Synergistic therapeutic actions of herbal ingredients and their mechanisms from molecular interaction and network perspectives

Antibacterial and Cytotoxic Activity of Compounds Isolated from Flourensia oolepis

The antibacterial and cytotoxic effects of metabolites isolated from an antibacterial extract of Flourensia oolepis were evaluated. Bioguided fractionation led to five flavonoids, identified as 2′,4′-dihydroxychalcone (1), isoliquiritigenin (2), pinocembrin (3), 7-hydroxyflavanone (4), and 7,4′-dihydroxy-3′-methoxyflavanone (5). Compound 1 showed the highest antibacterial effect, with minimum inhibitory concentration (MIC) values ranging from 31 to 62 and 62 to 250 μg/mL, against Gram-positive and Gram-negative bacteria, respectively. On further assays, the cytotoxic effect of compounds 1–5 was determined by MTT assay on acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia (CML) cell lines including their multidrug resistant (MDR) phenotypes. Compound 1 induced a remarkable cytotoxic activity toward ALL cells (IC₅₀ = 6.6–9.9 μM) and a lower effect against CML cells (IC₅₀ = 27.5–30.0 μM). Flow cytometry was used to analyze cell cycle distribution and cell death by PI-labeled cells and by Annexin V/PI staining, respectively. Upon treatment, 1 induced cell cycle arrest in the G₂/M phase accompanied by a strong induction of apoptosis. These results describe for the first time the antibacterial metabolites of F. oolepis extract, with 1 being the most effective. This chalcone also emerges as a selective cytotoxic agent against sensitive and resistant leukemic cells, highlighting its potential as a lead compound.

Actions of Huangqi decoction against rat liver fibrosis: a gene expression profiling analysis

Background

Huangqi decoction (HQD) is used for liver fibrosis and cirrhosis treatment in Chinese medicine. This study aims to investigate the pharmacological actions of HQD against liver fibrosis in rats by high-throughput gene expression profiling, network analysis and real-time qRT-PCR.

Methods

We analyzed the profiles of differentially expressed genes (DEGs) in dimethylnitrosamine (DMN)-induced liver fibrosis in rat. The liver tissue samples of control group (n = 3), model group (n = 3) and HQD group (n = 3) were examined by microarrays. Pathways were analyzed by KEGG. Pathway-gene and protein–protein interaction (PPI) networks were constructed with Cytoscape software. The expression of candidate genes was verified by qRT-PCR. P values less than 0.05 indicated statistical significance.

Results

Collagen deposition and hydroxyproline (Hyp) content were decreased in the HQD group compared with the model group (P < 0.001), while that of Hyp in the model group were increased compared with the control group (P < 0.001). In comparison with the model group, 1085 DEGs (all P < 0.05, |fold change| >1.5) and 52 pathways in the HQD group were identified. TGF-beta, ECM-receptor interaction, and the cell adhesion molecules pathways were significantly recovered by HQD (P < 0.001). A pathway-gene network was constructed, including 303 DEGs and 52 pathways, and 514 nodes and 2602 edges, among 142 genes with node degrees greater than 10. The expressions of PDGFra, PDGFrb, PDGFb, PDGFd, COL1A1, COL1A2, COL5A2, and THBS1 were significantly down-regulated by HQD (P < 0.001).

Conclusion

HQD down-regulated the expressions of PDGFra, PDGFrb, PDGFb, PDGFd, COL1A1, COL1A2, COL5A2 and THBS1, and TGF-β and PDGF signaling pathways in the DMN-induced liver fibrosis in rats.

Electronic supplementary material

The online version of this article (doi:10.1186/s13020-015-0066-5) contains supplementary material, which is available to authorized users.

Induction of Apoptosis in MCF-7 Cells via Oxidative Stress Generation, Mitochondria-Dependent and Caspase-Independent Pathway by Ethyl Acetate Extract of Dillenia suffruticosa and Its Chemical Profile

Dillenia suffruticosa, which is locally known as Simpoh air, has been traditionally used to treat cancerous growth. The ethyl acetate extract of D. suffruticosa (EADs) has been shown to induce apoptosis in MCF-7 breast cancer cells in our previous study. The present study aimed to elucidate the molecular mechanisms involved in EADs-induced apoptosis and to identify the major compounds in the extract. EADs was found to promote oxidative stress in MCF-7 cells that led to cell death because the pre-treatment with antioxidants α-tocopherol and ascorbic acid significantly reduced the cytotoxicity of the extract (P<0.05). DCFH-DA assay revealed that treatment with EADs attenuated the generation of intracellular ROS. Apoptosis induced by EADs was not inhibited by the use of caspase-inhibitor Z-VAD-FMK, suggesting that the cell death is caspase-independent. The use of JC-1 dye reflected that EADs caused disruption in the mitochondrial membrane potential. The related molecular pathways involved in EADs-induced apoptosis were determined by GeXP multiplex system and Western blot analysis. EADs is postulated to induce cell cycle arrest that is p53- and p21-dependent based on the upregulated expression of p53 and p21 (P<0.05). The expression of Bax was upregulated with downregulation of Bcl-2 following treatment with EADs. The elevated Bax/Bcl-2 ratio and the depolarization of mitochondrial membrane potential suggest that EADs-induced apoptosis is mitochondria-dependent. The expression of oxidative stress-related AKT, p-AKT, ERK, and p-ERK was downregulated with upregulation of JNK and p-JNK. The data indicate that induction of oxidative-stress related apoptosis by EADs was mediated by inhibition of AKT and ERK, and activation of JNK. The isolation of compounds in EADs was carried out using column chromatography and elucidated using the nuclear resonance magnetic analysis producing a total of six compounds including 3-epimaslinic acid, kaempferol, kaempferide, protocatechuic acid, gallic acid and β-sitosterol-3-O-β-D-glucopyranoside. The cytotoxicity of the isolated compounds was determined using MTT assay. Gallic acid was found to be most cytotoxic against MCF-7 cell line compared to others, with IC50 of 36 ± 1.7 μg/mL (P<0.05). In summary, EADs generated oxidative stress, induced cell cycle arrest and apoptosis in MCF-7 cells by regulating numerous genes and proteins that are involved in the apoptotic signal transduction pathway. Therefore, EADs has the potential to be developed as an anti-cancer agent against breast cancer.

Brine shrimp cytotoxicity and antimalarial activity of plants traditionally used in treatment of malaria in Msambweni district

CONTEXT

In Kenya, most people use traditional medicine and medicinal plants to treat many diseases including malaria. To manage malaria, new knowledge and products are needed. Traditional herbal medicine has constituted a good basis for antimalarial lead discovery and drug development.

