Evaluation of antiviral activity of South American plant extracts against herpes simplex virus type 1 and rabies virus

This paper describes the screening of different South American plant extracts and fractions. Aqueous and organic extracts were prepared and tested for antiherpetic (HSV-1, KOS and 29R strains) and antirabies (PV strain) activities. The evaluation of the potential antiviral activity of these extracts was performed by using an MTT assay for HSV-1, and by a viral cytopathic effect (CPE) inhibitory method for rabies virus (RV). The results were expressed as 50% cytotoxicity (CC(50)) for MTT assay and 50% effective (EC(50)) concentrations for CPE, and with them it was possible to calculate the selectivity indices (SI = CC(50)/EC(50)) of each tested material. From the 18 extracts/fractions tested, six extracts and four fractions showed antiviral action. Ilex paraguariensis, Lafoensia pacari, Passiflora edulis, Rubus imperialis and Slonea guianensis showed values of SI > 7 against HSV-1 KOS and 29-R strains and Alamanda schottii showed a SI of 5.6 against RV, PV strain.     

Inhibitory activity of extracts of Alternanthera brasiliana (amaranthaceae) against the herpes simplex virus

Five extracts from A. brasiliana, obtained through different procedures, showed anti-HSV activity. The best activity was detected in a fraction (B) that was obtained from the crude cold aqueous extract on Sephadex G₁₅. Fraction B showed low cellular toxicity and inhibition from 32.4% to 99.9% at concentrations from 6.2 to 50.0 μg/mL, exhibiting a therapeutic index of 32. Fractions obtained on Sephadex G₁₀₀ and reversed-phase column also showed considerable inhibition. Fraction B did not show any virucidal activity, however, its inhibitory activity was revealed during the later stages of the virus replication cycle. This fraction showed activity on DNA synthesis of infected cells.     

In vitro antiviral activity of Phyllanthus orbicularis extracts against herpes simplex virus type 1

The antiviral activity of butanol- and acetic acid-soluble fractions, prepared from the leaves and stems of Phyllanthus orbicularis H.B.K., has been investigated against acyclovir-sensitive or -resistant herpes simplex virus type 1 (HSV-1) strains, using human foreskin fibroblast (HFF) and green ape kidney (Vero) cell lines. Both fractions showed antiviral selectivity indexes (SI) from 10.3 to 22.8, while their extracellular virucidal activities reached SI values ranging from 371 to 1,040. Time-addition experiments suggested that the active compounds present in the studied fractions acted on early steps of the virus replication cycle.     

Antibacterial activity of medicinal plant extracts against periodontopathic bacteria

This study was performed to evaluate the antibacterial activity of Althaea officinalis L. roots, Arnica montana L. flowers, Calendula officinalis L. flowers, Hamamelis virginiana L. leaves, Illicium verum Hook. fruits and Melissa officinalis L. leaves, against anaerobic and facultative aerobic periodontal bacteria: Porphyromonas gingivalis, Prevotella spp., Fusobacterium nucleatum, Capnocytophaga gingivalis, Veilonella parvula, Eikenella corrodens, Peptostreptococcus micros and Actinomyces odontolyticus. The methanol extracts of H. virginiana and A. montana and, to a lesser extent, A. officinalis were shown to possess an inhibiting activity (MIC < or = 2048 mg/L) against many of the species tested. In comparison, M. officinalis and C. officinalis extracts had a lower inhibiting activity (MIC > or = 2048 mg/L) against all the tested species with the exception of Prevotella sp. Illicium verum methanol extract was not very active though it had a particular good activity against E. corrodens. The results suggest the use of the alcohol extracts of H. virginiana, A. montana and A. officinalis for topical medications in periodontal prophylactics.     

