Traditional uses, ten-years research progress on phytochemistry and pharmacology, and clinical studies of the genus Scutellaria

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria (Lamiaceae), which includes approximately 360-469 accepted species, is widespread in Europe, North America, East Asia, and South America. Several species have a long history being used as traditional medicines to treat respiratory, peptic, neurological, and hepatic and gall diseases. The phytochemistry and pharmacology of the genus Scutellaria have been developed dramatically in the past ten years, and the traditional uses and clinical studies of the genus have not been systematically summarized. Therefore, it is especially valuable to review the current state of knowledge to provide a basis for further exploration of its medicinal potential.

AIM OF THE REVIEW

The review aims to provide updated information on the ethnopharmacology, the ten-year research progress of phytochemistry and pharmacology, and clinical studies of Scutellaria and to explore the potential medicinal values and further studies of Scutellaria.

MATERIALS AND METHODS

This review is based on published studies and books from the library and electronic sources, including SciFinder, Scopus, PubMed, Web of Science, Baidu Scholar, CNKI, the online ethnobotanical database, and ethnobotanical monographs. This literature is related to ethnopharmacology, the ten-year research progress on the phytochemistry and pharmacology, and clinical studies of Scutellaria.

RESULTS

A total of 50 species, 5 subspecies and 17 varieties of the genus Scutellaria are used as traditional medicine with various biological activities. In the past ten years, 208 chemical constituents have been identified from 16 species and 1 variety of the genus Scutellaria, such as neo-clerodane diterpenoids, sesterterpenoids, terpenoids, flavonoids. Pharmacological research has demonstrated that the extracts and compounds identified from this genus exhibit extensive biological activities, including anticancer, antioxidant, anti-inflammatory, antiviral and antibacterial activities, effects on cardiovascular, cerebrovascular diseases as well as hepatoprotective and neuroprotective effects. The species S. baicalensis, S. barbata, and S. lateriflora and the main compounds baicalein, baicalin and wogonin are involved in clinical trials, which point the way for us to conduct further studies, such as study on the anticancer, antihypertensive, anti-infective, anti-inflammatory, neuroprotective and other effects of Scutellaria.

CONCLUSIONS

The species included in the genus Scutellaria can be used to treat cancer, infection, hepatic disorders, cardiovascular and cerebrovascular diseases, neurodegenerative diseases, and other diseases. Some indications in traditional medicines have been confirmed by modern pharmacological studies, such as anticancer, anti-inflammatory, anti-infective activity, and hepatoprotective and neuroprotective effects. The available literature indicated that most of the bioactivities could be attributed to flavonoids and neo-clerodane diterpenoids. Although there are some uses of Scutellaria in clinical practice, the existing research on this genus is still limited. In order to expand the development of medicinal resources of Scutellaria, the already studied species in this genus are recommended for more comprehensive investigation on their active substances, pharmacological mechanisms, quality control, clinical use and new drug research. Additionally, it is necessary to study species that their chemical composition or pharmacological activity have not yet been investigated, especially those used in folk medicine.

A novel study approach on Scutellaria altissima L. cultivated at the Ghirardi Botanic Garden (Lombardy, Italy)

Within an Open Science project, research was carried out to describe to the public of the Ghirardi Botanic Garden (BS, Lombardy, Italy) the invisible features of plants. This work is dedicated to Scutellaria altissima L. (Lamiaceae). Micromorphological, histochemical and phytochemical investigations were conducted on the vegetative and reproductive organs to correlate the structures involved in the emission of substances and their unique productivity. This work reports volatile organic compound (VOC) profiles of leaves and flowers and the composition of essential oil (EO) obtained from aerial parts of plants cultivated in Italy that have never been described before. Three morphotypes of glandular trichomes were observed: peltate, short-stalked capitate and long-stalked capitate. Peltate trichomes were the main producers of terpenes, short-stalked capitates of polysaccharides and long-stalked capitates of terpenes and polyphenols. The leaf VOC profile showed heterogeneous composition, with non-terpene derivatives as the major chemical class (71.04%), while monoterpene hydrocarbons represented almost the totality of the flower (99.73%). The leaf presented a higher number of total (37 versus 11) and exclusive (33 versus 7) compounds. (Z)-3-Hexenol acetate was most abundant in the leaf and (E)-β-ocimene in the flower. Four common compounds were detected: β-pinene, β-caryophyllene, γ-muurolene and germacrene-D. The EO contaied 21 compounds, dominated by β-caryophyllene, linalool and hexahydrofarnesyl acetone. This research allowed us to correlate morphotypes of the secretory structures with the production of secondary metabolites, with the aim of providing the public of the Ghirardi Botanic Garden with a dedicated iconographic approach, which accounts for olfactory perception linked to S. altissima.

Scutellaria barbata and Hedyotis diffusa herb pair for breast cancer treatment: Potential mechanism based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The Scutellaria barbata and Hedyotis diffusa (SH) herb pair is extensively used in Traditional Chinese Medicine for efficacy enhancement in cancer treatment in China and Asian countries. Superior clinical efficacy observations based on high dosages (≥60 g) motivated us to explore appropriate dosages and the underlying mechanisms of action.

AIM OF THE STUDY

To explore the efficacy and potential mechanisms of actions of SH through in vitro and in vivo experiments and network pharmacology.