OBJECTIVES

To determine in vivo antimalarial activity and brine shrimp toxicity of five medicinal plants traditionally used to treat malaria in Msambweni district, Kenya.

MATERIALS AND METHODS

A 0.2 ml saline solution of 100 mg/kg aqueous crude extracts from five different plant parts were administered orally once a day and evaluated for their in vivo chemosuppressive effect using Plasmodium berghei berghei-infected Swiss mice for four consecutive days. Their safety was also determined using Brine shrimp lethality test: Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) root, Dicrostachys cinerea (L) Wight et Am (Mimosaceae) root, Tamarindus indica L. (Caesalpiniaceae) stem bark, Azadirachta indica (L) Burn. (Meliaceae) root bark, and Acacia seyal Del. (Mimosaceae) root.

RESULTS

Parasitaemia was as follows: A. indica, 3.1%; D. cinerea, 6.3%; T. indica, 25.1%; A. seyal, 27.8%; and G. trichocarpa, 35.8%. In terms of toxicity, A. indica root bark extract had an LC50 of 285.8 µg/ml and was considered moderately toxic. T. indica stem bark extract and G. trichocarpa root extract had an LC50 of 516.4 and 545.8 µg/ml, respectively, and were considered to be weakly toxic while A. seyal and D. cinerea root extracts had a LC50 >1000 µg/ml and were, therefore, considered to be non-toxic.

DISCUSSION AND CONCLUSION

All extracts had antimalarial activity that was not significant compared to chloroquine (p ≥ 0.05). No extract was toxic to the arthropod invertebrate, Artemia salina L. (Artemiidae) larvae, justifying the continued use of the plant parts to treat malaria.

Synergistic anticancer effect of the extracts from Polyalthia evecta caused apoptosis in human hepatoma (HepG2) cells

OBJECTIVE

To evaluate the anticancer activity of the extract fraction of Polyalthia evecta (P. evecta) (Pierre) Finet & Gagnep and the synergistic anticancer effect of the extracts from P. evecta by using the ATR/FT-IR spectroscopy.

METHODS

The 50% ethanol-water crude leaf extract of P. evecta (EW-L) was prepared and was further fractionated to isolate various fractions. The anticancer activity was investigated from cytotoxicity against HepG2 using a neutral red assay and apoptosis induction by evaluation of nuclei morphological changes after DAPI staining. Synergistic anticancer effects of the extracts from P. evecta were performed using the ATR/FT-IR spectroscopy.

RESULTS

The result showed that the EW-L showed higher cytotoxicity and apoptosis induction in HepG2 cells than its fractionated extracts. The hexane extract exhibited higher cytotoxicity and apoptosis induction than the water extracts, but less than the EW-L. The combined water and hexane extracts apparently increased cytotoxicity and apoptosis induction. The %apoptotic cells induced by the extract mixture were increased about 2-fold compared to the single hexane extract.

CONCLUSIONS

The polar extract fraction is necessary for the anticancer activity of the non-polar extract fraction. The ATR/FT-IR spectra illustrates the physical interaction among the constituents in the extract mixture and reveals the presence of polyphenolic constituents in the EW-L, which might play a role for the synergistic anticancer effect.

Alkaline phosphatase activity-guided isolation of active compounds and new dammarane-type triterpenes from Cissus quadrangularis hexane extract

ETHNOPHARMACOLOGICAL RELEVANCE

The stem of Cissus quadrangularis L. (CQ) is used in traditional medicine to treat bone fractures and swelling. Anti-osteoporotic activity of CQ hexane extract has been reported, but the active compounds in this extract remain unknown. Thus, we aimed to identify the active compounds in CQ hexane extract using bioassay-guided isolation.

MATERIALS AND METHODS

The CQ hexane extract was fractionated sequentially with benzene, dichloromethane, ethyl acetate, and methanol. The examination of CQ extract and its fractions was guided by bioassays for alkaline phosphatase (ALP) activity during the differentiation of MC3T3-E1 osteoblastic cells. The cells were treated with or without the CQ extract and its fractions for a period of time, and then the stimulatory effect of the alkaline phosphatase enzyme, a bone differentiation marker, was investigated. The compounds obtained were structurally elucidated using spectroscopic techniques and re-evaluated for activity during bone differentiation.

RESULTS

A total of 29 compounds were isolated, viz., triterpenes, fatty acid methyl esters, glycerolipids, steroids, phytols, and cerebrosides. Four new dammarane-type triterpenes were isolated for the first time from nature, and this report is the first to identify this group of compounds from the Vitaceae family. Seven compounds, viz., glycerolipids and squalene, stimulated ALP activity at a dose of 10μg/mL. Moreover, the synergistic effect of these compounds on bone formation was demonstrated.

CONCLUSION

This report describes, for the first time, the isolation of active compounds from CQ hexane extract; these active compounds will be useful for the quality control of extracts from this plant used to treat osteoporosis.

Interactions between herbs and antidiabetics: an overview of the mechanisms, evidence, importance, and management

Complementary and alternative therapies are quickly gaining importance because they are perceived to be free of side effects due to their natural origin. However, herbal remedies are complex mixtures of bioactive entities, which may interact with prescription drugs through pharmacokinetic or pharmacodynamic mechanisms and sometimes result in life-threatening consequences. In particular, diabetes patients are often treated with multiple medications due to different comorbidities, and such patients use antidiabetic medications for their entire lives; thus, it is important to make the public aware of herb interactions with antidiabetic drugs. In this paper, we summarize the reports available on the interaction of herbal remedies with oral hypoglycemic agents and describe mechanisms, preclinical or clinical evidence, importance, and management strategies.

Anti-malarial activity of a polyherbal product (Nefang) during early and established Plasmodium infection in rodent models

BACKGROUND

The emerging resistance of Plasmodium species to currently available anti-malarials remains a public health concern, hence the need for new effective, safe and affordable drugs. Natural products remain a reliable source of drugs. Nefang is a polyherbal anti-malarial of the Cameroonian folklore medicine with demonstrated in vitro antiplasmodial and antioxidant activities. It is composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, Ocimum gratissimum (leaves). This study aimed at investigating the suppressive, prophylactic and curative activities of Nefang in Plasmodium infected rodent models.

