Antiviral activities of medicinal herbs traditionally used in southern mainland China

The genus Scutellaria an ethnopharmacological and phytochemical review

Scutellaria (HUANG QIN) (Lamiaceae), which includes about 350 species commonly known as skullcaps, is widespread in Europe, the United States and East Asia. Some species are taken to clear away the heat-evil and expel superficial evils in traditional Chinese medicine (TCM). The present paper reviews the ethnopharmacology, the biological activities and the correlated chemical compounds of Scutellaria species. More than 295 compounds have been isolated, among them flavonoids and diterpenes. Studies show that Scutellaria and its active principles possess wide pharmacological actions, such as antitumor, anti-angiogenesis, hepatoprotective, antioxidant, anticonvulsant, antibacterial and antiviral activities. Currently, effective monomeric compounds or active parts have been screened for pharmacological activity from Scutellaria in vivo and in vitro. Increasing data supports application and exploitation for new drug development.

Evaluation of Elephantopus scaber on the inhibition of chemical carcinogenesis and tumor development in mice

The effect of the active fraction of Elephantopus scaber L. (Asteraceae) (ES) on skin papillomas induced by 7,12-dimethylbenz(a)anthracene (DMBA) as an initiator and croton oil as promoter was studied in mice. The active fraction of E. scaber (100 mg/kg) on topical application delayed the onset of papilloma formation and reduced the mean number of papillomas and the mean weight of papillomas per mouse. The intraperitoneal administration of the active fraction of E. scaber also had a significant effect on subcutaneous injection of 20-methylcholanthrene (20-MCA)-induced soft tissue sarcomas in mice. It inhibited the incidence of sarcomas and reduced the tumor diameter compared to MCA-treated control animals. The subcutaneous administration of the active fraction of E. scaber significantly inhibited the growth of subcutaneously transplanted DLA and EAC solid tumors, delayed the onset of tumor formation, and increased the life span of tumor bearing mice. The present study thus indicates the tumor inhibitory activity of the active fraction of E. scaber against chemically induced tumors and its ability to inhibit the development of solid tumors.

Deoxyelephantopin, a novel multifunctional agent, suppresses mammary tumour growth and lung metastasis and doubles survival time in mice

BACKGROUND AND PURPOSE

Elephantopus scaber L. (Asteraceae) is a traditional herbal medicine with anti-cancer effects. We evaluated the in vitro and in vivo efficacy of a major sesquiterpene lactone constituent of E. scaber, deoxyelephantopin (DET), against mammary adenocarcinoma and the underlying molecular mechanism.

EXPERIMENTAL APPROACH

A variety of cellular assays, immunoblotting and immunohistochemistry, as well as both orthotopic and metastatic TS/A tumour models in BALB/c mice, were used. Test mice were pretreated and post-treated with DET or paclitaxel and mammary tumour growth evaluated.

KEY RESULTS

DET (< or =2 microg x mL(-1)) significantly inhibited colony formation, cell proliferation, migration and invasion of TS/A cells and induced G(2)/M arrest and apoptosis in TS/A cells. c-Jun N-terminal kinase-mediated p21(Waf1/Cip1) expression and caspase activation cascades were up-regulated by DET, effects suppressed by N-acetyl-L-cysteine. Moreover, tumour necrosis factor alpha-induced matrix metalloproteinase-9 enzyme activity and expression and nuclear factor-kappa B activation were abolished by DET. Pretreatment with DET was more effective than paclitaxel, for profound suppression of orthotopic tumour growth (99% vs. 68% reduction in tumour size) and lung metastasis of TS/A cells (82% vs. 63% reduction in metastatic pulmonary foci) and prolonged median survival time (56 vs. 37 days, P < 0.01) in mice. The levels of cyclooxygenase-2 and vascular endothelial growth factor in metastatic lung tissues of TS/A-bearing mice were attenuated by DET.

