In vitro antifungal activity of essential oils extracted from plants against fluconazole-susceptible and -resistant Candida albicans

Evaluation of antifungal and apoptotic effects of linalool, citral, and carvacrol separately and in combination with nystatin against clinical isolates of Pichia kudriavzevii

Pichia kudriavzevii (formerly Candida krusei) poses a significant threat to immunocompromised patients due to its inherent resistance to various antifungal drugs. This study explored the anticandidal potential of citral, linalool, and carvacrol in combination with nystatin against P. kudriavzevii strains.Using the microdilution method following CLSI guidelines, Minimum Inhibitory Concentrations (MICs) and fungicidal concentrations (MFCs) were determined. Citral exhibited MIC values ranging from 50 to 100 µg/ml, averaging 70.24 ± 16.99 µg/ml, while carvacrol had MIC values of 50 to 100 µg/ml, averaging 86.90 ± 16.99 µg/ml. Linalool demonstrated weaker antifungal activity, with MIC values between 100 and 200 µg/ml, averaging 150 ± 38.73 µg/ml. The study assessed the synergistic effectsof these phenols with nystatin through fractional inhibitory concentration indices (FICIS). In addition, flow cytometry was employed to assess apoptosis induction in P. kudriavzevii cells.Carvacrol displayed a remarkable synergistic effect in combination with nystatin against all 21 isolates tested. Conversely, linalool showed synergy in 17 isolates, while citral exhibited synergy in only 2 isolates. These findings highlight distinct patterns of synergy between the different compounds and nystatin against P. kudriavzevii. Also, Carvacrol emerged as the most potent inducer of apoptosis across all P. kudriavzevii strains, followed by citral and linalool. This suggests that carvacrol not only possesses a stronger antifungal effect but also has a more pronounced ability to trigger programmed cell death in P. kudriavzevii. In conclusion, the study supports the potential of carvacrol, citral and linalool, as anticandidal agents, suggesting their supplementation with nystatin for treating P. kudriavzevii infections.

Natural Substances as Valuable Alternative for Improving Conventional Antifungal Chemotherapy: Lights and Shadows

Fungi are eukaryotic organisms with relatively few pathogenic members dangerous for humans, usually acting as opportunistic infections. In the last decades, several life-threatening fungal infections have risen mostly associated with the worldwide extension of chronic diseases and immunosuppression. The available antifungal therapies cannot combat this challenge because the arsenal of compounds is scarce and displays low selective action, significant adverse effects, and increasing resistance. A growing isolation of outbreaks triggered by fungal species formerly considered innocuous is being recorded. From ancient times, natural substances harvested from plants have been applied to folk medicine and some of them recently emerged as promising antifungals. The most used are briefly revised herein. Combinations of chemotherapeutic drugs with natural products to obtain more efficient and gentle treatments are also revised. Nevertheless, considerable research work is still necessary before their clinical use can be generally accepted. Many natural products have a highly complex chemical composition, with the active principles still partially unknown. Here, we survey the field underlying lights and shadows of both groups. More studies involving clinical strains are necessary, but we illustrate this matter by discussing the potential clinical applications of combined carnosic acid plus propolis formulations.

Mode of Antifungal Action of Daito-Gettou (Alpinia zerumbet var. exelsa) Essential Oil against Aspergillus brasiliensis

Plant-derived essential oils (EOs) are used in medicines, disinfectants, and aromatherapy products. Information on the antifungal activity of EO of Alpinia zerumbet var. exelsa (known as Daito-gettou) found in Kitadaito Island, Okinawa, is limited. Therefore, we aimed to evaluate the antifungal activity of EOs obtained via steam distillation of leaves of Daito-gettou, which is a hybrid of A. zerumbet and A. uraiensis. Daito-gettou EO showed antifungal activity (minimum inhibitory concentration = 0.4%) against Aspergillus brasiliensis NBRC 9455, which was comparable to that of A. zerumbet found in the Okinawa main island. Gas chromatography/mass spectrometry revealed that the main components of Daito-gettou EOs are γ-terpinene, terpinen-4-ol, 1,8-cineole, 3-carene, and p-cymene. Terpinen-4-ol content (MIC = 0.075%) was 17.24%, suggesting that the antifungal activity of Daito-gettou EO was mainly attributable to this component. Daito-gettou EO and terpinen-4-ol inhibited mycelial growth. Moreover, calorimetric observations of fungal growth in the presence of Daito-gettou EO showed a characteristic pattern with no change in the initial growth rate and only a delay in growth. As this pattern is similar to that of amphotericin B, it implies that the action mode of Daito-gettou EO and terpinen-4-ol may be fungicidal. Further studies on the molecular mechanisms of action are needed for validation.

