Anti-oxidative and DNA protecting effects of flavonoids-rich Scutellaria lateriflora

Scutellaria lateriflora (American skullcap), a native plant of North America, has been used by Americans and Europeans as a nerve tonic for more than 200 years. In vivo studies have shown anxiolytic activity ofS. lateriflora in animals and humans. However, the neuroprotective mechanisms ofS. lateriflora are not fully understood. Oxidative stress plays a vital role in the neurodegenerative and neuropsychiatric diseases such as anxiety, Alzheimer's disease, depression, and Parkinson's disease. Bioactive compounds present in various medicinal plants neutralize or scavenge toxic free radicals and thus suppress oxidative stress. Therefore, the objective of this study was to investigate the antioxidant effects of S. lateriflora. The antioxidant potential of aqueous or ethanolic extracts of S. lateriflora was determined in mouse brain tissue using various biochemical assays. Protective effects of S. lateriflora against oxidative stress induced DNA fragmentation was determined using plasmid DNA. The ethanolic and aqueous extracts scavenged the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The ethanolic extract reduced tert-butyl peroxide-induced reactive oxygen species (ROS) and lipid peroxides in the mouse brain homogenates. Furthermore, the ethanolic extract of S. lateriflora protected hydrogen peroxide-UV induced cleavage of supercoiled plasmid DNA. In conclusion, S. lateriflora exhibited significant antioxidant effects. The current findings posit S. lateriflora as one of the potential experimental herbal drugs that should be screened for its therapeutic potential against various oxidative stress associated mental disorders.

Bioassay-guided isolation of neo-clerodane diterpenoids from Scutellaria barbata

Bioassay-guided isolation of the aerial part of Scutellaria barbata yielded three new neo-clerodane diterpenoids scutebatas P-R (1-3), together with two known ones: scutebata E (4) and scutebarbatine B (5). The chemical structures of the isolated compounds were elucidated by spectroscopic methods (NMR and MS) and by comparison with the spectroscopic data reported in the literature. All compounds except 3 showed weak cytotoxicity with IC50 values ranging from 35.11 to 42.73 μM against K562 cell lines, and compounds 1, 2, and 5 also displayed weak activities against HL60 cell lines.

Minor iridoids from Scutellaria albida ssp. albida. Inhibitory potencies on lipoxygenase, linoleic acid lipid peroxidation and antioxidant activity of iridoids from Scutellaria sp

A new iridoid glycoside, 6'-O-E-caffeoyl-mussaenosidic acid , in addition to one known aglycon, four known triterpenes and one known flavonoid, were isolated from the aerial parts of Scutellaria albida subsp. albida. Furthermore, 12 iridoids with similar structures isolated from Scutellaria sp., were examined for their inhibitory potency on lipoxygenase and lipid peroxidation, as well as their antioxidant activity, in comparison to known antioxidants e.g. caffeic acid, nordihydroguaretic acid (NDGA) and trolox. AAPH, DPPH and soybean lipoxygenase (LOX) assays were used for the tests. This investigation led to interesting observations considering the Structure-Activity Relationship. According to our results, the presence of a p-coumaroyl group optimized and even dramatically changed the biological responses of the investigated iridoids.

Scutellaria barbata D. Don extract synergizes the antitumor effects of low dose 5-fluorouracil through induction of apoptosis and metabolism

Traditional Chinese medicines have been recognized as a new source of anticancer drugs or chemotherapy adjuvant to enhance the efficacy of chemotherapy and to ameliorate the side effects. This study aimed to investigate the antitumor effects of combined Scutellaria barbata D. Don extract (SBE) and 5-FU treatment in vitro and in vivo and the potential mechanisms. SBE was prepared and analyzed by HPLC. Tumor growth inhibition both in vitro and in vivo, cell apoptosis, apoptosis related protein expressions (P53, bid, bax, bcl-2), caspase-3 activities and 5-FU related enzymes were assessed. SBE could significantly synergize the antitumor effects of low dose 5-FU both in vivo and in vitro. SBE could increase the apoptosis inducing effect of low dose 5-FU in both Bel-7402 and HCT-8 cells. Also, caspase-3 activities, P53 and bax expressions were significantly increased, while bid and bcl-2 expressions were significantly decreased in drug combination groups, compared with individual drug treatment groups. Furthermore, SBE could significantly decrease the mRNA levels of dihydropyrimidine dehydrogenase. These results showed that combined treatment with SBE and low dose 5-FU can significantly inhibit the tumor growth both in vitro and in vivo, which might be related with apoptosis and regulations of 5-FU metabolism.

