Eremophilane Sesquiterpenes from an Endophytic Fungus Periconia Species

Abstract

Nine new polyoxygenated eremophilane sesquiterpenes, periconianones C-K (1-9), including one unusual isoeremophilane sesquiterpene, periconianone C (1), and four trinor-eremophilane sesquiterpenes, periconianones H-K (6-9), were isolated from the endophytic fungus Periconia sp. F-31. Compound 1 is the first furan-type isoeremophilane reported containing a linkage of C-8/C-11 and a 7,12-epoxy moiety. These compound structures, including absolute configurations, were elucidated through extensive spectroscopic data analysis, electronic circular dichroism, Mo2(AcO)4-induced circular dichroism, and single-crystal X-ray diffraction (Cu Kα). Compounds 2, 5, and 9 showed inhibition effects on lipopolysaccharide-induced NO production in BV2 cells by 10.2%, 18.3%, and 16.1% at a concentration of 1.0 μM, respectively, which is comparable to the positive control curcumin (12.9% at 1.0 μM).

The Furan Shuffling Hypothesis: A Biogenetic Proposal for Eremophilane Sesquiterpenoids

“…The 1 H and 13 CNMR spectra of synthetic 2 were in agreement with the spectra reported in the literature for the isolated material, and both the opened and closed structures of 2 were observed in the 1 [7] do not differ significantly. The 1 H and 13 CNMR spectra of synthetic 2 were in agreement with the spectra reported in the literature for the isolated material, and both the opened and closed structures of 2 were observed in the 1 [7] do not differ significantly.…”

“…[5] One example of afurantype eremophilane is microsphaeropsisin B( 1), am ember isolated from co-cultivation of the endophytic fungus Tricho-derma sp.3 07 with the aquatic pathogenic bacterium Acinetobacter johnsonii B2. [7] Thes tructure of 2 was confirmed by single-crystal X-ray analysis,which revealed the three-carbon moiety to be positioned at C8 of the decalin core and not at position C7, as in all congeners previously described. [7] Thes tructure of 2 was confirmed by single-crystal X-ray analysis,which revealed the three-carbon moiety to be positioned at C8 of the decalin core and not at position C7, as in all congeners previously described.…”

The Furan Shuffling Hypothesis: A Biogenetic Proposal for Eremophilane Sesquiterpenoids

“…[6] Recently,t he group of Dai reported the isolation of periconianone C( 2), an unusual furan-type iso-eremophilane that was also isolated from an endophytic fungus,n amely Periconia sp.F -31. [7] Thes tructure of 2 was confirmed by single-crystal X-ray analysis,which revealed the three-carbon moiety to be positioned at C8 of the decalin core and not at position C7, as in all congeners previously described. Theg roup of Dai suggested that this linkage originates biosynthetically from ap inacol rearrangement of the dihydroxylated eremophilane 3.A dditional oxidation events of the rearranged compound 4 and ketalization would then form 2.T his biogenetic proposal is supported by the isolation of the putative precursor 3 from the same extracts of the fungus as 2.…”

Phenolic Compounds from Endophytic Pseudofusicoccum sp. Isolated from Annona muricata

“…A. muricata have been studied for the bioactive natural products produced by its endophytic fungal populations. [14][15][16][17][18][19][20][21][22][23] 14,15,17 and sesquiterpenes: periconianones C-K. 19 Secondary metabolites of endophytic fungi of A. muricata showed anticancer activities. 22,23 Periconiasins A and B showed significant cytotoxicity against human colon cancer cells (HCT-8).…”

“…15,20 Periconianones D, G and K showed antioxidant activity due to lipopolysaccharide-induced nitric oxide (NO) inhibition. 19 Nigeria's rich plant biodiversity presents the opportunity to discover a plethora of biologically important compounds expressed by the millions of endophytic microbial communities inherent in these plants. 24 Investigations of the endophytic fungal populations of some Nigerian medicinal plants have revealed the enormous potentials possessed by these organisms as sources of compounds of pharmaceutical and industrial importance.…”