Berberine Synergy with Amphotericin B against Disseminated Candidiasis in Mice

Pharmacological and therapeutic effects of Berberis vulgaris and its active constituent, berberine

Barberry (Berberis vulgaris L. family Berberidaceae) is well known in Iran and various parts of this plant including its root, bark, leaf and fruit have been used as folk medicine. The two decades of research has demonstrated different pharmacological and therapeutic effects of B. vulgaris and its isoquinoline alkaloids (particularly berberine). Studies carried out on the chemical composition of the plant show that the most important constituents of this plant are isoquinoline alkaloids such as berberine, berbamine and palmatine. Berberine represents one of the most studied among the naturally occurring protoberberine alkaloids. In addition to B. vulgaris (barberry), berberine is present in many other plants and is used for the treatment of different diseases. This article reviews the traditional uses and pharmacological effects of total extract and the most active ingredient of B. vulgaris (berberine).

Synergic effect of grape seed extract with amphotericin B against disseminated candidiasis due to Candida albicans

Amphotericin B (Amp B) is considered as a drug of choice for treatment of fungal infections, but it causes severe side effects such as renal damage. To lessen the severity, it is often combined with the azole, but data reporting resistance of Candida albicans to the azole have been recently increasing. Thus, finding a new product that can reduce Amp B dose by combination seems to be important. In the present study, we investigated a synergic effect of grape seed extract (GSE) combined with Amp B against the fungus. Our results showed that the GSE alone inhibited growth of C. albicans yeast cells, and that in a murine model of disseminated candidiasis mice groups given GSE before intravenous inoculation with the yeast cells survived longer than diluent-received (control) mice groups (P<0.05). This GSE antifungal effect was dose-dependent. Upon combination of GSE plus Amp B, the combination therapy strikingly retarded the yeast growth as determined by the broth susceptibility method. Against the disseminated disease, mice given diluent (negative control), Amp B (0.5mg/kg of body weight), or GSE (2mg/kg of body weight) had mean survival times (MSTs) of approximately 11.4, 14.4, and 17.6 days, respectively. However, mice treated with the combination of the doses of Amp B and GSE had a MST value of 38.4 days, surviving an average of 24 days longer than Amp B alone-treated mice groups. This MST value from the combination-received mice group was greater than the MST value from the mice group given four times the Amp B dose (2mg/kg of body weight). All these data indicate that the combination therapy can reduce more than 75% of Amp B dose, implying that GSE has a synergic effect with Amp B.

Synergic anticandidal effect of epigallocatechin-O-gallate combined with amphotericin B in a murine model of disseminated candidiasis and its anticandidal mechanism

In the present study, we investigated synergic anticandidal effect of epigallocatechin-O-gallate (EGCG) in a murine model of disseminated candidiasis caused by Candida albicans. In addition, its mechanism was examined. In the animal system, EGCG-given BALB/c mice group intraperitoneally (i.p.) before intravenous (i.v.) inoculation with viable C. albicans yeast cells survived longer than diluent-received (control) mice group (p<0.05). EGCG treatment inhibited the hyphal formation from the yeast form of C. albicans, causing growth-inhibition of the candidal cells. In experiments determining synergic effect, mice given diluent (control), Amp B (amphotericin B; 0.5 mg/kg of body weight), or EGCG (2 mg/kg) had mean survival times (MST) of approximately 10.9, 11.7, and 13.9 d, respectively. However, mice administered combination of Amp B (0.5 mg/kg) plus EGCG (2 mg/kg) had a MST value of 42.1 d, surviving an average of app. 30 d longer than the Amp B alone-received mice groups. The MST value from the combination-treated mice groups was much greater than MST value from mice groups that received four times the Amp B dose. These results indicate that EGCG, which has anticandidal activity causing blockage of the hyphal formation, has the synergism combined with Amp B against disseminated candidiasis.

Immunoregulatory activity by daucosterol, a β-sitosterol glycoside, induces protective Th1 immune response against disseminated Candidiasis in mice

In the present study, we investigated immunomodulatory effect of daucosterol, a beta-sitosterol glycoside, against disseminated candidiasis caused by Candida albicans. Results showed that direct interaction of daucosterol with C. albicans yeast cells resulted in no growth-inhibition by in vitro susceptibility analysis. In contrast, mice given daucosterol (DS) intraperitoneally before intravenous challenge with live C. albicans yeast cells survived longer than DS-untreated control mice against disseminated candidiasis (P<0.05). By assessment of the fungal CFU in kidneys, DS-treated mice before the challenge developed about 81% fewer kidney CFU than untreated controls. This protection was removable by pretreatment of mice with anti-CD4+ antibody before the DS-treatment and challenge with the yeast. However, the protection was transferable by the CD4+ T cells from DS-treated mice not infected with the yeast. ELISA analysis revealed there were predominant production of IFNgamma and IL-2 cytokines as compared to IL-4, and IL-10 productions in DS-treated mice. By treatment of DS-given mice with anti-mouse IFNgamma, the protection was also abolished. Our studies show that DS protects mice against disseminated candidiasis by the CD4+ Th1 immune response.

