Activity of Ku Shen compounds against Staphylococcus aureus and Streptococcus mutans

Ten compounds were isolated from the Chinese crude drug, Ku Shen (Sophora flavescens Aiton). Seven compounds showed antimicrobial activity against Staphylococcus aureus and Streptococcus mutans. The activity principles were identified as kurarinone, sophoraflavanone G, iso-kurarinone, kuraridine, kushenol C, D and nor-anhydroicaritin.     

Antimicrobial activity of terpenoids from Copaifera langsdorffii Desf. against cariogenic bacteria

In the present work, the anticariogenic activities of nine labdane type‐diterpenes and four sesquiterpenes were investigated. Among these metabolites, (‐)‐copalic acid (CA) was the most active compound displaying MIC values very promising (ranging from 2.0 to 6.0 µg/mL) against the main microorganisms responsible for dental caries: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis and Lactobacillus casei. Time kill assays performed with CA against the primary causative agent (S. mutans) revealed that, in the first 12 h, this compound only inhibits the growth of the inoculum (bacteriostatic effect). However, its bactericidal effect is clearly noted thereafter (between 12 and 24 h). Also, CA did not show a synergistic effect when combined with the anticariogenic gold standard (chlorhexidine, CHD) in the checkerboard assays against S. mutans. In conclusion, the results points out CA as an important metabolite in the search for new effective anticariogenic agents. Copyright © 2010 John Wiley & Sons, Ltd.     

In vitro anti‐adhesive activity of green tea extract against pathogen adhesion

Camellia sinensis polysaccharide has been reported to possess anti‐adhesive activity against pathogens. The present study was designed to investigate whether hot water extracts obtained from green tea leaves might inhibit pathogen adhesion to human or mouse cell lines. Green tea extract‐4 (CSI‐4) with the maximum yield of 4% (w/v) is composed of a major proportion of carbohydrates containing 40% uronic acids, but lack of catechins. It showed strong inhibitory activities against hemagglutination mediated by pathogens Helicobacter pylori, Propionibacterium acnes and Staphylococcus aureus with the minimum inhibitory concentrations of 0.01‐0.5 mg/mL. CSI‐4 further demonstrated an inhibitory effect on the adhesion of these pathogens to host cell lines with the IC₅₀ values (50% inhibition of adhesion) of 0.14–2.3 mg/mL. It exhibited the highest activity against P. acnes, but no inhibitory effects were observed against Lactobacillus acidophilus, Bifidobacterium bifidum, Escherichia coli, or Staphylococcus epidermidis. Our results suggest that CSI‐4 may exert a selective anti‐adhesive effect against certain pathogenic bacteria with no adverse effects against beneficial or commensal bacteria. Copyright © 2008 John Wiley & Sons, Ltd.     

Evaluation of the liver protective principles from the root of Cudrania cochinchinensis var. gerontogea

Three components in the EtOAc and n-BuOH fractions, obtained from the ethanol extract of Cudrania cochinchinensis var. gerontogea (Moraceae) were evaluated for their hepatoprotective activities in rats on carbon tetrachloride (CCl₄) and D -galactosamine (D -GalN)-induced hepatotoxicity. Three flavonoids (25 mg/kg), wighteone, naringenin and populnin (kaempferol-7-glucoside), exhibited greater hepatoprotective effects on CCl₄-induced liver injury than on D -GalN-induced hepatotoxicity by reversing the altered serum enzymes (SGOT and SGPT) and preventing the development of hepatic lesions, including liver centrilobular inflammation, cell necrosis, fatty change, ballooning degeneration in CCl₄ intoxication and necrosis of the portal area in D-GalN intoxication. Wighteone and naringenin (25 mg/kg) isolated from the EtOAc fraction showed a better hepatoprotective effect against CCl₄-induced liver injury than that of populnin (25 mg/kg) obtained from the n-BuOH fraction. Furthermore, wighteone protected the liver, not only against CCl₄-induced hepatotoxicity, but also against D -GalN-induced liver injury. These results demonstrated that wighteone and naringenin are two active hepatoprotective principles from Cudrania cochinchinensis var. gerontogea.     

Inhibitory activity of Dodonaea viscosa var. angustifolia extract against Streptococcus mutans and its biofilm

Ethnopharmacological relevance

The leaves of Dodonaea viscosa var. angustifolia (DVA) are traditionally used for the treatment of fever, colds, oral thrush, toothaches and related problems. Streptococcus mutans is implicated in many oral infections. This study investigated the inhibitory activity of DVA extract against Streptococcus mutans and its biofilm.