Acaricidal toxicities of 1-hydroxynaphthalene from Scutellaria barbata and its derivatives against house dust and storage mites

The essential oil of Scutellaria barbata was extracted using a steam distillation and then evaluated via fumigant and contact toxicity bioassays against Dermatophagoides farinae, Dermatophagoides pteronyssinus, and Tyrophagus putrescentiae. The acaricidal toxicities of 1-hydroxynaphthalene from S. barbata oil and its derivatives were determined and compared with those of benzyl benzoate. Based on the LD50 values of 1-hydroxynaphthalene derivatives against D. farinae, D. pteronyssinus, and T. putrescentiae, obtained using a fumigant toxicity bioassay, the acaricidal activity of 1-hydroxynaphthalene (2.11, 2.37, and 4.50 µg/cm2) was 4.76, 6.00, and 2.68 times higher than that of benzyl benzoate (10.05, 9.50, and 12.50 µg/cm2) in the corresponding order, which was followed by that of 2-hydroxynaphthalene (9.50, 9.00, and 11.50 µg/cm2). On the contact toxicity bioassay, the acaricidal activity of 1-hydroxynaphthalene (0.79, 0.92, and 2.50 µg/cm2) was 9.49, 6.52, and 3.76 times higher than that of benzyl benzoate (7.50, 6.00, and 9.41 µg/cm2), which was followed by that of 2-hydroxynaphthalene (4.21, 4.80, and 6.50 µg/cm2). In conclusion, our results indicate that S. barbata oil and 1-hydroxynaphthalene derivatives might be effective natural agents for the management of house dust and storage mites.

Oroxylin A induces dissociation of hexokinase II from the mitochondria and inhibits glycolysis by SIRT3-mediated deacetylation of cyclophilin D in breast carcinoma

Oroxylin A is a major active component of the Chinese traditional medicinal plant Scutellaria baicalensis Georgi, which has been reported as a potential anticancer drug. We demonstrated that, Oroxylin A inhibited the glycolysis and the binding of hexokinase II (HK II) with mitochondria in human breast carcinoma cell lines, which was dependent on sirtuin-3 (SIRT3). The level of SIRT3 in mitochondria was increased by Oroxylin A. Then SIRT3 deacetylated cyclophilin D, diminished its peptidyl-prolyl cis-trans isomerase activity and induced its dissociation from the adenine nucleotide translocator. Finally, SIRT3-induced inactivation of cyclophilin D resulted in the detachment of mitochondrial HK II and the inhibition of glycolysis. These results have important implications for the metabolism reprogramming effect and the susceptibility to Oroxylin A-induced mitochondrial cytotoxicity through the regulation of SIRT3 in breast carcinoma.

Cytotoxic and antioxidant properties of selected Scutellaria species from the Western Ghats of Peninsular India

CONTEXT

Scutellaria (Lamiaceae), commonly known as 'Skullcaps', has been extensively used in Traditional Chinese Medicine (TCM). Recently, much emphasis has been given to this genus due to the rich source of bioflavonoids that contribute to its biological properties. Therefore, different species of Scutellaria are being explored worldwide.

OBJECTIVES

Cytotoxic, antioxidant, and phytochemical properties of Scutellaria colebrookiana Benth and S. violacea (Heyne ex Benth) Don collected (October 2009-February 2010) from Western Ghats of India have been analysed.

MATERIALS AND METHODS

In vitro cytotoxicity and free radical scavenging effects of root extracts in various solvents were analysed. Spectrophotometric and HPLC methods were performed for phytochemical analysis.