Antiviral activity of Undaria pinnatifida against herpes simplex virus

The major component of an aqueous extract of the seaweed Undaria pinnati fi da has been identified previously as a galactofucan (GFS), a sulfated polysaccharide. The galactofucan was partially purified and the material tested in this study is 75% pure galactofucan sulfate. GFS was evaluated for antiviral activity against 32 clinical strains of herpes simplex virus (HSV): 14 strains of HSV-1 and 18 strains of HSV-2. Twelve strains (four HSV-1 and eight HSV-2) were resistant to acyclovir (ACV-R) and 20 strains (10 HSV-1 and 10 HSV-2) were susceptible to ACV (ACV-S). The median IC(50) of GFS for the 14 strains of HSV-1 was 32 micro g/mL. The median IC(50) of GFS for the 18 strains of HSV-2 was 0.5 micro g/mL. GFS is significantly more active against clinical strains of HSV-2 than HSV-1, p < 0.001. The mode of action of the GFS was shown to be the inhibition of viral binding and entry into the host cell. The cytotoxicity of GFS was >4.0 mg/mL in the neutral red dye uptake assay indicating that GFS is non-toxic in this assay.     

Anti-plasmodial activity of the extracts of some Kenyan medicinal plants

Ethnopharmacological relevance

The spread of drug resistant Plasmodium falciparum strains necessitates search for alternative newer drugs for use against malaria. Medicinal plants used traditionally in preparation of herbal medicines for malaria are potential source of new anti-malarial drugs.

Aim of the Study

To identify the anti-plasmodial potential of twelve plants used in preparing herbal remedies for malaria in Kilifi and Tharaka districts of Kenya.

Materials and Methods

Twelve plants used traditionally for anti-malarial therapy in Kilifi and Tharaka districts were extracted with water/methanol yielding twenty-three extracts. The extracts were tested against chloroquine sensitive (NF54) and resistant (ENT30) P. falciparum strains in vitro using ³Hypoxanthine assay.

Results

Seven (30%) extracts showed activity against P. falciparum with IC₅₀ values below 20 μg/ml. The remaining 16 extracts showed low or no activity. The most active extracts were from Zanthoxylum chalybeum (Rutaceae) with an IC₅₀ value of 3.65 μg/ml, Cyperus articulatus (Cyperaceae) with 4.84 μg/ml, and Cissampelos pareira (Menispermaceae) with 5.85 μg/ml.

Conclusions

This study revealed plants, that are potential sources of anti-malarial compounds. Anti-plasmodial activities of extracts of T. simplicifolia, C. pareira, and C. articulatus are reported for the first time.     

Anti-plasmodial activity of some Kenyan medicinal plant extracts singly and in combination with chloroquine

Sixty organic and aqueous extracts of eleven plants used for the control of malaria by local communities in Kisii District, Kenya were screened for in vitro anti-plasmodial activity. The plants selection was based on existing ethnobotanical information and interviews with local communities. The extracts were tested against chloroquine sensitive and resistant laboratory adapted strains of Plasmodium falciparum. The study revealed that 63.6% of the plants were active (IC50 < or = 100 microg/mL). Extracts of four plants, Ekebergia capensis, Stephania abyssinica, Ajuga remota and Clerodendrum myricoides gave IC50 values below 30 microg/mL against both chloroquine sensitive and resistant P. falciparum strains. Combination of extracts of E. capensis and C. myricoides with chloroquine against the multi-drug resistant P. falciparum isolate (V1/S) revealed synergistic effect. The plants which showed activity may be useful as sources for novel anti-plasmodial compounds.     

Diuretic effect of the crude extracts of Carissa edulis in rats

Carissa edulis (forssk) vahl (Apocynaceae) is used traditionally for the treatment of headache, chest complaints, rheumatism, gonorrhoea, syphilis, rabies and as a diuretic. In the present study, the diuretic activity of different extracts of Carissa edulis was investigated. The diuretic activity of the different extracts of Carissa edulis in a dose range of 50-1000 mg/kg was assessed orally in rats using hydrochlorothiazide as a standard drug. The root bark maceration extract showed no effect on the urine output up to a dose of 1000 mg/kg, while the root bark soxhlet extract produced a significant increase (P < 0.05) in urine output at a dose of 1000 mg/kg. The root wood maceration and root wood soxhlet extracts produced a significant increase in urine output at a dose of 50 mg/kg, with a P-value of <0.05. Urinary electrolyte excretion was also affected by the extracts: the root bark soxhlet extract increased urinary excretion of sodium, potassium and chloride ions; root wood maceration extract increased excretion of sodium and potassium, while root wood soxhlet extract increased excretion of potassium ion. These findings support the traditional use of Carissa edulis as a diuretic agent.     

