Anti-cariogenic properties of tea (Camellia sinensis)

Various components in green and black tea, the beverages made by infusing appropriately processed dried leaves of Camellia sinensis, notably simple catechins, have properties in vitro that suggest an anti-cariogenic activity. These include: a direct bactericidal effect against Streptococcus mutans and S. sobrinus; prevention of bacterial adherence to teeth; inhibition of glucosyl transferase, thus limiting the biosynthesis of sticky glucan; inhibition of human and bacterial amylases. Studies in animal models show that these in-vitro effects can translate into caries prevention. A limited number of clinical trials in man suggest that regular tea drinking may reduce the incidence and severity of caries. If substantiated, this could offer a very economical public health intervention.     

In vitro antifungal activity and mechanism of action of chitinase against four plant pathogenic fungi

To determine why chitinase has different antifungal activity on different pathogenic fungi in vitro, we purified recombinant rice chitinase from Pichia pastoris and investigated its antifungal activity against four fungi - Rhizopus stolonifer (Ehrenb. et Fr.) Vuill, Botrytis squamosa Walker, Pythium aphanidermatum (eds.) Fitzp, and Aspergillus niger van Tiegh. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the surface microstructure and proportion of chitin in the cell wall of the four fungi, respectively. The results showed that the chitinase exhibited different antifungal activities against the four fungi, which was directly correlated to the surface microstructure and the proportion of chitin in the fungal cell wall. It will help understanding the antifungal mechanism of the recombinant chitinase and further determining its application scope on crop protection and post-harvest storage of fruits and vegetables. ((c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).     

In vitro antifungal activity of mercurobutol

Mercurobutol, in its commercial form, exhibits fungistatic and fungicidal activities against both yeasts: Candida albicans, C. tropicalis, Torulopsis glabrata, Pityrosporum spp., and filamentous fungi: dermatophytes, Aspergillus fumigatus, mainly saprophytic or potentially pathogenic fungi of the cutaneo-mucous flora. Minimal inhibitory concentrations on this antiseptic indicate a high susceptibility of the species tested, that could justify the enlargement of the indication of the drug to the complementary treatment of most cutaneous mycosis.     

Preventive effects of green tea (Camellia sinensis var. assamica) on diabetic nephropathy

Purpose

This study aimed to evaluate the preventive effects of Camellia sinensis var. assamica (CSVA) on diabetic nephropathy in in vitro and in vivo models.

Materials and Methods

MDCK cells were incubated with 1 mM of oxalate with or without different concentrations of CSVA, then MTT and malondialdehyde (MDA) assays were performed to investigate the preventive effects of CSVA on oxalate-induced cytotoxicity and oxidative stress. Thirty male db/db mice were divided into three groups. Group 1 were fed AIN-93G ad libitum; group 2 were fed AIN-93G mixed with 10% fermented CSVA ad libitum; group 3 were fed AIN-93G mixed with 10% non-fermented CSVA ad libitum. The mice were sacrificed 14 weeks later, and the serum glucose level, 24-hour urine chemistry, and morphological changes in the kidneys were examined.

Results

As CSVA concentrations increased, viable MDCK cells increased in concentration. MDA production decreased over time in the CSVA treated group. The creatinine clearance of group 3 was lower than those of groups 1 and 2. The amount of urine microalbumin and protein in group 1 were higher than those in groups 2 and 3. Also, more glomerulus basement membrane foot processes were preserved in groups 2 and 3.

Conclusion

In conclusion, CSVA has beneficial preventive tendencies towards diabetic nephropathy in both in vitro and in vivo models.     

In vitro antifungal oral drug and drug-combination activity against onychomycosis causative dermatophytes.

We present the results of studies of the in vitro susceptibility of 52 isolates of Trichophyton rubrum and 40 of Trichophyton mentagrophytes to griseofulvin, terbinafine, itraconazole, ketoconazole, fluconazole and cyclopiroxolamine. All test strains were recovered from patients with toe nail onychomycosis and the minimum inhibitory concentration (MIC) of each antifungal against both species was individually assessed. In addition, we investigated the MIC of the combination of cyclopiroxolamine and itraconazole and cyclopiroxolamine and ketoconazole. The NCCLS approved procedure M38-A as modified by Santos and Hamdan was employed. The studies of the two drug combinations were conducted with a checkerboard design. Analysis of the data revealed that terbinafine was the most effective in vitro against all isolates, followed in order by itraconazole, cyclopiroxolamine, ketoconazole and fluconazole. We observed no significant difference in the in vitro susceptibility profiles between either species to any of the antifungals (P<0.05). Our in vitro results confirm that terbinafine is the most effective of the antifungals included in this study. Furthermore, synergistic interactions were found in the two drug combinations with all of the dermatophyte test isolates. The latter results are in agreement with clinical data that show synergism between oral and topical antifungals in the treatment of onychomycosis.     

