Antioxidant and antifungal activities in vitro of essential oils and extracts of twelve Algerian species of Thymus against some mycotoxigenic Aspergillus genera

The aim of the study was to determine the phenolic and flavonoid content of essential oils (EOs), chloroform and ethanolic extracts of 12 Algerian Thymus species and evaluate their antioxidant and antifungal activities. EOs (1.73 ± 0.30–15.00 ± 1.24 μg/mg), chloroform extracts (33.8 ± 2.42–160.93 ± 3.88 μg/mg) and ethanol extracts (27.01 ± 3.56 –148.46 ± 4.40 μg/mg) showed considerable phenolic content. Flavonoids values of chloroform extracts ranged between 3.39± 0.17 and 20.27 ± 0.29 μg/ml while ethanolic extracts values ranged between 2.81 ± 0.11 and 26.64 ± 0.18 μg/mg. Results of DPPH showed that EOs, chloroform and ethanolic extracts exhibited strong radical scavenging activity (IC50 = 21.75 ± 6.54–338.22 ± 2.99 μg/ml, 22.91 ± 5.59–90.93 ± 1.36 μg/ml, and 33.51 ± 5.72–103.80 ± 4.54 μg/ml, respectively). Inhibition of β-carotene bleaching was potentially performed by all EOs (66.48 ± 2.41–94.06 ± 2.68 %), chloroform extracts (68.98± 1.58–95.30± 1.99%), and ethanolic extracts (62.15 ± 2.51–92.36± 1.15%). The antifungal activity of EOs and extracts was tested using the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). The EOs (0.1 ± 0.00 mg/ mL – 1.06 ± 0.46 mg/mL), chloroform (0.1 ± 0.00 mg/ mL –1.06 ± 0.46 mg/mL) and ethanol (0.1 ± 0.00 mg /mL–1.6 ± 0.00 mg/mL) showed remarkable antifungal activity against mycotoxigenic Aspergillus genera. The MFC of EOs (1.0 ± 0.34 mg/mL and > 4.8 mg/mL) , chloroform (0.26 ± 0.11 mg/mL and > 1.6 mg/mL) and ethanol (0.2 ± 0.00 mg/mL and > 1.6 mg/mL) were fungicidal in nature higher than MICs. The findings of the study indicated that Thymus spp. EOs and extracts could be used as natural alternatives for food industry.

https://acgpubs.org/doc/20220107214746A3-RAFC-2107-2149.pdf

In this study, antibacterial and antifungal properties of four medlar extracts obtained using four different solvents, ethanol, methanol, acetone and water, were investigated. The disk diffusion method was used to determine the antimicrobial effects of the extracts. In addition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) values were determined. The antibacterial effect of the pure water extract of medlar on S. aureus bacteria was found to be high (11.46 mm). In addition, the MIC and MBC values of the pure water extract were determined as 35.15 and 23.39 µg/mL for S. aureus bacteria. When the antifungal effect was examined, the antifungal effect of the pure water extract of medlar against P. crysogenum was found to be high (14.00 mm). The MIC and MFC values of the pure water extract of medlar are 23.43 and 11.72 µg/mL for P. crysogenum, respectively. Therefore, it was concluded that the pure water extract had the highest antimicrobial effect.

Antifungal Activity of Beluntas “Indian Camphorweed” (Pluchea indica) Ethanol Extract on Candida albicans In Vitro Using Different Solvent Concentrations

Objective Oral candidiasis is an infection caused by pathogenic fungi Candida albicans, with a considerably high prevalence of 20 to 72%. Indian camphorweed (Pluchea indica) also known as “beluntas” as the local name has been known as a traditional medicine in Indonesia. The objective of this study is to research the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of beluntas ethanolic extract against the growth of C. albicans. Materials and Methods The MIC and MFC were measured by microdilution assay and total plate count respectively with a variation of solvents (DMSO 1%, 10%, and 4%) and beluntas extract with concentrations between 0.3125 and 200 mg/mL. Amphotericin and nystatin were used as a comparison. Statistical Analysis One-way analysis of variance and posthoc Tukey test were used to determine the significant difference between treatments. Results It was found that the MIC ranged from 50 to 200 mg/mL in the test with DMSO 10% solvent and MFC was found to be at a concentration of 200 mg/mL. However, there is a significant inhibitory effect and killing effect from DMSO 10% against C. albicans (p = 0.000). MIC was also found within concentrations of 100 mg/mL of beluntas extract in DMSO 4%. In this study, the DMSO 4% concentration neither showed significant inhibitory effects nor killing effects; therefore, the result was acceptable (p = 0.357). Conclusion Ethanol extract of beluntas (P. Indica) has the potential of being an antifungal agent with inhibitory activity in concentrations ≥100 mg/mL, which is similar to nystatin (p = 0.278). The MFC for the extract was above 100 mg/mL, which cannot be measured with this method as a higher concentration of DMSO is needed, which had a toxic effect on the tested fungi.

