Investigation of some Hypericum species native to Southern of Brazil for antiviral activity

Novel approach to combat antibiotic resistance: evaluation of some Armenian herb crude extracts for their antibiotic modulatory and antiviral properties

AIMS

One of the strategies to combat antibiotic resistance can be the use of plant materials in combination with antibiotics, taking into account that phytochemicals can act as antibiotic resistance-modifying agents. This can give a second life to the traditional antibiotics. The aim was to evaluate antibiotic modulatory effect of crude extracts from Agrimonia eupatoria, Hypericum alpestre, Rumex obtusifolius and Sanguisorba officinalis herbs towards several commercial antibiotics using some Gram-positive and Gram-negative bacteria.

METHODS

The antibiotic modulatory activity was tested by determining MICs of antibiotics in the absence and presence of plant crude extracts at subinhibitory concentrations. Antiviral potential of different extracts of tested plant materials was also explored by double overlay plaque assay.

RESULTS

The tested plant crude extracts exhibited high modulatory activity towards used antibiotics. Particularly, high modulatory activity was observed with extracts of H. alpestre and R. obtusifolius. Many plant-antibiotic combinations induced the decrease in MICs of antibiotics up to ~fourfold indicating synergy. Moreover, the similar change was observed at both subinhibitory concentrations (MIC/2 and MIC/4) of the same plant crude extract. High anti-phage activity of plants with the exception of Lilium armenum against T4 phage of Escherichia coli C-T4 was also shown.

CONCLUSIONS

Plant crude extract or commercial antibiotic combinations significantly increased the efficiency of antibiotics. Tested plant materials with exception of L. armenum have antiviral property.

SIGNIFICANCE AND IMPACT OF THE STUDY

For the first time, antibiotic modulatory activity of tested herb extracts was shown, which could have potential in practical applications. Tested plant materials with exception of L. armenum could have prospective, as a source of new antiviral compounds.

Digoxin reduces the mutagenic effects of Mitomycin C in human and rodent cell lines

Digoxin is a drug widely used to treat heart failure and studies have demonstrated its potential as anticancer agent. In addition, digoxin presents the potential to interact with a series of other compounds used in medicine. The aim of the present study was to evaluate in vitro the cytotoxicity, genotoxicity and mutagenicity of digoxin and its potential to interact with the mutagen Mitomycin C (MMC). The cytotoxicity of digoxin was assessed by employing the MTT method and the comet assay was performed to assess the genotoxicity of this medicine in CHO-K1 and HeLa cell lines. Besides, the cytokinesis-block micronucleus assay was performed to assess the mutagenicity and the antimutagenicity of this drug. The Ames assay was also performed with TA98 and TA100 strains of S. typhimurium. Results showed that digoxin was cytotoxic, genotoxic and mutagenic for HeLa and CHO-K1 cell lines at concentrations many times higher than those observed in human therapeutic conditions. Nevertheless, an antimutagenic effect against the mutagen MMC was observed on both cell lines in concentrations near those used therapeutically in humans. This chemoprotective effect observed is an interesting finding that should be better explored regarding its impact in anticancer chemotherapy.

Evaluation of the cytotoxic effect and antibacterial, antifungal, and antiviral activities of Hypericum triquetrifolium Turra essential oils from Tunisia

Background

A number of bio-active secondary metabolites have been identified and reported for several Hypericum species. Many studies have reported the potential use of the plant extracts against several pathogens. However, Hypericum triquetrifolium is one of the least studied species for its antimicrobial activity. The aim of the present study was to evaluate the cytotoxic effect of the essential oils of Hypericum triquetrifolium as well as their antimicrobial potential against coxsakievirus B3 and a range of bacterial and fungal strains.