RESULTS

Chloroform extract exhibited significant cytotoxicity in Dalton's Lymphoma Ascites (DLA) and Ehrlich Ascites Carcinoma (EAC) cells with IC(50) values 150 and 140 µg/mL for S. colebrookiana and 250 and 280 µg/mL for S. violacea, respectively. Moreover, the extract was effective in scavenging free radicals and inhibiting membrane peroxidation in vitro with IC(50) values 158.3 and 167.5 (superoxide), 17.5 and 28.0 (hydroxyl), 76.25 and 69.75 (DPPH), 24.5 and 28.0 (ABTS), 69.75 and 64.6 (lipid peroxidation), 41 and 31.5 µg/mL (erythrocyte hemolysis), respectively. Antioxidant effect observed with acetone extract was also comparable to that of chloroform extract. Phytochemical screening revealed the presence of baicalein.

DISCUSSION AND CONCLUSION

Scutellaria species of Western Ghats showed cytotoxic and antioxidant potential and the presence of baicalein. This suggests that S. colebrookiana and S. violacea could be used as alternative sources for baicalein in view of the reported scarcity of S. baicalensis.

[Estimating medicinal yield of Seutellaria baicalensis in Beijing-Tianjin-Hebei region based on 3S technology]

Resources survey of traditional Chinese medicine and reserves estimation are found to be the most important issues for the protection and utilization of traditional Chinese medicine resources, this paper used multi-spatial resolution remote sensing images (RS) , geographic information systems (GIS) and global positioning system (GPS) , to establish Scutellaria resources survey of 3S data platform. Combined with the traditional field survey methods, small-scale habitat types were established based on different skullcap reserve estimation model, which can estimate reserves of the wild Scutellaria in Beijing-Tianjin-Hebei region and improve the estimation accuracy. It can provide an important parameter for the fourth national survey of traditional Chinese medicine resources and traditional Chinese medicine reserves estimates based on 3S technology by multiple spatial scales model.

Baicalin, a natural compound, promotes regulatory T cell differentiation

BACKGROUND

CD4(+)CD25(+)Foxp3(+) regulatory T (T(reg)) cells inhibit autoimmunity and protect against tissue injury. The development of these T(reg) cells is controlled by the regulator protein Foxp3, which can be enhanced by the in vitro activation of Foxp3 in the presence of transforming growth factor-beta. However, little is known about alternative methods, such as the use of natural products, for controlling Foxp3-mediated T(reg) cell differentiation.

METHOD

HEK 293 T cells were transfected with Foxp3 expression plasmid, and then treated with different compounds, Foxp3 mRNA expression was determined by real-time RT-PCR. CD4(+)CD25(-)T cells were stimulated with Baicalin, Foxp3 protein expression were analyzed by flow cytometry and confocal microscopy, the regulatory function of T cells stimulated with Baicalin was detected by the carboxyfluorescien succinimidyl ester.

RESULTS

We demonstrated that Baicalin, a compound isolated from the Chinese herb Huangqin, induced Foxp3 protein expression in cultured T cells, promoted T(reg) cell differentiation and regulatory activity. Our data also indicated that Baicalin restored Foxp3 expression following its initial interleukin-6-mediated inhibition and induced Foxp3 expression in vitro.

CONCLUSIONS

These data suggest that Baicalin may promote T(reg) cell differentiation and regulatory activity and may serve as a promising natural immunosuppressive compound for treating autoimmune inflammatory diseases.

[Wogonin inhibits IGF-1-stimulated cell growth and estrogen receptor α expression in breast adenocarcinoma cell and angiogenesis of chick chorioallantoic membrane]

The aim of the present study was to investigate the involvements of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. MCF-7 cells (human breast adenocarcinoma cell line) were subjected to several drugs, including IGF-1, wogonin and ER inhibitor ICI182780, alone or in combination. MTT assay was used to detect breast cancer proliferation. Western blot was used to analyze ERα and p-Akt expression levels. CAM models prepared from 6-day chicken eggs were employed to evaluate angiogenesis inhibition. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis. These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model.

