Chemical Composition and Antioxidant Activity of Aquilaria Malaccensis Leaf Extract

In this study, water extraction (WE) and methanol etraction (ME) of A.malaccensis dried leaves (DL) and fresh leaves (FL) were investigated for its in vitro antioxidant activity that may contribute to their pharmacological effects. Total phenolic content (TPC) of this plants were determined by Folin-Ciaocalteu assay while antioxidant potential were evaluated by CUPRAC and DPPH method

Estimate of Small Stiffness and Damping Ratio in Residual Soil Using Spectral Analysis of Surface Wave Method

Research in the important parameters for modeling the dynamic behavior of soils has led to rapid development of the small strain stiffness and damping ratio for use in the seismic method. It is because, the experimental determination of the damping ratio is problematic, especially for hard soils sample. Many researchers have proved that the surface wave method is a reliable tool to determine shear wave velocity and damping ratio profiles at a site with very small strains level. Surface wave methods based on Rayleigh waves propagation and the resulting attenuation curve can become erroneous when higher modes contribute to the soil’s response. In this study, two approaches has been used to determine the shear strain amplitude and damping ratio of residual soils at small strain level using Spectral Analysis of Surface Wave (SASW) method. One is to derive shear strain amplitude from the frequency-response curve and the other is to derive damping ratio from travel-time data. Then, the results are compared to the conventional method

Estimate of Small Stiffness and Damping Ratio in Residual Soil Using Spectral Analysis of Surface Wave Method

Research in the important parameters for modeling the dynamic behavior of soils has led to rapid development of the small strain stiffness and damping ratio for use in the seismic method. It is because, the experimental determination of the damping ratio is problematic, especially for hard soils sample. Many researchers have proved that the surface wave method is a reliable tool to determine shear wave velocity and damping ratio profiles at a site with very small strains level. Surface wave methods based on Rayleigh waves propagation and the resulting attenuation curve can become erroneous when higher modes contribute to the soil’s response. In this study, two approaches has been used to determine the shear strain amplitude and damping ratio of residual soils at small strain level using Spectral Analysis of Surface Wave (SASW) method. One is to derive shear strain amplitude from the frequency-response curve and the other is to derive damping ratio from travel-time data. Then, the results are compared to the conventional method

In Vitro Antioxidant Activity and Phytochemical Screening of Aquilaria Malaccensis Leaf Extracts

The present study investigated water extraction (WE) and methanol extraction (ME) of A. malaccensis dried leaves (DL) and fresh leaves (FL) for its in vitro antioxidant activity that may contribute to their pharmacological effects. Total phenolic content (TPC) of this plant was determined by Folin-Ciaocalteu assay, while antioxidant potential were evaluated by TAC, CUPRAC and DPPH method. Tests for steroids, triterpenoids, flavonoids, saponins, tannins and alkaloids were positive in both water and methanol extracts. WEDL showed the highest inhibition of the DPPH radical (48.07 ± 0.68 %) at concentration 1000 ug/ml and IC50 value was found to be 1.091 mg/ml, relative to ascorbic acid, having an IC50 of 0.219 mg/ml. It also showed the highest CUPRAC value (3.32 ± 0.01µg/ml) as well as the highest TPC and TAC (181.11 ± 0.61 and 398.74 ± 0.66 gallic acid equivalent (GAE) mg/g) at a concentration of 1000 µg/ml) as compared to the other studied extracts. In conclusion, the results of this study clearly indicated that the extracts of A. malaccensis possess significant antioxidant activities and could be used as a potential source of natural antioxidant agents that may be due to the presence of phytochemicals