Benzopyran derivatives from endophytic Daldinia eschscholzii JC-15 in Dendrobium chrysotoxum and their bioactivities

Abstract

Five new benzopyran derivatives (2-6) and a new natural product (1) were isolated from endophytic Daldinia eschscholzii in Dendrobium chrysotoxum and determined as (R)-2,3-dihydro-2,5-dihydroxy-2-methylchromen-4-one (1), (2R, 4S)-2,3-dihydro-2-methyl-benzopyran-4,5-diol (2), (R)-3-methoxyl-1-(2,6-dihydroxy phenyl)-butan-1-one (3), 7-O-α-d-ribosyl-5-hydroxy-2-methyl-4H-chromen-4-one (4), 7-O-α-d-ribosyl-2,3-dihydro-5-hydroxy-2-methyl-chromen-4-one (5), daldinium A (6). These compounds were evaluated for their antimicrobial activity, anti-acetylcholinesterase, nitric oxide inhibition, anticoagulant, photodynamic antimicrobial activities and glucose uptake of adipocytes. Some compounds showed photoactive antimicrobial activities and glucose uptake stimulating activities.

Volatiles from the ascomyceteDaldinia cf. childiae(Hypoxylaceae), originating from China

“…The compounds 36 and 37 have also previously been reported from Daldinia, 29 which further supports the biosynthetic hypothesis. The methyl esters methyl salicylate (19) and methyl 2,6-dihydroxybenzoate (20) found in the headspace extracts exhibit the same aromatic ring substitution patterns as observed for 21 and 22 and may arise by degradation of these chromanones.…”

“…1 H NMR (700 MHz, CDCl 3 ): δ = 7.34 (d, 3 J H,H = 1.7 Hz, 1H, CH, Z isomer), 7.30 (d, 3 J H,H = 1.5 Hz, 1H, CH, E isomer), 6.39 (dd, 3 J H,H = 3.3, 1.8 Hz, 1H, CH, Z isomer), 6.34 (dd, 3 J H,H = 3.3, 1.8 Hz, 1H, CH, E isomer), 6.25 (d, 3 J H,H = 3.3 Hz, 1H, CH, Z isomer), 6.18 (d, 3 J H,H = 11.8 Hz, 1H, CH, Z isomer), 6.12 (d, 3 J H,H = 3.3 Hz, 1H, CH, E isomer), 5.56 (dt, 3 J H,H = 11.7, 7.3 Hz, 1H, CH, Z isomer), 2.43 (ddt, 3 J H,H = 7.3, 7.3 Hz, 4 J H,H = 1.6 Hz, 2H, CH 2 , Z isomer), 2.17 (dt, 3 J H,H = 7.1, 7.1 Hz, 2H, CH 2 , E isomer), 1.47 (q, 3 J H,H = 7.3 Hz, 2H, CH 2 , Z isomer), 1.45 (q, 3 J H,H = 7.5 Hz, 2H, CH 2 , E isomer), 1.39-1.22 (m, 24H, 12 × CH 2 , E + Z isomer), 0.89 (t, 3 J H,H = 7.2 Hz, 6H, 2 × CH 3 , E + Z isomer) ppm. 13 C NMR (175 MHz, CDCl 3 ): δ = 153.6 (C q , E isomer), 153.6 (C q , Z isomer), 141.3 (CH, E isomer), 141.3 (CH, Z isomer), 131.7 (CH, Z isomer), 130.5 (CH, E isomer), 118.6 (CH, E isomer), 117.3 (CH, Z iso-mer), 111.2 (CH, E isomer), 111.2 (CH, Z isomer), 108.8 (CH, Z isomer), 106.0 (CH, E isomer), 33.0 (CH 2 , E isomer), 32.0 (2 × CH 2 , E + Z isomer), 29.7 (CH 2 , Z isomer), 29.7 (CH 2 , E isomer), 29.7 (CH 2 , Z isomer), 29.7 (2 × CH 2 , E + Z isomer), 29.6 (CH 2 , Z isomer), 29…”

Recent progress in biodiversity research on the Xylariales and their secondary metabolism

“…A large number of known as well as novel benzenoids, benzopyranes, and benzopyrane-glucosides has been isolated from an endophytic D. eschscholtzii from Dendrobium chrystotoxum [106], along with one cyclohexene named daldinium A (75). No significant bioactivities were found in antimicrobial assays, but one glucoside, 7-O-α-D-ribosyl-5hydroxy-2-methyl-4H-chromen-4-one (76), induced a glucose consumption rate of 17.3%, as compared to the positive controls insulin and berberine (24.8 and 24.6%, respectively).…”

Polyketides From the Endophytic Fungus Cladosporium sp. Isolated From the Mangrove Plant Excoecaria agallocha

“…Thus, the structures of 1 and 2 were unambiguously elucidated as (2 R )- and (2 S )-7- O -α-D- ribofuranosyl-5-hydroxy - 2-methylchroman-4-one, respectively. This is the first time that to solidify the absolute configuration of compound 1 , although it was reported last year (Hu et al, 2017 ).…”

“…Herein we report five new polyketides ( 2 – 6 ) (Figure 1 ) isolated from the EtOAc extract of Cladosporium sp. OUCMDZ-302, along with the ten known structures (Figure S36 and Table S1 ), (2 R )-7- O -α-D-ribofuranosyl-5-hydroxy - 2-methylchroman-4-one ( 1 ) (Hu et al, 2017 ), 7- O -α-D-ribosyl-5-hydroxy-2-propylchromone ( 7 ) (Zhao et al, 2015 ), 3-(2,3-dihydroxy phenoxy)butanoic acid ( 8 ) (Dai et al, 2009 ), (2 S ,4 S )-4-methoxy-2-methylchroman-5-ol ( 9 ) (Wu et al, 2010 ), (2 S ,4 S )-2-methylchroman-4,5-diol ( 10 ) (Teles et al, 2005 ), (±)-5,7-dihydroxy-2-methyl chroman-4-one ( 11 ) (Rao et al, 1994 ), (±)-5-hydroxy-2-methylchroman-4-one ( 12 ) (Dai et al, 2006 ), 1-(2,6-dihydroxyphenyl) ethanone ( 13 ) (Dhami and Stothers, 1965 ), 1-(2,6-dihydroxyphenyl)-1-butanone ( 14 ) (Huang et al, 2005 ), and 2-butyryl-3,5-dihydroxycyclohex-2-enone ( 15 ) (Igarashi et al, 1993 ). Compound 7 showed inhibitory activity against H1975 cell line with an IC 50 value of 10.0 μM.…”