Chemical compositions and antimicrobial activities of four different Anatolian propolis samples

Propolis means a gum that is gathered by bees from various plants. It is known for its biological properties, having antibacterial, antifungal and healing properties. The aims of this study were to evaluate the antimicrobial activity of four different Anatolian propolis samples on different groups of microorganisms including some oral pathogens and comparison between their chemical compositions. Ethanol extracts of propolis (EEP) were prepared from four different Anatolian propolis samples and examined whether EEP inhibit the growth of the test microorganisms or not. For the antimicrobial activity assays, minimum inhibitory concentrations (MIC) were determined by using macrodilution method. The MIC values of the most effective propolis (TB) were 2 microg/ml for Streptococcus sobrinus and Enterococcus faecalis, 4 microg/ml for Micrococcus luteus, Candida albicans and C. krusei, 8 microg/ml for Streptococcus mutans, Staphylococcus aureus, Staphylococcus epidermidis and Enterobacter aerogenes, 16 microg/ml for Escherichia coli and C. tropicalis and 32 microg/ml for Salmonella typhimurium and Pseudomonas aeruginosa. The chemical compositions of EEP's were determined by high-temperature high-resolution gas chromatography coupled to mass spectrometry. The main compounds of four Anatolian propolis samples were flavonoids such as pinocembrin, pinostropin, isalpinin, pinobanksin, quercetin, naringenin, galangine and chrysin. Although propolis samples were collected from different regions of Anatolia all showed significant antimicrobial activity against the Gram positive bacteria and yeasts. Propolis can prevent dental caries since it demonstrated significant antimicrobial activity against the microorganisms such as Streptococcus mutans, Streptococcus sobrinus and C. albicans, which involves in oral diseases.     

In vitro antimicrobial activity of a novel propolis formulation (Actichelated propolis)

AIMS: This study compared in vitro activities of Actichelated propolis (a multicomposite material obtained with mechano-chemichal activation) and of a hydroalcoholic extract of propolis. METHODS AND RESULTS: Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), determined by means of microdilution broth method, against five strains of Staphylococcus aureus, Streptococcus pyogenes, Haemophilus influenzae, Enterococcus spp., Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, showed a greater potency of Actichelated propolis (MIC range: 0.016-4 mg flavonoids ml(-1)) in respect to the hydroalcoholic extract (MIC range: 0.08-21.4 mg flavonoids ml(-1)). Concentrations of Actichelated propolis active against adenovirus, influenza virus, parainfluenza virus and herpes virus type 1 were at least 10 times lower than those of the hydroalcoholic extract. Preincubation of Strep. pyogenes and H. influenzae with subinhibitory concentrations of Actichelated propolis (1/4 and 1/8 x MIC) significantly reduced the number of bacteria that adhered to human buccal cells. CONCLUSIONS: Actichelated propolis has proven to possess antibacterial and antiviral activity higher than a hydroalcoholic extract, being also able to interfere on bacterial adhesion to human oral cells. SIGNIFICANCE AND IMPACT OF THE STUDY: This new formulation of propolis showing better antimicrobial and physical characteristics could improve the application of propolis in respiratory tract infections.     

Comparsion ofin vitro activities of antifungal drugs and propolis against yeasts isolated from patients with superficial mycoses

Thein vitro susceptibilities of propolis and antifungal drugs were determined against some yeasts isolated from patients with superficial mycoses. The agents tested included fluconazole, itraconazole, ketoconazole, terbinafine and propolis. MICs were determined by the broth microdilution technique following National Committee for Clinical Laboratory Standards document M27-P. For allCandida albicans isolates from the patients with superficial mycoses, ketoconazole presented higher (P<0.05) efficiency than that of the other antifungal agents tested. The geometric mean MIC values of antifungal drugs and propolis against the yeasts tested ranged from 0.087 to 12.69 μg/mL and 0.4–0.6 μg/mL, respectively. Propolis also showed an important antifungal activity against the yeasts tested, MIC ranges of the propolis were between 0.01–1.65 μg/mL. Based on these results, propolis requires further investigation as a potential agent for the treatment of superficial mycoses.     

