Purpureone, an antileishmanial ergochrome from the endophytic fungus Purpureocillium lilacinum

Abstract

The ethyl acetate extracts prepared from the mycelia of three endophytic fungi Purpureocillium lilacinum, Aspergillus sp., and Fusarium sp., isolated from the roots of Rauvolfia macrophylla (Apocynaceae) were screened for their antiprotozoal activity in vitro against Plasmodium falciparum (NF54), Leishmania donovani, Trypanosoma brucei rhodesiense, and Trypanosoma cruzi. Amongst these extracts, the one from P. lilacinum showed potent antileishmanial activity against L. donovani (IC50 value of 0.174 μg mL−1) with good selectivity (SI=94.9) toward the L6 cell line, whereas the other extracts were inactive and not selective. The fractionation and purification of the active extract from P. lilacinum by column chromatography over silica gel yielded a new ergochromone derivative (1), together with six known compounds: (22E,24R)-stigmasta-5,7,22-trien-3-β-ol (2), (22E,24R)-stigmasta-4,6,8(14),22-tetraen-3-one (3), emodin (4), chrysophanol (5), aloe-emodin (6), and palmitic acid, whose structures were elucidated spectroscopically. Compound 1 was tested in vitro for its antiparasitic activities against the above listed parasites and for its antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Escherichia coli, Providencia stuartii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The compound displayed potent antileishmanial activity against L. donovani with an IC50 value of 0.63 μg mL−1 (0.87 μm) with good selectivity (SI=49.5) toward the L6 cell line. It also exhibited good antibacterial activity against three of the tested microbial strains B. cereus, E. coli ATCC879, and P. stuartii ATCC29916 with minimum inhibitory concentrations below 62.6 μg mL−1. Compound 1 is thus a promising active compound that could be investigated for antileishmanial and antimicrobial drug development.

Bioactive secondary metabolites from new endophytic fungus Curvularia. sp isolated from Rauwolfia macrophylla

“…Endophytes are microorganisms that inhabit the inner tissue of their hosts and perform various ecological relationships without showing visible host infection symptoms [4–6]. Isolation of three endophytic fungi namely Aspergillus sp., Fusarium sp., and Purpureocillium lilacinum from the stem bark of Rauwolfia macrophylla were recently reported [7]. The last endophytic fungus ( Purpureocillium lilacinum ) was among them specifically studied due to its potent antiprotozoal activity against Leishmania donovani (IC 50 0.174 μg mL -1 ); which was attributed to its production of purpureone, an ergochrome moiety [7].…”

“…Isolation of three endophytic fungi namely Aspergillus sp., Fusarium sp., and Purpureocillium lilacinum from the stem bark of Rauwolfia macrophylla were recently reported [7]. The last endophytic fungus ( Purpureocillium lilacinum ) was among them specifically studied due to its potent antiprotozoal activity against Leishmania donovani (IC 50 0.174 μg mL -1 ); which was attributed to its production of purpureone, an ergochrome moiety [7]. It should be considered that different factors such as the plant organs, genotypic and geographic location influence the endophytic fungal community structure [8].…”

Cytotoxic Tetrahydroxanthone Dimers from the Mangrove-Associated Fungus Aspergillus versicolor HDN1009

“…Compound 2 was constructed by connecting the two monomeric units via the linkage of C-2 and C-4′, based on the HMBC correlations from H-2′ to C-1′ and C-9a′; OH-1′ to C-1′; C-2′ and C-9a′; H 3 -11′ to C-2′; C-3′ and C-4′; OH-1 to C-1; C-2 and C-9a; and H-3 to C-4′. Based on the HMBC correlations from H-4′ to C-4a′ and C-3′; OH-1′ to C-1′; C-2′ and C-9a′; H 3 -11′ to C-2′; C-3′ and C-4′; OH-1 to C-1; C-2 and C-9a; and H-3 to C-2′ ( Figure 2 ), the planar structure of compound 3 was completed by connecting the two monomeric units via the linkage between C-4 and C-2′, which was the same as purpureone, whose absolute configuration has not been reported [ 8 , 9 ].…”

Antibiotics from Extremophilic Micromycetes

“…Several structural families can be distinguished among isolated compounds. Isocoumarins (111-120), dihydroisocoumarins (121)(122)(123)(124)(125)(126)(127), and other lactones (128-148) can be distinguished among cyclic esters. Most of the new and known metabolites can be assigned to phenols and their derivatives and diphenyl esters (177)(178)(179)(180)(181)(182)(183)(184)(185)(186)(187)(188)(189).…”