MATERIALS AND METHODS

SH lyophilized powder (SHLP) was prepared from decoctions and the active ingredients were identified using high performance liquid chromatography (HPLC). Proliferation and migration experiments in vitro and tumor growth in vivo were performed to evaluate the effects of SHLP on breast cancer. Corresponding potential target genes for SHLP components and breast cancer were extracted from established databases and the Protein-Protein Internetwork of shared genes were constructed using STRING database. Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation clusters were acquired and the top 30 pathways were presented. At last, as one of pathways indicated by enriched results, apoptosis was validated with flow cytometric analysis and caspase-3, 8, 9 activities.

RESULTS

Seventy-five ingredients were identified from SHLP by HPLC. High SHLP doses inhibited proliferation and migration of three types of breast cancer cells in vitro and tumor growth in nude mice. After target genes extraction and intersection, the top 30 KEGG clusters were enriched, including PI3K-Akt, cell cycle and other related pathways like VEGF, Micro-RNAs and NF-κB, besides, key genes in apoptosis were mapped. In the last, apoptosis was validated by flow cytometric analysis and caspase-3, 8, 9 activities after SHLP treatment.

CONCLUSION

High SHLP dosages inhibited breast cancer in vitro and in vivo, enriched by network pharmacology and confirmed by flow cytometric analysis and caspase activation, with apoptosis was identified as one of the mechanisms of action of SHLP. SHLP administration with higher doses is recommended for clinical usage.

A review of the ethnopharmacology, phytochemistry, pharmacology, and quality control of Scutellaria barbata D. Don

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria barbata D. Don (S. barbata) is a well-known perennial herb that is used in traditional Chinese and Korean medicine. In China, it is known as Ban Zhi Lian, while in Korea, it is known as Banjiryun. In the Traditional Chinese Medicine (TCM) system, S. barbata has heat-clearing and detoxifying properties (Qingre Jiedu in Chinese).

AIM OF THE REVIEW

To provide a systematic review on current multifaceted understanding of S. barbata, with particular emphasis on the correlation between its traditional applications and pharmacological activities.

MATERIALS AND METHODS

All available S. barbata-related information from internet databases, including PubMed, Science Direct, Elsevier, China National Knowledge Internet, and Google Scholar (up to October 2018) were searched. Additional information was gathered from classical books on Chinese Herbals, Chinese Pharmacopoeia, and so on.

RESULTS

In the TCM system, S. barbata is mainly prescribed for its heat-clearing and detoxifying effects. More than 203 compounds have been isolated and identified from this herb, with neo-clerodane diterpenoids and flavonoids as the main compounds. Most neo-clerodanes have been demonstrated to have cytotoxic effects against different cancer cell types in vitro. The S. barbata extracts exhibited anti-inflammatory, anti-microbial, antitumor, and other pharmacological activities. To add, flavonoids, including wogonin, baicalein, apigenin, naringenin, and scutellarin, were identified as the key to quality control.

CONCLUSIONS

The heat-clearing effects of S. barbata could be attributed to its anti-inflammatory and hepatoprotective activities, whereas its detoxifying effects might be due to the anti-microbial functions of neo-clerodane diterpenoids and flavones. S. barbata may display anti-tumor effects and through active ingredient analysis, neo-clerodane diterpenoids are suggested to be its representative compounds. Overall, many pre-clinical studies have been conducted but very little concrete evidences are available on its specific effects, which are of therapeutic relevance.

Phytotoxic neo-clerodane diterpenoids from the aerial parts of Scutellaria barbata

Bioactivity guided the isolation of extracts from the aerial parts Scutellaria barbata D. Don to discover neo-clerodane diterpenoids with potent phytotoxic activity. Of the 34 isolates, 13 neo-clerodane diterpenoids were described for the first time. The structures of these undescribed compounds were elucidated by extensive analysis of NMR spectroscopic data, and the absolute configurations of scutebarbolides A and L and scutebata W were determined by X-ray diffraction. The phytotoxic activity of all compounds against the growth of the roots and shoots of L. perenne and L. sativa seedlings were first reported, and some compounds showed considerable inhibitory effects, especially scutebarbolide K, whose inhibition rates were higher than those of the positive control at concentrations ranging from 25 to 200 μg/mL. When L. perenne and L. sativa seedlings were treated at a concentration of 200 μg/mL, scutebarbolide K caused wilting symptoms on and finally death of these two tested plant seedlings. In addition, the structure-activity relationships of these neo-clerodane diterpenoids were also discussed.

Rationale and design to assess the efficacy and safety of HT047 in patients with acute ischemic stroke: A multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase II trial

BACKGROUND

Though several neuroprotective agents have been evaluated as potential treatments for acute ischemic stroke, none have demonstrated a definitive treatment efficacy, which remains elusive. HT047 is an herbal extract of Scutellaria baicalensis and Pueraria lobata, both of which have been widely used to treat ischemic stroke in traditional Korean medicine. The aims of this trial are to investigate whether HT047 can improve neurologic status, particularly motor function, in acute ischemic stroke patients, and to determine the safety of HT047.

