The preparation is described of a cell-free system from developing cotyledons of Phaseolus vulgaris cv. Canadian Wonder which is capable of binding ethylene. The binding is saturable and the apparent dissociation constant for ethylene is 6.4·10(-10) M in solution. The binding site is associated with subcellular particles and treatment with Triton X-100 results in substantial solubilisation of the activity. The kinetics of association and dissociation of the ligand and the binding site are described. The system is heat labile and binding activity is diminished by treatment with some proteolytic enzymes.
The aim of this study was to compare the antioxidant capacity and total phenolic content as well as the chemical groups of fresh, oven-dried and stir-fried tamarind (Tamarindus indica L.) leaves. Methanol was used for extraction of fresh, oven-dried and stir-fried tamarind leaves. The stir-fried leaves were prepared using medium heat for 10 minutes prior to extraction and chemical analysis while dried leaves were obtained by oven drying at 60°C for 3 hours. The stir-fried leaves had significantly highest total phenolic content (TPC) (139.87 mg/g) and percentage DPPH radical-scavenging inhibition (69.92%) while the fresh leaves had the lowest TPC (39.31 mg/g) and antioxidant capacity (16.46%). The FTIR spectral data suggest that the heat treatment increased the amine groups as well as the antioxidant capacity of the tamarind leaves. To increase the antioxidant capacity, the tamarind leaves should be prepared in a stir-frying process.
This work aims to determine antioxidant, total phenolic content and Fourier transform infrared spectroscopy (FTIR) analysis of breadfruit leaves which are essential in management of diabetes. The methanolic extracts of breadfruit leaves was used to analyze for total phenolic content and antioxidant. Total phenolic content of the extracts was measured using the Folin–Ciocalteu assay while the antioxidant activity of plant extracts was measured by the 1, 1-diphenyl-2-picryhyradrazyl (DPPH) radical scavenging assay. FTIR analysis was used to determine the chemical components in the leaves. Total phenolic content in fresh breadfruit leaves (144.16 mg/g ± 17.98) was comparable to those of green tea. The results showed the breadfruit leaves extracts exhibited potent antioxidant activity. The presence of OH group also suggests antioxidant capacity of breadfruit leaves to deactivate free radicals as glucose itself could react with hydrogen peroxide in the presence of iron and copper ions to form hydroxyl radical.
Bioactive compounds of Orthosiphon stamineus have been known to have the beneficial effects on health. Efficient extraction of these beneficial compounds is very important. The study was conducted to determine the efficiency of methanol as an extraction solvent for bioactive compound extraction of O. stamineus raw materials. Leaf sample was extracted in 25, 50 and 100% methanol and distilled water for 2, 4 and 8 hours at 40 0 C. The free radical scavenging activity (FRSA) method was used to determine antioxidant capacity and Follin-Ciocalteu method was used to determine samples total phenolic compounds. The quantification of bioactive constituents by using the high performance liquid chromatography (HPLC) and the standard markers was used for this analysis such as rosmarinic acid (RA), sinensetin (SEN) and 3-hydroxy-5,6,7,4-tetramethoxyflavone (TMF). The current research shows that the yield of RA concentration was high in 50% methanol extracts at 2, 4 and 8 h of extraction. For the FRSA result showed that methanol at 50% and 100% was the most effective concentration levels inhibition between 45-55% at 8 hours' time extraction. For the total phenolic compound, the 50% methanol concentration in O. stamineus leaf had the highest value compared with 0%, 25% and 100% methanol concentration. But, it was observed that time extraction did not influence the TPC values for different concentrations of methanolic extracts. These indicated that time extraction had affected the total capacities of antioxidant and 50% methanolic extracts was the best concentration for indicated the TPC in the O. Storminess leaf.
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