Comparative study of in vitro methods to analyse the antifungal activity of propolis against yeasts isolated from patients with superficial mycoses

AIM: To test a total of 15 strains belonging to four species of yeasts by different in vitro methods against propolis and itraconazole (ITC). METHODS AND RESULTS: Three methods were compared for susceptibility testing of yeast isolates to propolis: disc diffusion method, agar dilution method and National Committee for Clinical Laboratory Standards (NCCLS, M27A) broth microdilution method. ITC was selected as the antifungal agent for comparison study. Using the broth microdilution method, the geometric mean for MIC (microg ml(-1)) with regard to all isolates was < or =0.06 for propolis and < or =0.35 for ITC. The broth microdilution and the agar dilution methods were in good agreement (75%) for propolis against yeasts isolated from patients with superficial mycoses. Using the diffusion method, all strains showed a broad zone of inhibition at the first available reading time (24 or 48 h). An increase of MIC values was accompanied by a decrease of growth inhibition zone diameter. A favourable correlation was found between MIC and inhibition zone around the disc for propolis sample and the correlation coefficient was: r = -0.626 (P < 0.01). CONCLUSIONS: This study suggests the potential value of the agar dilution and disc diffusion method as a convenient alternative method for testing of yeasts to propolis. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated that propolis and ITC were very active against yeasts from patients with superficial mycoses. The other prominent finding in this study is that RPMI 1640 with L-glutamine was the available broth for the in vitro susceptibility testing of yeasts.     

Effect of Mexican propolis extracts from Apis mellifera on Candida albicans in vitro growth

Propolis is a resinous substance collected by bees (Apis mellifera) from different trees and bushes. Due to its antifungal, antibacterial, antiviral and antiparasitic properties, it has continued to be very popular throughout the time showing variable activity depending on its geographical origin. In Mexico, information about this product is very limited. The aim of this work was to evaluate the antifungal activity of four propolis ethanolic extracts from three different Mexican states, and four commercial extracts on Candida albicans growth. A reference strain (ATCC 10231) and 36 clinical isolates of C. albicans were used. The Minimal Inhibitory Concentration (MIC) was determined by the dilution on agar method. Growth curves on Sabouraud Dextrose broth with and without different propolis ethanolic extracts concentrations were performed. In addition, whether the effect was fungistatic or fungicide was determined. The propolis ethanolic extract obtained from Cuautitlán Izcalli, State of Mexico, showed the best biological activity, inhibiting 94.4% from the clinical isolates at 0.8 mg/ml; the reference strain was inhibited at 0.6 mg/ml. The propolis effect was fungistatic in low concentrations and fungicide in concentrations higher to MIC. The Mexican propolis ethanolic extract could be further investigated for its alternative use for the treatment of some C. albicans infections.     

<Emphasis Type="Italic">In vitro</Emphasis> antifungal activity of propolis samples of Czech and Slovak origin

Propolis has been used in traditional folk medicine for ages owing to a number of biological effects. Four propolis samples of Czech and one of Slovak origin were extracted using Soxhlet apparatus and analysed by thin-layer chromatography. Raw propolis samples and their extracts were tested by microdilution broth method to determine minimal inhibitory concentration (MIC) in eight strains of human pathogenic fungi. Raw propolis samples showed a lower in vitro antifungal activity than their extracts. In general, the petroleum ether extracts exhibited the highest in vitro antifungal activity (MIC range of 16–64 μg/ml). The content of flavonoids in the samples varied according to region. The highest amount of flavonoids was found in sample A that originated from Broumov (4%). The most susceptible to the propolis extracts were Trichophyton mentagrophytes and Candida albicans. The propolis samples of Czech and Slovak origin and their extracts showed a considerable in vitro antifungal effect which was associated especially with nonpolar petroleum ether and toluene extracts. There was only a partial correlation between flavonoids content and in vitro antifungal activity.     