METHODS

A multicenter, double-blind, randomized, placebo-controlled, 3-arm parallel group, phase II trial will be conducted in patients who have had an acute ischemic stroke within the past 14 days. The participating patients must have a Fugl-Meyer assessment (FMA) motor score ≤55, with arm or leg weakness, and Korean version of the National Institutes of Health Stroke scale (K-NIHSS) score of ≥4 and ≤15. Seventy-eight participants will be randomized in a 1:1:1 ratio and given high-dose HT047 (750 mg 3 times a day), low-dose HT047 (500 mg 3 times a day), or a placebo for 12 weeks. The primary endpoint is the change in FMA motor score between baseline and week 12. Secondary endpoints are as follows: the change in FMA motor score at weeks 4 and 8 from baseline; the change in FMA motor score at weeks 4, 8, and 12 from baseline according to the timing of treatment initiation (either within 1 week, or 1-2 weeks), or according to the presence of prognostic risk factors (hypertension, diabetes, dyslipidemia, etc); the change in K-NIHSS and Korean versions of the modified Rankin scale (K-mRS) and the modified Barthel index at weeks 4 and 12 from baseline; and the proportion of subjects at week 12 with a K-NIHSS score of 0 to 2, or with K-mRS scores of 0, ≤1, and ≤2.

DISCUSSION

This study is a 1st-in-human trial of HT047 to explore the efficacy and safety in acute ischemic stroke patients. The results will provide the appropriate dosage and evidence of therapeutic benefit of HT047 for stroke recovery.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02828540) Registered July 11, 2016.

Regulatory effect of a Chinese herbal medicine formula on non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become a major cause of chronic liver disease. The Chinese herbal medicine (CHM) Dachaihu decoction (DCHD) has been proved to treat NAFLD with good efficacy in previous studies. Based on the TCM principle of formula formation, we divided DCHD into soothing liver part, invigorating spleen part, and dredging intestine part. Marshall officially proposed the concept of “intestinal-hepatic axis”, which systematically explains the interactions between the intestine and liver. We hypothesized that the effect of CHM on NAFLD is achieved by regulating the liver and intestine. Thus, we aimed to investigate the possible effect of a CHM formula on NAFLD in a rat model.

AIM

To investigate the effects of a CHM formula (a decoction of Chinese thorowax root, scutellaria root, and white peony root) on NAFLD and its regulatory effect on the “intestinal-liver” axis.

METHODS

Sixty rats were randomly divided into control, model, pioglitazone hydrochloride (PH), and CHM (a decoction of Chinese thorowax root, scutellaria root, and white peony root) groups. An NAFLD rat model was established using a high-fat high-fructose diet for 16 wk. From the 13th week, rats were administered with PH or a decoction of Chinese thorowax, scutellaria, and white peony root (CHM group) for 4 wk. Rats in the control group and model group were administered with an equal volume of distilled water. At the end of the study, blood was collected via the abdominal aorta. Liver tissues were harvested and any morphological changes were observed by hematoxylin-eosin (HE) staining, Oil red O staining, and Masson staining. In addition, blood lipids, liver function markers, and triglyceride (TG) in liver tissues were analyzed. The levels of transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), Toll-like receptor-4 (TLR4), and nuclear factor-kappa B (NF-кB) in liver tissues and secreted immunoglobulin A (sIgA) in intestinal tissues were analyzed by ELISA, and protein and mRNA expression of occludin and zonula occludens-1 (ZO-1) in the intestine were measured using Western blot and reverse transcription-quantitative polymerase chain reaction, respectively. The endotoxin level in plasma was detected by endpoint chromogenic assay.

RESULTS

Compared to the normal control group, the liver coefficient, serum TG, total cholesterol (TC), low density lipoprotein (LDL), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), blood glucose, plasma endotoxin, and the levels of TG, TNF-α, TGF-β, NF-kB, and TLR4 in liver tissues increased significantly in the model group, while serum high density lipoprotein (HDL), intestinal sIgA, and protein and mRNA expression of occludin and ZO-1 decreased significantly in the model group (P < 0.01). PH and CHM attenuated the elevated liver coefficient, serum TG, TC, LDL, AST, and ALT, blood glucose, plasma endotoxin, and the levels of TG, TNF-α, TGF-β, NF-kB, and TLR4 in liver tissues and increased serum HDL levels compared to the model group (P < 0.01). Intestinal sIgA and the protein and mRNA expression of intestinal occludin and ZO-1 were significantly increased in the PH group compared to the model and CHM groups (P < 0.01).

CONCLUSION

The decoction of Chinese thorowax root, scutellaria root, and white peony root is beneficial in regulating lipid metabolism and liver function, which indicates that it has a good effect on the liver. To a certain extent, this CHM formula can affect both the liver and intestine, while its effect on the liver is superior to that on the intestine.

Anti-proliferative and anti-migratory effects of Scutellaria strigillosa Hemsley extracts against vascular smooth muscle cells

ETHNOPHARMACOLOGICAL RELEVANCE

The abnormal increase in vascular smooth muscle cell (VSMC) proliferation and migration are critical events in the pathogenesis of cardiovascular diseases (CVDs) including restenosis and atherosclerosis. The dried roots of Scutellaria baicalensis Georgi (common name: Huangqin in China) have been confirmed to possess beneficial effects on CVD by clinical and modern pharmacological studies. Flavonoids in Huangqin exert anti-proliferative and anti-migratory effects. Similar to Huangqin, Scutellaria strigillosa Hemsley (SSH) has been used to clear heat and damp and is especially rich in flavonoids including wogonin, wogonoside, baicalein, and baicalin. However, there have been few of reports about pharmacological activities of SSH.

