Development of a Topical Amphotericin B and Bursera graveolens Essential Oil-Loaded Gel for the Treatment of Dermal Candidiasis

First report of amphotericin B resistant Candida haemulonii isolated from the ICU of a referral hospital in Indonesia

Background and Objectives

Amphotericin B is a broad-spectrum antifungal agent commonly used to treat Candida haemulonii infection. C. haemulonii was isolated from patients reported to be intrinsically resistant to amphotericin B, encoded by the ERG2 and ERG11 genes. However, there have been limited studies concerning amphotericin B-resistant C. haemulonii in Indonesia. The objective of this study is to explore the phenotypic and genotypic characteristics (ERG2 and ERG11) of C. haemulonii isolated from the ICU of a referral hospital in Indonesia.

Materials and Methods

Identification and susceptibility tests were conducted using VITEK2. Thereafter, DNA was extracted and amplified using conventional PCR followed by DNA sequencing (Sanger method).

Results

The results of the phenotypic susceptibility test showed that all C. haemulonii were resistant to amphotericin B. ERG2 and ERG11 sequences showed the same amino acid sequence and corresponded to references that are resistant to amphotericin B.

Conclusion

The resistant properties of C. haemulonii against amphotericin B found in this study require further exploration, including comparing resistant and sensitive C. haemulonii to amphotericin B. In addition, it is necessary to analyze other genes besides ERG2 and ERG11.

Therapeutic Applications of Essential Oils from Native and Cultivated Ecuadorian Plants: Cutaneous Candidiasis and Dermal Anti-Inflammatory Activity

Essential oils are a complex mixture of aromatic substances whose pharmacological actions, including antimicrobial, antioxidant, anticancer, and anti-inflammatory activities, have been widely reported. This study aimed to evaluate the anti-Candida and dermal anti-inflammatory activity of essential oils from native and cultivated Ecuadorian plants. Essential oils from Bursera graveolens, Dacryodes peruviana, Mespilodaphne quixos, and Melaleuca armillaris were isolated by hydrodistillation and were characterized physically and chemically. Its tolerance was analyzed by in vitro and in vivo studies. The antifungal activity was studied against Candida albicans, Candida glabrata, and Candida parapsilosis, whereas the anti-inflammatory effect was evaluated by a mouse ear edema model. The main compounds were limonene, α-phellandrene, (E)-methyl cinnamate, and 1,8-cineole, respectively. All essential oils showed high tolerability for skin application, antifungal activity against the three Candida strains, and anti-inflammatory efficacy by decreasing edema and overexpression of pro-inflammatory cytokines. Dacryodes peruviana essential oil showed the highest antifungal activity. On the other hand, Dacryodes peruviana and Melaleuca armillaris showed the greatest anti-inflammatory potential, decreasing edema by 53.3% and 65.25%, respectively, and inhibiting the overexpression of TNF-α, IL-8, IL-17A, and IL-23. The results suggest that these essential oils could be used as alternative therapies in the treatment of both cutaneous candidiasis and dermal inflammation.

Exploring the Potential of Extracts from Sloanea medusula and S. calva: Formulating Two Skincare Gels with Antioxidant, Sun Protective Factor, and Anti-Candida albicans Activities

Sloanea is a plant genus, native to tropical regions, used in medicinal practices for its anti-inflammatory properties. This study aimed to determine the antioxidant activity, sun protective factor (SPF), and antifungal of extracts obtained from two species of Sloanea and to develop extract-based gels with antioxidants, photoprotective, and anti-Candida albicans effects. Ethanolic extracts from S. medusula and S. calva collected in Chocó, Colombia, were used for antioxidant activity and SPF determination using the DPPH assay and the Mansur equation, respectively. Extracts were characterized using HPLC-MS and used to prepare the gels. The viscosity of the extract-based gels was evaluated using an MCR92 rheometer. In addition, the anti-Candida activity of extracts against five yeasts and anti-C. albicans of gels were evaluated following the Clinical and Laboratory Standards Institute M27, 4th Edition. High DPPH radical scavenging activity (42.4% and 44.7%) and a high SPF value (32.5 and 35.4) were obtained for the extracts of S. medusula and S. calva, respectively. Similarly, extract-based gels showed significant DPPH radical scavenging activity of 54.5% and 53.0% and maximum SPF values of 60 and 57. Extract from S. medusula showed an important antifungal activity against C. albicans (minimal inhibitory concentration (MIC) of 2 µg/mL). In contrast, S. calva extract was active against C. krusei, C. albicans (MIC of 2 µg/mL) and C. tropicalis (MIC of 4 µg/mL). Sloanea medusula gel (0.15%) exhibited an important C. albicans growth inhibition (98%), while with S. calva gel (0.3%) growth inhibition was slightly lower (76%). Polyphenolic and triterpenoid compounds were tentatively identified for S. medusula and S. calva, respectively. Both extracts can be considered promising sources for developing photoprotective gels to treat skin infections caused by C. albicans.