Antifungal activity of some bis-5-methylbenzimidazole compounds

Twenty bis-5-methylbenzimidazole compounds were evaluated for their in vitro antifungal activity against Candida albicans and Candida tropicalis. Except for three all compounds exhibited an antifungal activity against these yeasts over a range of the minimum inhibitory concentration (MIC) between 25 and 800 mg/L.     

男性尿道炎和包皮龟头炎致病真菌的分布与药敏分析

目的了解男性念珠菌性尿道炎和包皮龟头炎的菌群分布及体外抗真菌药敏试验情况。方法菌株分离均来自复旦大学附属华山医院皮肤性病门诊临床症状轻重不一、真菌直接镜检阳性的61例患者。用科玛嘉念珠菌显色培养基及API 20C AUX鉴定系统进行菌种鉴定;采用CLSIM27-A2肉汤微量稀释法对61株临床分离念珠菌作了氟康唑、两性霉素B、氟胞嘧啶、伊曲康唑、伏立康唑、特比萘芬6种抗真菌药物敏感性测定。结果对培养阳性的61例菌株,通过科玛嘉念珠菌显色培养基及API 20C AUX鉴定系统作菌种鉴定,白念珠菌52例（85.2%）,近平滑念珠菌3例,光滑念珠菌2例,热带念珠菌2例,季也蒙念珠菌1例,克柔念珠菌1例。对52株白念珠菌的药敏试验显示氟康唑98.1%敏感,1.9%剂量依赖性敏感;氟胞嘧啶96.2%敏感,3.8%耐药;伊曲康唑44.2%敏感,40.5%剂量依赖性敏感,15.3%耐药;伏立康唑84.6%敏感,15.4%耐药;两性霉素B全部敏感;特比萘芬的MIC范围为1-64μg/ml,MIC50和MIC90皆为64μg/ml。结论在男性念珠菌性尿道炎和包皮龟头炎中,白念珠菌仍是第一位致病菌,体外药敏试验显示氟康唑、伏立康唑、氟胞嘧啶、两性霉素B对男性念珠菌性尿道炎均有较好的敏感性。     

Antifungal susceptibility of epigallocatechin 3-O-gallate (EGCg) on clinical isolates of pathogenic yeasts

This is the first report to investigate the antifungal susceptibility of 21 clinical isolates of seven Candida species to epigallocatechin 3-O-gallate (EGCg) and to compare with six antifungal agents, amphotericin B (AMPH), fluconazole (FLCZ), flucytosin (5FC), itraconazole (ITCZ), micafungin (MCFG), and miconazole (MCZ), using a method following the National Committee for Clinical Laboratory Standards (NCCLS) M27-A guidelines. Among the tested species, Candida glabrata exhibited the highest susceptibility to EGCg (MIC50, 0.5-1 microg/ml and MIC90, 1-2 microg/ml) compared favorably with FLCZ, although they were slightly less susceptible than to AMPH, 5FC, MCFG, ITCZ, and MCZ. Candida guilliemondii and Candida parapsilosis (MIC50, 1-4 microg/ml and MIC90, 2-16 microg/ml) were also susceptible to EGCg, although they appear to be slightly less susceptible to EGCg than C. glabrata and the other antifungal agents tested. Moreover, the susceptibility of Candida krusei strains (MIC50, 2 microg/ml and MIC90, 4-8 microg/ml) to EGCg was approximately 2- to 8-fold higher than those of 5FC and FLCZ. Our data indicate that EGCg can inhibit clinically pathogenic Candida species, although the concentrations of EGCg for antifungal susceptibility were slightly higher than those of tested antifungal agents on the whole. Based on these results, we suggest that EGCg may be effectively used as a possible agent or adjuvant for antifungal therapy in Candidiasis.     

