Sheikh Shreaz

Curcumin as a promising anticandidal of clinical interest

Curcumin, an important Asian spice, is part of many Indian food preparations. This work evaluates the antifungal activity of curcumin against 14 strains of Candida (10 clinical and 4 standard). Curcumin displayed antifungal properties against all tested Candida strains, with minimum inhibitory concentrations (MICs) varying from 250 to 2000 µg·mL⁻¹. The in vitro effect of curcumin on growth, sterol content, proteinase secretion, and H+ extrusion by plasma membrane ATPase was investigated for 2 standard strains Candida albicans ATCC 10261 and Candida glabrata ATCC 90030 and compared with the effect of fluconazole. At MIC, curcumin inhibited H+ extrusion in 2 species of Candida by 42% and 32% in the absence of glucose and by 28% and 18% in the presence of glucose. Respective inhibition of H+ extrusion caused by the MIC of fluconazole was 85% and 89% in the absence of glucose and 61% and 66% in its presence. Ergosterol content decreased by 70% and 53% for the 2 strains following exposure to curcumin at MIC; comparative values for fluconazole at MIC were 93% and 98%. Curcumin and fluconazole decreased proteinase secretion by 49% and 53%, respectively, in C. albicans and by 39% and 46%, respectively, in C. glabrata. In conclusion, curcumin is found to be active against all tested clinical and standard strains but is less effective than fluconazole. Antifungal activity of curcumin might be originating from alteration of membrane-associated properties of ATPase activity, ergosterol biosynthesis, and proteinase secretion.

Anticandidal activity of curcumin and methyl cinnamaldehyde

Cinnamaldehyde, its derivatives and curcumin are reported to have strong antifungal activity. In this work we report and compare anticandidal activity of curcumin (CUR) and α-methyl cinnamaldehyde (MCD) against 38 strains of Candida (3; standard, fluconazole sensitive, 24; clinical, fluconazole sensitive, 11; clinical, fluconazole resistant). The minimum inhibitory concentrations (MIC₉₀) of CUR ranged from 250 to 650 μg/ml for sensitive strains and from 250 to 500 μg/ml for resistant strains. MIC₉₀ of MCD varied between 100 and 250 μg/ml and 100-200 μg/ml for sensitive and resistant strains, respectively. Higher activity of MCD as compared to CUR was further reinforced by spot assays and growth curve studies. At their respective MIC₉₀ values, in the presence of glucose, average inhibition of H+-efflux caused by CUR and MCD against standard, clinical and resistant isolates was 24%, 31%, 32% and 54%, 52%, 54%, respectively. Inhibition of H+-extrusion leads to intracellular acidification and cell death, average pHi for control, CUR and MCD exposed cells was 6.68, 6.39 and 6.20, respectively. Scanning electron micrographs of treated cells show more extensive damage in case of MCD. Haemolytic activity of CUR and MCD at their highest MIC was 11.45% and 13.00%, respectively as against 20% shown by fluconazole at typical MIC of 30 μg/ml. In conclusion, this study shows significant anticandidal activity of CUR and MCD against both azole-resistant and sensitive clinical isolates, MCD is found to be more effective.

Anticandidal activity of Cassia fistula and its effect on ergosterol biosynthesis

Context: Cassia fistula Linn. (Caesalpiniaceae) has been used in folk medicine. Anthraquinone derivative rhein having antimicrobial properties is actively present in C. fistula fruit. Although, as yet there has been no study of its anticandidal potential. Objective: The present study was conducted to determine the phytochemical composition of fruit pulp and seed extract and their effect on Candida albicans ATCC 10261, Candida glabrata ATCC 90030 and Candida tropicalis ATCC 750, respectively. Materials and methods: The fruit pulp and seed extracts were tested for phytochemicals by various standard methods and rhein was identified by thin-layer chromatography. The anticandidal activity was determined by minimum inhibitory concentration (MIC), growth curve studies, cytotoxicity and ergosterol estimation assay. Results: The fruit pulp and seed extracts showed high content of phenolic compounds. Rhein was identified in both extracts, Rf 0.38. MICs of seed extract obtained with C. albicans, C. tropicalis and C. glabrata is 350, 300 and 300 μg/ml. However, for fruit pulp extract, these values significantly reduced to 150, 250 and 100 μg/ml, respectively. Comparative MIC values for fluconazole were 16, 16 and 04 µg/ml. At MICs, pulp reduced ergosterol content in cell membrane of C. albicans, C. tropicalis and C. glabrata by 54.42, 48.78 and 68.0%, seed extract by 38.11, 47.0 and 45.0%, whereas, fluconazole showed 93.56, 89.21 and 98.0%, respectively. Discussion and conclusion: C. fistula fruit pulp and seed extract possessed anticandidal activity. The result was significantly correlated between the MICs, cytotoxicity and ergosterol inhibition. It was concluded that the crude extract is a promising source for anticandidal compounds.

Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates

Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC(90) of cinnamaldehyde against different Candida isolates ranged 100-500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H(+) (-)ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.