AIM OF THE STUDY

To investigate the anti-proliferative and anti-migratory properties of Scutellaria strigillosa Hemsley extract (SSHE) in vitro and in vivo and explore its possible mechanism of action.

MATERIALS AND METHODS

The chemical constituents of SSHE were analyzed by ultra-high performance liquid chromatography coupled with triple time-of-flight mass spectrometry (UPLC-Triple-TOF-MS/MS). Cell proliferation and migration were investigated using BrdU incorporation assay and cell scratch test, respectively. The protein expression was determined by western blotting. In vivo, we established an artery ligation model of C57BL/6 mice and orally administered them with 50 or 100 mg/kg/day of SSHE. The carotid arteries were harvested and the intima-media thickness was examined 28 days post-ligation.

RESULTS

Twelve compounds were identified and tentatively characterized. SSHE significantly inhibited the VSMC proliferation and migration stimulated by PDGF-BB and decreased the relative protein expression of regulatory signaling intermediates. Furthermore, the expression of SM22α was significantly elevated in SSHE-pretreated VSMCs, whereas knockdown of SM22α impaired the PDGF-BB-induced proliferation and migration arrest. Meanwhile, both ROS generation and the phosphorylation of ERK decreased in SSHE-pretreated VSMCs. In carotid artery ligation mice model, SSHE treatment significantly inhibited neointimal hyperplasia.

CONCLUSIONS

SSHE significantly inhibited the PDGF-BB-induced VSMC proliferation, migration, and neointimal hyperplasia of carotid artery caused by ligation. Upregulation of SM22α expression, inhibition of ROS generation and ERK phosphorylation were, at least, partly responsible for the effects of SSHE on VSMCs.

Flavonoids from Scutellaria barbata inhibit activation of tumor-associated macrophages by blocking the Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB signaling pathway

OBJECTIVE

To determine the efficacy of Scutellaria barbata flavonoids and polysaccharides on Ishikawa endometrial carcinoma cells co-cultured with U937 macrophages.

METHODS

The presence of CD163 and CD206 was determined by flow cytometry. Thiazolyl Blue Tetrazolium Bromide assays were used to assess the proliferation effect of tumor-associated macrophages (TAMs) on Ishikawa cells. The secretion of interleukin (IL)-10 in the co-culture conditioned media was examined using an enzyme-linked immunosorbent assay. The protein expression levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and nuclear factor (NF)-κB p65 were detected by Western blot. The mRNA expression levels of TLR4 and MyD88 were analyzed by real-time polymerase chain reaction (PCR). The expression levels of IL-12, IL-1β and tumor necrosis factor-α (TNF-α) were evaluated with real-time PCR.

RESULTS

Compared with the U937 control group, the expression levels of CD163 and CD206 in the TAM group were higher (P < 0.05). TAMs co-cultured with Ishikawa cells for 24 or 48 h showed higher proliferation rates (P < 0.05). The expression levels of IL-12 decreased than compared with those in the U937 untreated group (P < 0.05) and those of the Scutellaria barbata flavonoids group (P < 0.05). The expression levels of CD206, CD163, IL-10, IL-1β and TNF-α, NF-κB p65 and TLR4/MyD88 in the TAMs control group were greater than those in the U937 untreated group (P < 0.05) and those of the Scutellaria barbata flavonoids group (P < 0.05).

CONCLUSION

Scutellaria barbata flavonoids may inhibit TAM activation by blocking the TLR4/MyD88/NF-κB signaling pathway.

Evaluation of antioxidant activity of extracts from the roots and shoots of Scutellaria alpina L. and S. altissima L. in selected blood cells

BACKGROUND

It is widely known that reactive oxygen species (ROS) can cause oxidative damage in cells and have been linked to the pathogenesis of oxidative diseases, such as atherosclerosis, ischemia, neurodegenerative disease, diabetes, or cancer. Recently, much attention has been focused on preventive strategies for oxidative stress and related diseases. Plants represent a source of bioactive compounds whose antioxidant activity may be useful in protecting against pro-oxidative reactions.

OBJECTIVES

The study determines the in vitro biological activity of the ethanolic extracts from the shoots and roots of Scutellaria species (S. altissima and S. alpina) in selected blood cells (blood platelets and lymphocytes).

MATERIAL AND METHODS

Platelet activity, both resting and after thrombin stimulation, was used to indicate the ability of the plant extracts to inhibit the production of superoxide anion radicals (O2 •-) and platelet lipid peroxidation. The generation of superoxide anion radicals was measured by cytochrome c reduction. Lipid peroxidation in blood platelets was measured by the level of thiobarbituric acid reactive substances (TBARS). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay was used to determine the protective effect of Scutellaria extracts on lymphocyte cells against oxidative damage induced by hydroxyl radicals.

RESULTS

Extracts (5-50 μg/mL) containing phenolic compounds from both Scutellaria species distinctly reduced nonenzymatic lipid peroxidation and arachidonic acid metabolism by blood platelets in vitro. When given at the tested concentration, the extracts reduced the generation of O2 •- in resting blood platelets and platelets activated by thrombin in vitro. All Scutellaria extracts (10 μg/mL) containing phenolic compounds also protected human lymphocytes against oxidative stress induced by hydrogen peroxide (H2O2).

