Synergistic effect of commercial mangosteen extract (Garcinia mangostana L.) and amoxicillin against methicillin-resistant Staphylococcus aureus (MRSA)

Antibiotic resistance occurs worldwide and has become a threat to humankind. Previous data have shown that antimicrobial resistance is a global issue demanding immediate resolution because it threatens the environment and society. The present work thus investigated the synergistic effects of commercial Garcinia mangostana L. (GML) extract and amoxicillin on the growth of methicillin-resistant Staphylococcus aureus (MRSA) bacterial cells. A commercial GML extract was screened for phytochemical properties, and the presence of α-mangostin was detected using high-performance liquid chromatography (HPLC). The antibacterial activity of the commercial GML extract with amoxicillin was analysed by minimum inhibitory concentration (MIC) and checkerboard assays. The morphology ultrastructure of bacteria was observed using transmission electron microscopy (TEM), after treatment with commercial GML extract, either single or in combination with amoxicillin. The MICs of amoxicillin and commercial GML extract against MRSA bacteria were 250.00 and 137.50 μg/mL, respectively. The checkerboard assay showed synergistic activity in the combination of commercial GML extract (34.38 µg/mL) and amoxicillin (62.50 µg/mL) at fractional inhibitory concentration (FIC) index of < 0.5. Damage to the structure of bacteria occurred due to the commercial GML extract plus amoxicillin. It was observed that the loss of bacterial cell membranes led to an irregular bacterial structure. These findings provided evidence that the combination of commercial GML extract and amoxicillin could reverse bacterial resistance in order to determine the susceptibility of traditional drugs

Optoelectronic Structure and Related Transport Properties of Ag2Sb2O6 and Cd2Sb2O7

Pomocí metody the full-potential linearized augmented-plane wave byla zkoumána elektronická struktura a termoelektrické vlastnosti Ag2Sb2O6 a Cd2Sb2O7. Modifikovaný potenciál Becke-Johnson byl aplikován k výměně korelační energie. Elektronické pásmové struktury odhalují, že minimální hodnota valenčního pásma a minimální pásmo vodivosti se vyskytují v bodě C, což naznačuje, že Ag2Sb2O6 a Cd2Sb2O7 mají přímé polovodičové energetické pásmo. Vyskytla se silná hybridizace mezi stavy Ag (Cd) -s / p a O-s / p. Optické vlastnosti, tj. Komplexní dielektrická funkce, odrazivost, index lomu a funkce ztráty energie, odhalují vysokou odrazivost v oblasti ultrafialové energie, což ukazuje na užitečnost těchto materiálů na stínění vysokoenergetických záření. Kombinací transportní teorie a metody from the full-potential linearized augmented-plane wave byly termoelektrické vlastnosti analyzovány jako funkce teploty. Vzhledem k vysokému tepelnému výkonu a úzkému pásmu jsou Ag2Sb2O6 a Cd2Sb2O7 vhodnými materiály pro použití v optoelektronických a termoelektrických zařízeních.Using the full-potential linearized augmented-plane wave method, the electronic structure and thermoelectric properties of Ag2Sb2O6 and Cd2Sb2O7compounds have been explored. The modified Becke–Johnson potential was applied to treat the exchange–correlation energy term. The electronic band structures reveal that the valence-band maximum and conduction-band minimum occur at C point, indicating that Ag2Sb2O6 and Cd2Sb2O7 are direct energy bandgap semiconductors. Strong hybridization appeared between Ag (Cd)-s/p and O-s/p states. The optical properties, i.e., complex dielectric function, reflectivity, refractive index, and energy loss function, reveal high reflectivity in the ultraviolet energy range, indicating usefulness of these materials in shields from high-energy radiation. Combining transport theory and the outputs from the full-potential linearized augmented-plane wave calculations, the thermoelectric properties were analyzed as functions of temperature. Due to their high thermopower and narrow bandgap, Ag2Sb2O6 and Cd2Sb2O7 are suitable materials for application in optoelectronic and thermoelectric devices