Cinnamic aldehydes affect hydrolytic enzyme secretion and morphogenesis in oral Candida isolates

Effect of cinnamaldehyde (CD), 4-hydroxy-3-methoxy cinnamaldehyde (HMCD) and 3,5-dimethoxy-4-hydroxy cinnamaldehyde (HDMCD) on growth and virulence factors of standard (Candida albicans 90028) and 26 oral isolates of C. albicans has been investigated. Growth was significantly inhibited by all three compounds in both solid and liquid medium, no systematic difference was observed between various isolates. MIC₉₀ ranged from 125 to 450 μg/ml for CD, 100-250 μg/ml for HMCD and 62.5-125 μg/ml for HDMCD. All oral isolates were found to be proteinase and phospholipase secretors, both proteinase and phospholipase secretion was significantly inhibited by all the three tested molecules. No systematic difference in secretion or its inhibition was observed between standard and oral isolates as also between various isolates. Average drop in proteinase and phospholipase secretion caused by ½ MIC of CD was 33% and 28%, HMCD; 46% and 44%, HDMCD; 59% and 54%. The standard strain and all the 26 oral isolates displayed morphogenesis under triggering experimental conditions; no difference was seen between standard and various isolates. In the absence of test compounds hyphae development at 300 min was 83% for standard strain whereas average hyphae development for oral isolates was 85%. Average hyphal transition was suppressed by all tested compounds. At ½ MIC concentration at 300 min average hyphal transition of standard and oral isolates was CD; 49% and 57%, HMCD; 45% and 38%, HDMCD; 5% and 5%. Average haemolytic activity of the three tested compounds varied from 10 to 15% at their highest MIC compared to 20% shown by fluconazole at typical MIC of 30 μg/ml.

Proton pumping ATPase mediated fungicidal activity of two essential oil components

This work evaluates the antifungal activity of two essential oil components against 28 clinical isolates (17 sensitive, 11 resistant) and 3 standard laboratory strains of Candida. Growth of the organisms was significantly effected in both solid and liquid media at different test compound concentrations. The minimum inhibitory concentrations (MICs) of Isoeugenol (compound 1) against 31 strains of Candida ranged 100–250 μg/ml and those of o ‐methoxy cinnamaldehyde (compound 2) ranged 200–500 μg/ml, respectively. Insight studies to mechanism suggested that these compounds exert antifungal activity by targeting H+‐ATPase located in the membranes of pathogenic Candida species. At their respective MIC90 average inhibition of H+‐efflux for standard, clinical and resistant isolates caused by compound 1 and compound 2 was 70%, 74%, 82% and 42%, 42% and 43%. Respective inhibition of H+‐efflux by fluconazole (5 μg/ml) was 94%, 92% and 10%. Inhibition of H+‐ATPase leads to intracellular acidification and cell death. SEM analysis of Candida cells showed cell membrane breakage and alterations in morphology. Haemolytic activity on human erythrocytes was studied to exclude the possibility of further associated cytotoxicity. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Interesting anticandidal effects of anisic aldehydes on growth and proton-pumping-ATPase-targeted activity.

Attention has been drawn to evaluate the antifungal activity of p-anisaldehyde (1), o-anisaldehyde (2) and m-anisaldehyde (3). To put forward this approach, antifungal activity has been assessed in thirty six fluconazole-sensitive and eleven fluconazole-resistant Candida isolates. Growth and sensitivity of the organisms were significantly effected by test compounds at different concentrations. The rapid irreversible action of compound-1, compound-2 and compound-3 on fungal cells suggested a membrane-located target for their action. We investigated their effect on H(+) ATPase mediated H(+)-pumping by various Candida species. All the compounds inhibit H(+)- ATPase activity at their respective MIC(90) values. Inhibition of H(+) ATPase leads to intracellular acidification and cell death. Scanning electron microscopy analysis revealed deep wrinkles, deformity and flowed content. Furthermore, it was also observed that position of methoxy group attached to the benzene ring decides antifungal activity of the compound. The present study indicates that compound-1, compound-2 and compound-3 have significant antifungal activity against Candida, including azole-resistant strains, advocating further investigation for clinical applications in the treatment of fungal infections.

Effect of Bimetallic Soybean Oil Based Polymer on Growth and Plasma Membrane H+-ATPase Activity Among Fungi

In view of bio-inorganic importance, iron and zinc incorporated soybean oil based polymer was prepared by condensation polymerization of oil based fatty amide polyole, sebacic acid, zinc acetate and ferric chloride in a process initiated by sodium ethoxide. Microwave assisted synthesis was used throughout the reaction as it is ecofriendly and requires minimal usage of solvents. Physical techniques such as FT-IR and 1HNMR have been used to establish the structure of the polymers. Standard laboratory methods like acid value, saponification value, iodine value, specific gravity and viscosity were used to study the chemical diversity of each product. Thermo gravimetry/differential thermal analyzer was used to analyse the thermal behavior of polymer. The synthesized compounds were subjected to biological study. The observed fungicidal characteristics of synthesized compounds indicate that these compounds might be promising antifungal agents defining a new class of antimycotics. The polymers were used in preparation of films which can be used as protective packaging material of edible items.

Synthesis of Sunflower Oil Based Bimetallic Polymer and Its Antifungal Studies

Bimetallic oil based polymer was prepared by condensation polymerization reaction. FTIR and 1H NMR have been used to support structure of the polymers. Thermal behavior of the polymer was established by thermogravimetry/differential thermal analysis (TG/DTA). The polymers were examined for their antifungal properties by performing minimum inhibitory concentration assessment, growth curve studies, and H+ extrusion studies using Candida species as model organisms. Growth and sensitivity of the organisms were significantly effected by test polymers at different concentrations. Insight studies to mechanism suggested that the synthesized polymers exerts their antifungal activity by targeting H+-ATPase mediated H+-pumping, inhibition of H+-ATPase leads to intracellular acidification and cell death.