Simple and Rapid Method for Wogonin Preparation and Its Biotransformation.

Tomasz Tronina,Agnieszka Bartmańska,Monika Mrozowska,Ewa Huszcza,Sandra Sordon,Jarosław Popłoński

doi:10.3390/ijms22168973

Abstract

Wogonin is one of the most active flavonoids from Scutellaria baicalensis Georgi (baikal skullcap), widely used in traditional Chinese medicine. It exhibits a broad spectrum of health-promoting and therapeutic activities. Together with baicalein, it is considered to be the one of main active ingredients of Chinese medicines for the management of COVID-19. However, therapeutic use of wogonin may be limited due to low market availability connected with its low content in baikal skullcap and lack of efficient preparative methods for obtaining this compound. Although the amount of wogonin in skullcap root often does not exceed 0.5%, this material is rich in wogonin glucuronide, which may be used as a substrate for wogonin production. In the present study, a rapid, simple, cheap and effective method of wogonin and baicalein preparation, which provides gram quantities of both flavonoids, is proposed. The obtained wogonin was used as a substrate for biotransformation. Thirty-six microorganisms were tested in screening studies. The most efficient were used in enlarged scale transformations to determine metabolism of this xenobiotic. The major phase I metabolism product was 4′-hydroxywogonin—a rare flavonoid which exhibits anticancer activity—whereas phase II metabolism products were glucosides of wogonin. The present studies complement and extend the knowledge on the effect of substitution of A- and B-ring on the regioselective glycosylation of flavonoids catalyzed by microorganisms.

Highlights

Scutellaria baicalensis Georgi (Skullcap or Baikal Skullcap) is one of the most widely used herbals in traditional Chinese medicine
The most abundant constituents of root that induce these effects occur in forms of glucuronides—baicalin (1) and wogonoside (2)—and its aglycons—baicalein (3) and wogonin (4) (Figure 1)
The authors hydrolyzed a series of glycosylated flavones including baicalin (1) as substrates to obtain their aglycones; wogonoside (2) was not used in that study

Summary

Introduction

Scutellaria baicalensis Georgi (Skullcap or Baikal Skullcap) is one of the most widely used herbals in traditional Chinese medicine. This medicinal plant originated and widely distributed in Asia, including China, North Korea, Japan, Russia and Mongolia, and is acclimatized and cultivated in Central European conditions, where it has become increasingly popular and used as a nutraceutical. The dried powdered root of this plant—Radix Scutellariae (skullcap root)—is commonly used. It has high flavonoid content, which gives it its yellow color and is the reason for its traditional name Golden root or Golden skullcap [2]. The most abundant constituents of root that induce these effects occur in forms of glucuronides—baicalin (1) and wogonoside (2)—and its aglycons—baicalein (3) and wogonin (4) (Figure 1)

Methods

Results

Conclusion