Evaluation of the antibacterial activity of Chilean plants traditionally used for wound healing therapy against multidrug-resistant Staphylococcus aureus

Anti-staphylococcal activity of Chilean medicinal plants traditionally used by the Huilliche people for wound healing therapy was evaluated against nine Staphylococcus aureus strains. Three extracts of 26 plant samples (20 species) were evaluated by agar overlay bioautography and MIC determination. Total phenolics and tannins were determined, and the antibacterial contribution of the latter was evaluated. The diffusion assay showed that 17 species were active against susceptible S. AUREUS and that 15 species were active against resistant S. aureus. Removal of tannins from extracts rendered only six species active. MIC-determination showed that 20 extracts had antibacterial activity on all eight strains, and the most potent MIC value was 64?μg/mL. Remarkably, 37 extracts were active against the otherwise multidrug-resistant vanthida strain. Our findings support the wound healing properties of Huilliche medicinal plants and the hypothesis that these plants are promising sources of potential anti-staphylococcal agents towards multidrug-resistant strains.     

In vitro activity of Brazilian medicinal plants,naturally occurring naphthoquinones and their analogues,against methicillin-resistant Staphylococcus aureus

Fourteen extracts from Brazilian traditional medicinal plants used to treat infectious diseases were used to look for potential antimicrobial activity against multiresistant bacteria of medical importance. Staphylococcus aureus strains were susceptible to extracts of Punica granatum and Tabebuia avellanedae. The minimum inhibitory concentrations (MICs) of the total extracts and of additional fractions of these plants were determined by employing strains of methicillin-resistant (MRSA) and -sensitive (MSSA) S. aureus, including isolates of the PFGE clone A, which is prevalent in Brazil and two ATCC reference strains. A mixture of ellagitannins isolated from P. granatum and two naphthoquinones isolated from T. avellanedae demonstrated antibacterial activity against all S. aureus strains tested. Semi-synthetic furanonaphthoquinones (FNQs) showed lower MICs than those exhibited by natural occurring naphthoquinones. The results indicate that these natural products can be effective potential candidates for the development of new strategies to treat MRSA infections.     

Antibacterial activity in spices and local medicinal plants against clinical isolates of Karachi,Pakistan

Context: Development of resistance in human pathogens against conventional antibiotic necessitates searching indigenous medicinal plants having antibacterial property. Twenty-seven medicinal plants used actively in folklore, ayurvedic and traditional system of medicine were selected for the evaluation of their antimicrobial activity for this study. Eleven plants chosen from these 27 are used as spices in local cuisine.

Objective: Evaluation of the effectiveness of some medicinal plant extracts against clinical isolates.

Material and methods: Nonedible plant parts were extracted with methanol and evaporated in vacuo to obtain residue. Powdered edible parts were boiled three times and cooled in sterile distilled water for 2?min each and filtrate collected. The minimum inhibitory concentration (MIC) of plant extracts and filtrates/antibiotics was evaluated against clinical isolates by microbroth dilution method.

Results: Water extract of Syzygium aromaticum L. (Myrtaceae) buds, methanol extracts of Ficus carica L. (Moraceae) and Olea europaea L. (Oleaceae) leaves and Peganum harmala L. (Nitrariaceae) seeds had MIC ranges of 31.25–250 µg/ml. S. aromaticum inhibited growth of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Salmonella enterica serovar Typhi and Pseudomonas aeruginosa. F. carica and O. europaea inhibited growth of S. aureus, S. epidermidis, and S. pyogenes whereas P. harmala was effective against S. aureus, Acinetobacter calcoaceticus and Candida albicans. Ampicillin, velosef, sulfamethoxazole, tetracycline and ceftazidime, cefotaxime, cefepime, which are used as control, had MIC ≥50 and 1.5 µg/ml, respectively, for organisms sensitive to extracts.

Discussion and conclusion: Mono/multiextract from identified plants will provide an array of safe antimicrobial agents to control infections by drug-resistant bacteria.     