Materials and Methods

Crude extract of the leaves was prepared using methanol. The time-kill curve for Streptococcus mutans at different concentrations of methanol extract after 6 and 24 h was determined. Biofilms of Streptococcus mutans were grown in the presence of subinhibitory concentration of extract (0.78 mg/ml) for 30 h and the bacterial counts were obtained after 6, 24 and 30 h. The chemical profile of the crude extract was obtained using gas chromatography-mass spectrometry (GC-MS).

Results

The reduction of Streptococcus mutans was concentration and exposure time dependent. The crude extract killed 48% of S. mutans at a lowest concentration of 0.1 mg/ml and 100% at 25 mg/ml after 6 h. Biofilm formation was reduced by 95, 97 and 99% after 6, 24 and 30 h of exposure to the subinhibitory concentration of crude extract respectively. GC–MS analyses revealed the presence of polyphenols such as catechin or chromene groups, chalcones with trimethoxyphenyl group and tannin with 4-O-β-D-xylopyranoside. At high concentration the crude extract was bactericidal to Streptococcus mutans but subinhibitory concentration significantly reduced the planktonic cells and biofilm formation.

Conclusions

These results suggest that this plant has the potential to be used to control S. mutans and its biofilm which are responsible for oral infections.     

Antiaggregation potential of berry fractions against pairs of Streptococcus mutans with Fusobacterium nucleatum or Actinomyces naeslundii

Coaggregation is an interspecies adhesion process, which is essential to the development of dental plaque. This is an in vitro study of the composition of the soluble solids in the berry juice molecular size fractions (<10 kDa, FI; 10–100 kDa, FII; >100 kDa, FIII) derived from apple, bilberry, blackcurrant, cloudberry, crowberry and lingonberry and their ability to inhibit and reverse coaggregation of the pairs of common species in dental plaque: Streptococcus mutans with Fusobacterium nucleatum or Actinomyces naeslundii. Inhibitory and reversal activity was found in the molecular size fractions FII and FIII of bilberry, blackcurrant, crowberry and lingonberry. The active fractions contained higher amounts of polyphenols (5–12% of soluble solids) than those without activity (<2% of soluble solids). Proanthocyanidins dominated in the active lingonberry juice fractions FII and FIII and also small amounts of anthocyanins were detected. Anthocyanins, proanthocyanidins and flavonol glycosides were prevalent in FII and FIII fractions of bilberry, blackcurrant and crowberry juices. Comparable amounts of sugars and titratable acids were present in the latter three berry juice fractions of different size. The results indicate that the high molecular size fractions of lingonberry, bilberry, blackcurrant and crowberry juices have antiaggregation potential on common oral bacteria, the potential being associated with their polyphenolic content. Copyright © 2010 John Wiley & Sons, Ltd.     

A Preliminary Investigation on the Antimicrobial Activity of Listerine®, Its Components,and of Mixtures Thereof

Listerine® is one of the most popular mouthwashes worldwide and claims to combat harmful bacteria. In the past century, its recipe was changed from an essential oil mouthwash to a five‐component mixture (thymol, menthol, eucalyptol, and methyl salicylate dissolved in 27% ethanol). The aim of this study was to get preliminary information about the antimicrobial activities of individual Listerine® components and their mixtures. We tested the bacterial strains Streptococcus mutans, Enterococcus faecalis, and Eikenella corrodens and the yeast Candida albicans. The established minimum inhibitory concentration (MIC) assay and the minimum bactericidal/fungicidal concentration (MBC/MFC) assay were applied. None of the combinations of two phenols at the concentrations contained within Listerine® were associated with either an additive or synergistic effect. Thymol had lower MIC and MBC/MFC values than the other Listerine® components and Listerine® against E. corrodens and C. albicans. The mixtures consisting of eucalyptol, methyl salicylate, and thymol were the most effective against S. mutans and E. faecalis and more effective than Listerine®. Our results demonstrate that the phenols and their concentrations as contained within Listerine® could be further optimized in terms of selecting those which increase their general effectiveness, at concentrations that do not induce harm. Copyright © 2015 John Wiley & Sons, Ltd.     