METHODS

Systemic acute oral toxicity of Nefang aqueous and ethanol extracts was assessed in mice up to a dose of 5,000 mgkg(-1) body weight. BALB/c mice and Wistar rats were inoculated with Plasmodium chabaudi chabaudi and Plasmodium berghei, respectively, and treated with Nefang, the Mangifera indica bark/Psidium guajava combination and a Psidium guajava leaf aqueous extracts (75, 150, 300 and 600 mgkg(-1) bwt). Their schizonticidal activity was then evaluated using the Peter's 4-day suppressive test). The prophylactic and curative (Rane's Test) activity of Nefang was also evaluated by determining the parasitaemia, survival time, body weight and temperature in pre-treated rodents.

RESULTS

Acute oral toxicity of the extract did not cause any observed adverse effects. Percent suppressions of parasitaemia at 600 mgkg(-1) bwt were as follows (P. berghei/P. chabaudi): Nefang - 82.9/86.3, Mangifera indica bark/Psidium guajava leaf combination extract - 79.5/81.2 and Psidium guajava leaf - 58.9/67.4. Nefang exhibited a prophylactic activity of 79.5% and its chemotherapeutic effects ranged from 61.2 - 86.1% with maximum effect observed at the highest experimental dose.

CONCLUSION

These results indicate that Nefang has excellent in vivo anti-malarial activities against P. berghei and P. chabaudi, upholding earlier in vitro antiplasmodial activities against multi-drug resistant P. falciparum parasites as well as its traditional use. Hence, Nefang represents a promising source of new anti-malarial agents.

System-level study on synergism and antagonism of active ingredients in traditional Chinese medicine by using molecular imprinting technology

In this work, synergism and antagonism among active ingredients of traditional Chinese medicine (TCM) were studied at system-level by using molecular imprinting technology. Reduning Injection (RDNI), a TCM injection, was widely used to relieve fever caused by viral infection diseases in China. Molecularly imprinted polymers (MIPs) synthesized by sol-gel method were used to separate caffeic acid (CA) and analogues from RDNI without affecting other compounds. It can realize the preparative scale separation. The inhibitory effects of separated samples of RDNI and sample combinations in prostaglandin E2 biosynthesis in lipopolysaccharide-induced RAW264.7 cells were studied. The combination index was calculated to evaluate the synergism and antagonism. We found that components which had different scaffolds can produce synergistic anti-inflammatory effect inside and outside the RDNI. Components which had similar scaffolds exhibited the antagonistic effect, and the antagonistic effects among components could be reduced to some extent in RDNI system. The results indicated MIPs with the characteristics of specific adsorption ability and large scale preparation can be an effective approach to study the interaction mechanism among active ingredients of complex system such as TCM at system-level. And this work would provide a new idea to study the interactions among active ingredients of TCM.

In vitro synergistic antioxidant activity and identification of antioxidant components from Astragalus membranaceus and Paeonia lactiflora

Many traditionally used herbs demonstrate significantly better pharmacological effects when used in combination than when used alone. However, the mechanism underlying this synergism is still poorly understood. This study aimed to investigate the synergistic antioxidant activity of Astragalus membranaceus (AME) and Paeonia Lactiflora (PL), and identify the potential antioxidant components by 1,1-diphenyl-2-picrylhydrazine (DPPH) radical spiking test followed by a high performance liquid chromatography separation combined with diode array detection and tandem mass spectrometry analysis (DPPH-HPLC-DAD-MS/MS). Eight AME-PL combined extracts (E1-E8) were prepared based on bioactivity-guided fractionation. Among them, E1 exhibited the strongest synergistic effect in scavenging DPPH radicals and reducing ferric ions (P<0.05). Moreover, E1 presented strong cytoprotection against H2O2-induced oxidative damage in MRC-5 cells by suppressing the decrease of the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities. A strong correlation between the increment of total phenolic/flavonoid and synergistic antioxidant activity, especially between the increment of total flavonoid and the increase in ferric reducing power was observed. Finally, seven antioxidant substances were identified in E1 as oxypaeoniflora, catechin, calycosin-7-O-β-D-glucopyranoside, fomononetin-7-O-β-D-glucopyranoside, 9,10-dimethoxy-pterocarpan-3-O-β-D-glucopyranoside, quercetin and 2'-dihydroxy-3',4'-dimethyl-isoflavan-7-O-β-D-glucopyranoside.

Bioactive equivalence of combinatorial components identified in screening of an herbal medicine

Purpose

To identify bioactive equivalent combinatorial components (BECCs) in herbal medicines. The exact composition of effective components in herbal medicines is often elusive due to the lack of adequate screening methodology. Herein, we propose a hypothesis that BECCs accounting for the whole efficacy of original herbal medicines could be discovered from a complex mixture of constituents.

Methods

We developed a bioactive equivalence oriented feedback screening method and applied it to discover the BECCs from an herbal preparation Cardiotonic Pill (CP). The operations include chemical profiling of CP, followed by an iterative loop of determining, collecting and evaluating candidate BECCs.

Results

A combination of 18 compounds was identified as BECCs from CP, which accounts for 15.0% (w/w) of original CP. We have demonstrated that the BECCs were as effective as CP in cell models and in a rat model of myocardial infarction.

Conclusions

This work answers the key question of which are real bioactive components for CP that have been used in clinic for many years, and provides a promising approach for discovering BECCs from herbal medicines. More importantly, the BECCs could be extended to improve quality control of herbal products and inspire an herbal medicines based discovery of combinatorial therapeutics.

Electronic supplementary material

The online version of this article (doi:10.1007/s11095-013-1283-1) contains supplementary material, which is available to authorized users.

Potential benefits of Chinese Herbal Medicine for elderly patients with cardiovascular diseases

Chinese Herbal Medicine (CHM), as the most common form of traditional Chinese medicine (TCM), has been playing an important role in the treatment of elderly cardiovascular diseases (CVDs) in China. In this paper, we briefly discuss on the potential benefits of CHM for elderly patients with CVDs. Initially, we summarize the characteristics of CVDs in the elderly, the present treatment of CVDs in the elderly, and the clinical applications of CHM for CVDs. Secondly, in addition to introducing the features of CHM, we discuss the differences between CHM and Western medicine. Lastly, the potential benefits of CHM are presented. We came to a conclusion that as mutual complementary, Western medicine and TCM together shall benefit the elderly patients with CVDs.