Antimicrobial Activity of the Tar Obtained from the Roots and Stems of Pinus brutia

The antimicrobial activity of the crude and methanol, hexane, chloroform, petroleum ether, ethyl acetate and n -butanol extracts of tar obtained from the roots and stems of Pinus brutia Ten., used in the folk medicine of Turkey, were screened in vitro for antimicrobial activity against clinically isolated bacterial strains: Staphylococcus aureus (15 isolates), Streptococcus pyogenes (12 isolates), Escherichia coli (17 isolates) and the yeast fungus Candida albicans (3 isolates) by the paper disc diffusion method. Results revealed that a crude extract of the tar is highly effective against all tested microorganisms by preventing their growth to a significant extent. All the organic extracts showed similar moderate antimicrobial activity against tested microorganisms at a concentration of 80 µg/mL. The results demonstrate that the crude tar extract has a very broad spectrum of activity, and suggests that it may be useful in the treatment of various microbial infections. The results suggest that traditional folk medicine could be used a guide in our continuing search for new natural products with potential medicinal properties.     

Scorpion antivenom effect of micropropagated Aristolochia elegans

Aristolochia elegans Mast. (Aristolochiaceae) has been used to treat scorpion envenoming in Mexican traditional medicine. In vitro studies of the pharmacological activity of raw extracts from A. elegans roots have shown activity against scorpion bite. The aim of the present study was to determine for the first time the antagonistic effect of hexane and methanol extracts of the aerial parts and roots from micropropagated A. elegans plants in a model of isolated guinea-pig ileum contracted by scorpion bite. Results showed that the methanol extracts of aerial organs (74%) and roots (65%) of micropropagated plants have a similar antitoxin activity against scorpion poisoning to hexane extracts of wild plants (65%). These results suggest that using methanol extracts from the micropropagated plant material instead of wild plant root extracts from A. elegans is an alternative for treatment against scorpion bite symptoms, and will contribute to the conservation of this medicinal species.     

Antimicrobial Activity of Medicinal Plants from Baja California Sur (México)

Ethanol extracts of 109 plants reported to be used in the traditional medicine of Baja California Sur (México) were tested for antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Streptococcus faecalis, Escherichia coli and Candida albicans. Of these, 64 were active against one or more test organisms.     

Antibacterial activity and in vitro cytotoxicity of extracts and fractions of Parkia biglobosa (Jacq.) Benth. stem bark and Ageratum conyzoides Linn. leaves

Many species of plants in African countries are widely used in the rural communities where there is little or no access to modern medicine. However, the safety and effectiveness of these medicinal plants are poorly evaluated. The stem bark of Parkia biglobosa Jacq. and leaves of Ageratum conyzoides Linn. were investigated for their antibacterial and cytotoxic activities. The plant materials were extracted with 95% ethanol, and fractionated with petroleum ether, chloroform and ethyl acetate. The antibacterial effects of the extracts and fractions of the plant materials were assayed on the bacterial cultures of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Methicillin Resistant Staphylococcus aureus (MRSA) and Clostridium perfringes. Ethanol extracts of P. biglobosa and A. conyzoides were screened for cytotoxicity using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. Two cancer cell lines (SK-MES 1 and SK-LU 1) and one normal cell line (human skin fibroblast cell line, FS5) were used for the screening of the extracts and the fractions obtained. The ethanolic extracts and fractions of P. biglobosa and A. conyzoides showed the best activity against E. coli, S. aureus and MRSA. All fractions of A. conyzoides leaves have no activity against P. aeruginosa. Human lung cancer cell lines (SK-LU 1 and SK-MES 1) and human skin fibroblast cell line (FS5 cells) were treated with various concentrations (3.9μg/ml-2mg/ml) of the extracts and fractions for 24h. SK-MES 1 cells are more susceptible to treatment with the plant fractions. All the fractions of A. conyzoides leaves and the petroleum ether fraction of P. biglobosa were cytotoxic to SK-MES 1 cells, which to some extent may support their traditional inclusion in herbal preparations for treatment of cancer. The overall results provided evidence that the studied plant extracts might be potential sources of new antibacterial and anticancer drug.     