Cytostatic activity against HEp-2 cells of methanol extracts from Viscum cruciatum Sieber parasitic on Crataegus monogyna Jacq. and two isolated principles

We have determined the cytostatic activity in vitro against HEp-2 cells of methanol extracts from V. cruciatum Sieber (Viscaceae) parasitic on C. monogyna Jacq. (Rosaceae), C. monogyna parasitized and C. monogyna. non-parasitized. The methanol extracts assayed exhibited a moderate degree of growth inhibition compared with the values obtained with the 6-mercaptopurine (solution used as a positive control). Hyperoside from C. monogyna showed only a low degree of growth inhibition. However, β-amyrin acetate, from V. cruciatum, exhibited a high degree of growth inhibition compared with the values obtained with the solution used as a positive control. © 1997 John Wiley & Sons, Ltd.     

Insect antifeedant principles from Vernonia cinerea

Four compounds, stigmasterol, stigmasterol-β-D -glucopyranoside, luteolin-7-0-glucopyranoside and dotriacontanoic acid isolated from Vernonia cinerea have shown significant antifeedant activity based on percent feeding-deterrence and effective doses (ED₅₀) against two lepidopterous insects, Spodoptera litura and Spilosoma obliqua. © 1998 John Wiley & Sons, Ltd.     

甜茶苷对变形链球菌致龋能力的影响

目的研究甜茶苷对变形链球菌Streptococcus mutans致龋能力的影响。方法将变形链球菌菌液加入甜茶苷后于恒温厌氧环境下培养,测试其pH值变化、黏附率,运用碳氢化合物法测定其表面疏水率。采用Bradford法以Neson-samogyi分别测量总蛋白的量以及还原糖的量,计算葡萄糖基转移酶(glucosyltransferase,GTF)活力,采用Anihrone法测量水不溶性葡聚糖(water-insoluble glucans,WIG)的量。结果加入甜茶苷的菌液pH变化值、黏附率、表面疏水率、GTF活力及WIG的量与对照组之间均有显著性差异(P<0.01)。结论甜茶苷对变形链球菌产酸能力、黏附能力、GTF活力及WIG合成具有显著抑制作用。     

Antimicrobial activity of medicinal plants against oral microorganisms

Ethanol extracts of eight plant species used traditionally in South Africa for the treatment of oral diseases were investigated for in vitro antimicrobial activity against oral pathogens namely Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, Actinomyces israelii, Candida albicans, Porphyromonus gingivalis, Privotella intermedia and Streptococcus mutans using the disk diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts were determined against these microorganisms using micro dilution. The cytotoxicity and therapeutic index (TI) of selected active extracts were also determined. Out of eight plants, six (Annona senegalensis, Englerophytum magalismontanum, Dicerocarym senecioides, Euclea divinorum, Euclea natalensis, Solanum panduriforme and Parinari curatellifolia) exhibited MIC values ranging from 25.0 mg/ml to 0.8 mg/ml. Gram negative bacteria were found to be more resistant to the plant extracts than Gram positive bacteria, except for Euclea natalensis which inhibited all three Gram negative bacteria tested in this study. All plant extracts showed moderate cytotoxicity on the Vero cell line. The fifty percent inhibitory concentration (IC₅₀) of all plants tested range from 92.3 to 285.1 μg/ml.     

Tart cherry (Prunus cerasus L.) fractions inhibit biofilm formation and adherence properties of oral pathogens and enhance oral epithelial barrier function

Dental caries, candidiasis, and periodontal disease are the most common oral infections affecting a wide range of the population worldwide. The present study investigated the effects of two tart cherry (Prunus cerasus L.) fractions on important oral pathogens, including Candida albicans, Streptococcus mutans, and Fusobacterium nucleatum, as well as on the barrier function of oral epithelial cells. Procyanidins and quercetin and its derivatives were the most important constituents found in the tart cherry fractions. Although the fractions showed poor antimicrobial activity, they inhibited biofilm formation by the three oral pathogens in a dose‐dependent manner. The tart cherry fractions also attenuated the adherence of C. albicans and S. mutans to a hydroxylapatite surface as well as the adherence of F. nucleatum to oral epithelial cells. Treating oral epithelial cells with the tart cherry fractions significantly enhanced the barrier function as determined by monitoring the transepithelial electrical resistance. In conclusion, this study showed that the tart cherry fractions and their bioactive constituents could be promising antiplaque compounds by targeting biofilm formation and adherence properties of oral pathogens. Furthermore, its property of increasing the epithelial barrier function may protect against microbial invasion of the underlying connective tissue.     