Chemical Composition and Synergistic Antioxidant Activities of Essential Oils from Atractylodes Macrocephala and Astragalus Membranaceus

Chemical composition of the essential oils derived from Atractylodes macrocephala (AMA), Astragalus membranaceus (AME) and AMA-AME herb pair was investigated using gas chromatography-mass spectrometry (GC-MS). Antioxidant activities were evaluated by 1,1-diphenyl-2-picyrlhydrazyl (DPPH) radical-scavenging and Trolox equivalent antioxidant capacity (TEAC) assays. Forty-five, ten and forty-three components were identified in AMA, AME and AMA-AME essential oils, respectively. AMA-AME essential oil exhibited a significantly higher radical scavenging capacity than the theoretical sum of those of the respective herb essential oils ( P < 0.05). Principal component analysis showed that twenty-three components contributed to the scavenging activities against DPPH and ABTS•+ radicals. Moreover, the concentrations of these major components exhibited various increases to some extent when compared with the theoretical sum of the respective herb essential oils. These findings suggest that combination of two or more herbs might be used as a promising source of natural antioxidants in the pharmaceutical and food industries.

Inhibition of HIV-1 enzymes, antioxidant and anti-inflammatory activities of Plectranthus barbatus

ETHNOPHARMACOLOGICAL RELEVANCE

Plectranthus barbatus is widely used in African countries as an herbal remedy to manage HIV/AIDS and related conditions.

AIM OF THE STUDY

To investigate the HIV-1 inhibitory, anti-inflammatory and antioxidant properties of P. barbatus and thereby provide empirical evidence for the apparent anecdotal success of the extracts.

MATERIALS AND METHODS

Ethanolic extract of P. barbatus's leaves was screened against two HIV-1 enzymes: protease (PR) and reverse transcriptase (RT). Cytotoxicity of the extract was determined through measuring tetrazolium dye uptake of peripheral blood mononuclear cells (PBMCs) and the TZM-bl cell line. Confirmatory assays for cytotoxicity were performed using flow cytometry and real-time cell electronic sensing (RT-CES). The free radical scavenging activity of the extract was investigated with 2,2-diphenyl-1-picrylhydrazyl while the anti-inflammatory properties of the plant extract were investigated using a Th1/Th2/Th17 cytometric bead array technique.

RESULTS

P. barbatus extract inhibited HIV-1PR and the 50% inhibitory concentration (IC50) was 62.0 µg/ml. The extract demonstrated poor inhibition of HIV-1 RT. Cytotoxicity testing presented CC50 values of 83.7 and 50.4 µg/ml in PBMCs and TZM-bl respectively. In addition, the extract stimulated proliferation in HIV negative and positive PBMCs treated. RT-CES also registered substantial TZM-bl proliferation after extract treatment. The extract exhibited strong antioxidant activity with an IC50 of 16 µg/ml and reduced the production of pro-inflammatory cytokines indicating anti-inflammatory potential.

CONCLUSION

This is the first demonstration of the in vitro anti HIV-1 potential of P. barbatus including direct activity as well as through the stimulation of protective immune and inflammation responses. The low cytotoxicity of the extract is also in agreement with the vast anecdotal use of this plant in treating various ailments with no reported side-effects.

Brine shrimp toxicity and antimalarial activity of some plants traditionally used in treatment of malaria in Msambweni district of Kenya

ETHNOPHARMACOLOGICAL RELEVANCE

In Kenya, most people especially in rural areas use traditional medicine and medicinal plants to treat many diseases including malaria. Malaria is of national concern in Kenya, in view of development of resistant strains of Plasmodium falciparum to drugs especially chloroquine, which had been effective and affordable. There is need for alternative and affordable therapy. Many antimalarial drugs have been derived from medicinal plants and this is evident from the reported antiplasmodial activity.

AIM OF THE STUDY

The present study reports on the in vivo antimalarial activity and brine shrimp lethality of five medicinal plants traditionally used to treat malaria in Msambweni district, Kenya.

MATERIALS AND METHODS

A total of five aqueous crude extracts from different plant parts used in traditional medicine for the treatment of malaria were evaluated for their in vivo antimalarial activity using Plasmodium berghei infected Swiss mice and for their acute toxicity using Brine shrimp lethality test.

RESULTS

The screened crude plant extracts suppressed parasitaemia as follows: Azadirachta indica (L) Burm. (Meliaceae), 3.1%; Dichrostachys cinerea (L) Wight et Arn (Mimosaceae), 6.3%; Tamarindus indica L. (Caesalpiniaceae), 25.1%; Acacia seyal Del. (Mimosaceae) 27.8% and Grewia trichocarpa Hochst ex A.Rich (Tiliaceae) 35.8%. In terms of toxicity, A.indica root bark extract had an LC50 of 285.8 µg/ml and was considered moderately toxic. T.indica stem bark extract and G.trichocarpa root extract had an LC50 of 516.4 and 545.8 µg/ml respectively and were considered to be weakly toxic while A.seyal and D.cinerea root extracts had a LC50>1000 µg/ml and were therefore considered to be non toxic.

CONCLUSIONS

The results indicate that the aqueous extracts of the tested plants when used alone as monotherapy had antimalarial activity which was significantly different from that of chloroquine (P≤0.05). The results also suggest that the anecdotal efficacy of the above plants reported by the study community is related to synergism of phytoconstituents since the assayed plant parts are used in combination with others to treat malaria. It is also evident that none of the screened plant extracts is toxic to the arthropod invertebrate, Artemia salina L. (Artemiidae) larvae, justifying the continued use of the plant parts to treat malaria. A.seyal, G.trichocarpa and T.indica have not been reported before for in vivo antimalarial activity and brine shrimp lethality.

Systems pharmacology strategies for drug discovery and combination with applications to cardiovascular diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Multi-target therapeutics is a promising paradigm for drug discovery which is expected to produce greater levels of efficacy with fewer adverse effects and toxicity than monotherapies. Medical herbs featuring multi-components and multi-targets may serve as valuable resources for network-based multi-target drug discovery.

MATERIALS AND METHODS

In this study, we report an integrated systems pharmacology platform for drug discovery and combination, with a typical example applied to herbal medicines in the treatment of cardiovascular diseases.

RESULTS

First, a disease-specific drug-target network was constructed and examined at systems level to capture the key disease-relevant biology for discovery of multi-targeted agents. Second, considering an integration of disease complexity and multilevel connectivity, a comprehensive database of literature-reported associations, chemicals and pharmacology for herbal medicines was designed. Third, a large-scale systematic analysis combining pharmacokinetics, chemogenomics, pharmacology and systems biology data through computational methods was performed and validated experimentally, which results in a superior output of information for systematic drug design strategies for complex diseases.