Development of an Antifungal Device Based on Oriental Mustard Flour to Prevent Fungal Growth and Aflatoxin B1 Production in Almonds

The present study describes the manufacture of an antifungal device composed of oriental mustard flour and hydroxyethyl-cellulose (H-OMF) and evaluates its efficacity in inhibiting Aspergillus flavus growth and aflatoxin B1 (AFB1) production in almonds. Additionally, it compares the H-OMF with allyl isothiocyanate (AITC) and a freeze-dried extract of yellow mustard flour (YMF-E); such substances were previously described as antifungal. Minimum inhibitory concentration (MIC), Minimum fungicidal concentration (MFC), the H-OMF in vitro antifungal activity, and the residual fungal population, as well as the production of AFB1 in almonds were determined. AITC and YMF-E showed significant antifungal activity in vitro. Additionally, the in vitro activity of H-OMF avoided mycelial growth by applying 30 mg/L. Almonds treated with AITC (5.07, 10.13, and 20.26 mg/L) and H-OMF (2000 and 4000 mg/L) showed a reduction in the population of A. flavus and the production of AFB1 to values below the limit of detection. YMF-E showed effectiveness by in vitro methodologies (MIC and MFC) but did not show efficacy when applied in almonds. Our findings indicated that the hydroxyethyl-cellulose-based device containing oriental mustard flour might be utilised as a fumigant to increase the safety of almonds and could be extended to other cereals or dry fruits.

POTENTIAL OF HERBAL MEDICINE IN ASIA FOR ORAL CANDIDIASIS THERAPY: A SYSTEMATIC REVIEW

The objective of this review was to provide antifungal recommendations for Oral Candidiasis (OC) derived from herbal medicine based on the research results of the last 5 y. This systematic review was conducted according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines using the PubMed and Science Direct databases with studies published between 2016 and 2021. The review was conducted on 13 studies, in vitro and clinical trial. A total of 41 species of plants have studied its antifungal effects on Candida albicans. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) varied in the range of 0.098 µl/ml to 125 µl/ml for different types of plants and Candida samples, while the mean inhibition zone (ZOI) was 11 mm. The most recommended herbal medicine for the development of antifungal drugs for oral candidiasis therapy were Nigella sativa, Lawsonia inermis, and Zingiber officinale.

Inhibitory Effect of (-)-myrtenol alone and in combination with antifungal agents on Candida spp.

The aim of this study was to examine the effects of (-)-myrtenol alone and combined with antifungal agents against Candida spp. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration of (-)-myrtenol and fluconazole against C. albicans and C. parapsilosis strains was obtained using CLSI guidelines. Combination of (-)-myrtenol with antifungal drugs was determined by checkboard test. The (-) myrtenol showed MIC ranging from 256 to 512 µg/mL against both species assay. And the MFC was 512 µg/mL, demonstrated nature fungicidal (MFC/MIC < 4). In addition, combination of antifungal agents (amphotericin B and fluconazole) and (-) myrtenol showed synergistic and additive effects on strains assays. Based on these results, the present study demonstrates that (-) myrtenol showed strong fungicide activity against Candida spp. In addition, Combination of antifungal agents and (-) myrtenol reduces the effective concentrations of both the agents with synergistic to additive effects. Therefore, (-) myrtenol has potential to be developed into an antifungal agent.

The Antibacterial Synthetic Flavonoid BrCl-Flav Exhibits Important Anti-Candida Activity by Damaging Cell Membrane Integrity

Infections caused by Candida are very difficult to treat due to increasing antifungal resistance. Recent studies showed that patients with Candida infections resistant to fluconazole have very few treatment options. Therefore, finding new efficient antifungal agents is a matter of medical high priority. The aim of this study was to explore the antifungal potential of BrCl-flav-a representative of a new class of synthetic flavonoids with bromine as halogen substituent at the benzopyran core against four Candida clinical strains. Determination of minimum inhibitory concentration and minimum fungicidal concentration along with the time kill assay indicated a strong antifungal effect of BrCl-flav against C. albicans, C. parapsilosis, C. krusei and C. glabrata. The investigation of anti-Candida mechanism of action using fluorescence microscopy and scanning electron microscopy revealed that Br-Cl flav could inhibit fungal growth by impairing the membrane integrity, the resulting structural damages leading to cell lysis. BrCl-flav also showed important anti-virulence properties against Candida spp., inhibiting biofilm formation and yeast to hyphal transition. A strong synergistic antifungal effect against C. albicans strain was observed when BrCl-flav was used in combination with fluconazole. BrCl-flav has a good potential to develop new effective antifungal agents in the context of Candida spp. multidrug resistance phenomenon.