Candida albicans can utilize siderophore during candidastasis caused by apotransferrin

Ability of iron acquisition of pathogenic microorganisms functions as a virulence factor. Candida albicans, a fungal pathogen that requires iron for growth, is susceptible to growth retardation by high-affinity iron binding proteins such as transferrin. Recently, we reported that C. albicans could utilize the heme as a part of heme-containing proteins dissociated by heme oxygenase, CaHMX1. In search of another pathway that C. albicans can use to bypass the growth regulation produced by iron limitation, this present study examined utilization of non-candidal siderophores such as Desferal and rhodotorulic acid (RA) for acquisition of inorganic iron by the fungus. C. albicans secreting no siderophores was cultured in iron-free (pretreated with apotransferrin for 24 h) (culture medium). Once growth of the yeast reached stasis from iron starvation, a siderophore was added to the culture media. Results showed that cultures containing apotransferrin within a dialysis membrane recovered growth to the level of untreated controls, whereas C. albicans yeast cells in direct contact with soluble iron-free (apo) transferrin recovered growth only partially. When static growth from iron limitation was reached, the addition of siderophore-apotransferrin complex to culture medium also permitted the yeast to recover growth from apotransferrin growth regulation. All the data show that C. albicans can utilize the non-candidal siderophores for iron acquisition under transferrin regulation as can pathogenic bacteria.

Ginsenoside Rg1 helps mice resist to disseminated candidiasis by Th1 type differentiation of CD4+ T cell

Ginsenosides, the most important component isolated from Panax ginseng, exhibits a variety of biological activities. Particularly, ginsenoside Rg1 is known to have various immune-modulating activities such as increase of immune activity of T helper (Th) cells. In this present work, we investigated the effect of the Rg1 on Candida albicans growth. Results showed that direct interaction of the Rg1 to C. albicans yeast cells resulted in no growth inhibition as tested by agar diffusion susceptibility method. Reversely, mice given the Rg1 intraperitoneally (i.p.) before intravenous (i.v.) challenge with live C. albicans yeast cells protected the mice to experimental disseminated candidiasis. By kidney candidal CFU (colony forming unit) determination, the disease severity of the Rg1-treated mice was confirmed far less than Rg1-untreated control mice. The protection was transferable by CD4+ T cells (RGCD4T) isolated from Rg1-treated mice. ELISA analysis revealed that there were cytokine inductions of IFNgamma, IL-2, IL-4 and IL-10 from the RGCD4T, demonstrating the Th1-lineage development of predominant IFNgamma and IL-2 production. Anti-mouse IFNgamma antibody treatment of Rg1-treated mice abolished the protection to disseminated disease. Our studies show that ginsenoside Rg1 helps the host resists disseminated candidiasis by the CD4(+) T cell-mediated immune response led from a Th1-dominant cytokine response.

Potent in vitro synergism of fluconazole and berberine chloride against clinical isolates of Candida albicans resistant to fluconazole

In vitro interaction of fluconazole and berberine chloride was investigated against 40 fluconazole-resistant clinical isolates of Candida albicans. Synergism in fungistatic activity was found with the checkerboard microdilution assay. The findings of agar diffusion tests and time-kill curves confirmed the synergistic interaction, but no antagonistic action was observed.

Utilization of ferroproteins byCandida albicans during candidastasis by apotransferrin

Many reports have stated that some of the pathogenic bacteria can obtain iron from ferroproteins, such as cytochrome C, ferritin, hemin, hemoglobin, and myoglobin. These reports prompted us to determine if an opportunistic pathogenic fungus, Candida albicans, can utilize ferroproteins to circumvent the iron-regulatory effect of transferrin. The following assays were carried out to measure in vitro growth stimulation by the ferroproteins: as an initial step, C. albicans was cultured in iron-free (pretreated with apotransferrin for 24 h) culture medium. Once Candida albicans yeast cell growth reached stasis from iron starvation, individual ferroproteins were added to the culture media. Results showed that hemin, hemoglobin, and myoglobin supported a partial growth recovery. Additional studies with haptoglobin, a serum protein that interacts with the globin moiety of certain ferroproteins, established that C. albicans could obtain iron from the haptoglobin-ferroprotein complexes. These data indicate that the heme part of the ferroproteins is the source of iron. This implies that heme oxygenase, CaHMX1 might be involved in bringing about dissociation of heme-containing protein for iron-acquisition. In addition, anticandidal activity of transferrin takes place not only by the process of iron regulation, but also by direct interaction with the yeast cells.