-Voltage Pulsed Stimulation

“…The tropical bolete known as Phlebopus spongiosus is an edible ECM mushroom that is indigenous to northern Thailand and southern Vietnam [14][15][16][17]. This bolete is a highly priced crop (5 to 10 USD/kg) in northern Thailand.…”