Chemical constituents of the aerial parts of Scutellaria lateriflora and their alpha-glucosidase inhibitory activities

MeOH extracts of 37 herbs were tested in screening experiments for rat intestinal alpha-glucosidase. The MeOH extract of the aerial parts of Scutellaria lateriflora L. (Lamiaceae) significantly inhibited sucrase and maltase activities, using sucrose and maltase as the substrates. Enzyme inhibition guided-fractionation of the MeOH extract of S. lateriflora resulted in the isolation of a new diterpene glucoside, deacetylajugarin-IV 18-O-beta-D-glucopyranoside (1), along with 20 known phenolics (2-21). The structures of 1-21 were elucidated on the basis of MS and NMR data analyses. Baicalein (4) and baicalin (10), a glycoside of 4, showed moderate sucrase inhibitory activities at IC50 values of 14.9 and 36.3 microM, respectively, whereas luteolin (3), acteoside (16), leucosceptoside A (18), and isoacteoside (20) showed weak inhibitory activities at IC50 values of 811, 522, 727, and 443 microM, respectively. This is the first report on mammalian alpha-glucosidase inhibitory activities of S. lateriflora extract and identification of the constituents responsible for the activities. Apigenin (2), luteolin (3), 6-methoxyluteolin 4'-methyl ether (6), isoscutellarin 8-O-beta-D-glucuronide (7), luteolin 7-O-beta-D-glucuronide (9), wogonin 7-O-beta-D-glucuronide methyl ester (12), eriodictyol (13), naringenin (14), naringenin 7-O-beta-D-glucuronide (15), jionoside D (17), leucosceptoside A (18), and (+)-syringaresinol 4'-O-beta-D-glucopyranoside (21) were isolated from this plant for the first time. The inhibitory properties of S. lateriflora extract against alpha-glucosidase provide a prospect for its antidiabetic usage.

Studying on inclusion complexes of Wogonin with β-cyclodextrin and hydroxypropyl-cyclodextrin

The formation of the complexes of Wogonin with β-cyclodextrin (β-CD) and hydroxypropyl-cyclodextrin (HP-β-CD) was studied by fluorescence spectra and nuclear magnetic resonance spectroscopy (NMR). The formation constants (Ks) of complexes were determined by fluorescence method. The results suggested that HP-β-CD was easier to form inclusion with Wogonin than β-CD in solution. In different pH solutions, CDs have different inclusive capacity to Wo. β-CD was most suitable for inclusion of neutral form and HP-β-CD was suitable for acidic form. In addition, the experimental resulted confirmed the existence of 1:1 inclusion complex of Wogonin with CDs. Besides, kinetic studies of DPPH with Wogonin and CDs complexes were done. The results obtained indicated that the complex was the most reactive form. Special configuration of complex has been proposed on NMR technique.

[Study on chemical constituents of Scutelliaria regeliana]

OBJECTIVE

To study the chemical constituents in ethyl acetate fraction from the root of Scutelliaria regeliana.

METHOD

The compounds were isolated by silica gel column chromatography and HPLC, and their structures were elucidated by means of spectral analyses.

RESULT

23 compounds were isolated and identified.

CONCLUSION

Compound 1 is new, named as scutellariae flavonol, and the others were isolated from S. regeliana for the first time.

Analysis of essential oils from Scutellaria orientalis ssp. alpina and S. utriculata by GC and GC-MS

The chemical composition of the essential oils obtained from aerial parts of Scutellaria orientalis L. ssp. alpina (Boiss.) O. Schwarz and S. utriculata Labill. growing wild in Lebanon, were analyzed by GC and GC-MS. In S. orientalis ssp. alpina, strongly characterized by sesquiterpenes (41.2%) and particularly sesquiterpene hydrocarbons (31.7%), hexahydrofarnesylacetone (11.7%) was recognized as the main constituent, together with hexadecanoic acid (7.6%), caryophyllene (7.4%), caryophyllene oxide (6.8%), 4-vinylguaiacol (5.4%) and germacrene D (5.4%). S. utriculata oil was instead constituted above all by monoterpenes (42.2%), particularly oxygen containing monoterpenes (39.9%), and in this oil the main compounds were linalool (20.1%), 4-vinyl guaiacol (15.5%), alpha-terpineol (8.9%), (E)-nerolidol (8.9%) and geraniol (8.2%).

