The content of flavonoids especially baicalin and baicalein determined the medical quality of Scutellaria baicalensis which is a Chinese traditional medicinal plant. Here, we investigated the mechanism responsible for the content and composition of flavonoids in S. baicalensis under water deficit condition. The transcription levels of several genes which are involved in flavonoid biosynthesis were stimulated by water deficit. Under water deficit condition, fifteen up-regulated proteins, three down-regulated proteins and other six proteins were detected by proteomic analysis. The identified proteins include three gibberellin (GA)- or indoleacetic acid (IAA)-related proteins. Decreased endogenous GAs level and increased IAA level were observed in leaves of S. baicalensis which was treated with water deficit. Exogenous application of GA or α-naphthalene acelic acid (NAA) to plants grown under water deficit conditions led to the increase of endogenous GAs and the decrease of IAA and flavonoids, respectively. When the synthesis pathway of GA or IAA in plants was inhibited by application with the inhibitors, flavonoid levels were recovered. These results indicate that water deficit affected flavonoid accumulation might through regulating hormone metabolism in S. baicalensis Georgi.

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Salvia miltiorrhiza is an annual plant growing in China, Mongolia, Korea and some other Asian countries. The extract from S. miltiorrhiza roots has been used for supporting healthy cardiovascular and circulatory systems during the last decade. The active constituents of S. miltiorrhiza from different areas vary significantly, and the wild resources are overexploited. To adapt the demand for active constituents of S. miltiorrhiza against cardiovascular-related diseases, alternative materials need to be developed. The aim of the present work was to investigate the possibility of S. miltiorrhiza hairy roots as the alternative materials. The results showed that S. miltiorrhiza hairy roots are genetically stable. The contents of salvianolic acid B and tanshinone IIA, two main active constituents in hairy roots, determined by the assessment of combining fl ow cytometry and phytochemical analysis, are comparable to or significantly lower than in wild plant roots. The extract from S. miltiorrhiza hairy roots also had similar protection activity for hypoxia and reoxygenation injury in rat cardiac myocytes like that from wild plant roots. S. miltiorrhiza hairy roots may be alternative materials to obtain the drug or healthy food for cardiovascular-related diseases.

The active compounds in the roots of Scutellaria baicalensis Georgi, a traditional Chinese medicinal plant, are mainly fl avonoids which have anti-inflammatory, antitumour, and anti- HIV activity, respectively. The increasing annual average temperature has rendered the S. baicalensis plants grown in some ancient producing regions no longer suitable for their medicinal usage. Hydrogen peroxide plays an important role in root responses to abnormal temperature in S. baicalensis. Baicalin and baicalein and antioxidative enzymes were anticipated to detoxify H2O2 in S. baicalensis. Here, we show that abnormal temperatures (10 and 40 °C) decreased the content of flavonoids as compared with the normal temperature (30 °C), and the transcripts of UDP-glucuronate:baicalein 7-O-glucuronosyltransferase and β-glucuronidase involved in the interconversion between baicalin and baicalein were affected by the 40-°C treatment. High temperature also increased the activities of catalase and peroxidase. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the transcript levels of peroxidase 2, peroxidase 3, monodehydroascorbate reductase 2, and dehydroascorbate reductase were significantly increased under high-temperature conditions. The respective genes would be candidates for improvement of the adaptation of S. baicalensis plants to abnormal temperatures and for regulation of the contents of the active compounds.