CONCLUSIONS AND IMPLICATIONS

Our data provide evidence for the suppression of mammary adenocarcinoma by DET with several mechanisms and suggest that DET has potential as a chemopreventive agent for breast cancer.

Chemical composition and antiproliferative activity of essential oil from the leaves of a medicinal herb, Schefflera heptaphylla

Schefflera heptaphylla (L.) Frodin is a medicinal herb widely used as a main ingredient of the popular health tea formulation against infections in Southern China. Twenty-seven volatile compounds were identified by GC-MS analysis from the essential oil obtained from the leaves of S. heptaphylla, and 17 of them belonged to monoterpenes or sesquiterpenes. The main volatile constituent in S. heptaphylla was found to be a monoterpene, beta-pinene, comprising about 22% of the total volatile components. The essential oil showed significant antiproliferative activity against three cancer cell lines, MCF-7, A375 and HepG2 cells, with IC50 values of 7.3 microg/mL, 7.5 microg/mL and 6.9 microg/mL, respectively. The result of the cytotoxicity assay indicates that (-)-beta-pinene and (+)-beta-pinene (commercially available from Sigma) also possessed antiproliferative activity against the cancer cells MCF-7, A375 and HepG2 with IC50 values ranging from 147.1 to 264.7 microm.

New therapeutic aspects of flavones: the anticancer properties of Scutellaria and its main active constituents Wogonin, Baicalein and Baicalin

Traditional Chinese medicines have been recently recognized as a new source of anticancer drugs and new chemotherapy adjuvant to enhance the efficacy of chemotherapy and to ameliorate the side effects of cancer chemotherapies however their healing mechanisms are still largely unknown. Scutellaria baicalensis is one of the most popular and multi-purpose herb used in China traditionally for treatment of inflammation, hypertension, cardiovascular diseases, and bacterial and viral infections. Accumulating evidence demonstrate that Scutellaria also possesses potent anticancer activities. The bioactive components of Scutellaria have been confirmed to be flavones. The major constituents of Scutellaria baicalensis are Wogonin, Baicalein and Baicalin. These phytochemicals are not only cytostatic but also cytotoxic to various human tumor cell lines in vitro and inhibit tumor growth in vivo. Most importantly, they show almost no or minor toxicity to normal epithelial and normal peripheral blood and myeloid cells. The antitumor functions of these flavones are largely due to their abilities to scavenge oxidative radicals, to attenuate NF-kappaB activity, to inhibit several genes important for regulation of the cell cycle, to suppress COX-2 gene expression and to prevent viral infections. The tumor-selectivity of Wogonin has recently been demonstrated to be due to its ability to differentially modulate the oxidation-reduction status of malignant vs. normal lymphocytic cells and to preferentially induce phospholipase C gamma 1, a key enzyme involved in Ca(2+) signaling, through H(2)O(2) signaling in malignant lymphocytes. This review is aimed to summarize the research results obtained since the last 20 years and to highlight the recently discovered molecular mechanisms.

Ethnobotanical study of medicinal plants used by Hakka in Guangdong, China

ETHNOPHARMACOLOGICAL RELEVANCE

An ethnobotanical survey was conducted to collect information on the use of medicinal plants by the Hakka living in Guangdong.

AIM OF THE STUDY

This investigation was to document valuable knowledge represented by Hakka herbal medicine.

MATERIALS AND METHODS

Information was obtained from semi-structured interviews, personal conversations with practitioners, direct observations, and by reviewing studies of Hakka and Cantonese reported in the literature.

RESULTS

Our data covered 94 species belonging to 77 genera in 40 families. We found that most species used for medical purposes were for hepatitis (14 species) and skin diseases (12 species). These disorders are prevalent and are primarily treated with medicinal plants. For treatment, the plants were mainly used as teas (Luica, Bugingca and Lopêdca), medicinal baths and soups. The Hakka and non-Hakka people living in Guangdong use different medicinal plants and, in some cases, use the same medicinal plants differently.

