Dihydropergillin: a fungal metabolite with moderate plant growth inhibiting properties from Aspergillus ustus

Abstract

Dihydropergillin, C15H1804, is a newly discovered metabolite isolated from cultures of Aspergillus ustus found growing on seed of Pisum sativum var. macrocarpon. It is structurally related to pergillin and significantly inhibited wheat coleoptile growth at 10"3 and 10"4 M. Structural determination was by single-crystal X-ray diffraction analysis.

Sesquiterpenoids and Benzofuranoids from the Marine-Derived Fungus Aspergillus ustus 094102

“…ustus have been studied by many groups. Metabolites of this species include meroterpenoid mycotoxins, − isochromane derivatives, − drimane sesquiterpene esters, and ophiobolins . Many of them exhibited interesting biological activities, such as plant growth inhibition and inhibition of endothelin-type B receptors .…”

“…Metabolites of this species include meroterpenoid mycotoxins, − isochromane derivatives, − drimane sesquiterpene esters, and ophiobolins . Many of them exhibited interesting biological activities, such as plant growth inhibition and inhibition of endothelin-type B receptors . Further chemical study of this new strain was still worth conducting because the fermentation products showed cytotoxicity against B16 cell lines and antifungal activity against Candida albicans .…”

“…Eight drimane sesquiterpenes (1)(2)(3)(4)(5)(6)(7)(8), six isochromane derivatives (9)(10)(11)(12)(13)(14), and three known compounds, daldinin B (15), 9R-hydroxy-6β-[(2E,4E,6E)-octa-2,4,6-trienoyloxy]-5R-drim-7-en-11,12-olide (16), and pergillin (17), were isolated from the EtOAc extract of the marine-derived fungus Aspergillus ustus 094102. The structures of the new compounds were elucidated on the basis of spectroscopic analysis.…”

Synthesis and Structural Characterization of Natural Benzofuranoids

“…A solution of 4 (4.7 mg, 18.1 μmol) and 10% Pd/C (2.2 mg) in THF (3 mL) was stirred at rt under a H 2 atmosphere for 8.5 h. The reaction mixture was then filtered through Celite and washed with EtOAc. The filtrate was concentrated, and the resulting residue was purified by flash column chromatography (hexane–EtOAc, 6:1, v/v) to give a 1:1 inseparable mixture of 5 and 5′ (3.8 mg, 80%) as white solids: mp 116–117 °C (lit . 122–126 °C); UV (MeOH) λ max (log ε) 216 (3.46), 261 (3.15) nm; IR (KBr) ν max 3369, 2964, 2933, 2902, 2854, 1695, 1616, 1601, 1502, 1462, 1437, 1373, 1331, 1294, 1257, 1213, 1161, 1103, 1086, 1039, 1005 cm –1 ; 1 H NMR (CDCl 3 , 400 MHz, the signals marked with an asterisk are from the diastereomer at C-2) δ 7.46 (1H, d, J = 8.0 Hz, H-4), 7.46* (1H, d, J = 8.0 Hz, H-4), 6.80 (1H, d, J = 8.0 Hz, H-5), 6.80* (1H, d, J = 8.0 Hz, H-5), 4.98 (1H, d, J = 16.0 Hz, H-9), 4.98* (1H, d, J = 16.0 Hz, H-9), 4.91 (1H, d, J = 16.0 Hz, H-9), 4.91* (1H, d, J = 16.0 Hz, H-9), 4.43 (1H, d, J = 3.6 Hz, H-2), 4.42* (1H, d, J = 3.6 Hz, H-2), 3.02 (1H, d, J = 17.2 Hz, H-6), 3.02* (1H, d, J = 17.2 Hz, H-6), 2.94 (1H, d, J = 17.2 Hz, H-6), 2.94* (1H, d, J = 17.2 Hz, H-6), 2.35 (1H, m, H-11), 2.35* (1H, m, H-11), 1.63 (3H, s, H-10), 1.63* (3H, s, H-10), 1.159 (3H, d, J = 6.8 Hz, H-12), 1.155* (3H, d, J = 6.8 Hz, H-12), 0.87 (3H, d, J = 6.8 Hz, H-13), 0.87* (3H, d, J = 6.8 Hz, H-13); 13 C NMR (CDCl 3 , 100 MHz) δ 201.1 (C, C-3), 201.1* (C, C-3), 169.23 (C, C-9b), 169.18* (C, C-9b), 142.14 (C, C-5a), 142.09* (C, C-5a), 122.7 (CH, C-4), 122.7* (CH, C-4), 121.7 (CH, C-5), 121.7* (CH, C-5), 119.58 (C, C-3a), 119.55* (C, C-3a), 118.92 (C, C-9a), 118.89 (C, C-9a), 94.77 (C, C-7), 94.75* (C, C-7), 90.21 (C, C-2), 90.15* (C, C-2), 52.7 (CH 2 , C-9), 52.7* (CH 2 , C-9), 38.6 (CH 2 , C-6), 38.6* (CH 2 , C-6), 31.0 (CH, C-11), 30.9* (CH, C-11), 29.4 (CH 3 , C-10), 29.3* (CH 3 , C-10), 18.9 (CH 3 , C-13), 18.8* (CH 3 , C-13), 15.8 (CH 3 , C-12), 15.6* (CH 3 , C-12); HRESIMS m / z 285.1111 (calcd for C 15 H 18 O 4 Na, 285.1097).…”

“…However, the absolute configurations of 1 and 3 have not yet been determined. Pergillin ( 4 ) and dihydropergillin ( 5 ) were isolated from Aspergillus ustus by Cutler et al, and the structures of these compounds were determined by X-ray crystallography. Both of these compounds have been reported to significantly inhibit the growth of wheat coleoptile at concentrations of 10 –3 and 10 –4 M. Penicisochroman A ( 5 ), which is the methyl acetal derivative of pergillin, was isolated from Penicillium sp.…”