Neoclerodane diterpenoids from Scutellaria barbata

Eight new neoclerodane diterpenoids (1- 8), scutebatas H-O, together with eight known compounds, have been isolated from the whole plant of Scutellaria barbata D. Don. Their structures were elucidated on the basis of spectroscopic studies. In vitro cytotoxicity of selected compounds against cancer cell lines HL-60, SMMC-7721, A-549, MCF-7, and SW480 was evaluated. Compounds 5, 6, 7 showed moderate cytotoxicities against several human cancer cell lines, with IC50 values ranging from 12.6-31.4 µM. In addition, compound 1 showed selective cytotoxicity against MCF-7.

[Effects of baicalin against oxidative stress injury of SH-SY5Y cells by up-regulating SIRT1]

This study is to investigate the effect of baicalin (BL) against oxidative injury stress of SH-SY5Y cells induced by H2O2 and the possible mechanism. SH-SY5Y cells were pre-incubated with baicalin (25, 50, and 100 micromol x L(-1)) for 12 h prior to exposure to H2O2 (150 micromol x L(-1)) for 24 h. The viability of SH-SY5Y cells was measured by MTT assay. The contents of LDH and NO were determined. The percentage of apoptotic cells was assessed by flow cytometry (FCM). The content of Caspase-3 was tested by immunofluorescence histochemical method. BL at 50 and 100 micromol x L(-1) separately increased the cell viability and up-regulated SIRT1, reduced the contents of LDH, NO, Caspase-3 and the apoptotic percentage of SH-SY5Y cells. This study results suggest that baicalin could inhibit the H2O2-induced neuronal apoptosis. The further mechanism studies show that baicalin inhibit apoptosis via reducing Caspase-3 expression and up-regulating SIRT1.

[Effects of scutellaria stem-leaf total flavonoids on cardiocyte apoptosis induced by hypoxia/reoxygenation]

OBJECTIVE

To study the effect of Scutellaria baicalensis stem-leaf total flavonoids (SSTF) on cardiocyte apoptosis of neonatal rats induced by hypoxia/reoxygenation and its action of mechanism. METHODS Sixty one to two days old rats, male or female, were selected. Hypoxia/reoxygenation injured model was established in cultured cardiocytes of neonate rats. The cultured neonatal rat cardiocytes were divided into 5 groups, i.e., the normal control group, the hypoxia/reoxygenation injury group (as the model group, cultured cardiocytes were exposed to hypoxia 2 h and subsequently reoxygenated for 4 h), the hypoxia/reoxygenation injury plus 50 mg/L SSTF group (as the low dose SSTF group), the hypoxia/reoxygenation plus 100 mg/L SSTF group (as the middle dose SSTF group), and the hypoxia/reoxygenation plus 200 mg/L SSTF group (as the high dose SSTF group). The cell viability was detected by methyl thiazolyl tetrazolium (MTT) colorimetry. The apoptosis of cardiocytes was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and the apoptosis rate calculated. The Bcl-2 and Bax protein expressions were determined by immunohistochemistry.

RESULTS

Compared with the normal control group, the cell viability, Bcl-2 protein contents and Bcl-2/Bax decreased, the apoptosis rate and Bax protein contents increased in the model group (all P<0.01). Compared with the model group, the cell viability, Bcl-2 protein contents and Bcl-2/Bax increased, while the apoptosis rate and Bax protein contents decreased in each SSTF treated group (P<0.05, P<0.01). Compared with the low dose SSTF group, significant difference existed in each index of the high dose SSTF group (all P<0.05).

CONCLUSIONS

SSTF had protection on hypoxia/reoxygenation induced cardiocyte apoptosis. Its protective mechanism might be correlated with its up-regulation of the expression of Bcl-2 protein ahd down-regulation of the expression of Bax protein.

In vitro and in vivo antitumor activity of Scutellaria barbate extract on murine liver cancer

In the present study, we investigated the in vitro and in vivo antitumor effects of crude extract of Scutellaria barbate (CE-SB) on mouse hepatoma H22 cells. The MTT assay was used to determine the growth inhibition of H22 cells in vitro. The in vivo therapeutic effects of CE-SB were determined using H22 tumor bearing mice. Besides, the body weight, tumor weight, thymus index and spleen index of H22 bearing mice were also measured. The tumor inhibitory rate (IR) was calculated according to the mean weight of tumor (MWT). The phagocytotic function of macrophages was examined by observing peritoneal macrophages phagocytize chicken RBC. The results showed that CE-SB could inhibit the growth of hepatoma H22 Cells in vitro and in vivo. Furthermore, CE-SB could improve immune function of H22 tumor bearing mice. Together these results indicate that CE-SB has antitumor activity and seems to be safe and effective for the use of anti-tumor therapy.

