**3.2 Hydroxyl radical scavenging activity of different fraction of plant materials**

Hydroxyl radical scavenging activity of samples has been evaluated according to the method of Halliwell et al. [42]. Hydroxyl radical has been generated by the Fe3+ -ascorbate-EDTA-H2O2 system, which is known as Fenton reaction. The overall reaction mixture was a combination of phosphate buffer solution, FeCl3, EDTA, 2-deoxy-d-ribose, and sample extracts at different concentration. After that, it was placed into water bath at 36°C, and the reaction was initiated after addition of ascorbic acid and H2O2. The reaction had started, and it was sent for incubation at 36°C for maximum 1 hour, simultaneously thiobarbituric acid and HCl were added. The solution was heated for around 15 min at 100 °C followed by immediate cooling with water. The absorbance was taken at 532 nm, and it will reflect the free radical scavenging capability of samples by inhibiting the oxidation process in 2-deoxy-d-ribose in the presence of hydroxyl radical, and the ability was evaluated by using the following formula


**Table 3.**

*DPPH radical scavenging data analysis for standard catechin and crystal compound.*

Percentage of hydroxyl radical scavenging activity ¼ ½ � A0 � ð �� A1 � A2 100*=*A0

where A0 represents the absorbance of control without any sample. A1 represents the absorbance after incorporating the sample and 2-deoxy-D-ribose. A2 represents the absorbance of the sample without adding 2-deoxy-d-ribose. IC50 was investigated graphically after plotting percentage of inhibition against concentration into the graph, and the test had been repeated for three times for individual concentration of samples.