CONCLUSIONS

The present study suggests that the natural extracts from S. altissima and S. alpina have antioxidant properties and, therefore, may be beneficial in the prevention of diseases in which blood platelets and lymphocytes are involved, i.e., cancer or inflammatory and infective diseases.

A potential bio-control agent from baical skullcap root against listeriosis via the inhibition of sortase A and listeriolysin O

Listeria monocytogenes (LM) is a classical model intracellular pathogen and the leading cause of listeriosis, which has long been a global public health issue. The successful infection of LM is related to a series of virulence factors, such as the transpeptidase enzyme sortase A (SrtA) and listeriolysin O (LLO), which are crucial for bacterial internalization and escape from phagosomes respectively. It is speculated that targeting multiple virulence factors may be due to a synergistic effect on listeriosis therapy. In this study, an active flavonoids component of Scutellaria baicalensis Georgi, baicalein, was found to potently block both listerial SrtA catalyzed activity and LLO hemolytic activity within 16 μg/mL. After pretreatment with baicalein, 86.30 (±11.35) % of LM failed to associate with Caco-2 cells compared to the LM without preincubation (regarded as 100% internalization). Furthermore, baicalein addition may aid in bacterial degradation and clearance in macrophagocytes. During a 5 h observation, LM in cells incubated with baicalein showed significantly decreased vacuole escapes and sluggish endocellular growth. In addition, baicalein directly prevented LM-induced cells injury and mice fatality (survival rate from 10.00% to 54.55% in 4 days post-intraperitoneal injection). Taken together, as an antagonist against SrtA and LLO, baicalein can be further developed into a biotherapeutic agent for listeriosis.

Six New neo-Clerodane Diterpenoids from Aerial Parts of Scutellaria barbata and Their Cytotoxic Activities

Six new neo-clerodane diterpenoids (1: -6: ), scutebatas X - Z, A₁-C₁, along with twelve known ones (7: -18: ) were obtained via the phytochemical investigation of the aerial parts of Scutellaria barbata. Their structures were established by detailed spectroscopic analysis. The absolute configurations of 1: and 2: , as the representative members of this type, were identified based on a circular dichroic exciton chirality method. Moreover, in vitro cytotoxicity of compounds 1: -6: were evaluated against three human cancer cell lines (SGC-7901, MCF-7, and A-549) using the MTT method. Compound 6: showed cytotoxic activities against all the three cell lines with IC₅₀ values of 17.9, 29.9, and 35.7 µM, respectively.

Baicalin protects mice against Salmonella typhimurium infection via the modulation of both bacterial virulence and host response

BACKGROUND

The worsening problems of antibiotic resistance prompt the need for alternative strategies. Baicalin, which is isolated from Scutellaria baicalensisi, has been demonstrated to exhibit anti-inflammatory, anti-virulence and antimicrobial effects. Salmonella typhimurium is an important foodborne pathogenic bacteriaum that causes gastrointestinal disease in humans and many animals.

PURPOSE

The aim of this study was to investigate the effects of baicalin on S. typhimurium infection in mice and its possible mechanism in vitro.

STUDY DESIGN

To evaluate the effect of baicalin in vivo, mice were orally administered of baicalin, and then were infected by an intragastric administration of S. typhimurium. The minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of baicalin, baicalein, and oroxylin A against S. typhimurium were detected under the guides of the Clinical and Laboratory Standards Institute. In vitro, Caco-2 cells were infected with S. typhimurium in the presence or absence of baicalin, baicalein, and oroxylin A at sub-MICs.

METHODS

In the in vivo experiment, the body weight loss, the serum levels of TNFα,  IL-6, and lactic dehydrogenase (LDH), the pathological changes of the caecum and the caecum bacterial burdens were examined. The MICs and MBCs of baicalin, baicalein, and oroxylin A against S. typhimurium were detected by two-fold serial dilutions. In vitro, Caco-2 cells were infected with S. typhimurium, and the invasion capacity, TNFα, nitrate, and LDH were analysed. The transcription levels of Salmonella pathogenicity island 1 virulence associated genes (sopB, sopE, sopE2) of S. typhimurium in the presence of baicalin, baicalein, and oroxylin A were detected by qRT-PCR.

RESULTS

Our results showed that baicalin significantly decreased the body weight loss, the serum levels of TNFα,  IL-6, and LDH, and the caecum bacterial burdens of mice challenged with S. typhimurium. Histological examination showed that baicalin decreased the lesion in the caecum of S. typhimurium-infected mice. MICs and MBCs of baicalin, and oroxylin A. against S. typhimurium were > 128 µg/ml. MICs and MBCs of baicalein against S. typhimurium were 64 µg/ml, and > 128 µg/ml, respectively. Pretreatment of Caco-2 cells or S. typhimurium with baicalin, baicalein, and oroxylin A significantly inhibited the invasion of Caco-2 cells by S. typhimurium in a dose-dependent manner. Sub-MICs of baicalin, baicalein, and oroxylin A also significantly decreased the levels of TNFα, nitrate, and LDH from S. typhimurium-infected Caco-2 cells. Moreover, the transcription levels of sopB, sopE, and sopE2 were significantly suppressed by baicalin, baicalein, and oroxylin A.

CONCLUSIONS

These results demonstrated that baicalin is a promising agent for the prevention of S. typhimurium infection via the modulation of both bacterial virulence and host response.

