First synthetic report and antioxidant potential of natural product (±)-5,7-dihydroxy-8-methyl-3-(2',4'-dihydroxybenzyl)chroman-4-one from Chinese medicine Gan Luo Xin pill

Abstract

The first synthetic route of naturally occurring (±)-5,7-dihydroxy-8-methyl-3-(2’,4’-dihydroxybenzyl)chroman-4-one (1) from Gan Luo Xin pill was successfully accomplished. The synthetic route has been developed retro-synthetically in 9 simple steps with a high yield of ∼80%. The synthetic protocol was developed using readily available starting material phloroglucinol. The key intermediate 2,4,6-trihydroxy-3-methyl acetophenone (4) was synthesized via Vilsmeier–Haack reaction, followed by reduction using sodium cyanoborohydride and acylation reaction. LC-MS, IR, ¹H NMR, ¹³C NMR of 1 have been analyzed to confirm the structure of (±)-5,7-dihydroxy-8-methyl-3-(2’,4’-dihydroxybenzyl)chroman-4-one (1) and found in agreement with the natural molecule. The target compound showed 97% and 87% antioxidant activity in DPPH and ABTS assay at 1 mg/ml concentration, respectively. The compound (1) also showed ferric ion reducing activity with the absorbance of 0.18 at 700 nm. The present study could be useful in developing synthetic routes of other potential naturally occurring homoisoflavonoid.

Graphical abstract

keywords:

• Homoisoflavonoid
• Secondary metabolite
• Reterosynthesis
• Antioxidant act

Acknowledgements

The authors are thankful to the Director, ARI, Pune, India, for providing infrastructure and financial support. For financial assistance, Dr. Garima Mishra is thankful to the Department of Science and Technology (DST), New Delhi, India, for the WOS-A project SR/WOS-A/CS-88/2019.

Disclosure statement

There is no conflict of interest among the authors.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.