Simultaneous quantification of Echinacea species, Flos Lonicerae, Radix Scutellaria and Fructus Forsythiae combinations by rapid resolution liquid chromatography

Echinacea angustifolia and E. purpurea are commonly used in North America for their anti-bacterial effects. Flos Lonicerae, Radix Scutellaria and Fructus Forsythiae are traditional Chinese medicinal herbs commonly used for the treatment of complaints such as pneumonia, acute upper respiratory tract infection, and acute bronchitis. A reproducible, simple, and reliable rapid resolution liquid chromatographic (RRLC) method has been developed to analyze extracts of products formulated containing E. angustifolia, E. purpurea, Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae simultaneously in one run in less than 6 minutes. The method uses a C18-HST column, a mobile phase consisting of 0.1% aqueous phosphoric acid solution and acetonitrile, and UV detection at 327 nm and 229 nm. A stability test was performed that revealed that chlorogenic acid is more stable in acidic pH, and hence it is best to keep the extract of E. augustifolia, E. purpurea, Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae in mild acidic conditions at approximately pH 5.

Chromatographic fingerprint and quantitative analysis of seven bioactive compounds of Scutellaria barbata

Scutellaria barbata D. Don is widely used as a folk antitumor and anti-inflammatory agent in Asia. However, a simple and global quality control method for S. barbata was lacking. In this study, six phenolic compounds, including P-coumaric acid, scutellarin, apigenin 5-O-β-glucopyranoside, luteolin, apigenin and 4'-hydroxywogonin were obtained from S. barbata by phytochemical investigations. The six compounds plus baicalein show cytotoxcities to the nine human cancer cells, K562, MGC-803, HL60, SH-SY5Y, SW1116, SMMC-7221, SW480, HepG2 and KB. Subsequently, a high-performance liquid chromatography with photodiode array detector (HPLC-DAD) was developed for both fingerprint analysis of S. barbata and quantitative determination of the seven anticancer active compounds in S. barbata. The chromatographic separation was accomplished on an Ultimate™ XB-C18 column (4.6 x 250 mm, 5 µm) in 65 min. For fingerprinting, 26 common peaks were found and selected as characteristic peaks to assess the consistency of S. barbata samples. For quantitative analysis, the seven bioactive compounds showed good regression relationship ( R² > 0.999) within test ranges and the recovery of the method was in the range of 90-105 %. In brief, the present study provides the fingerprint analysis and quantitative methods for global and systematical quality control of S. barbata for its anticancer usage.

Two new phenols from Scutellaria barbata

Two new phenols, 2(S)-2’,7-dihydroxy-5,8-dimethoxyflavanone (1) and (S)-2-(4-hydroxyphenyl)-6-methyl-2,3-dihydro-4H-pyran-4-one (2), were isolated from the ethanol extract of Scutellaria barbata. Their structures were elucidated on the basis of spectroscopic analysis.

[The enhancing effect of Angelica dahurica extracts on absorption of baicalin--the active composition of Scutellaria]