Anti-HIV activity of medicinal plant extracts

As part of our screening of anti-AIDS agents from natural sources, ethanolic and aqueous extracts of 15 medicinal plants widely used in the folk medicine of the Iberian Peninsula were evaluated in vitro. Most of the extracts tested were relatively nontoxic to human lymphocytic MT-2 cells, but only the extracts of Tuberaria lignosa and Sanguisorba minor magnolii exhibited anti-HIV activity in an in vitro MTT assay. The aqueous extracts of these plants showed inhibitory effects against HIV-1 induced infections in MT-2 cells at concentrations ranging from 12.5 to 50 microg/ml and 50 microg/ml, respectively. Both extracts showed no appreciable cytotoxicity at these concentrations.     

Antiviral activity of medicinal plant extracts

Dichloromethane and ethanol extracts of 12 plants with a history of use in traditional medicine, were tested for antiviral activity against herpes simplex type I. The most potent inhibition was shown by ethanol extracts of Eugenia jambos, Cistus populifolius, Lippia alba, Chiranthodendron pentadactylon and Tuberaria lignosa. These extracts, and others that had no effect, were chosen for more extensive studies against poliovirus type 1 and vesicular stomatitis virus. It was found that the ethanol extracts of Eugenia jambos, Chiranthodendron pentadactylon and Santolina oblongifolia inhibited the replication of VSV, but none of the extracts investigated had any effect on poliovirus replication. © 1997 John Wiley & Sons, Ltd.     

Antiherpes virus activity of extracts from the medicinal plant Geranium sanguineum L

The herpes virus inhibitory effect of five extracts from the Bulgarian medicinal plant Geranium sanguineum L. (Geraniaceae) was investigated. The water extract (WE) from the aerial roots of the plant was the least toxic for cell cultures and inhibited significantly the replication of herpes simplex virus type 1 and type 2 (EC50 = 3.6-6.2 microg/ml) as shown by the reduction of virus induced cytopathogenic effect (CPE) and the protection of cells in MTT assay. The inhibition was dose-related, strain-specific and depended on virus inoculum. In higher concentrations (MIC90 = 120 microg/ml) the preparation exhibited strong extracellular virus inactivating activity. The presence of WE throughout the whole replicative cycle was necessary for the full expression of the antiviral effect. In a preliminary experiment in albino guinea pigs the extract delayed the development of herpetic vesicles following primary infection with HSV-1, strain Kupka. Phytochemical investigation of the plant preparation revealed the presence of flavonoids, catechins, a polyphenolic acid and condensed tannins. The inhibitory effect of the extract on herpes simplex virus replication is related to the rich content of polyphenol compounds.     

Antiviral activity of chilean medicinal plant extracts

Chilean flora is a potential source of bioactive compounds, including some with antiviral activity. Ninety aqueous and hydroaloholic extracts from 36 native and introduced plant species were screened for antiviral activity on herpes (HSV-1 and HSV-2) and HIV viruses. Furthermore, the samples were assayed for antimicrobial effect on pathogenic bacteria and a yeast. Plants were selected according to their indication of use for treating symptomatology of possible viral aetiology in Chilean folk medicine. The hydroaloholic extracts of Cassia stipulacea and Escallonia illintia exhibited detectable antiviral effects towards HSV-1 with IC₅₀ values of 80 and 40 μg crude extract/mL, respectively. Samples belonging to Aristotelia chilensis (IC₅₀ of 40 μg/mL), Drymis winteri (IC₅₀ values of 35 and 80μg/mL), Elytropus chilensis and Luma apiculata, with an IC₅₀ value of 100 μg/mL showed activity against HSV-2. None of the extracts showed activity against HIV at extract concentrations which were nontoxic for cells.     