In vitro antifungal activity of epigallocatechin 3-O-gallate against clinical isolates of dermatophytes

Previously, we reported that epigallocatechin 3-O-gallate (EGCg) has growth-inhibitory effect on clinical isolates of Candida species. In this study, we investigated the antifungal activity of EGCg and antifungal agents against thirty-five of dermatophytes clinically isolated by the international guidelines (M38-A2). All isolates exhibited good susceptibility to EGCg (MIC₅₀, 2-4 µg/mL, MIC₉₀, 4-8 µg/mL, and geometric mean (GM) MICs, 3.36-4 µg/mL) than those of fluconazole (MIC₅₀, 2-16 µg/mL, MIC₉₀, 4-32 µg/mL, and GM MICs, 3.45-25.8 µg/mL) and flucytosin (MIC₅₀, MIC₉₀, and GM MICs, >64 µg/mL), although they were less susceptible to other antifungal agents, such as amphotericin B, itraconazole, and miconazole. These activities of EGCg were approximately 4-fold higher than those of fluconazole, and were 4 to 16-fold higher than flucytosin. This result indicates that EGCg can inhibit pathogenic dermatophyte species. Therefore, we suggest that EGCg may be effectively used solely as a possible agent or combined with other antifungal agents for antifungal therapy in dermatophytosis.     

Antibacterial activity of black tea (Camelia sinensis) extract against Salmonella serotypes causing enteric fever

Alcoholic extract of black tea (Camelia sinensis) was assayed for its antibacterial activity against Salmonella serotypes causing enteric fever viz., Salmonella typhi and Salmonella paratyphi A. While all strains of S. paratyphi A tested were found sensitive, only 42.19% of S. typhi strains were inhibited by this extract. Further minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of black tea extract against S. paratyphi A was less compared with that against S. typhi.     

In vitro activity of cefuroxime against Moraxella (Branhamella) catarrhalis

Minimal inhibitory concentrations of cefuroxime were determined by an agar dilution procedure and compared with erythromycin and four other beta-lactam antibiotics (amoxycillin, amoxycillin + clavulanate, cefadroxil, cefaclor) on 76 strains of Moraxella (Branhamella) catarrhalis. Sixty four of them produced a beta-lactamase. Results show that the beta-lactamase of Moraxella (Branhamella) catarrhalis abrogates the activity of amoxycillin (MIC 90% = 4 mg/l) meanwhile the combination of amoxycillin-clavulanate is inhibitory at low concentration (MIC 90% = 0.25 mg/l). There are no difference in MICs between strains producing or not producing beta-lactamase with erythromycin (MIC 90% = 0.25 mg/l). All the strains evaluated in this investigation, producing or not producing beta-lactamase have MIC 90% less than or equal to 2 mg/l for cefuroxime lower than those obtained for the two other cephalosporins.     

In vitro antifungal activity of DNA topoisomerase inhibitors

In this paper we report the results of the study of the in vitro effect of eight anticancer DNA topoisomerase inhibitors on the growth of Aspergillus fumigatus, A. niger, Candida glabrata and Cryptococcus neoformans. Only one compound, idarubicin, displayed promising antifungal activity against A. niger, C. glabrata and C. neoformans with MIC(50) values varying between 3.6 and 14.2 μM (1.8-7.1 μg/ml). Three other compounds, aclarubicin, doxorubicin and mitoxantrone, showed some antifungal activity against C. glabrata and C. neoformans with MIC(50) values in the mid micromolar range. The data of this study indicate that selected DNA topoisomerase inhibitors are a promising class of compounds for the development of new antifungal agents.     

In vitro activity of five antifungal agents against clinical isolates of Saccharomyces cerevisiae.

We evaluated the in vitro activity of fluconazole, itraconazole, ketoconazole, 5-fluorocytosine and amphotericin B against 30 clinical isolates of Saccharomyces cerevisiae by a broth microdilution method, following the NCCLS recommendation. Testing was performed either in RPMI-1640 or yeast nitrogen base (YNB). YNB supported the growth of all isolates tested, while results in RPMI-1640 were not obtained for six isolates (20%). The MIC of all three azoles in YNB were one or two dilutions higher than those obtained in RPMI-1640 (P=0.0001 for fluconazole and itraconazole, P=0.03 for ketoconazole). Elevated MICs were observed for all three azoles, while all the isolates were susceptible to 5-fluorocytosine and amphotericin B. All MIC values were confirmed by spectrophotometric reading. Six strains of S. cerevisiae isolated from the faeces and consecutive blood cultures from an AIDS patient over a 7-month period were typed by electrophoretic karyotyping (EK). EK showed the maintenance of the same karyotype over time suggesting that the faecal isolate changed from a colonizing to infection-causing strain. The relative resistance of S. cerevisiae to azole drugs as well as its ability to cause widespread infections may promote the emergence of this species as a pathogen in immunosuppressed patients.     

