Chemical Constituents of Papulaspora immersa, an Endophyte from Smallanthus sonchifolius (Asteraceae), and Their Cytotoxic Activity

Abstract

Papulaspora immersa H. H. Hotson was isolated from roots and leaves of Smallanthus sonchifolius (Poepp. and Endl.) H. Rob. (Asteraceae), traditionally known as Yacon. The fungus was cultured in rice, and, from the AcOEt fraction, 14 compounds were isolated. Among them, (22E,24R)-8,14-epoxyergosta-4,22-diene-3,6-dione (4), 2,3-epoxy-1,2,3,4-tetrahydronaphthalene-c-1,c-4,8-triol (10), and the chromone papulasporin (13) were new secondary metabolites. The spectral data of the known natural products were compared with the literature data, and their structures were established as the (24R)-stigmast-4-en-3-one (1), 24-methylenecycloartan-3β-ol (2), (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (3), (-)-(3R,4R)-4-hydroxymellein (5), (-)-(3R)-5-hydroxymellein (6), 6,8-dihydroxy-3-methylisocoumarin (7), (-)-(4S)-4,8-dihydroxy-α-tetralone (8), naphthalene-1,8-diol (9), 6,7,8-trihydroxy-3-methylisocoumarin (11), 7-hydroxy-2,5-dimethylchromone (12), and tyrosol (14). Compound 4 showed the highest cytotoxic activity against the human tumor cell lines MDA-MB435 (melanoma), HCT-8 (colon), SF295 (glioblastoma), and HL-60 (promyelocytic leukemia), with IC₅₀ values of 3.3, 14.7, 5.0 and 1.6 μM, respectively. Strong synergistic effects were also observed with compound 5 and some of the isolated steroidal compounds.

New Isocoumarin Derivatives and Meroterpenoids from the Marine Sponge-Associated Fungus Aspergillus similanensis sp. nov. KUFA 0013

“…However, in order to comply with the recent “International Code of Nomenclature for algae, fungi and plants (The Melbourne Code)”, the strain was renamed Aspergillus similanensis (KUFA0013). The ethyl acetate extract of its culture furnished, besides chevalones B and C [ 9 , 10 ], p -hydroxybenzaldehyde, reticulol ( 2c ) [ 11 ], 6,8-dihydroxy-3-methylisocoumarin ( 2a ) [ 12 ], a meroterpenoid S14-95 ( 4 ) [ 13 ], pyripyropene E ( 5 ) [ 14 ], two new isocoumarins which we have named similanpyrones A ( 1 ) and B ( 2b ), a new chevalone analog ( 3 ), and a new natural product which we have named pyripyropene S ( 6 ) [ 15 ] ( Figure 1 ). Compounds 1 , 2a – c , 3 – 6 were evaluated for their antimicrobial activity against Gram positive ( Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633) and Gram negative ( Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) bacteria, Candida albicans ATCC 10231, as well as multidrug-resistant isolates from the environment.…”

Endophytes, a Potential Source of Bioactive Compounds to Curtail the Formation–Accumulation of Advanced Glycation End Products: A Review

“…Other antiAGEs phenolic compounds that have been reported in endophytes such as resveratrol, a stilbene [124][125][126][127][128], tyrosol [131][132][133][134], ellagic acid [80,91], and 2,4-diacetylphloroglucinol [68] are shown in Figure 6. Other antiAGEs phenolic compounds that have been reported in endophytes such as resveratrol, a stilbene [124][125][126][127][128], tyrosol [131][132][133][134], ellagic acid [80,91], and 2,4-diacetylphloroglucinol [68] are shown in Figure 6.…”

“…Other antiAGEs phenolic compounds that have been reported in endophytes such as resveratrol, a stilbene [ 124 , 125 , 126 , 127 , 128 ], tyrosol [ 131 , 132 , 133 , 134 ], ellagic acid [ 80 , 91 ], and 2,4-diacetyl-phloroglucinol [ 68 ] are shown in Figure 6 .…”

“…Figure 5 shows some antiAGEs flavonoids reported as metabolites in endophytes consisting of: apigenin and derivatives such as vitexin and isovitexin [78,81,90,[103][104][105], kaempferol and derivatives [91,110,111], luteolin [78,81,113], quercetin and derivatives [81,88,90,91,113], catechin [78], daidzein [118], genistein [90,118], icariin [78] and rutin and derivatives [78,81,91]. Other antiAGEs phenolic compounds that have been reported in endophytes such as resveratrol, a stilbene [124][125][126][127][128], tyrosol [131][132][133][134], ellagic acid [80,91], and 2,4-diacetylphloroglucinol [68] are shown in Figure 6. Other antiAGEs phenolic compounds that have been reported in endophytes such as resveratrol, a stilbene [124][125][126][127][128], tyrosol…”

Bioactive Steroids Bearing Oxirane Ring

“…Figure 16. A 3D graph showing the predicted and calculated antiprotozoal activity of a steroid bearing an 8,14-epoxy group from fungus Papulaspora immersa (70) with over 94% confidence. The 3D graph mentioned would typically represent the relationship between the chemical structure of the steroid and its predicted and calculated antiprotozoal activity.…”