Antibacterial properties of traditionally used Indian medicinal plants

In search of broad-spectrum antibacterial activity from traditionally used Indian medicinal plants, 66 ethanolic plant extracts were screened against nine different bacteria. Of these, 39 extracts demonstrated activity against six or more test bacteria. Twelve extracts showing broad-spectrum activity were tested against specific multidrug-resistant (MDR) bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamases (ESbetaL)-producing enteric bacteria. In vitro efficacy was expressed in terms of minimum inhibitory concentration (MIC) values of plant extracts. MIC values ranged from 0.32-7.5 mg/ml against MRSA and 0.31-6.25 mg/ml against ESbetaL-producing enteric bacteria. The overall activity against all groups of bacteria was found in order of Plumbago zeylanica > Hemidesmus indicus > Acorus calamus > Camellia sinensis > Terminalia chebula > Terminalia bellerica > Holarrhena antidysenterica > Lawsonia inermis > Mangifera indica > Punica granatum > Cichorium intybus and Delonix regia. In addition, these extracts showed synergistic interaction with tetracycline, chloramphenicol and ciprofloxacin against S. aureus and/or Escherichia coli. The ethanolic extracts of more than 12 plants were found nontoxic to sheep erythrocytes and nonmutagenic, determined by Ames test using Salmonella typhimurium test strains (TA 97a, TA 100, TA 102 and TA 104). Based on above properties, six plants-Plumbago zeylanica, Hemidesmus indicus, Acorus calamus, Punica granatum, Holarrhena antidysenterica and Delonix regia-were further subjected to fractionation-based study. Ethyl acetate, acetone and methanol fractions of more than six plants indicated that the active phytocompounds were distributed mainly into acetone and ethyl acetate fractions, whereas they were least prevalent in methanol fractions as evident from their antibacterial activity against MDR bacteria. Gram-positive and Gram-negative MDR bacteria are almost equally sensitive to these extracts/fractions, indicating their broad-spectrum nature. However, strain- and plant extract-dependent variations in the antibacterial activity were also evident. Time-kill assay with the most promising plant fraction Plumbago zeylanica (ethyl acetate fraction) demonstrated killing of test bacteria at the level lower than its MIC. Further, identification of active constituents in each fraction and their additive and synergistic interactions are needed to exploit them in evaluating efficacy and safety in vivo against MDR bacteria.     

Screening of Mexican Medicinal Plants for Antiprotozoal Activity

The MeOH extracts from 19 Mexican medicinal plants belonging to different families have been assessed for antiprotozoal activity against Entamoeba histolytica and Giardia lamblia. Five plant extracts, derived from Acalypha phleoides, Cnidoscolus tehuacanensis, Geranium niveum, Hellianthella quinquenervis and Teloxys graveolens, were found to possess significant activity against both protozoa, but were less potent than metronidazole. These findings tend to support the ethnomedical use of the species for the treatment of infectious diarrhoea in Mexican traditional medicine.     

Medicinal plant extracts with efflux inhibitory activity against Gram-negative bacteria

It was hypothesised that extracts from plants that are used as herbal medicinal products contain inhibitors of efflux in Gram-negative bacteria. Extracts from 21 plants were screened by bioassay for synergy with ciprofloxacin against Salmonella enterica serotype Typhimurium, including mutants in which acrB and tolC had been inactivated. The most active extracts, fractions and purified compounds were further examined by minimum inhibitory concentration testing with five antibiotics for activity against Enterobacteriaceae and Pseudomonas aeruginosa. Efflux activity was determined using the fluorescent dye Hoechst 33342. Eighty-four extracts from 21 plants, 12 fractions thereof and 2 purified molecules were analysed. Of these, 12 plant extracts showed synergy with ciprofloxacin, 2 of which had activity suggesting efflux inhibition. The most active extract, from Levisticum officinale, was fractionated and the two fractions displaying the greatest synergy with the five antibiotics were further analysed. From these two fractions, falcarindiol and the fatty acids oleic acid and linoleic acid were isolated. The fractions and compounds possessed antibacterial activity especially for mutants lacking a component of AcrAB-TolC. However, no synergism was seen with the fractions or purified molecules, suggesting that a combination of compounds is required for efflux inhibition. These data indicate that medicinal plant extracts may provide suitable lead compounds for future development and possible clinical utility as inhibitors of efflux for various Gram-negative bacteria.     

