Rearranged Sesquiterpenes and Branched Polyketides Produced by the Endophyte Camarops sp.

Abstract

Two rearranged sesquiterpenes, 3,5,9-trihydroxy presilphiperfolane (1) and 4-deoxy-10-oxodihydrobotrydial (2), and two branched polyketides, 4-((E)-pent-1-enyl)-3-((1'S,2'S)-1',2'-dihydroxybut-3-enyl)-5H-furan-2-one (3) and (2E,4R)-2,4-dimethylnon-2-enoic acid (4), along with three known compounds (2E,4S)-2,4-dimethyloct-2-enoic acid (5), xylarenone C (6), xylarenone D (7), were isolated from solid substrate cultures of Camarops sp., an endophyte of Alibertia macrophylla (Rubiaceae). The structures were established by means of NMR and HRESIMS analyses. The absolute stereochemistry of 3 was determined through the application of the modified Mosher method. Compounds 6 and 7 exhibited cytotoxic activity against leukemia (HL-60), melanoma (MDA/MB-435), colon (HCT-8) and glioblastoma (SF-295) human tumor lines, while compounds 4-7 presented acetylcholinesterase inhibition.

New Benzaldehyde and Benzopyran Compounds from the Endophytic Fungus Paraphaeosphaeria sp. F03 and Their Antimicrobial and Cytotoxic Activities

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Recent efforts devoted to the discovery of biologically active natural products from endophytic fungi have resulted in the identification of secondary metabolites with cytotoxic, zoosporicidal, antimicrobial, antiproliferative, and anti-inflammatory activities [1][2][3][4]. To date, only 2 studies have been reported in the literature involving the evaluation of secondary metabolites from strains of endophytic fungi isolated from Paepalanthus sp.

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Natural Products from Endophytic Fungi Associated with Rubiaceae Species

“…The continuing search for endophytes associated on A. macrophylla led to five new eremophilane sesquiterpenes: xylarenones C-G (14)(15)(16)(17)(18) isolated from solid cultures of Camarops sp. (Boliniaceae) [100,101]. This fungus was also able to produce two rearranged sesquiterpenes: 3,5,9-trihydroxy presilphiperfolane (19) and 4-deoxy-10-oxodihydrobotrydial (20); two branched polyketides: 4-((E)-pent-1-enyl)-…”

“…The continuing search for endophytes associated on A. macrophylla led to five new eremophilane sesquiterpenes: xylarenones C–G ( 14 – 18 ) isolated from solid cultures of Camarops sp. (Boliniaceae) [ 100 , 101 ]. This fungus was also able to produce two rearranged sesquiterpenes: 3,5,9-trihydroxy presilphiperfolane ( 19 ) and 4-deoxy-10-oxodihydrobotrydial ( 20 ); two branched polyketides: 4-((E)-pent-1-enyl)-3-((1’S,2’S)-1’,2’-dihydroxybut-3-enyl)-5H-furan-2-one ( 21 ) and (2E,4R)-2,4-dimethylnon-2-enoic acid ( 22 ); seven phenolic derivatives: p -hydroxyphenyllactic acid ( 23 ), phenyllactic acid ( 24 ), p -hydroxybenzoic acid ( 25 ), p -hydroxybenzaldehyde ( 26 ), n -butyl-3,4- dihydroxybenzoate ( 27 ), n -hexyl-3,4-dihydroxybenzoate ( 28 ) and n -octyl-3,4-dihydroxybenzoate ( 29 ); and the known compound (2E,4S)-2,4- dimethyloct-2-enoic acid ( 30 ) ( Figure 5 ) [ 102 ].…”

“…associated with A. macrophylla , exhibited AChE inhibitory activity and showed a detection limit of 10.0 μg ( 7 , 12 , 13 ) and 30.0 μg ( 9 ), respectively [ 98 , 99 ]. On the other hand, xylarenone C ( 14 ) isolated from Camarops sp., had a minimum AChE inhibitory concentration of 6.25 μg, while the others compound ( 15 , 22 , and 30 ) from Camarops sp., showed weak acetylcholinesterase (AChE) inhibitory activity [ 101 ]. Recently, the sesquiterpenoids colletotrichines A( 133 ) and B ( 134 ) produced by C. gloeosporioides inhibited AChE activity with the half-maximal inhibitory concentration IC 50 values of 28.0 and 38.0 μg mL −1 , respectively [ 125 , 126 ].…”

“…The eremophilane sesquiterpenes xylarenone C ( 14 ) and xylarenone D ( 15 ), isolated from Camarops sp., exhibited cytotoxic activity against human tumor cell lines, such as leukemia (HL-60), melanoma (MDA/MB-435), colon (HCT-8), and glioblastoma (SF-295). The antiproliferative effect was evaluated following 72h of treatment, and the compounds 14 and 15 were more active against MDA/MB-435 (IC 50 = 2.4 μg mL −1 ) and HL-60 (IC 50 = 1.2 μg mL −1 ) cells, respectively [ 101 ]. Eremophilane sesquiterpene compounds exhibit phytotoxic potential; antifungal, antibacterial, carcinostatic, and cytotoxic activities; and can act as a phytohormone [ 100 , 153 ].…”