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The chemical composition of the essential oil of Lindera subumbelliflora (Lauraceae) was investigated for the first time. The essential oil was obtained by hydrodistillation and fully characterised by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity of L. subumbelliflora essential oil was tested against Candida albicans and Streptococcus mutans using the broth microdilution assay, whereas the microbial biofilms were determined using a semi-quantitative static biofilm. A total of 28 components (99.6%) were successfully identified, which were characterised by β-eudesmol (14.6%), cis -α-bergamotene (11.0%), α-copaene (8.5%), dodecen-1-ol (8.5%), and ( E )-nerolidol (8.3%). The essential oil exhibited activity against Candida albicans and Streptococcus mutans with MIC values of 250 and 500 µg/mL, respectively. The essential oil increased the biofilm of Candida albicans by 38.25%, however, decreased the biofilm of Streptococcus mutans by 47.89% when treated with 500 µg/mL. Thus, the essential oil has a promising application in dentistry via inhibition of the growth of Candida albicans and Streptococcus mutans. However, the antibiofilm activity of the essential oil is only applicable for cariogenic Streptococcus mutans.

The current study describes the chemical composition, antifungal, antibiofilm, antibacterial and molecular docking studies of Syzygium dyerianum growing in Malaysia. The essential oil was obtained through hydrodistillation and characterized using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The antifungal and antibacterial activities were developed using the broth microdilution assay, whereas the effect on the microbial biofilms was determined using a semi-quantitative static biofilm assay. A total of 31 components were identified, which represent 99.5 % of the essential oil. The results revealed that the essential oil consisted mainly of β -pinene (15.6 %), α -terpineol (13.3 %), α -pinene (11.1 %), caryophyllene oxide (8.8 %), limonene (8.1 %), borneol (6.0 %) and viridiflorol (5.1 %). The results of the microdilution method showed that essential oil exhibited activity against Candida albicans and Streptococcus mutans with minimal inhibitory concentration values of 125 and 250 μg/mL, respectively. Furthermore, essential oil decreased the biofilm of C. albicans and S. mutans by 20.11 ± 0.27 % and 32.10 ± 4.81 % when treated with 250 μg/mL. The best docking energy was observed with viridiflorol (-29.7 kJ/mol). This study highlights that essential oil can potentially be a natural antifungal, antibacterial, and antibiofilm agent that could be applied in the pharmaceutical and food industries., (© 2024 Walter de Gruyter GmbH, Berlin/Boston.)

Phenotypic switching is characterized as a virulence factor of Candida spp. This study was carried out to evaluate the phenotypic switching ability of C. krusei ATCC 14243 and to determine its effect on the biological properties, adherence capacity and susceptibility towards chlorhexidine digluconate (CHX). To induce switched generations C. krusei was cultured under nitrogen-depleted growth conditions by adding phloxine B. These phenotypically switched colonies were designated as the 1st generation. Subsequent sub-culturing was performed to produce the 2nd, 3rd and 4th switched generations. The recovery of the 3rd generation was the highest at 85.7% while that of the 4th generation was lower at 70.8%, and the recovery of the 1st and 2nd generations gradually reduced to 46.6% and 36.4%, respectively. All generations of C. krusei were susceptible towards CHX. The unswitched C. krusei was the most susceptible but the least adherent to coated hard surfaces. The 2nd generation was the least susceptible, but with the highest adherent ability. The minimum inhibition concentration and minimal fungicidal concentration of C. krusei of all generations were determined at 0.4 mg mL(-1) . These observations suggest that the switching activity of C. krusei induces changes to its biological properties and susceptibility towards CHX., (© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)