Antiviral activity of some Nigerian medicinal plant extracts

Plants from Northern Nigeria with a history of use in both human and veterinary traditional medicine have been investigated for their antiviral activity and their cytotoxicity determined. Extracts were tested against poliovirus, astrovirus, herpes simplex viruses and parvovirus, using the microtitre plate inhibition tests. Most of the extracts have activity against more than one virus at a dose rate of between 100 and 400 microg/100 microl.     

Antidiarrhoeal activity of some Egyptian medicinal plant extracts

The antidiarrhoeal activity of six Egyptian medicinal plant extracts (200 and 400 mg kg(-1)) and their effect on motility of isolated rabbit's duodenum was investigated. Phytochemical screening of the plant extracts for their active constituents was also carried out by TLC. Oral administration of methanol extract from Conyza dioscoridis (CD) or Alhagi maurorum (AM) in a 200 mg kg(-1) dose exhibits a significant antidiarrhoeal effect against castor oil-induced diarrhoea, while Mentha microphylla (MM), Convolvulus arvensis (CA), Conyza linifolia (CL) produced no significant effect. In a dose of 400 mg kg(-1), Mentha microphylla, Conyza dioscoridis, Alhagi maurorum, Zygophyllum album (ZA), and Conyza linifolia produced a significant (P<0.01) effect, while Convolvulus arvensis produced no antidiarrhoeal effect in rats. Methanol extract of Mentha microphylla, Conyza dioscoridis, Zygophyllum album, and Convolvulus arvensis induced a dose-dependent (0.4-2.8 mg ml(-1)) relaxation of rabbit's duodenal smooth muscle. Alhagi maurorum and Conyza linifolia increased the contractile force in concentrations between 0.4 and 1.6 mg ml(-1). Higher concentrations (>3.2 mg ml(-1)) caused a rapid depressant effect. The depressant effect induced by Alhagi maurorum (in a higher dose) and Zygophyllum album appeared to be due to calcium channel blocking effect, since CaCl(2) could not restore the contractile response of the tissue impregnated in calcium free-medium. However, a ganglionic blocking effect appeared to be a possible mechanism of action of Mentha microphylla and Conyza dioscoridis since a stimulant dose of nicotine could not restore the contractile response of the tissue. The effect of Convolvulus arvensis and Conyza linifolia was not through any of the common mediators. Phytochemical screening revealed the presence of tannins, flavonoids, unsaturated sterols/triterpenes, carbohydrates, lactones and proteins/amino acids as major constituents.     

In vivo antiviral activity of Stephania cepharantha against herpes simplex virus type-1

The antiviral activity of a MeOH extract of Stephania cepharantha (root tubers), its CHCl3-soluble fraction (alkaloid fraction) and the major alkaloid FK-3000 (1) were investigated in BALB/c mice cutaneously infected with HSV-1 strain 7401H. At doses of 125 and 250 mg/kg body weight, p.o., the MeOH extract significantly delayed skin lesion on score 2 (vesicles in the local region), limited the development of further lesions on score 6 (mild zosteriform lesion) and prolonged the mean survival time of HSV-1 infected mice. After p.o. administration of the CHCl3-soluble fraction at doses of 25 and 50 mg/kg or FK-3000 (1) at 10 and 25 mg/kg, similar results were obtained. Although the alkaloid improved the survival of infected mice, it had a narrow therapeutic index.     

Antiinflammatory activity of some medicinal plant extracts from Venezuela

Six medicinal plant extracts from Venezuela, used in traditional medicine, were investigated for their anti-inflammatory potential against adjuvant-carrageenan-induced inflammation (ACII). All doses expressed here are as equivalents of dried starting plant materials (1.50 g dry plant/kg body wt.). The most interesting plant extracts were Synedrella nodiflora, and the hexane leaf extract of Bursera simaruba. In ACII, orally administered extracts (at doses 40 and 80 mg/kg, respectively), inhibited both the acute and chronic phases of this experimental model of inflammation, mainly the chronic phase. These extracts exhibited potent anti-inflammatory activity daily throughout the experiment, and were as effective as reference drugs, phenylbutazone (80 mg/kg) and indomethacin (3 mg/kg).     