CONCLUSIONS

This strategy integrating different types of technologies is expected to help create new opportunities for drug discovery and combination.

Synergistic effect of fucoidan with antibiotics against oral pathogenic bacteria

BACKGROUND

Fucoidan is a sulphated polysaccharide that is primarily extracted from brown seaweeds; it has been broadly studied in recent years due to its numerous biological properties, including anticoagulant, antithrombotic, antitumour and antiviral activities.

OBJECTIVE AND DESIGN

In this study, fucoidan was evaluated against oral bacteria, either alone or with antibiotics, via the broth dilution method and chequerboard and time-kill assay.

RESULTS

Minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) values for the fucoidan against all the tested bacteria ranged between 0.125 and 0.50/0.25 and 1.00mgml(-1), for ampicillin 0.125 and 64/0.5 and 64μgml(-1) and for gentamicin 2 and 256/4 and 512μgml(-1), respectively. Furthermore, the MIC and MBC were reduced to one half-eighth as a result of the combination of the fucoidan with antibiotics. One to 3h of treatment with MIC50 of fucoidan with MIC50 of antibiotics resulted from an increase of the rate of killing in colony forming units (CFUs) ml(-1) to a greater degree than was observed with alone.

CONCLUSION

These results suggest that fucoidan is important in the antibacterial actions of the agents.

Computational approaches for exploring the potential synergy and polypharmacology of Duhuo Jisheng Decoction in the therapy of osteoarthritis

The Duhuo Jisheng Decoction (DHJSD), a traditional Chinese medicine (TCM), has been widely used to treat osteoarthritis (OA). However, the mechanisms of action of the DHJSD have not been clearly elucidated. In the present study, the compounds in the DHJSD were characterized by three computational methods; the ligand clustering, chemical space distribution and network construction and analysis methods. The compounds that formed the medical composition of the DHJSD were divided into 10 clusters and possessed a broad diversity in chemical space distribution. The compounds also had the same coverage of chemical space as the OA drug/drug‑like compounds from DrugBank. In addition, multiple active compounds were identified as able to target multiple proteins in the drug‑target association networks (D‑T networks). A certain number of key compounds in the D‑T networks have been previously reported in the literature. The present study also constructed drug‑drug association networks (D‑D networks) and classified the DHJSD compounds into five clusters. The clusters represented multiple diverse combinations binding to the OA targets. These results suggested that the DHJSD had drug‑ and lead‑like compounds with potential synergy and polypharmacology against OA.

Comparative study of pharmacokinetics and tissue distribution of osthole in rats after oral administration of pure osthole and Libanotis buchtormensis supercritical extract

ETHNOPHARMACOLOGICAL RELEVANCE

Libanotis buchtormensis is the source of an important traditional medicine from Shaanxi province of China used in the treatment of many illnesses. Libanotis buchtormensis supercritical extract (LBSE) has analgesic, sedative and anti-inflammatory qualities. Osthole is one of the major bioactive components of LBSE; it is known for its significant anti-tumor, analgesic, and anti-inflammatory properties, it also alleviates hyperglycemia.

AIM OF THE STUDY

The purpose of the present study was to compare the pharmacokinetics and tissue distribution of osthole in Sprague-Dawley (SD) rats after oral administration of pure osthole and LBSE. The two preparations were administered at the same osthole dose (approximately 130 mg/kg). The results should provide some guidance for the clinical applications of Libanotis buchtormensis.

MATERIALS AND METHODS

Comparative pharmacokinetics and tissue distribution of osthole in SD rats after oral administration of pure osthole and LBSE were analyzed using reversed-phase high-performance liquid chromatography (RP-HPLC). All pharmacokinetic data were analyzed using 3P97 software. Samples of blood and internal organs (heart, liver, spleen, lungs and kidney) were collected and pretreated according to the experimental schedule. After pretreatment, plasma and tissue samples were extracted using ether-ethyl acetate mixture (3:1, v/v). The concentration of osthole in the plasma and tissues were determined using the RP-HPLC method.

RESULTS

The procedure described in this paper shows good precision and stability and is suitable for the osthole assays in biological samples. We found that the average plasma concentration-time profile of osthole after oral administration of osthole and LBSE showed a single peak. There were also clear differences between plasma concentrations of osthole after oral administration of pure osthole and LBSE. Non-osthole ingredients in LBSE showed some pharmacokinetic interactions with osthole and hence decreased its absorption levels (p<0.05). Our results show different tissue distribution of osthole in the single and composite administration regimens.

CONCLUSIONS

This study compares the pharmacokinetic characteristics and tissue distribution of osthole in rats after oral administration of pure osthole and LBSE; the results might be useful in clinical application of this traditional Chinese herbal medicine.

Anti-obesity effect of HT048, a herbal combination, in high fat diet-induced obese rats

This study evaluated the anti-obesity effects of HT048, a combination of C. pinnatifida fruit and C. unshiu peel extracts, in high-fat diet (HFD)-induced obese rats. 4-Week-old male Sprague Dawley (SD) rats were divided into normal and high fat diet (HFD) groups. The HFD groups were further divided into five groups treated with distilled water, orlistat (40 mg/kg, twice daily, p.o) and HT048 (30, 100 and 300 mg/kg, twice daily, p.o.) for 12 weeks. Orlistat, an anti-obesity drug, was used as positive control in the HFD-induced obese rats. We measured the food intake, body weight, epididymal adipose tissue and liver weights, and serum total cholesterol (TC), triglyceride (TG), alanine transaminase (ALT), and aspartate aminotransferase (AST) levels. The body weight and epididymal adipose tissue and liver weights of the HT048 100 and 300 mg/kg treated groups were significantly lower than that of the HFD control group. Also, serum TC, TG, ALT, and AST levels in the HT048 100 and 300 mg/kg treated groups were significantly decreased. Moreover, the orlistat treated group showed significantly reduced body weight and improved serum lipoprotein, compared with the HFD control group. These results show that HT048 supplements improved obesity-related body weight and serum lipoprotein parameters in a HFD-induced obese rat model.