CONCLUSIONS

The fast disappearance of traditional culture and natural resources due to urbanization and industrialization suggests that unrecorded information may be lost forever. Thus, there is an urgent need both to record this valuable Hakka medicinal knowledge and to encourage its transfer to the next generation.

The in vitro anti-herpes simplex virus type-1 and type-2 activity of Long Dan Xie Gan Tan, a prescription of traditional Chinese medicine

BACKGROUND

Long Dan Xie Gan Tan (LDXGT), a decoction of radix gentianae for purging the pathogenic inflammation of the liver, is a widely used prescription among many in traditional Chinese medicine. The prescription is primarily used to treat the disorders induced by damp-heat in the liver and the gall bladder.

METHODS

In this study, the in vitro anti-herpes simplex virus type-1 (HSV-1) and type-2 (HSV-2) activity of the water extract of LDXGT was investigated.

RESULTS

LDXGT water extract was shown to exhibit anti-HSV activity. The IC(50) values of LDXGT against HSV-1 and HSV-2 infections were 257.5 +/- 12.2 and 494.6 +/- 1.8 microg/ml, respectively. It had a CC(50) value of 4,077.2 +/- 2.4 microg/ml towards Vero cells and showed no cytotoxic effect at a concentration of 2,000 microg/ml or below. The prescription was also found to inactivate HSV-2 infectivity in a dose-, time- and temperature-dependent manner.

CONCLUSIONS

In summary, the water extract of LDXGT was concluded to inhibit HSV-1 and HSV-2 infection at different magnitudes of potency, and our observations also suggested that the effect was likely mediated by directly inactivating the virus infectivity.

Ethnomedicines and ethnomedicinal phytophores against herpesviruses

Herpesviruses are important human pathogens that can cause mild to severe lifelong infections with high morbidity in susceptible adults. Moreover, Herpes simplex virus (HSV) type 2, for example, has been reported to be responsible for increased transmission and disease progression of human immunodeficiency virus (HIV). Therefore, the discovery of novel anti-HSV drugs deserves great efforts. Herbal medicinal products have been used as source of putative candidate drugs in many diseases. However, in case of viral diseases the development of antivirals from natural source is less explored probably because within the virus there are few specific targets where the small molecules can interact to inhibit or kill the virus. The currently available antiherpes drugs are nucleoside analogs that did not cure the lifelong or recurrent infections and the use of these drugs often lead to the development of viral resistance coupled with the problem of side effects, recurrence and viral latency. However a wide array of herbal products, used by diverse medicinal systems throughout the world, showed high level of antiherpesvirus activities and many of them have complementary and overlapping mechanism of action, either by inhibiting viral replication, or viral genome synthesis. This chapter will summarize some of the promising herbal extracts and purified compounds isolated from the herbal sources by several laboratories. Cases with proven in vitro and documented in vivo activities, along with their structure-activity relationship against herpesviruses are discussed.

Limitations of current prophylaxis against influenza virus infection

Avian influenza has been a source of worldwide concern since Hong Kong authorities detected the first outbreak in 1997. Mainly as a result of poultry-to-human transmission, more than 200 cases of infection in humans have been attributed to the A/H5, A/H7, and A/H9 viral subtypes, with a case fatality rate for A/H5N1 infections exceeding 50%. A mutant or reassortant virus capable of efficient human-to-human transmission can set off a pandemic. Increased attention to prophylaxis against viral infection has identified several potentially complementary approaches: nonpharmacologic measures (eg, travel restrictions), vaccination, chemotherapeutic agents, and herbal/natural products. All have significant limitations that point out the need for additional modalities. Herbal/natural products, particularly those based on green tea extract, offer promise as adjuncts or alternatives to current interventions and warrant further evaluation in well-controlled human trials.

