Microwave‐assisted extraction coupled with countercurrent chromatography for the rapid preparation of flavonoids from Scutellaria barbata D. Don

As a famous Chinese herb having good inhibitory effects on numerous human cancers both in vitro and in vivo, Scutellaria barbata D. Don attracts extensive attention worldwide. In this work, four flavonoids named scutellarin, baicalin, luteolin, and apigenin were simply and rapidly prepared from S. barbata by microwave‐assisted extraction coupled to countercurrent chromatography. Extraction conditions including irradiation time, extraction temperature, liquid/solid ratio, and microwave power were optimized using an orthogonal array design method. The extract of S. barbata was separated and purified with a two‐phase solvent system composed of hexane/ethyl acetate/methanol/acetic acid/water (1:5:1.5:1:4, v/v/v/v/v) and 4.5 mg of scutellarin, 4.6 mg of baicalin, 1.1 mg of luteolin, 2.1 mg of apigenin were obtained from 2.0 g original sample in a single run. The purities of scutellarin, baicalin, luteolin, and apigenin determined by HPLC were 93.6, 97.3, 97.6, and 98.4%, respectively. The targeted compounds were identified by LC with MS and ¹H NMR spectroscopy. The total time including extraction, separation, and purification was <300 min. Compared to traditional methods, microwave‐assisted extraction coupled to countercurrent chromatography method is more simple and rapid for the extraction, separation, and purification of flavonoid compounds from natural products.     

Antiradical and antioxidant activity of flavones from Scutellariae baicalensis radix

We evaluated the antioxidant properties of four main flavones from Scutellaria baicalensis: baicalein, wogonin and their glucuronides – baicalin and wogonoside. We used three in vitro assays: free radical scavenging with 2,2′-diphenylpicrylhydrazyl radical, transition metal ions reducing power by phosphomolybdenum assay and inhibition of the hydroxyl radical-induced peroxidation of linoleic acid assay. All flavones have antioxidant capacity, which differs depending on the structure and mechanisms of activity. In all tests, only baicalein – the aglycone with three adjacent hydroxyl groups – exhibited consistent antioxidant effect. Wogonin protected linoleic acid against oxidation. Baicalin displayed less potent antioxidant properties whereas wogonoside did not have significant antioxidant activity.     

Systematic study on metabolism and activity evaluation of Radix Scutellaria extract in rat plasma using UHPLC with quadrupole time‐of‐flight mass spectrometry and microdialysis intensity‐fading mass spectrometry

Radix Scutellaria is a widely used traditional Chinese medicine in the treatment of various diseases. However, the activities of the absorbed components and metabolites of its main flavones in rat plasma need further investigation. In this study, a systematic method based on ultra‐high performance liquid chromatography with quadruple time‐of‐flight mass spectrometry was developed to speculate the absorbed components and metabolites of the main flavonoids in Radix Scutellaria extract in rat plasma sample after oral administration of the extract. Twelve compounds, including four prototype components and eight metabolites, were confirmed in drug‐containing plasma. In these metabolites, five were originally detected in rat plasma. The possible metabolic pathways of these polyhydroxy flavones in vivo were described and clarified. Microdialysis with intensity‐fading mass spectrometry was originally employed to investigate the binding affinities of the absorbed components and metabolites with α‐glucosidase. The order of their binding affinities was P4 > P3 > P2 > P1≥M5 > M3 > M1. The research result is helpful to deepen the understanding of the absorbed components and metabolic pathways of main flavones from Radix Scutellaria, and provide a new approach to screen potential inhibitors from in vivo components originated from Chinese herb.     

Antimicrobial flavonoids isolated from Indian medicinal plant Scutellaria oblonga inhibit biofilms formed by common food pathogens

Scutellaria oblonga Benth., a hitherto phytochemically unexplored Indian medicinal folklore plant was extracted with acetone and subjected to chromatography to yield nine flavonoids, for the first time from this plant. Antimicrobial assays were performed against 11 foodborne pathogens, and three molecules (Techtochrysin, Negletein and Quercitin-3-glucoside) depicted significant activity. These molecules were assessed for their rate of antibacterial action using time–kill curves which depicted complete inhibition of most of the bacteria within 12–16 h. The significant biofilm-reducing capability exhibited by these three molecules formed a significant finding of the current study. In most of the experiments, a 90–95% reduction in biofilms was observed. Thus, flavonoids as natural molecules from S. oblonga could be further researched to be used as potent antimicrobial and antibiofilm agents.     

