Introduction to dermatological treatment
Richard Ashton, Barbara Leppard in Differential Diagnosis in Dermatology, 2021
Those active against yeasts such as Candida and Pityrosporum species: Polyenes. Nystatin (named after the New York State Department of Health) is only effective against Candida. It is cheaper than the imidazoles but has the disadvantage that it stains everything it comes into contact with yellow. Amphotericin B is a broad spectrum polyene antifungal agent used as lozenges for treating Candida infections in the mouth.Imidazoles are broad spectrum antifungal agents and work for yeasts as well as dermatophytes (see left).Clioquinol is effective against Candida and various bacteria but not against dermatophytes. It is usually combined with a topical steroid (e.g. Betnovate CUK). It stains the skin and clothing yellow.
Antifungals
Rajendra Prasad, Mahmoud A. Ghannoum in Lipids of Pathogenic Fungi, 2017
Polyenes constitute a major class of anti-Candida drugs and are known to bind with the plasma membrane leading to altered permeability and subsequent death of the organism.11-15 There appears to be a direct association between the sensitivity of an organism to a polyene and the presence of sterols in the plasma membrane of the cells. All organisms susceptible to polyenes, e.g., yeasts, algae, protozoa and mammalian cells, contain sterols in their outer membrane, while all the resistant organisms do not contain sterols.16 Studies with Acholeplasma laidlawaii, which is also unable to synthesize sterols, provide further proof of the association between the sensitivity of an organism to polyene and to the presence of sterols.17,18 When A. laidlawaii was grown in a sterol-deficient medium, the cells were resistant to polyenes; when grown in sterol-containing media, sterols were incorporated into the plasma membrane and the organism became sensitive to polyenes.18
Small-Molecule Targeted Therapies
David E. Thurston, Ilona Pysz in Chemistry and Pharmacology of Anticancer Drugs, 2021
Retinoid molecules are hydrophobic and consist of a polyene chain with polar and cyclic entities at either end (Figure 6.106). The conjugated polyene chain system is formed of alternating C=C double bonds, and is responsible for the typical yellow, orange, or red color of the retinoids. There are three generations of retinoid-based therapeutic agents, the first including retinol itself, tretinoin (retinoic acid), isotretinoin, alitretinoin, and retinal. Second-generation analogues include etretinate and its metabolite acitretin, and adapalene, bexarotene and tazarotene represent third-generation agents. The first- and second-generation retinoids interact with several types of retinoid receptors due to the flexibility imparted by their alternating single and double bonds. However, third-generation retinoids are less flexible and so are more specific, interacting with fewer types of retinoid receptors. Some of these analogues are used orally for acute promyelocytic leukemia, some topically for skin disorders including acne, and some for both therapeutic purposes. Structures of all-trans-retinol, tretinoin (VesanoidTM), bexarotene (TargtretinTM), and alitretinoin (PanretinTM).
Functional Foods and Nutraceuticals as Dietary Intervention in Chronic Diseases; Novel Perspectives for Health Promotion and Disease Prevention
Published in Journal of Dietary Supplements, 2018
Carotenoids are a widespread group of naturally occurring fat-soluble pigments found in plants and animals (Mortensen, 2006). They belong to the class of bioactive compounds known as isoprenoid polyenes and are classified by the following characteristics: (a) vitamin A precursors that do not pigment such as β-carotene; (b) pigments with partial vitamin A activity such as cryptoxanthin, β-apo-8′-carotenoic acid ethyl ester; (c) non–vitamin A precursors that do not pigment or pigment poorly such as violaxanthin and neoxanthin; and (d) non–vitamin A precursors that pigment such as lutein and zeaxanthin (Omayma and Singab, 2013). Carotenoid is one of the most complex bioactive compounds due to its structure, which bears multiple conjugated double bonds and cyclic end groups, which makes them capable of forming various stereoisomers with different chemical and physical properties (Omayma and Singab, 2013). Reports have revealed that over 700 carotenoids have been identified; however, only 50 can be found in the human diet and are absorbed and metabolized effectively (Grune et al., 2010; Eroglu and Harrison et al., 2013). Examples of these metabolizable carotenoids often made available to the blood include lycopene, xanthin, beta-carotene, alpha-carotene, lutein, zeaxanthin, beta-cryptoxanthin. These carotenoids can also be found in plant foods such as vegetables, tomatoes, and watermelon (Yeum and Russell, 2002; Roodenburg et al., 2000). Epidemiological studies indicate that a high intake of carotenoids is beneficial to human health and is due to their antioxidant activities (Miller et al., 1996)
An evaluation of ibrexafungerp for the treatment of invasive candidiasis: the evidence to date
Published in Expert Opinion on Pharmacotherapy, 2021
Rhonda E Colombo, Jose A Vazquez
Invasive candidiasis is a significant cause of infection-related morbidity and mortality. The increasing rate of nosocomial candidemia represents a major threat, particularly due to the emergence of multidrug-resistant Candida species, such as C. glabrata and C. auris. There are currently a limited number of antifungal options for the treatment of invasive candidiasis, and each agent has certain limitations. Unfortunately, echinocandins, the preferred initial therapy for candidemia and invasive candidiasis, are only available in intravenous formulations. Azoles, a mainstay of candidal treatment, are plagued by increasing resistance concerns and potential drug–drug interactions. Polyenes are hampered by drug-associated toxicities, as well as the need for intravenous administration. Thus, there remains a need for an additional potent antifungal agent with activity against resistant fungal pathogens, has a good bioavailability profile, is safe and easy to use, and finally, is effective in the treatment of candidemia and invasive candidiasis.
Prophylaxis for aspergillosis in patients with haematological malignancies: pros and cons
Published in Expert Review of Anti-infective Therapy, 2018
Alessandro Busca, Livio Pagano
Pros-Cons. Polyenes include AmB deoxycholate (d-AmB) and LF-AmB, namely L-AmB and AmB lipid complex (ABLC). Polyenes are fungicidal for yeasts and molds. The use of d-AmB in hematologic patients has been fairly uniformly abandoned due to the occurrence of severe side effects, and most of the international guidelines recommend against the use of d-AmB for treatment of IFI. None of the two LF-AmB is licensed for prophylaxis of IFI in hematologic patients.
Related Knowledge Centers
- Amphotericin B
- Antifungal
- Nystatin
- Organic Chemistry
- Organic Compound
- Saturated & Unsaturated Compounds
- Carbon–Carbon Bond
- Diene
- Candicidin
- Natamycin