In vitro activity of amphotericin B and anidulafungin against Candida spp. biofilms

Invasive infections caused by Candida spp. are increasing worldwide and are becoming an important cause of morbidity and mortality in immunocompromised patients. A large number of manifestations of candidiasis are associated with the formation of biofilms on inert or biological surfaces. Candida spp. biofilms are recalcitrant to treatment with conventional antifungal therapies. The aim of this study was dual 1) to determine the prevalence of biofilm producers among clinical isolates from catheter (16 C. albicans ) and blood culture (2 C. albicans and 30 C. tropicalis), and 2) to determine the activity of amphotericin B and anidulafungin against C. albicans and C. tropicalis biofilms of 24 and 48 hours of maturation. Biofilms were developed using a 96-well microtitre plate model and production and activity of antifungal agents against biofilms were determined by the tetrazolium (XTT) reduction assay. Of catheter and blood isolates, 62.5 and 56.25%, respectively, produced biofilms. By species, 68.42% of C. albicans and 53.33% of C. tropicalis were biofilm producers. C. albicans biofilms showed more resistance to amphotericin B and anidulafungin than their planktonic counterparts. Complete killing of biofilms was never achieved, even at the highest concentrations of the drugs tested. Anidulafungin displayed more activity than amphotericin B against C. albicans biofilms of 24 hours of maturation (GM MIC 0.354 vs. 0.686 microg/ml), but against C. tropicalis biofilms amphotericin B was more active (GM MIC 11.285 vs. 0.476 microg/ml). In contrast, against biofilms with 48 hours maturation, amphotericin B was more active against both species.     

Steroidal saponins from Asparagus acutifolius

Six new steroidal saponins (1-6) were isolated from the roots of A. acutifolius L., together with a known spirostanol glycoside (7). Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR, FABMS and HRESIMS). Compounds 4-7 demonstrated antifungal activity against the human pathogenic yeasts C. albicans, C. glabrata and C. tropicalis with MICs values between 12.5 and 100 microg/ml.     

In-vitro activity of 5-fluorocytosine against 1,021 Spanish clinical isolates of Candida and other medically important yeasts

The aim of this study was to determine the prevalence of primary resistance to 5-fluorocytosine (5FC) among clinical isolates of yeasts in Spain where this drug is not currently available for therapy. We have tested the in vitro activity of 5FC against 1,021 recent yeast clinical isolates, including 522 Candida albicans, 140 Candida parapsilosis, 68 Candida glabrata, 41 Candida dubliniensis, 50 Candida guilliermondii, 34 Candida tropicalis, 28 Candida krusei, 20 Candida famata, 11 Cryptococcus neoformans, 5 Cryptococcus albidus, 43 Rhodotorula spp., 24 Trichosporon spp., 5 Saccharomyces cerevisiae, 9 Pichia spp., and 21 isolates from other 11 yeast species. The MICs were determined by the ATB Fungus agar microdilution test (bioMerieux, France) and the following interpretive breakpoints were used: susceptible, > 4 microg/ml; intermediate, 8 to 16 microg/ml; resistant, > 32 microg/ml. 5FC was very active against Candida spp. and other medically important yeasts as 852 (83.4%) of the studied isolates were susceptible (MIC < 4 microg/ml). The species most susceptible to 5FC were C. dubliniensis (100%of isolates; MIC90, 0.25 microg/ml), C. famata (100% of isolates; MIC90, 0.25 microg/ml), C. guilliermondii (98%of isolates; MIC90, 0.25 microg/ml), C. glabrata (95.5% of isolates; MIC90, 0.25 microg/ml), and C. neoformans (90.9% of isolates; MIC90, 2 microg/ml). Primary resistance to 5FC was very uncommon, and a MIC > 32 microg/ml, indicator of in vitro resistance, was observed in 106 isolates (10.4%): 77 C. albicans (16.5% of isolates; MIC90, > 128 microg/ml), 9 C. parapsilosis (6.4% of isolates; MIC90, 8 microg/ml), 4 C. albidus (80% of isolates, MIC50, > 128 microg/ml), 3 C. glabrata (4.4% of isolates; MIC90, 0.25 microg/ml), 3 C. tropicalis (8.8% of isolates; MIC90, 4 microg/ml), 2 C. krusei (7.1% of isolates; MIC90, 8 microg/ml), 2 Rhodotorula spp. (4.6% of isolates, MIC90, 1 microg/ml), 8 Trichosporon spp. (33.3% of isolates; MIC90, 64 microg/ml), and 1 C. lipolytica (50% of isolates). Interestingly, most C. albicans (67 out of 77 isolates) resistant to 5FC were serotype B isolates.     