Flavonoid alkaloids from Scutellaria moniliorrhiza with anti-inflammatory activities and inhibitory activities against aldose reductase

Four undescribed flavonoid alkaloids, as two pairs of enantiomers, were initially isolated as a racemate from the whole plant of Scutellaria moniliorrhiza. By means of chiral HPLC, four isomers, named scumonilines A-D, were successfully separated, and their chemical structures including absolute configurations were established by mass as well as NMR spectroscopy and CD technique. In vitro, four flavonoid alkaloids showed anti-inflammatory activities, with IC₅₀ values against the release of β-glucuronidase from polymorphonuclear leukocytes of rats being in the range 5.16-5.85 μΜ. Moreover, four compounds were evaluated for their inhibitory activities against aldose reductase, and gave IC₅₀ values in the range 2.29-3.03 μΜ.

Scutellaria: Debates on the anticancer property

The widespread use of plants as accessible anticancer agents leads to the identification of many natural source chemotherapeutic agents. Scutellaria one of the popular genus of flowering plants has been used for various human illnesses for thousands of years. Scutellaria has anti-metastatic, anti-proliferative, anti-invasion, anti-angiogenic and apoptosis effects in vitro as well as in vivo. Despite numerous reports on the cytotoxic-antitumor activity of the plant, there are still some issues need further consideration. Issues such as unjustified interpretations, lack of attention to the pharmacokinetics profile and weak study design may affect the final decision about the use of plants as anticancer agents and possibly needs reconsideration. In this review, we have summarized the potential health benefits of Scutellaria and its active components also the underlying mechanism of cytotoxicity and antitumor activity. Meanwhile we have discussed concerns may interfere with the precise conclusion.

Enhanced anticancer effects of Scutellaria barbata D. Don in combination with traditional Chinese medicine components on non-small cell lung cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Experience-based herbal medicine as a complementary to modern western medicine has triggered an array of studies in quest of novel anticancer drugs. Scutellaria barbata D. Don (SB) is commonly used to treat different types of cancers, but its molecular mechanism of action is not clearly understood. In this study, we attempted to elucidate the mode of action of a traditional Chinese medicine prescription with a total of 14 components, named Lian-Jia-San-Jie-Fang (LJSJF, in Chinese), where SB works as the "principle" against non-small cell lung cancer (NSCLC) cells.

MATERIALS AND METHODS

Four different NSCLC cell lines (A549, H460, H1650, and H1975) were used. Cytotoxicity, in vitro tumorigenicity, gene expression, and protein expression were analyzed by MTT assay, soft agar assay, real-time PCR, and Western blots, respectively.

RESULTS

Among the 14 components in LJSJF, SB was the only one to possess cytotoxic effects at its pharmacologically relevant doses. Additionally, we observed synergistically dose-dependent cytotoxic effects of SB in combination with other LJSJF components. After SB or LJSJF treatment, significant reductions in colony number and/or size were observed in A549 and H460; a notable dose-dependent decrease in EGFR was observed in A549, H460, and H1650; significant downregulation in EGFR and its downstream signaling targets mTOR and p38MAPK were also observed in A549 and H460; and p53 and p21 were significantly increased while survivin, cyclin D1, and MDM2 were significantly decreased in A549. Additionally, p53, p21, and Mettl7b were decreased, but p73 was increased in H460. Neither EGFR nor p53 was changed in H1975. Therefore, SB or LJSJF may induce cytotoxic effects by regulating multiple and/or distinct apoptotic pathways in different NSCLC cells.

CONCLUSION

LJSJF exerts more pronounced cytotoxic effects against NSCLC cells than SB does by synergistically regulating the underlining molecular mechanisms including EGFR and/or p53 signaling pathways.

Neo-clerodane diterpenoids from the whole plants of Scutellaria formosana

Scuteformoids A-J, ten previously undescribed neo-clerodane diterpenoids along with one known analogue, were isolated from petroleum ether soluable fraction of the whole plants of Scutellaria formosana. The differences among these compounds are the substituents and stereochemistry at C-13. Their structures were elucidated by 1D and 2D NMR experiments, and the absolute configurations of Scuteformoids A, C, E, F, and I were further confirmed by single-crystal X-ray diffraction. Scuteformoids A, C, D, F, H, and I were evaluated for their inhibitory effects against HIV lytic replication and cytotoxic activities. All of them showed weak anti-HIV activities, with EC₅₀ values ranging from 48.24 to 79.17 μg/mL.

Clerodane diterpenoids from Scutellaria formosana with inhibitory effects on NO production and interactions with iNOS protein

A phytochemical study on Scutellaria formosana afforded five previously undescribed spiro-diterpenoids, scutellapenes A-E. The structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of these compounds were established by the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. Scutellapenes B-E possess a spiro-diterpenoid skeleton. All of the compounds showed inhibitory effects on LPS-induced nitric oxide (NO) production in murine microglial BV-2 cells. The further molecular docking studies revealed that these bioactive compounds had strong interactions with the iNOS protein.