Antimicrobial activity of essential oil and various extracts of fruits of greater cardamom

Greater cardamom (Amomum subulatum Roxb. Zingiberaceae) commonly known as "Bari ilaichi" is a well known plant used in Ayurvedic and Unani medicine. It has been used for the treatment of various diseases and disorders like gastric ulcer. Therefore antimicrobial activity of petroleum ether, methanol and aqueous extracts from leaves and roots, essential oil and isolated vasicine from A. vasica were tested against various microorganisms. Antimicrobial activity was done by disc diffusion method. The zone of inhibition observed was compared with that of standard drugs, ciprofloxacin and fluconazole. Minimum inhibitory concentration was determined against microorganisms used in the study. The results of this study reveal that methanol extract of fruits of A. subulatum shows remarkable antimicrobial activity against Escherichia coli whereas in case of other microorganisms used it was found inferior to the standard drug used. Methanol extract of rind showed good antimicrobial activity against Staphylococcus aureus. It was found that the essential oil isolated was effective against majority of microorganisms used viz. Bacillus pumilus, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Saccharomyces cerevisiae.     

In vitro anti-herpes simplex viruses and anti-adenoviruses activity of twelve traditionally used medicinal plants in Taiwan

As an effort to search for new antiviral agents from traditional medicine, the hot water (HW) extract of twelve traditionally used medicinal plants in Taiwan was evaluated for their in vitro anti-herpes simplex viruses (HSV; including HSV-1 and HSV-2) and anti-adenoviruses (ADV; including ADV-3, ADV-8 and ADV-11) activities with a XTT-based colorimetric assay. Results showed that the tested HW extracts exhibited anti-HSV and anti-ADV activities at different magnitudes of potency. Among the twelve medicinal plants, Boussingaultia gracilis var. pseudobaselloides (Basellaceae) and Serissa japonica (Rubiaceae) possessed broad spectrum of antiviral activity. Ardisia squamulosa (Myrsinaceae) and Artemisai princeps var. orientalis (Compositae) were more effective in inhibiting ADV-8 replication than the other four viruses. Cell cytotoxic assay demonstrated that all tested HW extracts had CC50 values higher than their EC50 values. It was concluded that the twelve traditionally used medicinal plants in Taiwan possessed antiviral activity, and some of them merit further investigation.     

Antiviral effect of aqueous plant extracts in tissue culture]

The aqueous extracts from 178 kinds of medicinal plants belonging to 69 families were examined from the point of their virustatic activity against herpes-, influenza-, vaccine- and poliovirus. 75 kinds proved to be virustatic against one or more kinds of virus. Nearly one-third of the active plants belong to families that are known as especially rich in tannin. Besides the virustatic activity a great number of extracts showed also a cytostatic activity.     

Screening for Protozoocidal Activity of Spanish Plants

Crude extracts of Spanish plants (60 representing 12 species from 7 families) have been screened for antiparasitic activity against Leishmania infantum and Trichomonas vaginalis. 30% of the extracts showed activity against one of the parasites and 15% of the extracts were active against both tests organisms. The most promising extracts originate from plants used in traditional medicine, such as Inula montana L. (Asteraceae), Bupleurum rigidum L. (Apiaceae) and Scrophularia scorodonia L. (Scrophulariaceae).     

Indian Medicinal Plants: A Potential Source for Anticandidal Drugs

Alcoholic and aqueous crude extracts of 37 traditionally-used medicinal plants were screened for antifungal activity against the pathogenic yeast, Candida albicans, and dermatophytes, Epidermophyton floccosum, Microsporum gypseum and Trichophyton rubrum. Alcoholic extracts of these 37 plants were demonstrated to have antifungal activity. Twenty-one extracts showed strong activity and the remaining 16 plants exhibited moderate activity against Candida albicans and to one or more dermatophytes. Such activity was detected in only 16 aqueous extracts. Alcoholic extracts of five medicinal plants were selected for further studies on the basis of their strong anticandidal activity. Minimum inhibitory concentration (MIC) values of these five extracts revealed their varied anticandidal potency. MIC values ranged between 4-9 mg/ml. Comparatively high potency was observed in the extracts of Plumbago zeylanica (4mg/ml) followed by Terminalia bellirica and Phyllanthus emblica (7 mg/ml), each Holarrhena antidysentrica (8 mg/ml), and least in Terminalia chebula (9 mg/ml). Preliminary phytochemical analysis of these extracts showed the presence of many biologically active constituents.     