A systems biology approach to uncovering pharmacological synergy in herbal medicines with applications to cardiovascular disease

Background. Clinical trials reveal that multiherb prescriptions of herbal medicine often exhibit pharmacological and therapeutic superiority in comparison to isolated single constituents. However, the synergistic mechanisms underlying this remain elusive. To address this question, a novel systems biology model integrating oral bioavailability and drug-likeness screening, target identification, and network pharmacology method has been constructed and applied to four clinically widely used herbs Radix Astragali Mongolici, Radix Puerariae Lobatae, Radix Ophiopogonis Japonici, and Radix Salviae Miltiorrhiza which exert synergistic effects of combined treatment of cardiovascular disease (CVD). Results. The results show that the structural properties of molecules in four herbs have substantial differences, and each herb can interact with significant target proteins related to CVD. Moreover, the bioactive ingredients from different herbs potentially act on the same molecular target (multiple-drug-one-target) and/or the functionally diverse targets but with potentially clinically relevant associations (multiple-drug-multiple-target-one-disease). From a molecular/systematic level, this explains why the herbs within a concoction could mutually enhance pharmacological synergy on a disease. Conclusions. The present work provides a new strategy not only for the understanding of pharmacological synergy in herbal medicine, but also for the rational discovery of potent drug/herb combinations that are individually subtherapeutic.

What does it take to synergistically combine sub-potent natural products into drug-level potent combinations?

There have been renewed interests in natural products as drug discovery sources. In particular, natural product combinations have been extensively studied, clinically tested, and widely used in traditional, folk and alternative medicines. But opinions about their therapeutic efficacies vary from placebo to synergistic effects. The important questions are whether synergistic effects can sufficiently elevate therapeutic potencies to drug levels, and by what mechanisms and at what odds such combinations can be assembled. We studied these questions by analyzing literature-reported cell-based potencies of 190 approved anticancer and antimicrobial drugs, 1378 anticancer and antimicrobial natural products, 99 natural product extracts, 124 synergistic natural product combinations, and 122 molecular interaction profiles of the 19 natural product combinations with collective potency enhanced to drug level or by >10-fold. Most of the evaluated natural products and combinations are sub-potent to drugs. Sub-potent natural products can be assembled into combinations of drug level potency at low probabilities by distinguished multi-target modes modulating primary targets, their regulators and effectors, and intracellular bioavailability of the active natural products.

Harnessing traditional Chinese medicine to improve cancer therapy: issues for future development

Traditional Chinese medicine (TCM) has recently yielded a number of chemical compounds with clinically significant anticancer activity. The theory of TCM formulas, however, unlike Western medicine, is based on the interactions of the various Chinese medicinal materials in the body, rather than the activity of a single purified chemical compound. Mechanisms for the possible synergistic anticancer effects of components in TCM formulas have recently been postulated. Advanced research on the clinical effects of TCM formulas, however, has been hampered by inconsistent dosage formulations and unreliable quality control. Scientific challenges in dosage formulation and methods for ensuring quality control of TCM products will be discussed.

An overview of the evidence and mechanisms of herb-drug interactions

Despite the lack of sufficient information on the safety of herbal products, their use as alternative and/or complementary medicine is globally popular. There is also an increasing interest in medicinal herbs as precursor for pharmacological actives. Of serious concern is the concurrent consumption of herbal products and conventional drugs. Herb-drug interaction (HDI) is the single most important clinical consequence of this practice. Using a structured assessment procedure, the evidence of HDI presents with varying degree of clinical significance. While the potential for HDI for a number of herbal products is inferred from non-human studies, certain HDIs are well established through human studies and documented case reports. Various mechanisms of pharmacokinetic HDI have been identified and include the alteration in the gastrointestinal functions with consequent effects on drug absorption; induction and inhibition of metabolic enzymes and transport proteins; and alteration of renal excretion of drugs and their metabolites. Due to the intrinsic pharmacologic properties of phytochemicals, pharmacodynamic HDIs are also known to occur. The effects could be synergistic, additive, and/or antagonistic. Poor reporting on the part of patients and the inability to promptly identify HDI by health providers are identified as major factors limiting the extensive compilation of clinically relevant HDIs. A general overview and the significance of pharmacokinetic and pharmacodynamic HDI are provided, detailing basic mechanism, and nature of evidence available. An increased level of awareness of HDI is necessary among health professionals and drug discovery scientists. With the increasing number of plant-sourced pharmacological actives, the potential for HDI should always be assessed in the non-clinical safety assessment phase of drug development process. More clinically relevant research is also required in this area as current information on HDI is insufficient for clinical applications.

The potential of metabolic fingerprinting as a tool for the modernisation of TCM preparations

A vast majority Chinese herbal medicines (CHM) are traditionally administered as individually prepared water decoctions (tang) which are rather complicated in practice and their dry extracts show technological problems that hamper straight production of more convenient application forms. Modernised extraction procedures may overcome these difficulties but there is lack of clinical evidence supporting their therapeutic equivalence to traditional decoctions and their quality can often not solely be attributed to the single marker compounds that are usually used for chemical extract optimisation. As demonstrated by the example of the rather simple traditional TCM formula Danggui Buxue Tang, both the chemical composition and the biological activity of extracts resulting from traditional water decoction are influenced by details of the extraction procedure and especially involve pharmacokinetic synergism based on co-extraction. Hence, a more detailed knowledge about the traditional extracts' chemical profiles and their impact on biological activity is desirable in order to allow the development of modernised extracts that factually contain the whole range of compounds relevant for the efficacy of the traditional application. We propose that these compounds can be identified by metabolomics based on comprehensive fingerprint analysis of different extracts with known biological activity. TCM offers a huge variety of traditional products of the same botanical origin but with distinct therapeutic properties, like differentially processed drugs and special daodi qualities. Through this variety, TCM gives an ideal field for the application of metabolomic techniques aiming at the identification of active constituents.

Anti-Parkinsonian drug discovery from herbal medicines: what have we got from neurotoxic models?

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicines are used to treat Parkinson's disease (PD) in ancient medical systems in Asian countries such as India, China, Japan and Korea based on their own anecdotal or experience-based theories.

AIM OF THE REVIEW

To systematically summarize and analyze the anti-Parkinsonian activities of herbal preparations (including active compounds, herbal extracts and formulations) investigated in the neurotoxic models of PD and provide future references for basic and clinical investigations.

MATERIALS AND METHODS

All the herbal materials tested on in vitro and in vivo neurotoxic models of PD were retrieved from PubMed database by using pre-set searching strings. The relevant compounds and herbal extracts with anti-Parkinsonian activities were included and analyzed according to their chemical classifications or biological activities.

