Treatment of systemic fungal infections in older patients: achieving optimal outcomes

Total synthesis of (±)-(1β,4β,4aβ,8aα)-4,8a-dimethyl-octahydro-naphthalene-1,4a(2H)-diol

The first total synthesis of (±)-(1β,4β,4aβ,8aα)-4,8a-dimethylocta-hydronaphthalene-1,4a(2H)-diol (1), a degraded sesquiterpene isolated from a fermentation broth of Streptomyces albolongus, has been achieved via three different synthetic approaches (13–15 steps) starting from racemic Wieland–Miescher ketone (2).

Pharmacological significance of triazole scaffold

The triazole nucleus is one of the most important and well known heterocycles which is a common and integral feature of a variety of natural products and medicinal agents. Triazole nucleus is present as a core structural component in an array of drug categories such as antimicrobial, anti-inflammatory, analgesic, antiepileptic, antiviral, antineoplastic, antihypertensive, antimalarial, local anaesthetic, antianxiety, antidepressant, antihistaminic, antioxidant, antitubercular, anti-Parkinson's, antidiabetic, antiobesity and immunomodulatory agents, etc. The broad and potent activity of triazole and their derivatives has established them as pharmacologically significant scaffolds. The basic heterocyclic rings present in the various medicinal agents are 1,2,3-triazole and 1,2,4-triazole. A large volume of research has been carried out on triazole and their derivatives, which has proved the pharmacological importance of this heterocyclic nucleus. The present paper is an attempt to review the pharmacological activities reported for triazole derivatives in the current literature with an update of recent research findings on this nuclei.

Synthesis and antifungal activities of novel 2-aminotetralin derivatives

Novel 2-aminotetralin derivatives were synthesized as antifungal agents. The 2-aminotetralin scaffold was chemically designed to mimic the tetrahydroisoquinoline ring of the lead molecule described before. Their antifungal activities were evaluated in vitro by measuring the minimal inhibitory concentrations (MICs). Compounds 10a, 12a, 12c, 13b, and 13d are more potent than fluconazole against seven testing human fungal pathogens. Compound 10b exhibits much higher antifungal activities against all of the four fluconazole-resistant clinic Candida albicans strains than the control drugs including amphotericin B, terbinafine, ketoconazole, and itraconazole. The mode of action of some compounds to the potential receptor lanosterol 14alpha-demethylase (CYP51) was investigated by molecular docking. The studies presented here provide a new structural type for the development of novel antifungal compounds. Furthermore, 10b was evaluated in vivo by a rat vaginal candidiasis model, and it was found that 10b significantly decreases the number of fungal colony counts.

Design, synthesis, and antifungal activities in vitro of novel tetrahydroisoquinoline compounds based on the structure of lanosterol 14alpha-demethylase (CYP51) of fungi

Novel tetrahydroisoquinoline compounds were designed by coupling structure-based de novo design based on the structure of lanosterol 14alpha-demethylase (CYP51). The chemical synthesis and the antifungal activities in vitro of them were reported. The results exhibited that all of the lead compounds showed potent antifungal activities, in which compounds 6 and 7 had equal or stronger antifungal activities against five test fungi than that of fluconazole. The studies presented here provided the antifungal lead compounds. The affinity of the lead molecules for CYP51 was mainly attributed to their non-bonding interaction with the apoprotein, which was different from the azole antifungal agents.

Use of amphotericin B lipid complex in elderly patients

OBJECTIVES

The safety and effectiveness of amphotericin B lipid complex (ABLC) treatment in elderly patients was investigated using a large multicenter database.

METHODS

Data analysis was conducted on retrospectively collected patient data from 572 patients >65 years of age and 2930 patients < or =65 years of age treated for fungal infections at 160 North American hospitals.

RESULTS

Patients were typically treated with ABLC for Candidiasis, multiple fungal pathogen infections and Aspergillosis, or were treated empirically. The median cumulative dose of ABLC in patients >65 years of age and those 65 years of age was similar (3000 and 3258 mg, respectively, P=0.127). Despite higher median pretreatment serum creatinine (S-Cr) among patients >65 years of age (1.7 mg/dl vs. 1.4 mg/dl, respectively), both groups showed only a 0.1mg/dl median S-Cr change from baseline by the end of therapy (P=0.525). Clinical response was 56 and 51%, respectively, in patients >65 years of age and patients 65 years of age or younger (P=0.049).

CONCLUSIONS

This study suggests that ABLC can be safely and effectively used in the treatment of invasive fungal disease in elderly patients.

Antifungal drugs used for systemic mycoses

Table 1 summarizes the antifungal agents commonly used for the treatment of systemic mycoses. The treatment of these conditions remains a challenge. This is particularly the case with infections in neutropenic patients where mortality rates remain high despite the development of new drugs and the evaluation of drug combinations. Much attention has been focused on the development of new antifungal drugs that can provide a solution to this problem without concurrent toxicity and without the risk of drug resistance.

Structure-based de novo design, synthesis, and biological evaluation of non-azole inhibitors specific for lanosterol 14alpha-demethylase of fungi

The active site of lanosterol 14alpha-demethylase (CYP51) was investigated via MCSS functional group mapping and LUDI calculations. Several non-azole lead molecules were obtained by coupling structure-based de novo design with chemical synthesis and biological evaluation. All of the lead molecules exhibited a strong inhibitory effect on CYP51 of Candida albicans. They occupy the substrate-binding site and interfere with the binding of azole antifungal agents in a competitive manner. The mode of action of the lead molecules was validated by spectrophotomeric analysis and SAR studies. This is the first successful example reported for the inhibitor design of the cytochrome P450 superfamily using the de novo design strategy. Because the affinity of the lead molecules for CYP51 was mainly attributed to their nonbonding interaction with the apoprotein, the studies presented here afford the opportunity to develop novel antifungal agents that specifically interact with the residues in the active site and avoid the serious toxicity arising from coordination binding with the heme of mammalian P450s.