Antifungal effects of hydrolysable tannins and related compounds on dermatophytes, mould fungi and yeasts

A series of hydrolysable tannins and related compounds was evaluated for antifungal activities against filamentous fungi (Epidermophyton floccosum; Microsporum canis; Microsporum gypseum; Trichophyton mentagrophytes; Trichophyton rubrum; Trichophyton tonsurans; Trichophyton terrestre; Penicillium italicum; Aspergillus fumigatus; Mucor racemosus; Rhizopus nigricans) and opportunistic yeasts (Candida albicans; Candida glabrata; Candidata krusei; Cryptococcus neoformans), using the agar dilution method. While all samples had no activity against the filamentous fungi in concentrations of 1.1-5.9 microM (1000 microg/ml), the phenolic compounds displayed significant potencies against all the opportunistic yeasts tested but C. albicans, with minimum inhibitory concentrations ranging from 0.02 to 0.1 microM (16-125 microg/ml). Although the presence of galloyl groups in flavonoids did not necessarily produce activity, this structural element, an HHDP moiety or its oxidatively modified entity proved to be an important structural feature of hydrolysable tannins. Comparison of dilution methods provided strong evidence of dependence of MIC values on the test method. Employing the microdilution broth method, the ellagitannin corilagin (MIC 0.8 nM) was found to be similarly potentially active as amphotericin B (MIC 0.5 nM) and sertaconazole (MIC 0.9 nM) against Candida glabrata strains. The order of effectiveness observed being 64- and 4-8-fold increased for corilagin and the reference compounds respectively, when compared with that of the agar dilution test.     

Cassia alata and the preclinical search for therapeutic agents for the treatment of opportunistic infections in AIDS patients.

In our search for therapeutic agents from natural sources with potential for the treatment of opportunistic infections in patients afflicted with acquired immunodeficiency syndrome (AIDS), we investigated antibacterial and antifungal activities of water extracts of Cassia alata (C. alata). The extracts are traditionally used in Ivory Coast, West Africa to treat bacterial infections caused by Escherichia coli (E. coli), and fungal infections caused by Candida albicans (C. albicans) and dermatophytes. Our working hypothesis was that the extract contains active ingredient(s) which can be isolated, identified and developed into useful antibacterial/antifungal agents for the treatment of opportunistic infections in patients with AIDS. We used the broth dilution and agar dilution methods. Specifically, we focused on E. coli and C. albicans and the effectiveness of the extracts was evaluated relative to those of standard antibacterial agent chloramphenicol and antifungal agent amphotericin B. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the water extract of C. alata against E. coli were 1.6 mg/ml and 60 mg/ml, respectively; corresponding data for chloramphenicol were 2 micrograms/ml and 10 micrograms/ml. Similarly, the MIC and minimum fungicidal concentration (MFC) for the extract against C. albicans were 0.39 mg/ml and 60 mg/ml in contrast to 0.58 micrograms/ml and 0.98 micrograms/ml for amphotericin B. From the dose-response curve plots, the extract had an IC50 of 31 mg/ml for E. coli and 28 mg/ml for C. albicans. The data suggest that C. alata extracts contain agent(s) which have therapeutic potential and might be useful if isolated and developed for the treatment of opportunistic infections of AIDS patients.     