Hepatoprotective and antioxidative effects of total phenolics from Laggera pterodonta on chemical-induced injury in primary cultured neonatal rat hepatocytes

Although Laggera pterodonta as a folk medicine has been widely used for several centuries to ameliorate some inflammatory ailments as hepatitis in China, there have been no studies of the hepatoprotective and antioxidative effects of this plant. In this paper, the hepatoprotective effect of total phenolics from L. pterodonta (TPLP) against CCI4-, D-GalN-, TAA-, and t-BHP-induced injury was examined in primary cultured neonatal rat hepatocytes. TPLP inhibited the cellular leakage of two enzymes, hepatocyte ASAT and ALAT, caused by these chemicals and improved cell viability. Moreover, TPLP afforded much stronger protection than the reference drug silibinin. Meanwhile, DPPH and superoxide radicals scavenging activities of TPLP were also determined. The present investigation is the first to report chemical-induced injury model in primary cultured neonatal rat hepatocytes and provide evidence for the hepatoprotective and antioxidative effects of L. pterodonta. Neutralizing reactive oxygen species by nonenzymatic mechanisms may be one of main mechanisms of TPLP against chemical-induced hepatocyte injury. Furthermore, The total phenolic content of L. pterodonta and its main component type were quantified, and its principle components isochlorogenic acids were isolated and authenticated. These data support the folkloric uses of L. pterodonta in the treatment of hepatitis.

Antiviral triterpenoids from the medicinal plant Schefflera heptaphylla

Schefflera heptaphylla (L.) Frodin is a principal ingredient of an herbal tea formulation widely used for the treatment of common cold in southern China. An extract of the long leafstalk of the compound leaf of S. heptaphylla exhibited the most potent antiviral activity against respiratory syncytial virus (RSV). Further antiviral-guided fractionation and isolation of the leafstalk extract of S. heptaphylla led to obtain two highly active pure triterpenoids, namely 3alpha-hydroxylup-20(29)-ene-23,28-dioic acid and 3-epi-betulinic acid 3-O-sulfate, together with an inactive saponin, 3alpha-hydroxylup-20(29)-ene-23,28-dioic acid 28-O-alpha-l-rhamnopyranosyl-(1-->4)-O-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside. An antiviral assay using a cytopathic effect (CPE) reduction method showed that the two triterpenoids possessed broader antiviral activity against respiratory syncytial virus (RSV) with a similar 50% inhibition concentration (IC(50)) value of 6.25 microg/mL, influenza A (H1N1) virus with IC(50) values of 25 and 31.3 microg/mL, Coxsackie B3 (Cox B3) virus with IC(50) values of 12.5 and 20 microg/mL and herpes simplex virus type 1 (HSV-1) with IC(50) values of 18.8 and 25 microg/mL, respectively, whereas the saponin did not have antiviral activity against these four viruses at a concentration of 100 microg/mL.

Pomegranate juice may be a potential addition to anti-Behçet armamentarium: a hypothesis

Behçet's disease (BD) is a systemic vasculitis. We speculate that local or systemic administration of the pomegranate juice may be useful in the treatment of BD. Immunomodulatory, antioxidants and antibacterial characteristics of pomegranate juice may rationalize this hypothesis.

Comparison of plants used for skin and stomach problems in Trinidad and Tobago with Asian ethnomedicine

This paper provides a preliminary evaluation of fifty-eight ethnomedicinal plants used in Trinidad and Tobago for skin problems, stomach problems, pain and internal parasites for safety and possible efficacy. Thirty respondents, ten of whom were male were interviewed from September 1996 to September 2000 on medicinal plant use for health problems. The respondents were obtained by snowball sampling, and were found in thirteen different sites, 12 in Trinidad and one in Tobago. The uses are compared to those current in Asia. Bambusa vulgaris, Bidens alba, Jatropha curcas, Neurolaena lobata, Peperomia rotundifolia and Phyllanthus urinaria are possibly efficacious for stomach problems, pain and internal parasites. Further scientific study of these plants is warranted.

