Biological capacities of seven Chilean ferns

Sticherus squamulosus, Hymenophyllum dentatum, Blechnum microphyllum, Polypodium Feuillei, Blechnum chilense, Lophosoria quadripinnata, and Lissopimpla excelsa are native fern species found in southern Chile and are often used in traditional medicine. However, their bioactive properties have not been confirmed. In this study, ethanolic extracts of ferns exhibited significant antibacterial capacity against human pathogens. H. dentatum and S. squamulosus were selected for further analysis owing to their antimicrobial and antioxidant capacities. The entire H. dentatum extract exhibited fungistatic and fungicidal capacity on Botrytis cinerea and Penicillium digitatum, with minimum inhibitory concentration values of 1.56 mg/mL and 6.25 mg/mL and minimum fungicidal concentration values of 6.25 mg/mL and 12.5 mg/mL, respectively. The S. squamulosus extract presented the highest rutin content (222.5 µg/g fern). In addition, the ethanolic extract of H. dentatum inhibited 91% of DPPH radicals. Therefore, both types of ferns can be used in the food industry.

Plant Secondary Metabolites on Efflux-Mediated Antibiotic Resistant Stenotrophomonas Maltophilia: Potential of Herbal-Derived Efflux Pump Inhibitors

During the process of adapting to metal contamination, plants produce secondary metabolites that have the potential to modulate multidrug-resistant (MDR) phenotypes; this is achieved by inhibiting the activity of efflux pumps to reduce the minimum inhibitory concentrations (MICs) of antimicrobial substrates. Our study evaluated the effect of secondary metabolites of belowground parts of Pteris vittata L. and Fallopia japonica, two metal-tolerant plants from northern Vietnam, on six antibiotic-resistant Stenotrophomonas maltophilia strains possessing efflux pump resistance mechanisms that were isolated from soil and clinical samples. The chemical composition of aqueous and dichloromethane (DCM) fractions extracted from P. vittata and F. japonica was determined using UHPLC-DAD-ESI/QTOF analysis. The antibacterial and efflux pump inhibitory activities of the four fractions were evaluated for the six strains (K279a, 0366, BurA1, BurE1, PierC1, and 502) using a microdilution assay at fraction concentrations of 62.5, 125, and 250 μg/mL. The DCM fraction of F. japonica exhibited remarkable antibacterial activity against strain 0366, with a MIC of 31.25 μg/mL. Furthermore, this fraction also significantly decreased gentamicin MIC: four-fold and eight-fold reductions for BurA1 and BurE1 strains, respectively (when tested at 250 μg/mL), and two-fold and eight-fold reductions for K279a and BurE1 strains, respectively (when tested at 125 μg/mL). Pure emodin, the main component identified in the DCM fraction of F. japonica, and sennidine A&B only reduced by half the MIC of gentamicin (when tested at 30 μg/mL). Our results suggest that the DCM fraction components of F. japonica underground parts may be potential candidates for new bacterial efflux pump inhibitors (EPIs).

A short critique on biomining technology for critical materials

Being around for several decades, there is a vast amount of academic research on biomining, and yet it contributes less to the mining industry compared to other conventional technologies. This critique briefly comments on the current status of biomining research, enumerates a number of primary challenges, and elaborates on some kinetically-oriented strategies and bottom-up policies to sustain biomining with focus on critical material extraction and rare earth elements (REEs). Finally, we present some edge cutting developments which may promote new potentials in biomining.