Antioxidant and antimicrobial activities of Morchella conica Pers.

Antioxidant capacity and antimicrobial activities of Morchella conica Pers. extracts obtained with ethanol were investigated in this study. Four complementary test systems; namely DPPH free radical scavenging, -carotene/linoleic acid systems, total phenolic compounds and total flavonoid concentration were used. Inhibition values of M. conica ethanol extracts, buthylated hydroxyanisol (BHA) and -tocopherol standards were found to be 96.9, 98.9 and 99.2%, respectively, at aconcentration of 160 ìg/ml. When compared the inhibition levels of methanol extract of M. conica and standards in linoleic acid system, it was observed that the higher the concentration of both M. conicaethanol extract and the standards the higher the inhibition effect. Total flavonoid amount was 9.17±0.56ìg mg-1 quercetin equivalent while the phenolic compound amount was 41.93±0.29 ìg mg-1 pyrocatecholequivalent in the ethanolic extract. The antimicrobial effect of M. conica ethanol extract was tested against six species of Gram-positive bacteria, seven species of Gram-negative bacteria and one speciesof yeast. The M. conica ethanol extract had a narrow antibacterial spectrum against tested microorganisms. The most susceptible bacterium was M. flavus. The crude extract was found active on S. aureus ATCC 25923 and S. aureus Cowan I. The M. conica ethanol extract did not exhibit anticandidal activity against C. albican

Free-radical scavenging capacity and antimicrobial activity of wild edible mushroom from Turkey

Antioxidant capacity and antimicrobial activities of Ramaria flava (Schaeff) Quel. (RF) extracts obtained with ethanol were investigated in this study. Four complementary test systems; namely DPPH freeradical scavenging, -carotene/linoleic acid systems, total phenolic compounds and total flavonoid concentration have been used. Inhibition values of R. flava extracts, BHA and -tocopherol standardswere found to be 94.7, 98.9 and 99.2%, respectively, at 160ƒÊg/ml. When compared the inhibition levels of ethanol extract of R. flava and standards in linoleic acid system, it was observed that the higher theconcentration of both RF ethanol extract and the standards the higher the inhibition effect. Total flavonoid amount was 8.27}0.28 ƒÊg mg-1 quercetin equivalent while the total phenolic compound amountwas 39.83}0.32 ƒÊg mg-1 pyrocatechol equivalent in the ethanolic extract. The ethanol extract of R. flava inhibited the growth of Gram-positive bacteria better than Gram-negative bacteria and yeast. The crude extract showed no antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Morganella morganii and Proteus vulgaris. The antimicrobial activity profile of R. flava against tested strains indicated that Micrococcus flavus, Micrococcus luteus and Yersinia enterocolitica was the most susceptible bacteria of all the test strains. R. flava was found to be inactive against Candida albicans

Sintering effects on chemical and physical properties of bioactive ceramics

The objective of this study was to characterize the chemical and physical properties of bioactive ceramics prepared from an aqueous paste containing hydroxyapatite (HA) and beta tri-calcium phosphate (β-TCP). Prior to formulating the paste, HA and β-TCP were calcined at 800 °C and 975 °C (11 h), milled, and blended into 15%/85% HA/β-TCP volume-mixed paste. Fabricated cylindrical rods were subsequently sintered to 900 °C, 1100 °C or 1250 °C. The sintered specimens were characterized by helium pycnometry, X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), and inductively coupled plasma (ICP) spectroscopy for evaluation of porosity, crystalline phase, functional-groups, and Ca:P ratio, respectively. Mechanical properties were assessed via 3-point bending and diametral compression. Qualitative microstructural evaluation using scanning electron microscopy (SEM) showed larger pores and a broader pore size distribution (PSD) for materials sintered at 900 °C and 1100 °C, whereas the 1250 °C samples showed more uniform PSD. Porosity quantification showed significantly higher porosity for materials sintered to 900 °C and 1250 °C (p< 0.05). XRD indicated substantial deviations from the 15%/85% HA/β-TCP formulation following sintering where lower amounts of HA were observed when sintering temperature was increased. Mechanical testing demonstrated significant differences between calcination temperatures and different sintering regimes (p < 0.05). Variation in chemical composition and mechanical properties of bioactive ceramics were direct consequences of calcination and sintering.Peer reviewedChemical Engineerin

Synthesis of calcium hydroxyapatite-tricalcium phosphate (HA-TCP) composite bioceramic powders and their sintering behavior

Composite (biphasic) mixtures of two of the most important inorganic phases of synthetic bone applications-namely, calcium hydroxyapatite (Ca-10(PO4)(6)(OH)(2) (HA)) and tricalcium phosphate (Ca-3(PO4)(2) (TCP))-were prepared as submicrometer-sized, chemically homogeneous, and high-purity ceramic powders by using a novel, one-step chemical precipitation technique. Starting materials of calcium nitrate tetrahydrate and diammonium hydrogen phosphate salts that were dissolved in appropriate amounts in distilled water were used during powder precipitation runs. The composite bioceramic powders were prepared with compositions of 20%-90% HA (the balance being the TCP phase) with increments of 10%, The pellets prepared from the composite powders were sintered to almost full density in a dry air atmosphere at a temperature of similar to 1200 degrees C. Phase-evolution characteristics of the composite powders were studied via X-ray diffractometry as a function of temperature in the range of 1000 degrees-1300 degrees C, The sintering behavior of the composite bioceramics were observed by using scanning electron microscopy. Chemical analysis of the composite samples was performed by using the inductively coupled plasma-atomic emission spectroscopy technique