Antiviral activity and constituent ofArdisia chinensis benth against coxsackie B3 virus

Ardisia chinensis Benth is a medicinal plant traditionally used in the area of Yao minority in Southern China. The in vitro antiviral activities of extracts and fractions from Ardisia chinensis were tested by the cytopathic effect (CPE) reduction assay in the present study. As a result, both the aqueous extract and the 95% ethanol extract of Ardisia chinensis showed in vitro antiviral activity against Coxsackie B3 (Cox B3) virus to different extents, and the aqueous extract possessed more potent activity than the ethanol extract. Bioassay-guided fractionation revealed that the antiviral activity of Ardisia chinensis was attributed mainly to its high polar fractions, and finally identified to be a polysaccharide. The Ardisia chinensis polysaccharide (ACP) fractionated from the aqueous extract exhibited a significant antiviral effect against Cox B3 with a 50% inhibitory concentration (IC(50)) of 3.9 microg/mL and a selective index (SI) over 256. Preliminary characterization indicated that ACP is a neutral polysaccharide in which d-glucose is the major component. The average molecular weights of ACP were determined to be 40037 Da (Mw), 28297 Da (Mn) and 33758 Da (Mp) by gel permeation chromatography.

Photochemopreventive Effect of Pomegranate Fruit Extract on UVA-mediated Activation of Cellular Pathways in Normal Human Epidermal Keratinocytes

UVA is the major portion (90-99%) of solar radiation reaching the surface of the earth and has been described to lead to formation of benign and malignant tumors. UVA-mediated cellular damage occurs primarily through the release of reactive oxygen species and is responsible for immunosuppression, photodermatoses, photoaging and photocarcinogenesis. Pomegranate fruit extract (PFE) possesses strong antioxidant and anti-inflammatory properties. Our recent studies have shown that PFE treatment of normal human epidermal keratinocytes (NHEK) inhibits UVB-mediated activation of MAPK and NF-kappaB pathways. Signal transducers and activators of transcription 3 (STAT3), Protein Kinase B/AKT and Map Kinases (MAPKs), which are activated by a variety of factors, modulate cell proliferation, apoptosis and other biological activities. The goal of this study was to determine whether PFE affords protection against UVA-mediated activation of STAT3, AKT and extracellular signal-regulated kinase (ERK1/2). Immunoblot analysis demonstrated that 4 J/cm2 of UVA exposure to NHEK led to an increase in phosphorylation of STAT3 at Tyr705, AKT at Ser473 and ERK1/2. Pretreatment of NHEK with PFE (60-100 microg/mL) for 24 h before exposure to UVA resulted in a dose-dependent inhibition of UVA-mediated phosphorylation of STAT3 at Tyr705, AKT at Ser473 and ERK1/2. mTOR, structurally related to PI3K, is involved in the regulation of p70S6K, which in turn phosphorylates the S6 protein of the 40S ribosomal subunit. We found that UVA radiation of NHEK resulted in the phosphorylation of mTOR at Thr2448 and p70S6K at Thr421/Ser424. PFE pretreatment resulted in a dose-dependent inhibition in the phosphorylation of mTOR at Thr2448 and p70S6K at Thr421/Ser424. Our data further demonstrate that PFE pretreatment of NHEK resulted in significant inhibition of UVA exposure-mediated increases in Ki-67 and PCNA. PFE pretreatment of NHEK was found to increase the cell-cycle arrest induced by UVA in the G1 phase of the cell cycle and the expression of Bax and Bad (proapoptotic proteins), with downregulation of Bcl-X(L) expression (antiapoptotic protein). Our data suggest that PFE is an effective agent for ameliorating UVA-mediated damages by modulating cellular pathways and merits further evaluation as a photochemopreventive agent.