Evaluation of some medicinal plant extracts for antidiarrhoeal activity

The antidiarrhoeal effect of seven plant extracts namely: the aerial parts of Euphorbia paralias L. (EP), Bidens bipinnata L. (BB), Cynachum acutum L. (CyAc), Diplotaxis acris (Forssk.) Boiss (DA), Convolvulus fatmensis (CF) and Schouwia thebaica Webb (ST) and the leaves of Plantago major L. (PM), was evaluated on castor oil-induced diarrhoea, gastrointestinal movement in rats (charcoal meal) and on the motility of duodenum isolated from freshly slaughtered rabbits. A significant antidiarrhoeal effect of the tested plant extracts against castor oil-induced diarrhoea in rats was achieved by 200 and 400 mg/kg. The tested plant extracts decreased the gastrointestinal movement as indicated by the significantly (p<0.05 to 0.001) decreased distance travelled by the charcoal meal. The large dose of the tested plant extracts was slightly more effective than the small one. The antidiarrhoeal effect was confirmed by the reported dose dependent inhibition of the motility of duodenum isolated from freshly slaughtered rabbits. The EP and PM methanol extract produced a transient stimulation followed by inhibition in doses of less than 0.05 and 1.6 mg/kg, respectively. Higher concentrations caused rapid muscle relaxation. Tannins, flavonoids, unsaturated sterols/triterpenes, carbohydrates, lactones and proteins/amino acids were reported as major active constituents of the tested plants.     

药用植物提取物抗烟草花叶病毒活性的研究

目的研究我国传统药用植物抗烟草花叶病毒(tobacco m osa ic v irus,TM V)的作用,为从植物中开发抗病毒类生物农药提供依据。方法采用局部枯斑法和叶碟法对我国78科162种药用植物提取物的抗TM V侵染和增殖作用进行测定。结果在10 m g/mL水平下,19种植物提取物可有效抑制TM V侵染,9种植物提取物有明显抑制TM V增殖作用。结论大多数药用植物提取物具有一定抗TM V侵染活性,仅少数药用植物提取物有较好的抗TM V增殖作用。     

Evaluation of some Moroccan medicinal plant extracts for larvicidal activity

The larvicidal properties of 16 extracts of four Moroccan medicinal plants: Calotropis procera (Wild.), Cotula cinerea (L.), Solanum sodomaeum (L.) and Solanum elaeagnifolium (CAV.) were tested against Anopheles labranchiae mosquito larvae. Among the extracts tested, nine exhibited high larvicidal activity with LC(50) (24 h) ranging from 28 to 325 ppm.     

Antifungal activity of medicinal plant extracts; preliminary screening studies

ETHNOPHARMACOLOGICAL RELEVANCE: In the setting of HIV and organ transplantation, opportunistic fungal infections have become a common cause of morbidity and mortality. Thus antifungal therapy is playing a greater role in health care. Traditional plants are a valuable source of novel antifungals. AIM OF THE STUDY: To assess in vitro antifungal activity of aqueous plant extracts. The minimum inhibitory concentrations were determined for each extract in the setting of human pathogenic fungal isolates. MATERIALS AND METHODS: Plants were harvested and identification verified. Aqueous extracts were obtained and antifungal susceptibilities determined using serial dilutional extracts with a standardized microdilution broth methodology. Twenty-three fungal isolates were cultured and exposed to the plant extracts. Five known antifungals were used as positive controls. Results were read at 48 and 72 h. RESULTS: Of the 14 plants analyzed, Fragaria virginiana Duchesne, Epilobium angustifolium L. and Potentilla simplex Michx. demonstrated strong antifungal potential overall. Fragaria virginiana had some degree of activity against all of the fungal pathogens. Alnus viridis DC., Betula alleghaniensis Britt. and Solidago gigantea Ait. also demonstrated a significant degree of activity against many of the yeast isolates. CONCLUSION: Fragaria virginiana, Epilobium angustifolium and Potentilla simplex demonstrate promising antifungal potential.