Development and characterization of simple sequence repeat (SSR) markers based on a full-length cDNA library of Scutellaria baicalensis.

Scutellaria baicalensis Georgi is an herbaceous perennial plant used as one of the staple Chinese herbal medicines in China with a long officinal history. However, research on S. baicalensis is currently limited due to the lack of genome and gene expression information. A full-length cDNA library from leaves and roots of S. baicalensis subjected to water deficit and heat, conditions that have been shown to affect baicalein accumulation, was constructed. There were 6491 expressed sequence tags (ESTs) obtained. UniGenes were assembled by BLAST similarity searches and annotated with Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). A total of 78 simple sequence repeats (SSRs) were identified and SSR markers associated with the active ingredients of S. baicalensis were selected. EST-SSR transferability was determined from 5 populations from different areas. This study is the first to produce a large volume of gene expression data from S. baicalensis to facilitate gene discovery in S. baicalensis and provide an important resource for molecular genetic and functional genomic studies in this species.

In vitro study of the tocolytic effect of oroxylin A from Scutellaria baicalensis root.

Scutellariae Radix is one of the well-known tocolytic Chinese herbs. Oroxylin A is isolated from the root of Scutellaria baicalensis. The main syndrome of preterm birth is caused by uterus contractions from excitatory factors. Administration of tocolytic agents is a strategy to prevent the occurrence of preterm births. The aim of this study was to investigate the effects of oroxylin A on contractions of uterine strips isolated from non-pregnant female Wistar rats (250-350 g). Contractions of the uterus were induced with acetylcholine (Ach) (1 microM), PGF2alpha (0.1 microM), oxytocin (10-3 U/ml), KCl (56.3 mM), tetraethylammonium (TEA; 1 and 10 mM), 4-aminopyridine (4-AP; 5 mM), glipizide (30 microM), a nitric oxide synthase (NOS) inhibitor (LNNA; 10-3M), a beta-receptor blocker (propranolol; 10 microM), and a cyclooxygenase inhibitor (indomethacin; 60 microM). The inhibitory effects of the amplitude and frequency of spontaneous contractions by oroxylin A were antagonized with Ach (IC50 22.85 microM), PGF2alpha (IC5027.28 microM), oxytocin (IC50 12.34 microM), TEA; 1 and 10 mM (IC50 52.73 and 76.43 microM), 4-AP (IC50 67.16 microM), and glipizide (IC5027.53 microM), but oroxylin A was not influenced by Ca2+-free medium, LNNA, propranolol, or indomethacin. Otherwise, oroxylin A-mediated relaxation of the rat uterus might occur through opening of uterine calcium-dependent potassium channels or adenosine triphosphate potassium channel activation. This suggests that oroxylin A is the tocolytic principle constituent of Scutellariae Radix, and oroxylin A may provide a lead compound for new tocolytic drug development in the future.

Orthogonal array design for the optimization of supercritical fluid extraction of baicalin from roots of Scutellaria baicalensis Georgi.

Supercritical fluid was used to extract baicalin from the roots of Scutellaria baicalensis Georgi. An orthogonal array design (OAD), OA(9)(3(4)), was employed as a chemometric method for the optimization of the supercritical fluid extraction of baicalin from the herbal medicine. Four parameters, namely, modifiers, temperature and pressure of supercritical fluid, and the dynamic extraction time, were studied and optimized by a three-level OAD in which the interactions between the parameters were neglected. Determinations of the extracts were performed by high-performance liquid chromatography. The effects of parameters were studied using analysis of variance. The results showed that selection of the modifier was the main factor in attaining higher yields of baicalin. While the other three factors had some effect on the extraction of the compound, the effect was much less than that of the modifiers. 1,2-Propanediol-modified supercritical fluid was more effective than 95% ethanol-modified supercritical carbon dioxide or methanol-modified supercritical carbon dioxide for the extraction of baicalin from the solid matrix. Finally, experimental conditions were proposed which can provide the highest extraction yield with respect to the considered factors.

[RAPD analysis of Scutellaria baicalensis from different germplasms].

OBJECTIVE: To provide reference for breeding Scutellaria baicalensis from different germplasms,and to explore their genetic diversities and different strains. METHOD: The RAPD method was applied to the study on S. baicalensis from different germplasms by use of 14 random primers about 10 bp, and SAPD-analysis of 34 S. baicalensis from different germplasms was carried out by using the method of withingroups-linkage in SPSS 10.0. RESULTS: 14 among 115 primers were selected to amplify about 165 segments of DNA. Among them, 132 segments of DNA, 80.0% of the total, can represent genetic of diversities of S. baicalensis. According to RAPD analysis, 34 germplasms of S. baicalensis were classified into A, B, C and D categories. CONCLUSION: S. baicalensis from different germplasms shows abundant genetic diversities. Germplasms from Shandong like Mengyin 3, Menyin 2 and Pingyi have close distance (0.315) in genetic background, which can be chosen for breeding of cultivated. Though genetic characters are similar in the morphology, the geological distribution of S. baicalensis and its morphology have not certain correlation. The complex genetic background of S. baicalensis indicate that the work of the selective breeding and management for breeding of S. baicalensis have to be strengthened.

[Study on identification of wild and cultirated Radix Scutellariae in different growing years].

OBJECTIVE: To identify Radix Scutellariae (Huangqin) of different growth years, to distinguish whether it's wild or cultivated and to provide useful information for the quality control of Huangqin crude drug. METHOD: By using morphological and histological methods, we studied 87 individuals of 45 specimens from 12 habitats of 5 provinces of China, which grew wild or were cultivated in different growing years. Moreover, 22 commercial samples of Huangqin from 7 provinces were also investigated. RESULT: The identification was performed base on morphological and histological characteristics, such as, the shape, color, cork, remaining stems, decayed central xylem, and vessels arrangement, xylem cork ring, growth rings, etc. CONCLUSION: We established an identification method for distinguishing Huangqin wild or cultivated in different growing years. Furthermore, the structure of annual rings in the transection of Radix Scutellariae has been discovered for the first time.