RESULTS

A total of 51 herbal medicines were analyzed. A diversity of compounds isolated from herbal materials were reported to be effective on neurotoxic models of PD by modulating multiple key events or signaling pathways implicated in the pathogenesis of PD. The main structure types of these compounds belong to catechols, stilbenoids, flavonoids, phenylpropanoids and lignans, phenylethanoid glycosides and terpenes. Although some herbal extracts and formulations have shown positive results on PD animal models, the relative compounds accounting for the effects and the underlying mechanisms remain to be further investigated.

CONCLUSIONS

Herbal medicines can be an alternative and valuable source for anti-Parkinsonian drug discovery. Compounds classified into stilbenoids, flavonoids, catechols and terpenes may be the most promising candidates for further investigation. Some well-studies compounds such as baicalein, puerarin, resveratrol, curcumin and ginsenosides deserve further consideration in clinical trials. In-depth experimental studies are still needed to evaluate the efficacy of herbal extracts and formulations in PD models.

Synergistic interactions of saponins and monoterpenes in HeLa cells, Cos7 cells and in erythrocytes

In phytomedicine complex extracts consisting of phenolics, monoterpenes or saponins are traditionally used. It is often impossible to attribute the biological activity of an extract to one or few compounds. As an explanation of the superior activity of extracts, a synergistic effect of combinations of active compounds has been suggested. Since lipophilic monoterpenes or saponins targeting the biomembrane usually accompany polar polyphenols in phytomedical preparations, we decided to investigate their effect as single substances and in combination to gain further insight into potential synergistic effects of herbal medicine. Combinations of the monoterpenes α-pinene, thymol and menthol with the monodesmosidic saponins digitonin, aescin, glycyrrhizic acid and Quillaja saponin demonstrated strong synergistic activity. The IC(50) of haemolysis was lowered by a factor of 10-100 from 316μg/ml to 2μg/ml for aescin, 157μg/ml to 11μg/ml for Quillaja saponins and 20μg/ml to 3μg/ml for digitonin when combined with thymol. A similar significant synergistic cytotoxicity occurred both in HeLa and Cos7 cells by combining the α-pinene, thymol and menthol with the saponins. The IC(50) of glycyrrhizic acid was lowered by a factor 100 from around 300μg/ml to around 1-10μg/ml and the IC(50) of aescin, digitonin and Quillaja saponins about the factor 10. Monoterpenes and monodesmosidic saponins have a common target, the biomembrane, which is present in all animal, fungal and bacterial cells. Disturbance of membrane fluidity and permeability is the mode of action. This activity is non-specific which makes it extremely difficult for bacteria and fungi to develop resistance. This explains the overall success of these molecules as defence chemicals in the plant kingdom. The synergistic effect of combinations of saponins with monoterpenes opens a complete new field of possible applications in medicine to overcome resistance in multidrug resistant microbial and human cell.

Analgesic effect and mechanism of the three TCM-herbal drug-combination Tou Feng Yu pill on treatment of migraine

It is well known that pain is one of the most important characteristics of migraine. Therefore, it is important and interesting to investigate the analgesic effect and mechanism of drugs which are used to treat migraine. Tou Feng Yu pill (TFY) is a traditional Chinese herbal medicine, consisting of the three Chinese herbal drugs Radix Angelicae dahuricae (Baizhi), Rhizome Ligustici (Chuanxiong) and Folium Camelliae sinensis (green tea) for the treatment of migraine. In this study, we found that TFY could significantly reduce the writhing times induced by acetic acid and licking foot response induced by formalin, and extend the writhing latent period. But the analgesic effect was not observed at hot-plate test. Meanwhile, experimental migrainous model induced by nitroglycerin was used to investigate the therapeutic effect of TFY. Compared with the control group, the levels of plasma calcitonin gene related to peptide (CGRP), serum nitric oxide (NO) and contents of brain dopamine (DA) in TFY administration groups were significantly decreased, and the levels of plasma endothelin (ET) and contents of brain 5-hydroxytryptamine (5-HT) and norepinephrine (NE) were remarkably increased, also the ratio of ET/NO was clearly corrected. Furthermore, the improving effect of behavior abnormality was observed in TFY administration rats. Meanwhile, isolated vascular ring test indicated that TFY had an significant effect on vasomotion, and antagonize vasospasm; moreover TFY also could increase cerebral blood flow (CBF) and reduce cerebrovascular resistance index (RI) in normal rabbits, which verified the effect of TFY on vasomotion and abnormal hemorheology. All the results indicate that TFY has an effective therapeutical action on migraine, which may be related to three aspects as following: firstly, adjusting the level of neurotransmitters, neuropeptides and vasoactive substances, relieving neurogenic inflammation; secondly, improving vasomotion, increase cerebral blood flow, then improving hemorheology; finally, increasing pain threshold, relieving or preventing headache. These findings provide additional pharmacological information and may contribute for the further study and use of TFY as a phytomedicine.

Anti-inflammatory activity of Lychnophora passerina, Asteraceae (Brazilian "Arnica")

ETHNOPHARMACOLOGICAL RELEVANCE

Lychnophora passerina (Asteraceae), popularly known as "arnica," is used to treat inflammation, pain, rheumatism, contusions, bruises and insect bites in Brazilian traditional medicine.

MATERIALS AND METHODS

The anti-inflammatory activity of crude ethanolic extract of aerial parts of L. passerina and its ethyl acetate and methanolic fractions had their abilities to modulate the production of NO, TNF-α and IL-10 inflammatory mediators in LPS/IFN-γ-stimulated J774.A1 macrophages evaluated. Moreover, the crude ethanolic extract and derived fractions were also in vivo assayed by carrageenan-induced paw oedema in mice.

RESULTS

In vitro assays showed remarkable anti-inflammatory activity of L. passerina crude ethanolic extract (EE) and its ethyl acetate (A) and methanolic (M) fractions, through the inhibition of production of NO and TNF-α inflammatory mediators and induction of production of IL-10 anti-inflammatory cytokine. In vivo assays showed anti-inflammatory activity for EE 10% ointment, similar to the standard drug diclofenac gel. The A and M fraction ointments 20% presented anti-inflammatory activity.

CONCLUSION

The results obtained showed that possible anti-inflammatory effects of EE and its A and M fractions may be attributed to inhibition pro-inflammatory cytokines production, TNF-α and NO and to increased IL-10 production. EE, A and M ointments showed topical in vivo anti-inflammatory activity. The in vivo anti-inflammatory activity of EE of L. passerina may be related to synergistic effects of different substances in the crude extract. Therefore, traditional use of aerial parts of L. passerina in the inflammatory conditions could be beneficial to treat topical inflammatory conditions, as evidenced by the present study.