Skullcap (Scutellaria Baicalensis) Hexane Fraction Inhibits the Permeation of Ovalbumin and Regulates Th1/2 Immune Responses

Skullcap (Scutellaria baicalensis) is well known for its anti-inflammatory and anti-allergic effects. In our previous study, we found that skullcap could inhibit allergen permeation and regulate Th1/2 immune balance. To reveal the key fractions and components of skullcap, we fractionated skullcap extract into five fractions: hexane, chloroform, ethyl acetate, butanol, and water fraction. Among these fractions, the hexane fraction significantly suppressed the production of Th2-mediated cytokines (Interleukin (IL)-4, 5, 10 and 13) and increased Th1-mediated cytokines (Interferon (IFN)-γ and IL-12). Furthermore, the hexane fraction inhibited the permeation of ovalbumin (OVA), used as an allergen, across the intestinal epithelial cell monolayer. To confirm the active compounds in the hexane fraction, fatty acids were analyzed. Linoleic acid (LA, C18:2 (>59.7%)) was identified as the most important fatty acid in the skullcap hexane fraction. LA significantly suppressed IL-4 production and increased IFN-γ secretion, as well as inhibiting OVA permeation. Thus, LA significantly diminished the permeation of allergen by enhancing intestinal barrier function and regulated allergic responses to maintain Th1/Th2 immune balance.

Scutellaria barbata D. Don inhibits colorectal cancer growth via suppression of Wnt/β-catenin signaling pathway

OBJECTIVE

To investigate the effect of the ethanol extract of Scutellaria barbata D. Don (EESB) on colorectal cancer (CRC) growth and Wnt/β-catenin signaling pathway in vivo and in vitro.

METHODS

In vivo experiment, CRC xenograft mouse model was constructed with injection of HT-29 cells. Following xenograft implantation, twenty mice were randomly divided into EESB-treated group (n=10) and control group (n=10) by a random number table, and were given with intra-gastric administration of 2 g/kg EESB or saline, 5 days a week for 16 days, respectively. At the end of experiment, tumors were removed and weighed by electronic scales. The proliferation biomarker Ki-67 of tumor was evaluated by immunohistochemistry (IHC) assay. In vitro study, HT-29 cells were treated with 0, 0.5, 1.5, 2.5 mg/mL EESB for 24 h. At the end of the treatment, the viability and survival of HT-29 cells were determined by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and colony formation assay, respectively. The mRNA expression of c-Myc, Survivin and adenomatous polyposis coli (APC) was examined by reverse transcription-polymerase chain reaction (RT-PCR) both in tumor tissues of CRC xenograft mice and HT-29 cells. Protein expression of c-Myc, Survivin, APC, and β-catenin as well as β-catenin phosphorylation level were evaluated by IHC assay or Western blotting.

RESULTS

EESB significantly reduced tumor weight in CRC xenografts mice, compared with the control group (P<0.05). IHC assay showed that EESB significantly inhibited protein expression of Ki-67 in tumor tissues (P<0.05). MTT assay showed that EESB significantly reduced HT-29 cell viability in a dose-dependent manner (P<0.05). Colony formation assay showed that EESB dose-dependently decreased the survival of HT-29 cells (P<0.05). In addition, RT-PCR assay showed that EESB decreased the mRNA expression of c-Myc and Survivin and increased APC expression, both in tumor tissues of CRC xenograft mice and HT-29 cells (P<0.05). IHC assay or Western blotting showed that EESB decreased protein expression of β-catenin, c-Myc and Survivin, as well as increased APC expression and β-catenin phosphorylation in tumor tissues or HT-29 cells (P<0.05).

CONCLUSIONS

EESB significantly reduced tumor growth in CRC xenografts mice, and inhibited the viability and survival of HT-29 cells. EESB could suppress the activation of the Wnt/β-catenin pathway, which might be one of the mechanisms whereby Scutellaria barbata D. Don exerts its anticancer activity.

A study on the modulation of alpha-synuclein fibrillation by Scutellaria pinnatifida extracts and its neuroprotective properties

Aggregation of alpha-synuclein (α-SN) is a key pathogenic event in Parkinson's disease (PD) leading to dopaminergic degeneration. The identification of natural compounds inhibiting α-SN aggregation may have a major role in treating PD. Different Scutellaria species are known as valuable medicinal plants, primarily due to their high flavonoid levels. Scutellaria pinnatifida (S. pinnatifida) is endemic to Iran; however, the knowledge of its pharmaceutical properties is limited. Here we report that S. pinnatifida extracts have an anti-fibrillation effect on α-SN aggregation and neuroprotective properties on PC12 and primary dopaminergic neurons. Treatment during α-SN fibril formation with S. pinnatifida extracts showed that the extractions performed with dichloromethane (DCMEx) and n-butanol (BuOHEx) strongly inhibited α-SN fibrillation. TLC-based analysis revealed that S. pinnatifida contains a great amount of flavonoids with high antioxidant properties as shown using a radical scavenging assay. Further analysis using HPLC and Mass spectroscopy on the DCMEx revealed the presence of baicalein in this extract. We then selected the more efficient extracts based on cell viability and ROS scavenging on PC12 cells and tested their neuroprotective properties on primary dopaminergic neurons. Our results showed the extracts strongly protected against α-SN oligomers. Surprisingly, they also neutralized the severe toxicity of paraquat. Therefore, S. pinnatifida may be a potential valuable medicinal herb for further studies related to the treatment of PD.

Anti-tumor effect of Scutellaria barbata D. Don extracts on ovarian cancer and its phytochemicals characterisation

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria barbata D. Don is a widely used medicinal herb in China. It possess various medicinal properties including antioxidative, anti-inflammatory and anti-cancer effects. The aim of this study was to explore whether Scutellaria barbata D. Don could inhibit the growth of ovarian cancer cells in vitro and further investigate the underlying mechanisms.