DART-Orbitrap质谱法对黄芩药材的快速分析

将实时直接分析(DART)离子源与高分辨率质谱Orbitrap联用,建立了一种对黄芩药材进行快速定性定量分析的方法。定性分析时,对其中的化学成分进行标准品比对和二级质谱确证,同时参考相应文献进行确认。定量分析时,采用Full MS-SIM及Targeted-MS2扫描方式采集信号,Targeted-MS2扫描方式下分别对黄芩素和汉黄芩素的母离子和子离子的提取离子流图积分,通过峰面积计算含量。在黄芩药材中检出黄芩素、汉黄芩素、韧黄芩素Ⅱ、二羟基-二甲氧基黄酮、5,7,2',5'-四羟基-8,6'-二甲氧基黄酮和SkullcapflavonⅡ的[M+H]+峰。定量分析结果显示,黄芩素(m/z 271.06→123.01)的线性范围为49.7~447.3 ng,相关系数(r2)为0.995,平均加标回收率为87.0%;汉黄芩素(m/z 285.07→270.05)的线性范围为50.0~350ng,r2为0.995,平均加标回收率为66.0%。该方法可用于黄芩药材的快速定性检测和定量分析。     

木根黄芩中-新黄酮的光谱特征

从木根黄芩(Scutellaria planipes Nakai et Kitag.)中分离得到一新黄酮类化合物. 该化合物被鉴定为5,7,3′,6′-tetrahydroxy-6,8,2′-trimethoxyflavone. 它有很强的抑制5-酯氧合酶活性. 由于该化合物的A环全部被取代，因此，应用一般的光谱技术很难准确归属各碳的化学位移. 我们应用¹³C-¹³C相关谱和酰化位移方法，明确归属了各碳的信号，并订正了文献中对部分信号的错误归属.     

不同产地黄芩中黄芩甙及元素的含量比较

用高效液相色谱法和原子吸收光谱法分别对１０个不同产地正品黄芩中黄芩甙及元素的含量进行了分析比较。     

FLAVONOIDS OF THE AERIAL PART OF Scutellaria immaculate

Chrysin-7-O-glucuronide, scutellarein-7-O-glucoside, apigenin-7-O-glucoside, baicalein-7-O-glucoside, norwogonin-7-O-glucoside, oroxyloside, wogonoside, and the new glycoside immaculoside-5,8-dimethoxy-7-O--D-glucopyranosylflavone were isolated for the first time from the aerial part of white skullcap (Scutellaria immaculateNevski). The structure of the last was established using chemical transformations and spectral data.     

FTIR用于第4代太空诱变育种黄芩的分析

首次从整体上测定并对比分析了我国独创的太空诱变育种黄芩和地面组黄芩,以期为全面了解第4代太空诱变黄芩品质的变化和深入研究积累资料.结果表明两组样品的FTIR光谱的主要吸收峰的峰位、峰形大致相同,但吸收峰的强度却有明显差异,太空组黄芩中各主要吸收峰强度都比地面组明显增强,尤其是黄芩的主要活性成分黄酮类化合物(黄芩甙、黄芩素、汉黄芩甙、汉黄芩素及黄芩新素等)在3 391,1 655,1 069 cm-1等处吸收峰强度明显比地面组增强,说明太空组黄芩中主要活性成分黄酮类化合物及其他成分含量比地面组明显提高.这表明太空组黄芩的非晶态活性成分明显得到了优化.太空诱变育种有利于选育出活性成分提高的黄芩新品种,是中药材种质资源创新的快捷有效的途径之一.     

Anti-Photoaging Activity of Scutellaria barbata D. Don (Family Lamiaceae) on Ultraviolet B-Irradiated NIH-3T3 Skin Fibroblast and SKH-1 Hairless Mouse

We investigated whether Scutellaria barbata D. Don (Family Lamiaceae) (SBD), a traditional medicine used for heat clearing and detoxification, possesses antiphotoaging properties. Pretreatment of NIH-3T3 skin fibroblast cells with non-toxicological levels of water extract of SBD (WESBD) and ethanol extract of SBD (EESBD) restored the expression of procollagen type-1 (COL1A1), matrix metalloproteinase-1a (MMP-1a), interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemotactic protein-3 (MCP-3) genes following abnormal expression induced by ultraviolet B (UVB) irradiation. WESBD/EESBD administration to the dorsal skin area of hairless mice significantly (p < 0.05) inhibited UVB-induced wrinkle formation and epidermal thickness. The WESBD and EESBD treatments also restored the dermal collagen content, which was decreased by the UVB treatment, and normal COL1A1 and MMP-1a expression. Interestingly, both the WESBD and EESBD pretreatments significantly attenuated UVB-induced phosphorylation of protein kinase B (AKT) but not that of mitogen-activated protein kinases (MAPKs). This finding indicates that the antiphotoaging effects of WESBD and EESBD may be related to attenuation of UVB-induced overactivation of AKT phosphorylation. High performance liquid chromatography (HPLC) and mass spectrometry analysis revealed that isorhamentin and scutebarbatine I were major single components of EESBD. These results suggest that WESBD and EESBD may have potential in development as antiphotoaging agents.