Methods

The essential oils of Hypericum triquetrifolium harvested from five different Tunisian localities (Fondouk DJedid, Bou Arada, Bahra, Fernana and Dhrea Ben Jouder) were evaluated for their antimicrobial activities by micro-broth dilution methods against bacterial and fungal strains. In addition, the cytotoxic effect and the antiviral activity of these oils were carried out using Vero cell lines and coxsakievirus B3.

Results

The results showed a good antibacterial activities against a wide range of bacterial strains, MIC values ranging between 0.39-12.50 mg/ml and MBC values between 1.56-25.0 mg/ml. In addition, the essential oils showed promising antifungal activity with MIC values ranging between 0.39 μg/mL and 12.50 μg/mL; MFC values ranged between 3.12 μg/mL and 25.00 μg/mL; a significant anticandidal activity was noted (MIC values comprised between 0.39 μg/mL and 12.50 μg/mL). Although their low cytotoxic effect (CC₅₀ ranged between 0.58 mg/mL and 12.00 mg/mL), the essential oils did not show antiviral activity against coxsakievirus B3.

Conclusion

The essential oils obtained from Hypericum triquetrifolium can be used as antimicrobial agents and could be safe at non cytotoxic doses. As shown for the tested essential oils, comparative analysis need to be undertaken to better characterize also the antimicrobial activities of Hypericum triquetrifolium extracts with different solvents as well as their purified fractions and their pure secondary metabolites.

Uliginosin B, a phloroglucinol derivative from Hypericum polyanthemum: a promising new molecular pattern for the development of antidepressant drugs

In this study we have demonstrated that cyclohexane extract of Hypericum polyanthemum (POL) and its main phloroglucinol derivative uliginosin B (ULI) present antidepressant-like activity in rodent forced swimming test (FST). The involvement of monoaminergic neurotransmission on the antidepressant-like activity of ULI was evaluated in vivo and in vitro. POL 90 mg/kg (p.o.) and ULI 10 mg/kg (p.o.) reduced the immobility time in the mice FST without altering locomotion activity in the open-field test. The combination of sub-effective doses of POL (45 mg/kg, p.o.) and ULI (5 mg/kg, p.o.) with sub-effective doses of imipramine (10 mg/kg, p.o.), bupropion (3 mg/kg, p.o.) and fluoxetine (15 mg/kg, p.o.) induced a significant reduction on immobility time in FST. The pretreatment with SCH 23390 (15 μg/kg, s.c., dopamine D1 receptor antagonist), sulpiride (50 mg/kg, i.p., dopamine D2 receptor antagonist), prazosin (1mg/kg, i.p., α1-adrenoceptor antagonist), yohimbine (1mg/kg, i.p., α2-adrenoceptor antagonist) and pCPA (100 mg/kg/day, i.p., p-chlorophenilalanine methyl ester, inhibitor of serotonin synthesis, for four consecutive days) before ULI administration (10 mg/kg, p.o.) significantly prevented the anti-immobility effect in FST. ULI was able to inhibit synaptosomal uptake of dopamine (IC50 = 90 ± 38 nM), serotonin (IC50 = 252 ± 13 nM) and noradrenaline (280 ± 48 nM), but it did not bind to any of the monoamine transporters. These data firstly demonstrated the antidepressant-like effect of POL and ULI, which depends on the activation of the monoaminergic neurotransmission in a different manner from the most antidepressants.

Antiviral activity-guided fractionation from Araucaria angustifolia leaves extract

ETHNOPHARMACOLOGICAL RELEVANCE

Araucaria angustifolia (Bert.) O. Kuntze (Araucariaceae) is a Brazilian medicinal plant traditionally used for the treatment of various illnesses including dried skin, wounds, shingles, and sexually transmitted diseases.

AIM OF THE STUDY

The rationale of the study was to provide evidence of its antiherpes activity in order to confirm its popular use that could be related to herpes disease.