MATERIALS AND METHODS

Effects of Scutellaria barbata D. Don on the viability of ovarian cancer A2780 cells were measured by MTT assay. Apoptosis was measured by cell morphologic observation through DAPI staining and Annexin V-FITC staining assay for apoptosis analysis. The migration of ovarian cancer cells which exposed to Scutellaria barbata D. Don were measured by wound healing and transwell chamber assays. The protein levels of caspase 3/9, Bcl-2 and MMP-2/9 in human ovarian cancer cells treated with Scutellaria barbata D. Don were assessed by western blotting analysis. The potential bioactive compounds were characterized by HPLC-Q-TOF-MS.

RESULTS

The present study was to investigate the anticancer effects of crude extracts from Scutellaria barbata D. Don on ovarian cancer A2780 cells by MTT, DAPI staining, wound healing assay, transwell migration assay and western blotting analysis. Our study showed that Scutellaria barbata D. Don reduced the viability of A2780 cells and induced apoptosis by down-regulated Bcl-2 protein and increased Caspase 3/9 proteins. Furthermore, migration of A2780 cells were significantly inhibited by Scutellaria barbata D. Don and the underlying mechanism may be related to the decrease of MMP-2/9. The main constituents from Scutellaria barbata D. Don were identified to be thirteen flavonoids. A HPLC-Q-TOF-MS analysis of Scutellaria barbata D. Don indicated the presence of 14 flavonoids compounds, which may contribute to the anticancer activity of the Scutellaria barbata D. Don.

CONCLUSIONS

Scutellaria barbata D. Don could inhibit proliferation and induce apoptosis in A2780 cells through mitochondrial pathway. Moreover, the inhibitory effect of Scutellaria barbata D. Don on the migration of ovarian cancer cells was associated with the down-regulation of MMP-2/9 expression. These findings could shed a light on the therapy of ovarian cancer.

[Studies on flavonoids from Scutellaria moniliorrhiza]

By means of preparative HPTLC and column chromatography over silica gel and Sephadex LH-20, nineteen flavonoids were isolated and purified from the whole plants of Scutellaria moniliorrhiza. Based on the physico-chemical properties and spectral data, their structures were identified as： apigenin (1), luteolin (2), wogonin (3), oroxylin A (4), 6-methoxynaringein (5), 5,7,4'-trihydroxy-6,8-dimethoxyflavone (6), 5,7,8-trimethoxyflavone (7), 3,5,6,7-tetramethoxyflavone (8), 7-hydroxy-4',5,6,8-tetramethoxyflavone (9), 5,7,2'-trihydroxy-6-methoxyflavanone (10), 5,7,4'-trihydroxy-6-methoxyflavone (11), 5,7-dihydroxy-6,8-dimethoxy -flavone (12), 5,2',6'-trihydroxy-7,8-dimethoxyflavone (13), 5,7,2'-trihydroxy-8-methoxyflavone (14), 5,2'-dihydroxy-7,8-dimethoxyflavanone (15), 2'-hydroxy-5,7,8-trimethoxyflavone (16), 5-hydroxy-7,8-dimethoxyflavone (17), 5,2'-dihydroxy-7,8-dimethoxyflavone (18), and 5-hydroxy-6,7,8-trimethoxyflavone (19). For the first time, compounds 1-19 were isolated from S. moniliorrhiza, and compounds 6, 8, 9, 12, 19 were isolated from the Scutellaria genus.

Protective effect of Scutellaria species on AAPH-induced oxidative damage in human erythrocyte

BACKGROUND

Scutellaria baicalensis is a well-known plant in traditional Chinese medicine. Recently, several Scutellaria species with therapeutic potential have been recognized worldwide. Scutellaria colebrookiana and Scutellaria violacea, native to the Western Ghats of India, are reported to possess free radical scavenging efficacy. At present, the protective effect of these Scutellaria spp. against 2,2' azobis (2-amidinopropane) hydrochloride (AAPH)-induced oxidative damage in human erythrocytes has been analyzed.

METHODS

Oxidative stress in erythrocyte was induced by AAPH. The inhibition of hemolysis, membrane lipid peroxidation, and protein damage by chloroform extracts of Scutellaria spp. was assessed biochemically. Phytochemicals of the extracts were analyzed by Fourier transform infrared spectrophotometer (FTIR).

RESULTS

Approximately 95% of erythrocytes were lysed by AAPH over 3 h of incubation. Significant reduction in hemolysis was observed by the extracts, and the IC50 values were 18.3 and 23.5 μg/mL for S. colebrookiana and S. violacea, respectively. Both the extracts were found to inhibit AAPH-induced lipid peroxidation in ghost membrane with IC50 92±2.8 and 70±5.6 μg/mL. In the analysis of the membrane proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the AAPH-induced degradation of actin was found reduced by both the extracts. The FTIR spectrum revealed the presence of polyphenols, carboxylic acids, alkanes, and aromatic compounds in extracts. In quantitative analysis, the total polyphenolic content estimated was 380±0.23 and 203.7±1.4 mg of gallic acid equivalent per gram extract of S. colebrookiana and S. violacea.

CONCLUSIONS

Results indicate that S. colebrookiana and S. violacea are capable of protecting erythrocytes from oxidative damage. This cytoprotective effect of the extract is possibly by its antioxidant property.