Elsevier

South African Journal of Botany

Volume 112, September 2017, Pages 48-53
South African Journal of Botany

Identification of 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one with antimicrobial activity from Dodonaea viscosa var. angustifolia

https://doi.org/10.1016/j.sajb.2017.05.024Get rights and content
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Highlights

  • 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl) was newly isolated, elucidated and identified from D. viscosa var. angustifolia.

  • This flavone has a broad spectrum antimicrobial activity.

  • The safety of this flavone was established using a cytotoxicity test.

  • It has potential to be developed into a therapeutic agent.

Abstract

The aim of this study was to isolate a chemical constituent from Dodonaea viscosa var. angustifolia, investigate its effect on a range of pathogens and identify the major beneficial compound.

Leaves were dried, milled and a methanol crude extract was prepared. Fractions were obtained using column chromatography. Antimicrobial activity of these fractions against various microorganisms was determined using a microdilution technique. The most effective fraction was purified by flash chromatography, and characterized and identified using GC–MS, NMR, UV–Vis and FT-IR. Cytotoxicity tests were carried out on human embryonic kidney cells.

Six fractions (F1–F6) were separated. Fraction 5 had the most antimicrobial activity (MIC 0.39 mg/ml). On further fractionation of Fraction 5, two subfractions (F5.1 and F5.2) were obtained. F5.1 showed better antimicrobial activity (0.2 mg/ml) compared to the F5.2. F5.1 was identified as new compound, 5,6,8-Trihydroxy-7,4-dimethoxyflavone (5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one) with a molecular formula C17H14O and molecular weight 330.28 amu. The concentrations of newly isolated, elucidated and identified compound that inhibited cells by 50% (IC50) was 0.03 mg/ml.

In conclusion, DVA leaves contain 5,6,8-Trihydroxy-7,4-dimethoxyflavone which has antimicrobial activities against common pathogens and unicellular fungi and it proved to be safe. Therefore it has the potential to be developed into a therapeutic agent.

Keywords

Antimicrobial
Flavone
Dodonaea angustifolia
5,6,8-Trihydroxy-7-methoxy
4H-chromen-4-one, D. viscosa var. angustifolia

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