To explore the mechanism of the absorption enhancement of Angelica dahurica extract (Ade), the absorption mechanism of baicalin in the Scutcllaria water extraction as well as the effect of Angelica dahurica extract on absorption of baicalin were investigated. In order to determine the main absorption site, everted intestinal sac model was used to study the effect of Angelica dahurica extract on the absorption of baicalin at duodenum, jejunum, ileum and colon. In situ single pass intestinal perfusion model was performed to study the absorption of various concentrations of baicalin and the effect of Angelica dahurica extract on the absorption of baicalin at the main absorption site. To authenticate the consequence of perfusion by getting the blood from the hepatic portal vein and determine the concentration of the baicalin in the blood. The result showed that baicalin could be absorbed at all of the four intestinal segments with increasing absorption amount per unit as follows: ileum > colon > jejunum > duodenum. The absorption ofbaicalin in the duodenum significantly increased with Angelica dahurica extract, thus, duodenum was chosen to be the studying site. Apparent permeability values (Papp) and absorption rate constant (Ka) of baicalin in the duodenum increased gradually with higher concentrations. When the concentration of baicalin rises to a certain degree, the absorption increase had a saturable process, the absorption of baicalin may be an active transportation. Baicalin may be not a substrate of P-gp as verapamil which had not significantly affected the Papp and Ka of baicalin. The absorption of baicalin in the duodenum significantly increased (P < 0.01) in the two models with Angelica dahurica extract and the concentration of baicalin in the blood from the hepatic portal vein showed that the Angelica dahurica extract can increase the absorption of baicalin.

[Determination of four effective components from total flavonoids of Scutellaria barbata by high performance liquid chromatography]

OBJECTIVE

To establish a HPLC method for simultaneous determination of 4 effective components from total flavonoids of Scutellaria barbata (FSB).

METHODS

The HPLC method was developed on an Agilent Zorbax C₁₈ column (4.6 mm × 250 mm, 5 μm). The mobile phase was composed of 1% HAc and CH₃OH:CH₃CN (80:20) with a linear gradient elution. The flow rate was 1.0 ml/min, and UV detection wave length was set at 280 nm. The column temperature was maintained at 30°C.

RESULT

The linear range of 4 effective components (scutellarin, isoscutellarein-8-O-glucuronide, isoscutellarein and luteolin) was 0.14-11.20 μg, 0.03-2.40 μg, 0.007-0.560 μg and 0.027-2.160 μg, respectively. The average recovery for 4 effective components was (101.9 ± 1.4)%, (103.5 ± 0.6)%, (98.1 ± 2.9)% and (100.5 ± 2.3)%, respectively. The contents of 4 flavonoids were determined, with scutellarin 7.3%-14.3%, isoscutellarein-8-O-glucuronide 2.4%-9.3%, isoscutellarein 0.3%-0.5%, and luteolin 0.2%-0.6%, respectively.

CONCLUSION

The method can be used effectively to evaluate the quality of FSB.

Protective effects of baicalin against ischemia/reperfusion injury in rat liver

The cytoprotective properties of baicalin (1), a flavonoid glycoside isolated from Scutellaria baicalensis, have been investigated against injury to the liver caused by ischemia/reperfusion (I/R). Rats were subjected to 60 min of ischemia followed by 5 h of reperfusion, and 1 was administered intraperitoneally 24 and 1 h before ischemia. Following I/R, the levels of serum alanine aminotransferase and hepatic lipid peroxidation were elevated, whereas the hepatic glutathione content was decreased, with these changes attenuated by 1. Serum levels of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 were markedly increased by I/R, but suppressed by 1. Baicalin attenuated increases in inducible nitric oxide synthase, cyclooxygenase (COX)-2, and TNF receptor 1-associated protein expression and augmented an increase in heme oxygenase-1 (HO-1). The increase in TNF-α, IL-6, and, COX-2 mRNA expression was attenuated by 1, while the increase in HO-1 mRNA expression was augmented. Nuclear factor-κB nuclear localization was inhibited by 1, and this compound limited the rate of mitochondrial swelling and the activation of caspases-3 and -8 observed in I/R rats. Rats treated with 1 had markedly fewer apoptotic cells than I/R rats. It was concluded that baicalin (1) exhibits antioxidant, anti-inflammatory, and antiapoptotic effects, which protect against hepatocellular I/R-induced damage.

Hastifolins A-G, antifeedant neo-clerodane diterpenoids from Scutellaria hastifolia

From the aerial parts of Scutellaria hastifolia, family Lamiaceae (Labiatae), seven neo-clerodane diterpenoids (hastifolins A-G) were isolated. The products are similar to the known scuteparvin and are characterized by being trans-cinnamoyl derivatives. Structures and stereochemistry were determined by intensive NMR investigation. Six of the products form three pairs of epimers at C-13. Hastifolins A-C showed significant antifeedant activity.