Extraction and Optimization of Active Metabolites From Cluster Bean: An In Vitro Biological and Phytochemical Investigation

The current study aimed to explore active metabolites of locally recognized and high yielding cultivar cluster bean (BR-99) with a wide range of adaptability having antioxidant, antidiabetic, antimicrobial, and cytotoxic potential. Six solvents were used (crude methanol, n-hexane, chloroform, ethyl acetate, butanol, and aqueous) with escalating polarity for colorimetric determination of antioxidants such as total phenolic contents (TPC), total flavonoid contents (TFC), and free radical scavenging activity (FRSA) by DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay. Moreover, an antidiabetic and anticancer study was conducted by α-amylase inhibition and MTT (3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-tetrazolium bromide) assay. Biological investigations were carried out against the most commonly found infectious microbial strains. The significant results (P ≤ .001) of each activity were seen among six tested solvent extracts. The ethyl acetate and methanol extract have more antioxidant potential with the highest TPC (16.38 ± .13 mg GAE/g) and TFC (8.15 ± .24 mg CE/g), respectively. Similarly, methanol extract presented the highest free radical scavenging activity (46.31 ± .91%), followed by ethyl acetate, butanol, chloroform, aqueous, and n-hexane extract. However, the maximum α-amylase inhibition (62.54 ± 1.47%) and anticancer activity against human lung cancer cells were congregated (78.31 ± 1.46%) in butanol and chloroform, respectively. A positive correlation was seen between TPC with TFC (R²= .8356), FRSA (R²= .8381), and anti-diabetic activity (R²= .8082), which highlights the phenolic contents as strong anti-oxidant agents especially flavonoids. Each extract of cluster bean (BR-99) showed significant antimicrobial activities for all tested bacterial strains except B. cereus and E. coli. The profound results of maximum antibacterial activity were witnessed by chloroform extract while ethyl acetate extracts showed great antifungal potential against all tested fungal strains. The HPLC quantitative analysis results of cluster bean (BR-99) revealed the presence of active phytochemicals such as gallic acid, HB acid, vanillic acid, kaempferol, sinapic acid, ferulic acid, salicylic acid, coumarins, quercetin, rutin, p-coumaric acid, and catechin, and the variation in both phytochemical and biological spectrums envisioned the cluster bean (BR-99) used in future as a cheap, safer, and potent source of bioactive drugs.

Antifungal Properties of Zataria multiflora on Candida species: A Systematic Review

BACKGROUND AND PURPOSE

Candida infections have increased significantly in the antimicrobial resistance era, and synthetic antifungal drugs have limitations. The present work aimed to review the antifungal properties of Zataria multiflora (Z. multiflora) as an herbal remedy.

METHOD

PubMed, Scopus, ScienceDirect, Web of Science, SID, Civilica, and Magiran databases were searched for the antifungal activity on in vitro, in vivo, dental biofilm, and clinical studies of Z. multiflora on Candida species.

RESULTS

Overall, 33 articles evaluated the effect of Z. multiflora on Candida species and classified them into four groups, as follows in vitro (23), dental biofilm (6), in vivo (2), and clinical studies (3). All studies considered Z. multiflora effective in reducing or even inhibiting the growth of Candida species. NoMFC significant differences were seen in the effect of Z. multiflora on susceptible Candida compared to the resistant groups of Candida in the studies. It was also influential in inhibiting C. parapsilosis, C. glabrata, C. krusei, C. kefyer, and C. zeylanoides.

CONCLUSION

Considering the side effects and resistance of current antifungal drugs as well as the benefits of using herbal medicines, such as lower cost, less likely to develop drug resistance, the absence of side effects, and toxicity compared with chemical ones, it is possible as a powerful alternative to replace or combine with the current antifungal for Candida infection therapy along with other therapies.

Evaluation of the Effects of Cuminum cyminum on Cellular Viability, Osteogenic Differentiation and Mineralization of Human Bone Marrow-Derived Stem Cells

Background and Objectives: Cuminum cyminum L. has long been used in the treatment of various diseases in multiple geographical regions. This study was performed to determine the effects of C. cyminum methanolic extract (CCT) on the cellular viability, alkaline phosphatase activity and mineralization of human mesenchymal stem cells. Materials and Methods: Bone marrow-derived stem cells were cultured in the presence of CCT at concentrations of 0, 0.001, 0.01, 0.1 and 1 μg/mL. Evaluations of cell morphology were performed on days 1, 3, 7 and 14. Cellular viability was evaluated on days 1, 3, 5 and 7. On the 7th and 14th day, alkaline phosphatase activity measurements and Alizarin red S staining were conducted to assess the osteogenic differentiation of stem cells. A real-time polymerase chain reaction was used to determine the expression levels of RUNX2, BSP, OCN, COL2A1 and β-catenin mRNAs. Results: Stem cells in the control group showed fibroblast-like morphology and the addition of CCT at 0.001, 0.01, 0.1 and 1 μg/mL did not generate noticeable changes in morphology compared with the untreated control group. The application of CCT did not produce significant changes in cellular viability or alkaline phosphatase activity compared with controls. Alizarin Red S staining was significantly increased with the application of CCT. Treatment with CCT increased the expressions of RUNX2, BSP and OCN. Conclusions: These results indicate that CCT enhanced the osteogenic differentiation of stem cells derived from bone marrow by regulating the expressions of RUNX2, BSP and OCN. Thus, the use of CCT may be applied to achieve beneficial effects on the mineralization of stem cells.