Evaluation of antiinflammatory activity of the total flavonoids ofLaggera pterodonta on acute and chronic inflammation models

The antiinflammatory effect of the total flavonoids of Laggera pterodonta (TFLP) was evaluated with various in vivo models of both acute and chronic inflammation. In the acute inflammation tests, TFLP significantly inhibited xylene-induced mouse ear oedema, carrageenan-induced rat paw oedema and acetic acid-induced mouse vascular permeability. In the carrageenan-induced rat pleurisy model, TFLP efficiently suppressed inflammatory exudate and leukocyte migration, reduced the serum levels of lysozyme (LZM) and malondialdehyde (MDA), increased the activity of serum superoxide dismutase (SOD), and also decreased the contents of total protein, nitric oxide (NO) and prostaglandin E2 (PGE2) in the pleural exudates. No marked effect of TFLP on the activity of serum glutathione peroxidase (GSH-PX) was observed. In the chronic inflammation experiment, TFLP inhibited cotton pellet-induced rat granuloma. The antiinflammatory mechanisms of TFLP are probably associated with the inhibition of prostaglandin formation, influence on the antioxidant systems and the suppression of LZM release. The acute toxicity study revealed that TFLP was nontoxic in mice up to an oral dose of 7.5 g/kg body weight.

Phytochemical screening and antiviral activity of some medicinal plants from the island Soqotra

Methanol and hot-aqueous extracts of 25 different plant species, used in Yemeni traditional medicine and growing, partly as endemic plants, on the island Soqotra have been investigated for their antiviral activity. In addition, the phytochemical identification of the main chemical constituents was performed. The extracts were assayed in two in vitro viral systems, which used influenza virus type A/MDCK cells and herpes simplex virus type 1/Vero cells, at non-cytotoxic concentrations. The herpes simplex virus type 1 showed more sensitivity than the influenza virus type A against the extracts investigated. The methanol extracts of Boswellia ameero, Boswellia elongata, Buxus hildebrandtii, Cissus hamaderohensis, Cleome socotrana, Dracaena cinnabari, Exacum affine, Jatropha unicostata and Kalanchoe farinacea showed anti-influenza virus type A activity with 50% inhibition (IC50) concentrations ranging from 0.7 to 12.5 microg/mL. In addition, 17 plants of the 25 investigated exhibited anti-HSV-1 activity. The antiviral activity of some active extracts was also observed on a molecular level.

Antiviral activity and mode of action of caffeoylquinic acids from Schefflera heptaphylla (L.) Frodin

Schefflera heptaphylla is a popular medicinal plant in southern China. Three caffeoylquinic acid derivatives, namely 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 3-O-caffeoylquinic acid, were isolated from this plant and investigated for their antiviral activity against respiratory syncytial virus (RSV). 3,4-Di-O-caffeoylquinic acid and 3,5-di-O-caffeoylquinic acid possessed potent anti-RSV activity. The median inhibitory concentrations (IC50) of 3,4-di-O-caffeoylquinic acid and 3,5-di-O-caffeoylquinic acid against RSV were 2.33 microM (1.2 microg/ml) and 1.16 microM (0.6 microg/ml), respectively, in a plaque reduction assay. The dicaffeoylquinic acids exhibited minimal cytotoxicity against HEp-2 cells with median cytotoxic concentration (CC50) higher than 1000 microM. The maximal non-cytotoxic concentration (MNCC) of the two dicaffeoylquinic acids were about 96.7 microM, which suggested their anti-RSV effect was not due to cytotoxicity. The antiviral action of 3,4-di-O-caffeoylquinic acid and 3,5-di-O-caffeoylquinic acid was specific against RSV, as they had no obvious antiviral activity against influenza A (Flu A), Coxsackie B3 (Cox B3), and Herpes simplex type one (HSV-1) viruses. Studies were performed that indicated that the dicaffeoylquinic acids could inhibit RSV directly, extracellularly, but only at much higher concentrations than seen in standard assays. Moreover, they could not inhibit RSV attachment to host cells, and could not protect HEp-2 cells from RSV infection at lower concentrations. The data suggest that the compounds exerted their anti-RSV effects via the inhibition of virus-cell fusion in the early stage, and the inhibition of cell-cell fusion at the end of the RSV replication cycle.