New Insights into Bioactive Compounds from the Medicinal Plant Spathodea campanulata P. Beauv. and Their Activity against Helicobacter pylori
ANTIBIOTICS-BASEL
Authors: Ngnameko, Corinne Raissa; Marchetti, Lucia; Zambelli, Barbara; Quotadamo, Antonio; Roncarati, Davide; Bertelli, Davide; Njayou, Frederic Nico; Smith, Stella, I; Moundipa, Paul F.; Costi, Maria Paola; Pellati, Federica
Abstract
The medicinal plant Spathodea campanulata P. Beauv. (Bignoniaceae) has been traditionally applied for the prevention and treatment of diseases of the kidney and urinary system, the skin, the gastrointestinal tract, and inflammation in general. The present work shows for the first time how chemical components from this plant inhibit Helicobacter pylori growth by urease inhibition and modulation of virulence factors. The crude extract and the main fractions of S. campanulata bark were tested on H. pylori isolated strains and the active ones were further fractionated. Fractions and sub-fractions of the plant crude extract were characterized by ultra-high-performance liquid chromatographic tandem high resolution-mass spectrometry detection (UHPLC-HRMS). Several phenolics and triterpenoids were identified. Among the sub-fractions obtained, SB2 showed the capacity to inhibit H. pylori urease in a heterologous bacterial model. One additional sub-fraction (SE3) was able to simultaneously modulate the expression of two adhesins (HopZ and BabA) and one cytotoxin (CagA). The flavonol kaempferol was identified as the most interesting compound that deserves further investigation as a new hit for its capacity to modulate H. pylori virulence factors.
Carbonation reactivity enhancement of gamma-C2S through biomineralization
JOURNAL OF CO2 UTILIZATION
Authors: Zhao, Sixue; Liu, Zhichao; Wang, Fazhou
Abstract
Most of the calcium silicates exhibit high carbonation reactivity, and thus start to be utilized in the production of low carbon concrete due to the growing pressure of carbon mitigation in the cement industry. In this study, powdered gamma-C2S, with limited hydraulicity, is preconditioned in a suspension consisting of urease-producing bacterium and urea. This biomineralization process induces the precipitation on the gamma-C2S surface of calcite crystals with spherical shape, the size of which is dependent on the urea suspension concentration. The effect of the pre-existing calcite crystals on the carbonation behavior, mechanical and micro-morphology of gamma-C2S compacts is investigated. Results indicate the compressive strength are significantly improved with the preexisting calcite crystals, and the increasing percentage is 43.66 % at 30 min carbonation and 0.25 mol/L urea concentration. The strength enhancement is found to be associated with the pre-existing calcite crystals acting as nucleation seeds which accelerate the carbonation at the early stage. In addition, the pre-existing calcite seeds induce the preferential formation of calcite in the crystalline carbonation products of gamma-C2S, which may be beneficial to the enhancement of the carbonated products.