MATERIALS AND METHODS

The crude hydroethanolic extract (HE) obtained from Araucaria angustifolia leaves was submitted to a sequential liquid-liquid extraction with solvents of increased polarity. The HE and fractions obtained were evaluated for cytotoxicity and antiherpes activity (Herpes Simplex Virus type 1) by MTT assay. The most active fractions were selected to perform an in vitro antiviral activity-guided chromatographic fractionation.

RESULTS

The ethyl acetate (EA) and n-butanol (NB) fractions have shown the best results for antiherpetic activity and their further fractionation yielded 22 subfractions. From these subfractions, 14 were active, and the most potent antiherpetic activity was obtained for NB1-4 subfraction with selectivity index (SI) of 57.51. Chemical analysis of NB1-4 subfractions revealed the presence of proanthocyanidins and the known biflavonoids (bilobetin, II-7-O-methyl-robustaflavone and cupressuflavone). The same biflavonoids have been detected in EA subfractions.

CONCLUSION

The present study has shown that the hydroethanolic extract from Araucaria angustifolia leaves as well as many different fractions and subfractions exhibited antiherpes activity, supporting the use of this plant species in folk medicine.

The in vitro antiviral activity of an aliphatic nitro compound from Heteropteris aphrodisiaca

We investigated the antiviral activity of an aliphatic nitro compound (NC) isolated from Heteropteris aphrodisiaca O. Mach. (Malpighiaceae), a Brazilian medicinal plant. The NC was tested for its antiviral activity against poliovirus type 1 (PV-1) and bovine herpes virus type 1 (BHV-1) by plaque reduction assay in cell culture. The NC showed a moderate antiviral activity against PV-1 and BHV-1 in HEp-2 cells, and the 50% inhibitory concentration (IC50) were 22.01 microg/ml (selectivity index (SI)=2.83) and 21.10 microg/ml (SI=2.95), respectively. At the highest concentration of the drug (40 microg/ml) a reduction of approximately 80% in plaque assay was observed for both viruses. The treatment of cells or virus prior to infection did not inhibit the replication of virus strains.

Herpes virus inhibitory substances from Hypericum connatum Lam., a plant used in southern Brazil to treat oral lesions

Hypericum connatum (Guttiferae) is used in southern Brazil in the treatment of lesions in the mouth, often related to acute herpetic gingivo-stomatitis. The chemical investigation of the plant revealed the presence of phloroglucinol derivatives and flavonoids. From the n-hexane extract of the aerial parts a phloroglucinol derivative, hyperbrasilol B, was isolated, while the methanolic extract afforded four flavonoids: amentoflavone, hyperoside, guaijaverine and luteoforol. The crude methanolic extract and fractions (n-hexane, dichloromethane and methanol) as well as the isolated compounds were tested for antiviral activity against herpes simplex viruses (HSV). Among the tested samples, luteoforol was the most active inhibiting the cytopathic effect (CPE) and reducing the viral titer of HSV-1 DNA viral strains KOS and VR733 (ATCC).

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.

The antidepressant-like effect of Hypericum caprifoliatum Cham & Schlecht (Guttiferae) on forced swimming test results from an inhibition of neuronal monoamine uptake

A crude (ECH) and a purified cyclohexane extract (HCP) of Hypericum caprifoliatum and their main phloroglucinol derivative (HC1) were evaluated regarding their action on monoaminergic systems, more precisely on dopamine. In rats and mice forced swimming test, ECH and HCP dose-dependently reduced the immobility time. The effect of the highest dose was prevented by a prior administration of either sulpiride or SCH 23390 (D(2) and D(1) dopamine receptor antagonist, respectively). HCP (360 mg/kg) decreased the locomotor activity of mice. ECH (90 mg/kg) caused hypothermia and potentiated apomorphine-induced (16 mg/kg) hypothermia in mice. HCP and HC1 inhibited, in a concentration-dependent and monophasic manner, the [(3)H]-DA, [(3)H]-NA and [(3)H]-5HT synaptosomal uptakes, but did not prevent the binding of specific ligands to the monoamine transporters. Moreover, when tested at the concentrations corresponding to its IC(50) on [(3)H]-DA uptake, HC1 did not induce a significant [(3)H]-DA release, while at a higher concentration (200 ng/ml) it enhanced significantly (by 12%) the synaptosomal DA release. These data suggest that the antidepressant-like effect of H. caprifoliatum on the forced swimming test is due to an increase in monoaminergic transmission, resulting from monoamine uptake inhibition, more potently of dopamine, which may be related to their phloroglucinol contents.