A call for using natural compounds in the development of new antimalarial treatments - an introduction

Natural compounds, mostly from plants, have been the mainstay of traditional medicine for thousands of years. They have also been the source of lead compounds for modern medicine, but the extent of mining of natural compounds for such leads decreased during the second half of the 20^th century. The advantage of natural compounds for the development of drugs derives from their innate affinity for biological receptors. Natural compounds have provided the best anti-malarials known to date. Recent surveys have identified many extracts of various organisms (mostly plants) as having antiplasmodial activity. Huge libraries of fractionated natural compounds have been screened with impressive hit rates. Importantly, many cases are known where the crude biological extract is more efficient pharmacologically than the most active purified compound from this extract. This could be due to synergism with other compounds present in the extract, that as such have no pharmacological activity. Indeed, such compounds are best screened by cell-based assay where all potential targets in the cell are probed and possible synergies identified. Traditional medicine uses crude extracts. These have often been shown to provide many concoctions that deal better with the overall disease condition than with the causative agent itself. Traditional medicines are used by ~80 % of Africans as a first response to ailment. Many of the traditional medicines have demonstrable anti-plasmodial activities. It is suggested that rigorous evaluation of traditional medicines involving controlled clinical trials in parallel with agronomical development for more reproducible levels of active compounds could improve the availability of drugs at an acceptable cost and a source of income in malaria endemic countries.

Antagonistic effects of two herbs in Zuojin Wan, a traditional Chinese medicine formula, on catecholamine secretion in bovine adrenal medullary cells

In order to research the target of superior efficacy and lesser side effects, combination of herbal materials has been applied to phytotherapy for thousands of years in China and some other countries. Zuojin Wan (ZJW), a famous traditional Chinese medicine formula, is used in treating gastric diseases in China. It is composed of two herbs, Rhizoma Coptidis (RC) and Fructus Evodiae (FE) in the ratio of 6: 1(w/w). In the present study, we examined the effects of ZJW, RC, FE and active components isolated from these herbs on catecholamine (CA) secretion and intracellular calcium ([Ca(2+)](i)) in cultured bovine adrenal medullary cells. Extracts of ZJW and RC and berberine, palmatine and jatrorrhizine, components of RC, all inhibited CA secretion and rise in [Ca(2+)](i) induced by acetylcholine (ACh), veratridine (Ver) and/or 56 mM K(+). On the other hand, extract of FE, evodiamine and rutaecarpine, components of FE, stimulated CA secretion and rise in [Ca(2+)](i) induced by ACh. Furthermore, different proportions of RC and FE caused different responses in CA secretion. The present findings suggest that two herbs in ZJW have opposite effects, i.e., inhibitory effect of RC and stimulatory effect of FE, on CA secretion induced by acetylcholine in cultured bovine adrenal medullary cells.

In-silico approaches to multi-target drug discovery : computer aided multi-target drug design, multi-target virtual screening

Multi-target drugs against selective multiple targets improve therapeutic efficacy, safety and resistance profiles by collective regulations of a primary therapeutic target together with compensatory elements and resistance activities. Efforts have been made to employ in-silico methods for facilitating the search and design of selective multi-target agents. These methods have shown promising potential in facilitating drug discovery directed at selective multiple targets.

Molecular networks for the study of TCM pharmacology

To target complex, multi-factorial diseases more effectively, there has been an emerging trend of multi-target drug development based on network biology, as well as an increasing interest in traditional Chinese medicine (TCM) that applies a more holistic treatment to diseases. Thousands of years' clinic practices in TCM have accumulated a considerable number of formulae that exhibit reliable in vivo efficacy and safety. However, the molecular mechanisms responsible for their therapeutic effectiveness are still unclear. The development of network-based systems biology has provided considerable support for the understanding of the holistic, complementary and synergic essence of TCM in the context of molecular networks. This review introduces available sources and methods that could be utilized for the network-based study of TCM pharmacology, proposes a workflow for network-based TCM pharmacology study, and presents two case studies on applying these sources and methods to understand the mode of action of TCM recipes.

Assessment of herbal medicinal products: challenges, and opportunities to increase the knowledge base for safety assessment

Although herbal medicinal products (HMP) have been perceived by the public as relatively low risk, there has been more recognition of the potential risks associated with this type of product as the use of HMPs increases. Potential harm can occur via inherent toxicity of herbs, as well as from contamination, adulteration, plant misidentification, and interactions with other herbal products or pharmaceutical drugs. Regulatory safety assessment for HMPs relies on both the assessment of cases of adverse reactions and the review of published toxicity information. However, the conduct of such an integrated investigation has many challenges in terms of the quantity and quality of information. Adverse reactions are under-reported, product quality may be less than ideal, herbs have a complex composition and there is lack of information on the toxicity of medicinal herbs or their constituents. Nevertheless, opportunities exist to capitalise on newer information to increase the current body of scientific evidence. Novel sources of information are reviewed, such as the use of poison control data to augment adverse reaction information from national pharmacovigilance databases, and the use of more recent toxicological assessment techniques such as predictive toxicology and omics. The integration of all available information can reduce the uncertainty in decision making with respect to herbal medicinal products. The example of Aristolochia and aristolochic acids is used to highlight the challenges related to safety assessment, and the opportunities that exist to more accurately elucidate the toxicity of herbal medicines.

Salvianolic acid B-vitamin C synergy in cardiac differentiation from embryonic stem cells

Inefficient cardiomyocyte differentiation limits the therapeutic use of embryonic stem (ES) cell-derived cardiomyocytes. While large collections of proprietary chemicals had been screened to improve ES cell differentiation into cardiomyocytes, the natural product library remained unexplored. Using a mouse ES cell line transfected with a cardiomyocyte-specific alpha-myosin heavy chain promoter-driven enhanced green fluorescent protein (EGFP) reporter, we screened 24 natural products with known cardioprotective actions. Salvianolic acid B (saB), while produced minimal effect on its own, concentration-dependently synergized with vitamin C in inducing cardiomyocyte differentiation, as demonstrated by an increase in EGFP(+) cells, beating area in embryoid bodies, and expression of cardiomyocyte maturity markers. This synergy is specific to cardiomyocyte differentiation, and is involved with collagen synthesis. The present study demonstrates the saB-vitamin C synergy in inducing ES cell differentiation into matured and functional cardiomyocytes, and this may lead to a practicable cocktail approach to generate ES cell-derived cardiomyocytes for cardiac stem cell therapy.