Two new bioactive ophiobolan sestertepenoids, named drophiobiolins A and B (1 and 2) were isolated from Drechslera gigantea, a fungus proposed as a mycoherbicide for biocontrol of Digitaria sanguinalis. They were isolated together with ophiobolin A, the main metabolite, 6-epi-ophiobolin A, 3-anhydro-6-epi-ophiobolin A, and ophiobolin I. Drophiobolins A and B were characterized by NMR, HRESIMS, and chemical methods as 7-hydroxy-7-(6-hydroxy-6-methylheptan-2-yl)-1,9a-dimethyl-3-oxo-3,3a,6,6a,7,8,9,9a,10,10a-decahydrodicyclopenta [a,d][8]annulene-4-carbaldehyde and 6-(hydroxymethyl)-3′,9,10a-trimethyl-5′-(2-methylprop-1-en-1-yl)-3a,4,4′,5′,10,10a-hexahydro-1H,3′H-spiro[dicyclopenta[a,d] [8]annulene-3,2′-furan]-5,7(2H,9aH)-dione. The relative configuration of drophiobolins A and B, which did not afford crystals suitable for X-ray analysis, was determined by NOESY experiments, while the absolute configuration was assigned by comparison of their experimental and TDDFT calculated electronic circular dichroism (ECD) spectra. The phytotoxic activity of drophiobolins A and B was tested by leaf-puncture assay on cultivated (Lycopersicon esculentum L.), as well as on host (Digitaria sanguinalis L.) and nonhost (Chenopodium album L.) weed plants, compared to that of ophiobolin A. Both of the newly identified ophiobolins showed significant phytotoxicity. Drophiobolins A and B exhibited cytotoxicity against Hela B cells with an IC50 value of 10 μM. However, they had a lesser or no effect against Hacat, H1299, and A431 cells when compared to that of ophiobolin A.
Drophiobiolins A and B, Bioactive Ophiobolan Sestertepenoids Produced by Dreschslera gigantea / Zatout, R.; Masi, M.; Sangermano, F.; Vurro, M.; Zonno, M. C.; Santoro, E.; Calabro, V.; Superchi, S.; Evidente, A.. - In: JOURNAL OF NATURAL PRODUCTS. - ISSN 0163-3864. - 83:11(2020), pp. 3387-3396. [10.1021/acs.jnatprod.0c00836]
Drophiobiolins A and B, Bioactive Ophiobolan Sestertepenoids Produced by Dreschslera gigantea
Zatout R.Primo
Membro del Collaboration Group
;Masi M.Secondo
Membro del Collaboration Group
;Sangermano F.Membro del Collaboration Group
;Calabro V.;Superchi S.Membro del Collaboration Group
;Evidente A.
Ultimo
Membro del Collaboration Group
2020
Abstract
Two new bioactive ophiobolan sestertepenoids, named drophiobiolins A and B (1 and 2) were isolated from Drechslera gigantea, a fungus proposed as a mycoherbicide for biocontrol of Digitaria sanguinalis. They were isolated together with ophiobolin A, the main metabolite, 6-epi-ophiobolin A, 3-anhydro-6-epi-ophiobolin A, and ophiobolin I. Drophiobolins A and B were characterized by NMR, HRESIMS, and chemical methods as 7-hydroxy-7-(6-hydroxy-6-methylheptan-2-yl)-1,9a-dimethyl-3-oxo-3,3a,6,6a,7,8,9,9a,10,10a-decahydrodicyclopenta [a,d][8]annulene-4-carbaldehyde and 6-(hydroxymethyl)-3′,9,10a-trimethyl-5′-(2-methylprop-1-en-1-yl)-3a,4,4′,5′,10,10a-hexahydro-1H,3′H-spiro[dicyclopenta[a,d] [8]annulene-3,2′-furan]-5,7(2H,9aH)-dione. The relative configuration of drophiobolins A and B, which did not afford crystals suitable for X-ray analysis, was determined by NOESY experiments, while the absolute configuration was assigned by comparison of their experimental and TDDFT calculated electronic circular dichroism (ECD) spectra. The phytotoxic activity of drophiobolins A and B was tested by leaf-puncture assay on cultivated (Lycopersicon esculentum L.), as well as on host (Digitaria sanguinalis L.) and nonhost (Chenopodium album L.) weed plants, compared to that of ophiobolin A. Both of the newly identified ophiobolins showed significant phytotoxicity. Drophiobolins A and B exhibited cytotoxicity against Hela B cells with an IC50 value of 10 μM. However, they had a lesser or no effect against Hacat, H1299, and A431 cells when compared to that of ophiobolin A.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
