Kensuke Hashimoto

Antioxidative sulphated flavonoids in leaves of Polygonum hydropiper

Abstract Three hydrophilic flavonoids were isolated and identified from leaves of Polygonum hydropiper as quercetin 3-sulphate, isorhamnetin 3,7-disulphate and tamarixetin 3-glucoside-7-sulphate. The structures were established by chemical and spectral evidence, and their antioxidative activity and effect on the generation of superoxide anion evaluated.

Antimicrobial tetrahydroanthraquinones from a strain of Alternaria solani.

Abstract Culture liquid and mycelia of a strain of Alternaria solani , which was isolated from a diseased Lycopersicon esculentum , afforded new tetrahydr

Altersolanol-related antimicrobial compounds from a strain of Alternaria solani

Abstract Four new altersolanol-related compounds, hydroxybostrycin, altersolanol G, altersolanol H and an atropisomer of alterporriol C, together with a mixture of alterporriol A and alterporriol B, have been isolated from the culture liquid of a strain of Alternaria solani obtained from a diseased Lycopersicon esculentum . Their structures have been established on the basis of spectral and chemical evidence. The structures of altersolanols G and H were shown to be 6-methoxy-1β,3β-dimethyl-2α,3α, 4β,8-tetrahydroxy-1,2,3,4-tetrahydroanthraquinone and 6-methoxy-3β-methyl-2β,3α,4β,8-tetrahydroxy- 1,2,3,4-tetrahydroanthraquinone, respectively.

Simultaneous high-performance liquid chromatographic determination of altersolanol A, B, C, D, E and F

A high-performance liquid chromatographic model for the simultaneous determination of altersolanol A–F by using a reversed-phase column with an acetonitrile-water gradient elution system is described. The analysis can be completed within 13 min, the detection limits are 0.2–0.5 pmol per injection (5 μl) and the relative standard deviations are 0.90–1.34%. The method was applied satisfactorily to the determination of altersolanols in culture media of a strain of Alternaria solani without any prepurification.