Ethnobotanical survey of folk toxic plants in southern part of Jordan

Thirteen representative phytogeographical sites in the southern part of Jordan was surveyed to recognize the folk toxic plant wealth by calculating of FL, RPL, and ROP values. One hundred and twenty-five toxic species were recorded in the area of study belonging to 56 plant families that were mentioned by three informants or more, 53 toxic species (42.4%) were popular, since they were cited by more than half of the maximum number of informants which is 30; therefore have Rank-Order Priority (ROP) value 50 or more, while 72 species (57.6%) were unpopular, since they were cited by less than half of the maximum number of informants; therefore have ROP value less than 50. Eighty species (63.5%) have known toxicity in neighboring countries while 46 species (36.5%) have not such known toxicity. Major toxic effects cited by popular species have exhibited major symptoms ranging from skin irritation, gastric and abdominal disturbances, abortion, sterility, neuralgic pains including hysteria, and fatigue. The studied area has been shown a high level of toxic species diversity, since it is dominated by at least four phytogeographical elements, which requires certain ecological awareness to protect and reserve the wild and endemic species from further threats to enhance the sustainable development.

Antiviral activity in vitro of Urtica dioica L., Parietaria diffusa M. et K. and Sambucus nigra L

Parietaria diffusa M. et K., Urtica dioica L. (Urticaceae) and Sambucus nigra L. (Caprifoliaceae) are plants usually used in popular medicine of central Italy for treating numerous diseases, first of all Herpes zoster. Several plant products have been described as potential antiviral agents, with special attention being devoted to those having retroviruses as etiological agents, including acquired immunodeficiency syndrome (AIDS), in which a retrovirus, the designated human immunodeficiency virus HIV, has been clearly identified as the primary cause of this disease. The present study proposes a preliminary screening of the antiviral activity of Parietaria diffusa, Sambucus nigra and Urtica dioica preparation against the feline immunodeficiency virus (FIV) infection. The feline immunodeficiency virus is a widespread lentivirus of domestic cats sharing numerous biological and pathogenic features with the human immunodeficiency virus (HIV). FIV infection in cats has therefore been proposed as an animal model for AIDS studies with respect to pathogenesis, chemotherapy, and vaccine development [Pedersen, N.C., 1993. Feline immunodeficiency virus infection. In: Levy, J.A. (Ed.), The Retroviridae. Plenum Press, New York; Bendinelli, M., Pistello, M., Lombardi, S., Poli, A., Garzelli, C., Matteucci, D., Ceccherini-Nelli, L., Malvaldi, G., Tozzini, F., 1995. Feline immunodeficiency virus: an interesting model for AIDS studies and an important cat pathogen. Clinical Microbiology Revue 8, 87-112; North, T.W., LaCasse, R.A., 1995. Testing anti-HIV drugs in the FIV model. Nature Medicine 1, 410-411; Matteucci, D., Pistello, M., Mazzetti, P., Giannechini, S., Isola, P., Merico, A., Zaccaro, L., Rizzati, A., Bendinelli, M., 2000. AIDS vaccination studies using feline immunodeficiency virus as a model: immunisation with inactivated whole virus suppresses viraemia levels following intravaginal challenge with infected cells but non-following intravenous challenge with cell-free virus. Vaccine 18, 119-130]. Early studies showed that some of them presented antiviral activity against infection of FIV as assayed by syncytia formation using feline kidney Crandell cells (CrFK).