Isolation and characterization of an antibacterial biflavonoid from an African chewing stick Garcinia kola Heckel (Clusiaceae)

Ethnopharmacological relevance

The use of African chewing sticks in maintaining oral health is widely practiced in African countries. It has been reported that chewing stick users have a lower rate of dental caries and a better general oral health than non-users. It is generally thought that the beneficial effect of chewing stick is attributed to the mechanical cleansing effect and antimicrobial substances present in the stick. However, the active antimicrobial substances remain uncharacterized.

Aim of the study

To provide a scientific basis for the anti-caries effect of African chewing sticks, the authors purify an active antibacterial compound from Garcinia kola Heckel, a Nigerian chewing stick and examined the antibacterial activity of this compound against the cariogenic bacterium Streptococcus mutans.

Materials and methods

Methanol extract was prepared from Garcinia kola and was further fractionated by solvent extractions. Silica gel chromatography was used to purify the antibacterial compound from the active fraction. The identity of the purified compound was determined by NMR analysis. The antibacterial activity of the purified compound was examined by standard microbiological assays.

Results

The antibacterial activity was found in the ether fraction and the active compound was isolated and determined to be a biflavonoid named GB1. GB1 was active against Streptococcus mutans and other oral bacteria with minimum inhibitory concentration (MIC) values of 32–64 μg/ml. The basis for the antibacterial effect of GB1 was investigated using Streptococcus mutans as the target. At 256 μg/ml, GB1 exhibited some bacteriocidal activity against Streptococcus mutans and induced the aggregation of Streptococcus mutans. GB1 has no apparent effects on protein synthesis and DNA synthesis but inhibited glucose uptake and utilization by Streptococcus mutans suggesting that GB1 exerts its antibacterial effect by inhibiting metabolism. GB1 also inhibited the formation of water-insoluble glucan by the extracellular glucosyltransferases from Streptococcus mutans in a dose-dependent manner. Streptococcus mutans did not develop resistance to GB1 upon subculturing in the presence of sub-MIC level of the biflavonoid.

Conclusion

The antibacterial effect and glucan synthesis-inhibition property of this biflavonoid may account for some of the beneficial effects reported in the chewing stick users.     

Screening of nine vasoactive medicinal plants for their possible calcium antagonistic activity. Strategy of selection and isolation for the active principles of Olea europaea and Peucedanum ostruthium

Fourteen different extracts of nine vasoactive medicinal plants used in European and African phytotherapy and traditional medicine were pharmacologically tested for their possible calcium antagonistic mode of action. The criteria for the selection of plants were: use in traditional medicine in the treatment of cardiovascular diseases, ‘nonspecific’ spasmolytic activity (mode of action not known), natural compounds with structural similarities to already known ‘calcium-antagonists’ or calcium-antagonists that have been found in species of the same tribe. All plant extracts were investigated against contractions of aortic strips induced by K⁺-depolarization. Extracts derived from Ammi visnaga, Guajacum officinale, Olea europaea, Peucedanum ostruthium and Ruta graveolens showed a clear activity, while Cryptolepis sanguinolenta, Leonurus cardiaca, Passiflora incarnata and Solidago gigantea showed no effect in this test. A comparison between K⁺- and norepinephrine-induced contractions evaluated the selectivity of the inhibition, which is demonstrated by the isolation and identification strategy for the Ca⁺⁺-antagonistic principles of Olea europaea leaves and Peucedanum ostruthium rhizomes.     

Screening of Australian plants for antimicrobial activity against Campylobacter jejuni

Campylobacter jejuni is the most common cause of acute enteritis in humans, with symptoms such as diarrhoea, fever and abdominal cramps. In this study, 115 extracts from 109 Australian plant species were investigated for their antimicrobial activities against two C. jejuni strains using an in vitro broth microdilution assay. Among the plants tested, 107 (93%) extracts showed activity at a concentration between 32 and 1024 µg/mL against at least one C. jejuni strain. Seventeen plant extracts were selected for further testing against another six C. jejuni strains, as well as Campylobacter coli, Escherichia coli, Salmonella typhimurium, Bacillus cereus, Proteus mirabilis and Enterococcus faecalis. The extract from Eucalyptus occidentalis demonstrated the highest antimicrobial activity, with an inhibitory concentration of 32 µg/mL against C. jejuni and B. cereus. This study has shown that extracts of selected Australian plants possess antimicrobial activity against C. jejuni and thus may have application in the control of this organism in live poultry and retail poultry products. Copyright © 2011 John Wiley & Sons, Ltd.     

