Isolation of ophiobolin A and its analogs as inhibitors to photosynthesis

doi:10.1271/BBB1961.48.803

Paper

Isolation of ophiobolin A and its analogs as inhibitors to photosynthesis

Published Mar 1, 1984 · Jin-Myeon Kim, Suong-Be Hyeon, A. Isogai

Agricultural and biological chemistry

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Abstract

DMSO-H2O, I gave II, III and IV. I yielded IV quantitatively upon treatment with an acid or base, whereas I was not converted into II, III and IV under the conditions of culture (pH 6.5 ~7) or isolation. In order to determine the stereochemistry of II, III and IV, 2H-NMRspectra of those compounds were obtained by converting from I using deuterated solvents. In the spectra of II and IV, signals were each observed at <53.3ppm and assigned to the C-6 position, while no deuterium signals were apparent in the spectrum of III. These indicated that the stereochemistries of II and IV were different from I only at C-6 and that III retained the same stereochemistry as I. From the above chemical and physicochemical data, II was determined as a C-6 epimer ofI, and III and IV were established as 3,4-anhydro-derivatives of I and II, respectively. These were denoted as 6-epiophiobolin A (II), anhydroophiobolin A (III) and anhydro-6-epiophiobolin A (IV), respectively. The 3,4-dehydrated derivative of ophiobolin A has been chemically obtained from I and is known as "anhydroophiobolin A"3) but the stereochemistry at C-6 has remainedobscure until now. Comparison of the published data of "anhydroophiobolin A"3) with those of III and IV proved this derivative to be identical with IV. We therefore propose that the hitherto known "anhydroophiobolin A" should be more exactly named as anhydro-6-epiophiobolin A. The inhibitory activities of those compounds to photosynthesis were measured using spinach leaf slices and chlorella and the results are shown in Table I, in comparison with diuron, bromacil and ioxynyl, which are all well known as Hill reaction inhibitors. The /50 values of I, II, III and IV to photosynthesis were between 10~4 and 10~3m. Ophiobolin A is known as a photosynthesis inhibitor causing the brown spot symptom in rice plants.4)

Study Snapshot

Key takeawayOphiobolin A and its analogs, 6-epiophiobolin A (II), anhydroophiobolin A (III), and anhydro-6-epiophiobolin A (IV), are potent inhibitors of photosynthesis, causing brown spot symptoms in

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Paper

Isolation of ophiobolin A and its analogs as inhibitors to photosynthesis

References

Citations

LC-MS/MS-Guided Molecular Networking for Targeted Discovery of Undescribed and Bioactive Ophiobolins from Bipolaris eleusines.

LC-MS/MS-guided molecular networking effectively discovers undescribed bioactive ophiobolins from Bipolaris eleusines, with some showing phytotoxic effects on green foxtails and cytotoxic activities against cancer cell lines.

Phytotoxic Secondary Metabolites from Fungi

Fungal phytotoxic secondary metabolites show high diversity in structures, phytotoxic activities, and modes of toxicity, making them promising candidates for future development and application as herbicides.

Characterization and phytotoxicity of ophiobolins produced by Bipolaris setariae

3-anhydro-ophiobolin A and 6-epi-ophiobolin A are the main phytotoxic determinants of Bipolaris setariae, and 6-epi-ophiobolin A shows potential antitumor potential against various human cancer cells.

Drophiobiolins A and B, Bioactive Ophiobolan Sestertepenoids Produced by Dreschslera gigantea.

Drophiobiolins A and B, produced by Drechslera gigantea, show significant phytotoxic activity against cultivated and weed plants, with potential as a bioherbicide for Digitaria sanguinalis biocontrol.

Recent Advances in the Total Synthesis of Natural Products Containing Eight-Membered Carbocycles (2009-2019).

Recent advances in total syntheses of natural products with eight-membered carbocycles show diversity and creativity, providing guidance for future synthetic efforts in this area.