Biological Activity of Bursera schlechtendalii Essential oil and the Roles of Its Chemical Components in the Wound Healing Process

Essential oils are composed of terpenes, some of which have properties related to healing. Bursera schlechtendalii essential oil (BSEO) is used to heal superficial wounds. However, there have been no studies verifying this property. The objectives of this study were to evaluate the healing activity of BSEO in a murine model and to propose the roles of its chemical components in this process. Healing activity was evaluated by an incision model, histological analysis was performed, and tensile strength and antibacterial activity were measured. The chemical composition of BSEO was determined by gas chromatography coupled with mass spectrometry (GC-MS), and the mechanisms of action of each chemical component during the phases of the healing process were proposed. In addition, acute dermal toxicity was evaluated. BSEO showed better wound closure at the macroscopic, histological, and tensile strength levels compared to controls and had an antibacterial effect. The major compound in BSEO was α-phellandrene. However, most of the monoterpenes identified in BSEO were in agreement with information found in the literature, so the possibility of synergy between the chemical components and their different targets in the healing process was schematically proposed. BSEO was shown to be safe in the dermal toxicity evaluation.

Semi-Solid Dosage Forms Containing Pranoprofen-Loaded NLC as Topical Therapy for Local Inflammation: In Vitro, Ex Vivo and In Vivo Evaluation

Pranoprofen (PRA)-loaded nanostructured lipid carriers (NLC) have been dispersed into blank gels composed of 1% of Carbomer 940 (PRA-NLC-Car) and 3% of Sepigel^® 305 (PRA-NLC-Sep) as a novel strategy to refine the biopharmaceutical profile of PRA, for dermal administration in the treatment of skin inflammation that may be caused by possible skin abrasion. This stratagem intends to improve the joining of PRA with the skin, improving its retention and anti-inflammatory effect. Gels were evaluated for various parameters such as pH, morphology, rheology, and swelling. In vitro drug release research and ex vivo permeation through the skin were carried out on Franz diffusion cells. Additionally, in vivo assays were carried out to evaluate the anti-inflammatory effect, and tolerance studies were performed in humans by evaluating the biomechanical properties. Results showed a rheological profile common of semi-solid pharmaceutical forms for dermal application, with sustained release up to 24 h. In vivo studies using PRA-NLC-Car and PRA-NLC-Sep in Mus musculus mice and hairless rats histologically demonstrated their efficacy in an inflammatory animal model study. No signs of skin irritation or modifications of the skin's biophysical properties were identified and the gels were well tolerated. The results obtained from this investigation concluded that the developed semi-solid formulations represent a fitting drug delivery carrier for PRA's transdermal delivery, enhancing its dermal retention and suggesting that they can be utilized as an interesting and effective topical treatment for local skin inflammation caused by a possible abrasion.

Gel Formulations with an Echinocandin for Cutaneous Candidiasis: The Influence of Azone and Transcutol on Biopharmaceutical Features

Caspofungin is a drug that is used for fungal infections that are difficult to treat, including invasive aspergillosis and candidemia, as well as other forms of invasive candidiasis. The aim of this study was to incorporate Azone in a caspofungin gel (CPF-AZ-gel) and compare it with a promoter-free caspofungin gel (CPF-gel). An in vitro release study using a polytetrafluoroethylene membrane and ex vivo permeation into human skin was adopted. The tolerability properties were confirmed by histological analysis, and an evaluation of the biomechanical properties of the skin was undertaken. Antimicrobial efficacy was determined against Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. CPF-AZ-gel and CPF-gel, which had a homogeneous appearance, pseudoplastic behavior, and high spreadability, were obtained. The biopharmaceutical studies confirmed that caspofungin was released following a one-phase exponential association model and the CPF-AZ gel showed a higher release. The CPF-AZ gel showed higher retention of caspofungin in the skin while limiting the diffusion of the drug to the receptor fluid. Both formulations were well-tolerated in the histological sections, as well as after their topical application in the skin. These formulations inhibited the growth of C. glabrata, C. parapsilosis, and C. tropicalis, while C. albicans showed resistance. In summary, dermal treatment with caspofungin could be used as a promising therapy for cutaneous candidiasis in patients that are refractory or intolerant to conventional antifungal agents.

