In vitro assessment of antibiotic-resistance reversal of a methanol extract from Rosa canina L.

The crude methanol extract of Rosa canina (RC) fruit was tested against multidrug-resistant (MDR) bacterial strains, including methicillin-resistant Staphylococcus aureus SA1199B, EMRSA16 and XU212 harbouring NorA, PBP2a and TetK resistance mechanisms, respectively, as well as S. aureus ATCC25923, a standard antimicrobial susceptible laboratory strain. The inhibition of the conjugal transfer of plasmid PKM101 and TP114 by the RC extract was also evaluated. The RC extract demonstrated a mild to poor antibacterial activity against the panel of bacteria having MIC values ranging from 256 to >512 μg/mL but strongly potentiated tetracycline activity (64-fold) against XU212, a tetracycline-effluxing and resistant strain. Furthermore, the extract showed moderate capacity to inhibit the conjugal transfer of TP114 and PKM101; transfer frequencies were between 40% and 45%. Cytotoxicity analysis of the RC extract against HepG2 cells line showed the IC50 > 500 mg/L and, thus, was considered non-toxic towards human cells. Phytochemical characterisation of the extracts was performed by the assessment of total phenolic content (RC: 60.86 mg TAE/g) and HPLC fingerprints with five main peaks at 360 nm. The results from this study provide new mechanistic evidence justifying, at least in part, the traditional use of this extract. However, the inhibition of bacterial plasmid conjugation opens the possibility of combination therapies to overcome antibiotic resistance

A Green Valorisation Approach Using Microwaves and Supercritical CO2 for High-Added Value Ingredients from Mandarin (Citrus deliciosa Tenore) Leaf Waste

WOS: 000458207300004Ciğeroğlu, ZeynepThe present study aims to increase the efficiency of a resource from waste to health by valorisation of it through cleaner, eco-friendly and less energy-consuming technical processes such as microwave-asissted (MAE) and supercritical fluid (SFE) extractions. On the other hand, optimization of the processes have been applied utilizing multivariate statistic technique such as Response surface Methodology (RSM) in order to consider any possible interaction between variables with less number of experiments as well as to model a response affected by several variables. The outcome of the present study indicates that the optimum conditions for MAE were 275W of microwave power together with 2g mandarin leaf for 45s; regarding SFE, 50 degrees C, 200bar and 0.39mL/min was found as the optimal condition to obtain the maximum yields of each dependent variable such as total phenolic material (TPM) and total flavonoid material (TFM), respectively. Additionally, antioxidant activity values measured by several methods such as cupric ion reducing antioxidant capacity (CUPRAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) were correlated positively with both TPM and TFM in the leaf extracts. Furthermore, scanning electron microscope (SEM) images indicated cell wall disruption in all the treatement groups compared to untreated samples.Research Fund of Istanbul University (Bilimsel Arastirma Projeleri Birimi, Istanbul Universitesi) [41685]The authors wish to thank for the support of the Research Fund of Istanbul University (Bilimsel Arastirma Projeleri Birimi, Istanbul Universitesi). Project number is 41685