In vitro activity of Melaleuca alternifolia (tea tree) oil against bacterial and Candida spp. isolates from clinical specimens

This study investigates the in vitro activity of tea tree oil (TTO) against a range of wild strains of microorganisms isolated from clinical specimens of leg ulcers and pressure sores. The antimicrobial effectiveness of TTO is determined in terms of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC). The isolates include methicillin-resistant Staphylococcus aureus (MRSA), S. aureus, faecal streptococci, beta-haemolytic streptococci, coagulase-negative staphylococci, Pseudomonas spp. and coliform bacilli. Eleven Candida spp. isolates from skin and vaginal swabs also are tested. Using an agar dilution assay, the MICs of TTO in 88 out of 90 isolates was 0.5-1.0% (v/v), whilst with P. aeruginosa it was >2% (v/v). A broth microdilution method was used to determine MIC and minimum cidal concentration (MCC) of 80 isolates. In 64 isolates, TTO produced an inhibitory and cidal effect at 3% and 4% (v/v), respectively. S. aureus and Candida spp. were the most susceptible to TTO, with MICs and MBCs of 0.5% and 1%, respectively. P. aeruginosa and the faecal streptococci isolates, with MICs and MBCs of >8%, were resistant to TTO.     

Black tea (Camellia sinensis) as a chemopreventive agent in oral precancerous lesions.

Oral carcinoma is the most common malignancy found in adult Indian men and the third most common in adult Indian women. About half of all cases are found to be associated with precancerous lesions, chiefly leukoplakia. We wanted to explore the possible benefits of black tea (Camellia sinensis) administered to patients with oral leukoplakia. Eighty-two subjects with oral leukoplakia underwent micronuclei and chromosomal assays on exfoliated oral mucosal epithelium, after which they received black tea in a fixed regimen. The micronuclei assay was repeated at 6 months, and the chromosomal study at 1 year. After the first year, the first 15 patients entered onto this study showed a significant decrease in the micronuclei frequency and chromosomal aberrations, which correlated with the clinical improvement. Several in vitro and animal studies have suggested the efficacy of tea in the chemoprevention of cancer. To the best of our knowledge, this is the first report on the effect of black tea in oral leukoplakia.     

In vitro and in vivo activity of a possible novel antifungal small molecule against Candida albicans

Nosocomial infections by fungi are important causes of morbidity and mortality, and the adhesion capacity of yeast on abiotic and biotic surfaces has been considered an important step in this process. Als3 proteins are widely studied for their ability to allow Candida albicans to bind to various surfaces. The objective of the present study was to verify, with more details, the action of F2768-0318 in relation to its antifungal activity as well as its ability to act on C. albicans virulence factors related to adhesion and biofilm formation in vitro and in vivo by inhibiting the Als3 protein. F2768-0318 was assessed in tests of biofilm formation and adhesion on abiotic surfaces (polystyrene plates) and adherence on biotic surfaces, including human endocervical (HeLa) cells, human umbilical vein endothelial cells (HUVECs), and fresh buccal epithelial cells (BEC). Our results showed F2768-0318 was useful in reducing the adhesion and biofilm formation of C. albicans on abiotic surfaces, indicating the possibility of treating hospital materials and preventing biofilm formation on these types of equipment. Further studies are still needed, including optimization of the molecule to allow this molecule to be effective on other types of surfaces, such as human cells.     

In vitro activity of LY146032 (Daptomycin) against selected aerobic bacteria

The in vitro activity of the new lipopeptide antibiotic LY146032 was generally four-fold greater (MIC 90 0. 5g/ml) than that of vancomycin against methicillin-susceptible or methicillin-resistantStaphybcoccus aureus and coagulase-negative species ofStaphylococcus. Enterococci,Streptococcus bovis, group B and viridans streptococci, andCorynebacterium group J-K isolates were inhibited by 4g/ml of LY146032, which represented activity equivalent to or greater than that of vancomycin. Unlike vancomycin, LY146032 was bactericidal forEnterococcus faecalis, Enterococcus faecium andListeria monocytogenes. Due to its bactericidal properties LY146032 appeared to represent an improvement over vancomycin and teicoplanin.     

Antifungal activity of Camellia sinensis crude extracts against four species of Candida and Microsporum persicolor

Objective of the study

Candidiasis and dermatophytoses are benign infections in humans and animals, but they are very dreaded diseases in immunocompromised individuals. These infections become resistant to different treatments which make them more dangerous. In this work, we tried to find a new way for treating them. So we were interested in the antifungal activity of Camellia sinensis (tea); this plant is known to have many health benefits.