Plant matter constitutes an important source for producing carbonaceous materials. This work deals with the preparation of active carbons from shells of<em> Parinari macrophylla</em> (agricultural waste in...Plant matter constitutes an important source for producing carbonaceous materials. This work deals with the preparation of active carbons from shells of<em> Parinari macrophylla</em> (agricultural waste in Niger). Physical, chemical and mixed activations are considered. Several parameters of preparation are optimized, as the nature of the activation gas (N<sub>2</sub> or CO<sub>2</sub>, dry and wet), the concentration of the activating agent (H<sub>3</sub>PO<sub>4</sub>), the time of impregnation and the pyrolysis temperature program. The active carbons are characterized through their iodine numbers, their specific surface areas and their porous volumes. Active carbons, produced from shells of <em>Parinari macrophylla</em> display iodine numbers up to 599 mg I<sub>2</sub>/g and specific surface areas up to 727 m<sup>2</sup>/g. They also show microporous characteristics, with a mean pore diameter, usually, lower than 20 <span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span> and a microporous surface percentage up to 88.7% and a microporous volume percentage up to 82.1%. The microporosity is far more developed for the active carbons produced by chemical activation.展开更多
Objective: To explore the possible inhibitory potentials and mechanism by Mobola plum(Parinari curatellifolia) seeds crude methanol(CE) and flavonoid-rich(FE) extracts on angiotensin-1-converting enzyme(ACE Ⅰ).Method...Objective: To explore the possible inhibitory potentials and mechanism by Mobola plum(Parinari curatellifolia) seeds crude methanol(CE) and flavonoid-rich(FE) extracts on angiotensin-1-converting enzyme(ACE Ⅰ).Methods: The sensitivity and kinetic model of inhibition of CE and FE on ACE Ⅰ using N-[3-(2-furyl)-acryloyl]-Phe-Gly-Gly as enzyme substrate for ACE Ⅰ was evaluated by Michealis Menten approach. The inhibition mechanism was explored from Lineweaver–Burk model and IC_(50) was determined from Cheng–Prusoff empirical analysis.Results: The IC_(50) of CE and FE were 13.54 and 39.38 mg/m L, respectively. Both extracts exhibited mixed type inhibition with the inhibitory constant(K_i) of CE was between0.38 and 0.37 mg/m L while that of FE showed a two-fold increase(1.62 mg/mL and0.28 mg/mL). FE on ACE Ⅰ demonstrated positive cooperativity with a Hill's coefficient of1.89.Conclusions: The study reveals the superior ACE Ⅰ inhibitory potential of CE over FE and suggest that mixed inhibition pattern of the enzyme might be the underlying mechanism of antihypertensive activity.展开更多
文摘Plant matter constitutes an important source for producing carbonaceous materials. This work deals with the preparation of active carbons from shells of<em> Parinari macrophylla</em> (agricultural waste in Niger). Physical, chemical and mixed activations are considered. Several parameters of preparation are optimized, as the nature of the activation gas (N<sub>2</sub> or CO<sub>2</sub>, dry and wet), the concentration of the activating agent (H<sub>3</sub>PO<sub>4</sub>), the time of impregnation and the pyrolysis temperature program. The active carbons are characterized through their iodine numbers, their specific surface areas and their porous volumes. Active carbons, produced from shells of <em>Parinari macrophylla</em> display iodine numbers up to 599 mg I<sub>2</sub>/g and specific surface areas up to 727 m<sup>2</sup>/g. They also show microporous characteristics, with a mean pore diameter, usually, lower than 20 <span style="white-space:nowrap;"><span style="white-space:nowrap;">Å</span></span> and a microporous surface percentage up to 88.7% and a microporous volume percentage up to 82.1%. The microporosity is far more developed for the active carbons produced by chemical activation.
文摘Objective: To explore the possible inhibitory potentials and mechanism by Mobola plum(Parinari curatellifolia) seeds crude methanol(CE) and flavonoid-rich(FE) extracts on angiotensin-1-converting enzyme(ACE Ⅰ).Methods: The sensitivity and kinetic model of inhibition of CE and FE on ACE Ⅰ using N-[3-(2-furyl)-acryloyl]-Phe-Gly-Gly as enzyme substrate for ACE Ⅰ was evaluated by Michealis Menten approach. The inhibition mechanism was explored from Lineweaver–Burk model and IC_(50) was determined from Cheng–Prusoff empirical analysis.Results: The IC_(50) of CE and FE were 13.54 and 39.38 mg/m L, respectively. Both extracts exhibited mixed type inhibition with the inhibitory constant(K_i) of CE was between0.38 and 0.37 mg/m L while that of FE showed a two-fold increase(1.62 mg/mL and0.28 mg/mL). FE on ACE Ⅰ demonstrated positive cooperativity with a Hill's coefficient of1.89.Conclusions: The study reveals the superior ACE Ⅰ inhibitory potential of CE over FE and suggest that mixed inhibition pattern of the enzyme might be the underlying mechanism of antihypertensive activity.