Antiviral Activity of Aloe Extracts against Cytomegalovirus

Substances extracted from the leaves of aloe plants have been reported to have antiviral effects against enveloped viruses in in vitro test systems. In the present studies, we have assessed the antiviral activity of partially purified extracts prepared from the gel portion of leaves of Aloe barbadensis Miller against human cytomegalovirus (CMV) by plaque inhibition tests (PIT), flow cytometry and morphometry assays. Six test extracts of gel filet portions of aloe leaves were prepared; i.e. R1 from immature leaves harvested in the early summer, S1 from mature leaves harvested in the autumn, F1 from S1 after freezing at −20°C, and R2, S2 and F2 which were ethanol treated extracts of R1, S1 and F1, respectively. When test aloe extracts were added at various concentrations during the course of infection with CMV, R1, S1 and F2 at concentrations of 10⁻¹ inhibited plaque formation. The addition of S1 to the medium between 12 and 36 h after initiation of CMV infection, a time of high DNA synthesis, caused the most effective plaque inhibition. Flow cytometric and morphometric analyses revealed no significant differences in aloe extract treated, CMV infected cells compared with non-aloe treated CMV infected control cells. The results suggest that a major mechanism of inhibition of CMV infection by aloe extracts is through interference with DNA synthesis.     

In vitro antimicrobial activity of Caesalpinia ferrea Martius fruits against oral pathogens

Aim

In the Amazon region of Brazil, the fruits of Caesalpinia ferrea Martius (Brazilian ironwood) are widely used as an antimicrobial and healing medicine in many situations including oral infections. This study aimed to evaluate the antimicrobial activity of Caesalpinia ferrea Martius fruit extract against oral pathogens.

Materials and methods

Polyphenols estimation and spectral analysis (¹H NMR) of the methanol extract were carried out. The microorganisms Candida albicans, Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis and Lactobacillus casei were tested using the microdilution method for planktonic cells (MIC) and a multispecies biofilm model. Chlorhexidine was used as positive control.

Results

Polyphenols in the extract were estimated at 7.3% and ¹H NMR analysis revealed hydroxy phenols and methoxilated compounds. MIC values for Candida albicans, Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis and Lactobacillus casei were 25.0, 40.0, 66.0, 100.0, 66.0 μg/mL, respectively. For the biofilm assay, chlorhexidine and plant extract showed no growth at 10⁻⁴ and 10⁻⁵ microbial dilution, respectively. At 10⁻⁴ and 10⁻⁵ the growth values (mean ± SD) of the negative controls (DMSO and saline solution) for Streptococcus mutans, Streptococcus sp. and Candida albicans were 8.1 ± 0.7, 7.0 ± 0.6 and 5.9 ± 0.9 × 10⁶ CFU, respectively.

Conclusion

Caesalpinia ferrea fruit extract can inhibit in vitro growth of oral pathogens in planktonic and biofilm models supporting its use for oral infections.     

Antivectorial Activities of Cashew Nut Shell Extracts from Anacardium occidentaleL.

Sodium salts of cashew nut shell extracts (CNSL) and anacardic acids isolated from Anacardium occidentale demonstrate a potent antivectorial activity against Aedes aegypti larvae and Biomphalaria glabrata snails. The structure–activity relationship is discussed, particularly the hydrogenation of CNSL and anacardic acids which lower dramatically these properties, showing the importance of the double bonds on the side chains of anacardic acids. © 1997 by John Wiley & Sons, Ltd.     

Antimicrobial activity of naturally occurring and synthetic phloroglucinols against Staphylococcus aureus

Several phloroglucinols were isolated from Chinese drugs, Di er cao (Hypericum japonicum Thunb.) and Xian he cao (Agromonia pilosa Ledb.). These compounds showed potent activity against Staphylococcus aureus. Phloroglucinol derivatives were synthesized and their activities compared with naturally occurring and synthetic phloroglucinols against Staphylococcus aureus. The most active derivatives were methylene-bis diacetyl-phloroglucinol, n-butanoylphloroglucinol, sarothralin and uliginosin B.