Trichophyton species susceptibility to green and red propolis from Brazil

Aims:  The in vitro antifungal activity of Brazilian green and red propolis was tested against different species of Trichophyton .
Methods and Results:  The antifungal activity of the Brazilian aqueous and alcoholic extracts of the green propolis and the alcoholic extract of red propolis was observed against Trichophyton rubrum , Trichophyton tonsurans and Trichophyton mentagrohytes samples, using as controls itraconazole and terbinafine. The minimal inhibitory concentration was determined following the microdilution method indicated by the 'Clinical and Laboratory Standards Institute'. The minimal fungicide concentration was determined by the absence of growth in liquid sabouraud culture medium. The data obtained showed that the green propolis alcoholic extract's antifungal activity was from 64 to 1024 μg ml⁻¹, whereas the red propolis alcoholic extract was from 8 to 1024 μg ml⁻¹.
Conclusions:  The antifungal activity of the red propolis alcoholic extract was more efficient than the green propolis alcoholic extract for all three species studied. The T. rubrum samples were shown to be more sensitive to the antifungal activity of the alcoholic extracts of the propolis.
Significance and Impact of the Study:  The antifungal potential of the alcoholic extracts of green and red propolis demonstrated suggest an applicable potential as an alternative treatment for dermatophytosis caused by these species.     

Activity of anidulafungin against Candida biofilms

Currently, no standardized method to study the in vitro activity of antifungal agents on biofilms is available, thus, the comparison among different authors is difficult. The studies discussed in this review use the XTT reduction to measure the activity of antifungals on biofilms of 24 h of maturation. To date, biofilm anidulafungin MICs of 47 isolates of Candida spp. (25 Candida albicans, 16 Candida tropicalis, 5 Candida dubliniensis and 1 Candida parapsilosis) have been published. The geometric mean MIC of anidulafungin on biofilms of Candida spp. is of 1.18 microg/ml. Against isolates of species with great capacity of biofilm formation, the geometric mean MIC is 0.325 (C. albicans), 2 (C. parapsilosis) and 0.5 microg/ml (C. dubliniensis). No echinocandin has activity on C. tropicalis biofilms. In addition, anidulafungin can be used for lock therapy of catheters since it is the echinocandin with the least in vitro paradoxical effect.     

Antifungal Activity of Sodium Bicarbonate Against Fungal Agents Causing Superficial Infections

Although sodium bicarbonate—NaHCO₃ (SB) has many domestic and medical, traditional and empirical uses, only little scientific documentation of its activity is available. The aims of this study were to investigate the antifungal activity of SB on the three fungal groups (yeasts, dermatophytes and molds) responsible for human skin and nail infections. We first evaluated the in vitro antifungal activity of SB on 70 fungal strains isolated from skin and nail infections: 40 dermatophytes, 18 yeasts and 12 molds. A concentration of 10 g/L SB inhibited the growth of 80 % of all the fungal isolates tested on Sabouraud dextrose agar. The minimal inhibitory concentration 90 (MIC90) of SB measured on Sabouraud dextrose agar, Sabouraud dextrose broth and potato dextrose broth was 5 g/L for the yeasts, 20 g/L for the dermatophytes and 40 g/L for the molds. In a second step, we prospectively evaluated the ex vivo antifungal activity of SB on 24 infected (15 dermatophytes, 7 yeasts and 2 molds) clinical specimens (15 nails and 9 skin scrapings). The fungal growth was completely inhibited for 19 (79 %) specimens and reduced for 4 (17 %) specimens after 7 days of incubation on Sabouraud dextrose–chloramphenicol agar supplemented with 10 g/L of SB as compared to Sabouraud dextrose–chloramphenicol agar without SB. In conclusion, we documented the antifungal activity of SB on the most common agents of cutaneous fungal infection and onychomycosis, and we specified the effective concentrations for the different groups of pathogenic fungi. The mechanism of action of SB has yet to be explored.     

