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The chestnut shell is usually discarded as agricultural waste and the random deposition of it can cause environmental problems. In this study, monodisperse crystalline Ag nanoparticles (AgNPs) were synthesized by a hydrothermal approach, in which the chestnut shell extract served as both reducing agent and stabilizer. The synthesized Ag nanoparticles were characterized by ultraviolet-visible (UV) spectrophotometry, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements. The TEM, XRD and XPS results revealed that the synthesized product was spherical Ag nanoparticles with a face-centered cubic crystal structure. The antimicrobial activity test indicated that the Ag nanoparticles modified by the chestnut shell extract had an obvious inhibitory effect on Escherichia coli, Staphylococcus aureus and Candida albicans. The measured MIC and MBC of functionalized chestnut-shell-extract AgNPs against E. coli, S. aureus and C. albicans is relatively low, which indicated that the present functionalized chestnut-shell-extract AgNPs are an efficient antimicrobial agent. [ABSTRACT FROM AUTHOR]

In order to improve the antimicrobial activity of Ag nanomaterial and minimum their toxicity, cinnamic acid has been utilized as both reducing agent and protecting ligand to synthesis of silver (Ag) nanoparticles (NPs). The synthesized cinnamic acid (CA) functionalized Ag nanoparticles (CA-AgNPs) have been characterized by Ultraviolet-visible spectrophotometry (UV), Fourier transform infrared absorption spectra (FTIR), Atomic force microscope (AFM), Transmission electron microscope (TEM). UV absorption results indicated that a strong absorption band peaked at 452 nm which can be ascribed to the surface plasmon resonance (SPR) of AgNPs. FTIR results of CA-AgNPs indicated that cinnamic acid was indeed bound on the AgNPs. TEM measurements indicated that the products are round spherical NPs with the average particle size of 52.8 nm. Antimicrobial activity tests revealed that CA-AgNPs have significant inhibitory effects on E. coli and C. albicans. The CA-AgNPs prepared in this study are expected to be developed as efficient antimicrobial agents. [ABSTRACT FROM AUTHOR]

In this study, the aqueous and ethanolic extracts (leaves, stems and fruits) from Morus alba L., a traditional Chinese medicine, were evaluated for their antioxidant and antimicrobial properties. Ethanolic extracts showed higher contents of both total phenolics and flavonoids than aqueous extracts. The total phenolic content was in the order of: leaf extracts > fruit extracts > stem extracts, whereas the total flavonoids was: leaf extracts > stem extracts > fruit extracts. Using DPPH assays, the concentrations providing 50% inhibition (IC50) values of aqueous extracts from leaves, stems and fruits were 7.11 ± 1.45 mg/ml, 86.78 ± 3.21 mg/ml and 14.38 ± 2.83 mg/ml, respectively, whereas the IC50 values of ethanolic extracts were 3.11 ± 0.86 mg/ml, 14.62 ± 2.45 mg/ml and 12.42 ± 2.76 mg/ml, respectively. In sum, the antioxidant activities of ethanolic extracts from M. alba L. were stronger than the aqueous extracts, and in the order of: leaf extracts > fruit extracts > stem extracts. The ethanolic extracts exhibited moderate antimicrobial activities, whereas the aqueous extracts showed poor antimicrobial properties in our test system. This study validated the medicinal potential of M. alba L. [ABSTRACT FROM AUTHOR]

Phellodendron amurense Rupr. bark extracts were examined for antioxidant activity, antimicrobial activity and antiviral activity on herpes simplex virus type 1 (HSV-1). Ethanol extract showed higher content of both total phenolic and flavonoid than aqueous extract. In DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay, the concentration providing 50% inhibition (IC50) values were 6.73 ± 0.87 mg/ml and 4.26 ± 0.59 mg/ml for aqueous and ethanol extracts respectively. Ethanol extract had a much higher antimicrobial activity than aqueous extract. Furthermore, the antiviral activity of the ethanol extract on HSV-1 was also tested. The maximum noncytotoxic concentration was 44.12 μg/ml for RC-37 cells. Plaque formation was inhibited by 74±6% when HSV-1 was pretreated with the extract prior to adsorption, whereas pretreatment of the cells with the extract, added during adsorption or after the adsorption only exhibited above 10% antiviral effect. This study has to some extent validated the medicinal potential of P. amurense bark. [ABSTRACT FROM AUTHOR]