Identification and genetic characterization of a new totivirus from Bursera graveolens in western Ecuador

The complete genomic sequence of a previously uncharacterized virus provisionally named "Bursera graveolens associated totivirus 1" (BgTV-1) was obtained from Bursera graveolens (Kunth) Triana & Planch., a tree known as "palo santo" in Ecuador. The BgTV-1 genome is a monopartite double-stranded RNA (dsRNA) that is 4794 nucleotides (nt) long (GenBank accession number ON988291). Phylogenetic analysis of the capsid protein (CP) and RNA-dependent RNA polymerase (RdRp) placed BgTV-1 in a clade with other plant-associated totiviruses. Amino acid (aa) sequence comparisons of putative BgTV-1 proteins showed the highest sequence similarity to those of taro-associated totivirus L (QFS21890.1-QFS21891.1) and Panax notoginseng virus A (YP_009225664.1- YP_009225665.1), with 51.4% and 49.8% identity, respectively, in the CP and 56.4% and 55.2% identity, respectively, in the RdRp. BgTV-1 was not detected in total RNA from either of the two endophytic fungi cultured from BgTV-1-positive B. graveolens leaves, suggesting that BgTV-1 may be a plant-infecting totivirus. Based on its distinct host and the low aa sequence similarity between the CP of BgTV-1 and its counterparts from the closest relatives, the virus described in this study should be assigned as a new member of the genus Totivirus.

Characterization and In Vivo Anti-Inflammatory Efficacy of Copal (Dacryodes peruviana (Loes.) H.J. Lam) Essential Oil

Essential oils are natural aromatic substances that contain complex mixtures of many volatile compounds frequently used in pharmaceutical and cosmetic industries. Dacryodes peruviana (Loes.) H.J. Lam is a native species from Ecuador whose anti-inflammatory activity has not been previously reported, thus the aim of this study was to evaluate the anti-inflammatory activity of D. peruviana essential oil. To that end, essential oil from D. peruviana fruits was isolated by hydrodistillation and characterized physically and chemically. The tolerance of the essential oil was analyzed by cytotoxicity studies using human keratinocytes. The anti-inflammatory activity was evaluated by an arachidonic acid-induced edema model in mouse ear. The predominant compounds in D. peruviana essential oil were α-phellandrene, limonene, and α-pinene, with the three compounds reaching approximately 83% of the total composition. Tolerance studies showed high biocompatibility of this essential oil with human keratinocytes. In vivo studies demonstrated a moisturizing effect and an alleviation of several events occurred during the inflammatory process after topical treatment with D. peruviana essential oil such as decline in skin edema; reduction in leukocytic infiltrate; and decrease in inflammatory cytokines TNFα, IL-8, IL-17A, and IL-23. Therefore, this essential oil could be an attractive treatment for skin inflammation.

Enhanced Transdermal Delivery of Pranoprofen Using a Thermo-Reversible Hydrogel Loaded with Lipid Nanocarriers for the Treatment of Local Inflammation

A biocompatible topical thermo-reversible hydrogel containing Pranoprofen (PF)-loaded nanostructured lipid carriers (NLCs) was studied as an innovative strategy for the topical treatment of skin inflammatory diseases. The PF-NLCs-F127 hydrogel was characterized physiochemically and short-time stability tests were carried out over 60 days. In vitro release and ex vivo human skin permeation studies were carried out in Franz diffusion cells. In addition, a cytotoxicity assay was studied using the HaCat cell line and in vivo tolerance study was performed in humans by evaluating the biomechanical properties. The anti-inflammatory effect of the PF-NLCs-F127 was evaluated in adult male Sprague Daw-ley^® rats using a model of inflammation induced by the topical application of xylol for 1 h. The developed PF-NLCs-F127 exhibited a heterogeneous structure with spherical PF-NLCs in the hydrogel. Furthermore, a thermo-reversible behaviour was determined with a gelling temperature of 32.5 °C, being close to human cutaneous temperature and thus favouring the retention of PF. Furthermore, in the ex vivo study, the amount of PF retained and detected in human skin was high and no systemic effects were observed. The hydrogel was found to be non-cytotoxic, showing cell viability of around 95%. The PF-NLCs-F127 is shown to be well tolerated and no signs of irritancy or alterations of the skin's biophysical properties were detected. The topical application of PF-NLCs-F127 hydrogel was shown to be efficient in an inflammatory animal model, preventing the loss of stratum corneum and reducing the presence of leukocyte infiltration. The results from this study confirm that the developed hydrogel is a suitable drug delivery carrier for the transdermal delivery of PF, improving its dermal retention, opening the possibility of using it as a promising candidate and safer alternative to topical treatment for local skin inflammation and indicating that it could be useful in the clinical environment.