Inhibition of Staphylococcus Aureus Mediated by Extracts from Iranian Plants

In order to find new antibacterial agents effective against Staphylococcus aureus, ethanolic extracts of 10 plants were tested. S. aureus (489 samples) were isolated either from healthy carriers (nose and throat) or clinical samples. Out of 489 isolates tested, 98.6% were sensitive to trimethoprim-sulfamethoxazole which was used as the reference antibiotic. From the plant extracts screened for antibacterial activity, Myrtus communis L. (leaves) had the greatest activity, inhibiting the growth of 99% of the isolates. Glycyrrhiza glabra L., Eucalyptus globolus Labill and Menta viridis L., were also active against the isolates inhibiting the growth of 90, 59.5 and 48.7% of the isolates, respectively. All of these extracts were active against the reference strains of S. aureus tested. Saturia hortensis L., Teucrium polium L., and Achillea santolina L., had very little antibacterial activity, while Trigonella foenum graecum L., Echium amoenum Fisch & Mey (flowers) and Juglans regia L. (leaves), had no antibacterial activity against the bacterial isolates.     

Inhibitors of Cyclic AMP Phosphodiesterase in Medicinal Plants.

Hot aqueous extracts of medicinal plants used in oriental medicine were tested for their inhibitory effect on beef heart phosphodiesterase to detect biologically active compounds present therein. Of 222 samples tested 22 showed reproducible inhibition. cAMP phosphodiesterase inhibitors contained in ANEMARRHENA ASPHODELOIDES were identified as norlignans and their structure activity relationship was investigated; CIS-hinokiresinol, the main inhibitor exhibited a prolongation effect on hexobarbital sleeping time in mice.     

Antimicrobial and Cytotoxic Activity of Some Medicinal Plants from Baja California Sur (Mexico)

Scientific evaluation of 25 ethanol extract of plants used in the traditional medicine of Baja California Sur (Mexico) were tested for microbial and HCT-116 cell growth inhibition. Ten extracts showed activity against the HCT-116 cell line, notably Asclepias subulata (Asclepiadaceae), Aristolochia brevipes (Aristolochiaceae) and Bursera odorata (Burseraceae). Haplopappus sonorensis (Asteraceae) Asclepias subulata and Bursera odorata inhibited Mycobacterium tuberculosis by 40, 45 and 67%, respectively, at a concentration of 100 µg/mL. Antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Candida albicans and Escherichia coli was determined, and Aristolochia monticola, A. brevipes, Hymenoclea monogyra and Hymenoclea sp. were found to be the most active. Xanthium strumarium showed low activity against C. albicans.     

Evaluation of the activity of 16 medicinal plants against Neisseria gonorrhoeae

50% Ethanolic extracts of various parts of 16 medicinal plants were evaluated for potential activity against clinical isolates and WHO strains of Neisseria gonorrhoeae, including multidrug-resistant (MDR) strains. Activity was calculated as percentage inhibition in comparison with penicillin and ciprofloxacin and strains were categorised as less sensitive, sensitive or highly sensitive to the extracts. The extracts caused differential inhibition of N. gonorrhoeae, with greater inhibition of the MDR strains. Among the extracts tested, 60% exhibited high activity whereas 20% showed moderate activity and 20% had little activity against N. gonorrhoeae.     

Antiviral Activities in Extracts of Turkish Medicinal Plants

A total of 16 ethanol extracts of Turkish medicinal plants were evaluated for antiviral activities against herpes simplex virus (HSV) and Sindbis virus (SINV). Extracts of Galanthus elwesii and Rheum ribes showed the most potent anti-HSV activities, while six other extracts had weaker activities. Galanthus elwesii and Leucojum aestivum were the most potent anti-SINV extracts with four others showing weaker activities. In total, five extracts were active against both viruses, three were selective for HSV and one was selective for SINV. Evidence for an antiviral photosensitizer was obtained in two anti-HSV extracts, in which activity was either completely dependent on light, or was con-siderably enhanced by light. Thus, several Turkish medicinal plants appear to be promising sources of antiviral activities.