Polyketides from the Cultured Lichen Mycobiont of a Vietnamese Pyrenula sp.

Abstract

A spore-derived mycobiont of a crustose Pyrenula sp. lichen collected in Vietnam was cultivated on a malt-yeast extract medium supplemented with 10% sucrose. Chemical investigation of the cultivated colonies led to the isolation of eight new alkylated decalin-type polyketides (1-8) along with three known compounds. The structures of these compounds were elucidated by spectroscopic and chemical means. This is the first instance of this type of polyketide being isolated from a cultured lichen mycobiont. The isolated polyketides 1 and 7 exhibited inhibitory activities against mammalian DNA polymerases α and β with IC50 values ranging from 8.1 to 19.5 μM. Compound 1 showed cytotoxic effects against the HCT116 human colon carcinoma cultured cell line with an IC50 value of 6.4 ± 0.7 μM.

Biosynthesis of Panaefluoroline B from the Cultured Mycobiont of Amygdalaria panaeola

“…In the other cases, where alanine, tyrosine, or leucine was supplemented to the agar medium, many other panaefluorolines were detected by TLC. It was thus decided to use [1,[2][3][4][5][6][7][8][9][10][11][12][13] …”

Cladobotric Acids: Metabolites from Cultures of Cladobotryum sp., Semisynthetic Analogues and Antibacterial Activity

“…lichen collected in Vietnam, which showed cytotoxic effects against HCT116 human colon carcinoma. 16 …”

Naphthoquinones From Cultured Mycobiont of Marcelaria cumingii (Mont.) and Their Cytotoxicity

“…Cultured lichen mycobionts have shown to be capable of producing diverse metabolites under stressed conditions that were not detectable in natural lichens, but are structurally related to fungal metabolites. [1][2][3] Trypetheliaceae is a family of crustose lichens with approximately 15 genera and 418 species around the world recorded. 4,5 Thailand is located in the tropical region with diverse distribution of lichens.…”

“…[13][14][15] Several mycobiont-derived onaphthoquinones were isolated; nonetheless, the absolute stereochemistry of these metabolites was not completely assigned. 3,13,14,16 Using the ascospore discharge technique, 17 M. cumingii was successfully cultured. Herein we reported the separation of the methanol extract of this cultured mycobiont ( Figure 1) resulting in the isolation of 5 naphthoquinones.…”