Antifungal Activity of Biocontrol Agents In Vitro and Potential Application to Reduce Mycotoxins (Aflatoxin B1 and Ochratoxin A)

Food bio-preservatives are requested as substituents of chemical pesticides in food. The aim of this study was to carry out a screening of twenty biocontrol agents (BCAs) for their potential fungicidal activity in vitro. Twenty BCAs were tested against ten pathogenic fungi. Some of the cell-free supernatants (CFS) tested showed in vitro antifungal activity versus pathogenic fungi. The highest fungicidal activity was observed in the fermented CFS of Paenibacillus chibensis CECT 375, Bacillus amyloliquefaciens CECT 493, and Pantoea agglomerans CECT 850, which showed a minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 125 and 250 g/L, respectively. The compounds responsible for the antifungal activity, such as organic and phenolic acids, were determined. Lactic acid, acetic acid, benzoic acid, and phenyllactic acid among others can be related to antifungal activity. HPLC-MS/MS analysis showed a reduction of ochratoxin A (OTA) and aflatoxin B1 (AFB1) up to 26% (Paenibacillus alvei CECT 2) and 55% (Paenibacillus polymyxa CECT 155), respectively. The present study prompts that metabolism products of BCAs are propitious for the bioconservation of food, due to their ability to reduce the proliferation of mycotoxigenic fungi and mycotoxins production.

Polyphenol-Rich Purified Bioactive Fraction Isolated from Terminalia catappa L.: UHPLC-MS/MS-Based Metabolite Identification and Evaluation of Their Antimicrobial Potential

Background: Antimicrobial resistance is a major threat to humankind and the advancement of resistance due to genetic modifications and other defense mechanisms that make the current antibiotics ineffective or less efficacious. Objective: This investigation aims to isolate bioactive compounds from the leaf acetone extract of Terminalia catappa and to evaluate their antimicrobial potential against human pathogenic organisms. Materials and Methods: The bioactive extract was subjected to column chromatography. The fractions were assessed for their minimum inhibitory concentration, minimum fungicidal concentration, and time kill assays. UHPLC-MS/MS analysis was used to identify the bioactive molecules in the fraction. Results: The isolated fraction exhibited antimicrobial activity, with the most sensitive being Staphylococcus aureus (clinical isolate) and Methicillin Resistant Staphylococcus aureus 1503 (0.097 mg/mL), and the fungi Trichophyton rubrum and Candida albicans were inhibited at 0.097 mg/mL. The time kill assay exhibited bactericidal properties towards S. aureus (clinical isolate) and Salmonella typhi (MTCC 733). Additionally, MRSA 1503 and Proteus vulgaris exhibited bacteriostatic activities. The UHPLC-MS/MS analysis revealed that the fraction was rich in polyphenols. Alkaloids and some ellagitannins were identified for the first time. Conclusion: The results highlight the significant inhibition of multidrug-resistant MRSA strains and fungi by the polyphenol-rich fraction. The investigation reveals the potential use of the identified compounds for antimicrobial use, which could lower the implication of multidrug resistance.

Effect of Hibiscus Sabdariffa Extract on Growth of Fusarium graminearum and the Expression of TRI4 and FG08079 Genes of the Fungus

Introduction: Fusarium graminearum produces trichothecenes, such as deoxynivalenol and secondary metabolite butenolide, which cause profound health problems in humans. In this research, the effect of acetone extract of Hibiscus sabdariffa is evaluated on growth of F. graminearum and expression of TRI4 and FG08079 genes, which are involved in deoxynivalenol and butenolide biosynthetic pathways, respectively. Methods: Minimal inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined. The expression of TRI4 and FG08079 genes were evaluated by teal-time PCR technique.Results: The MIC and MFC for acetone extract of Hibiscus sabdariffa against F. graminearum were 200 mg/mL and 400 mg/mL, respectively. Expression of TRI4 and FG08079 genes were significantly decreased by the acetone extract of red tea. Conclusion: The results showed that acetone extract of Hibiscus sabdariffa has inhibitory and fungicidal effects on F. graminearum and is effective in reducing the expression of TRI4 and FG08079 genes, which play important roles in deoxynivalenol and butenolide production.