Trypanocidal and antimicrobial activities of Moquinia kingii.

A chloroform crude extract (aerial part) and two compounds, apigenin (1) and cynaropicrin (2), isolated from Moquinia kingii were evaluated against Trypanosoma cruzi trypomastigotes in vitro. Antimicrobial activity was also screened using twenty-two strains including gram-positive and gram-negative bacteria and the yeasts Candida albicans and C. tropicalis. The chloroform crude extract, fractions and isolated compounds from M. kingii were active for both activities. The IC50 values for trypanocidal activity obtained for cynaropicrin and apigenin were 93.5 microg/ml and 181 microg/ml, respectively, while the minimum inhibitory concentrations (MICs) varied from 100 microg/ml to 2500 microg/ml, against the strains of bacteria and yeasts evaluated.     

Simple 1,4-benzoquinones with antibacterial activity from stems and leaves of Gunnera perpensa

From the dichloromethane extract of the leaves and stems of Gunnera perpensa two new, simple 1,4-benzoquinones and a known benzopyran-6-ol were isolated. From the methanol extract phytol was obtained. The two benzoquinones, 2-methyl-6-(-3-methyl-2-butenyl)benzo-1,4-quinone (1) and 3-hydroxy-2-methyl-5-(3-methyl-2-butenyl)benzo-1,4-quinone (2) and the benzopyran, 6-hydroxy-8-methyl-2,2-dimethyl-2H-benzopyran (3) were examined for antimicrobial properties together with the crude stem, leaf and root extracts. Minimum inhibitory concentration (MIC) assays were used to quantify antimicrobial activity and the MIC values for the crude extracts of stems, roots and leaves ranged between 100 microg and >16 mg/ml against the eight microorganisms investigated. Compound 1 showed significant antimicrobial activity with the most sensitive organism being Staphylococcus epidermidis with an MIC of 9.8 microg/ml. For compound 2, no activity was noted. Compound 3 exhibited good activity against the yeasts Cryptococcus neoformans (75 microg/ml) and Candida albicans (37.5 microg/ml).     

Cassia alata and the preclinical search for therapeutic agents for the treatment of opportunistic infections in AIDS patients.

In our search for therapeutic agents from natural sources with potential for the treatment of opportunistic infections in patients afflicted with acquired immunodeficiency syndrome (AIDS), we investigated antibacterial and antifungal activities of water extracts of Cassia alata (C. alata). The extracts are traditionally used in Ivory Coast, West Africa to treat bacterial infections caused by Escherichia coli (E. coli), and fungal infections caused by Candida albicans (C. albicans) and dermatophytes. Our working hypothesis was that the extract contains active ingredient(s) which can be isolated, identified and developed into useful antimicrobial/antifungal agents for the treatment of opportunistic infections in patients with AIDS. We used the broth dilution and agar dilution methods. Specifically, we focused on E. coli and C. albicans and the effectiveness of the extracts was evaluated relative to those of standard antibacterial agent chloramphenicol and antifungal agent amphotericin B. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the water extract of C. alata against E. coli were 1.6 mg/ml and 60 mg/ml respectively; corresponding data for chloramphenicol were 2 ug/ml. Similarly, the MIC and minimum fungicidal concentration (MFC) for the extract against C. albicans were 0.39 mg/ml and 60 mg/ml in contrast to 0.58 ug/ml and 0.98 ug/ml for amphotericin B. From the dose-response curve plots, the extract had an IC50 of 31 mg/ml for E. coli and 28 mg/ml for C. albicans. The data suggest that C. alata extracts contain agent(s) which have therapeutic potential and might be useful if isolated and developed for the treatment of opportunistic infections of AIDS patients.