Different extraction pretreatments significantly change the flavonoid contents ofScutellaria baicalensis

Abstract

Context Scutellaria baicalensis is one of the most commonly used medicinal herbs, especially in traditional Chinese medicine. However, compared to many pharmacological studies of this botanical, much less attention has been paid to the quality control of the herb’s pretreatment prior to extract preparation, an issue that may affect therapeutic outcomes. Objective The current study was designed to evaluate whether different pretreatment conditions change the contents of its four major flavonoids in the herb, i.e., two glycosides (baicalin and wogonoside) and two aglycons (baicalein and wogonin). Materials and methods An HPLC assay was used to quantify the contents of these four flavonoids. The composition changes of four flavonoids by different pretreatment conditions including solvent, treatment time, temperature, pH value, and herb/solvent ratio were evaluated. Results After selection of the first order time-curve kinetics, our data showed that at 50°C, 1:5 herb/water (in w/v) ratio and pH 6.67 yielded an optimal conversion rate from flavonoid glycosides to their aglycons. In this optimized condition, the contents of baicalin and wogonoside were decreased to 1/70 and 1/13, while baicalein and wogonin were increased 3.5 and 3.1 folds, respectively, compared to untreated herb. Discussion and conclusion The markedly variable conversion rates by different pretreatment conditions complicated the quality control of this herb, mainly due to the high amount of endogenous enzymes of S. baicalensis. Optimal pretreatment conditions obtained from this study could be used obtain the highest level of desired constituents to achieve better pharmacological effects.

Colon cancer chemopreventive effects of baicalein, an active enteric microbiome metabolite from baicalin

“…Our results showed that after 8 h of culture, water soaking (without enzymes) did not induce such transformation. The experimental condition in this water control was different from those of our previously published report, in which botanical enzymes significantly converted baicalin to baicalein ( 15 ). Thus, our results suggested that the enteric microbiome played a critical role in metabolizing baicalin to baicalein.…”

“…S. baicalensis is one of the most commonly used herbs in traditional medicine for the treatment of various inflammatory diseases in Asia. The representative constituents of S. baicalensis are a group of flavonoids that include glycosides (baicalin, wogonoside) and their aglycon metabolites (baicalein and wogonin), while baicalin occupies the major content of the total flavonoids ( 14 , 15 ). In recent years, the anticancer activities of S. baicalensis extract and its constituents were reported ( 36 , 37 ).…”

“…The root of Scutellaria baicalensis is a widely used herbal medicine in the traditional medical systems of China and Japan for a variety of inflammation related ailments ( 10 – 13 ). The major constituents of this botanical are a group of flavonoid glycosides, including baicalin, and wogonoside, of which baicalin is the major constituent in the herb ( 14 , 15 ).…”

Study of Baicalin Hydrolysis Kinetics in the Process of Its Extraction From Scutellaria Baicalensis Georgi Roots

“…Из литературных источников известно, что вид экстрагента, температура и время экстракции очень сильно влияют на качественный и количественный состав получаемого экстракта [19,20].…”

H2O2improves quality of Radix scutellariae through anti-oxidant effect

“…Moreover, baicalein and wogonin are easily absorbed in the stomach and small intestine as well as colon, and the baicalein is 7 times more than the baicalin,[ 5 ] these remind us that baicalein and wogonin have an excellent efficient therapy in clinic. Higher baicalein was valued highly, some practices of transforming glycosidase into their aglucon were appreciated,[ 6 7 ] therefore, the content of baicalein is major contributor to the quality of R. scutellariae , and to the ecological adaptation.…”