DPPH scavenging activity of the plant extract was carried out according to the method of Koleva et al 2002; Mathiesen et al 1995. 0.2 ml of methanolic solution of plant extract samples at different concentration (20- 100µg ml-l) was mixed with 0.8 ml of Tris Hcl buffer (100Mm, pH 7.4). One ml DPPH (500 M in methanol) solution was added to above mixture. The mixture was shaken vigorously and incubated for 30min in room temperature. Absorbance of the resulting solution was measured at 517nm UV-Visible Spectrophotometer (Systronics UV-Visible Spectophotometer 117, INDIA). All the assays were carried out in triplicates with BHA (Butylated Hydroxy Anisole) as a positive control. Blank was prepared without the addition of DPPH and for control 0.2 ml of methanol (without plant extract) was added. Percentage of DPPH scavenging activity determined as follows.

% DPPH radical-scavenging = [(Absorbance of control – Absorbance of test

Sample) / (Absorbance of control)] ? 100Control was the DPPH solution without plant extract.

Purified sample 2mg/ml in Methanol of Cordia wallichii and Celastrus paniculata extracts were taken for antioxidant activity with a standard BHA (Butylated Hydroxy Anisole) antioxidant. Decreased absorbance of the reaction mixture indicates stronger DPPH radical-scavenging activity. In this study, hexane and methanolic leaf extracts of both C. wallichii and C. paniculata were used.

This was carried out as described previously (Yildrim et al 2001; Lu and Foo). 1 ml of plant extract solution (final concentration 100-500 mg/l) was mixed with 2.5 ml phosphate buffer( 0.2 M, pH 6.6) and 2.5 ml potassium ferricyanide [ K₃Fe(CN₆)] (10g/l), then mixture was incubated at 50 degree C for 20 minutes. Two and one-half, 2.5 ml of trichloroacetic acid (100g/l) was added to the mixture, which was then centrifuged at 3000 rpm for 10 min. Finally, 2.5 ml of the supernatant solution was mixed with 2.5 ml of distilled water and 0.5 ml Fecl3 (1g/l) and absorbance measured at 700nm in UV-Visible Spectrophotometer (Systronics UV-Visible Spectophotometer 117, INDIA). As a control, ascorbic acid was used (final concentration 10 mg/ml).

Increased absorbance of the reaction mixture indicates stronger reducing power. In this study, hexane and methanolic leaf extracts of Cordia wallichii and Celastrus paniculata were used.

The percentage of DPPH racial scavenging activity presented in Table 1(a). Like reducing power, the DPPH racial scavenging activity of the extract increases with increasing concentration, only 19.27% DPPH racial scavenging. Nevertheless, it was 72.32% in the presence of 100 mg/l BHA (Butylated Hydroxy Anisole). Although this plant extract shows lower scavenging activity in comparison to BHA, it is remarkably higher than those of essential oils from the leaves of L.nobilis and the gum of A.cilicia (Alma et all 2003).

Figure 1

Table 1a: Antioxidant activity of hexane extract of

The methanolic extract of Celastrus paniculata was found to most effective than hexane extract. The DPPH racial scavenging activity of the extract increases with increasing concentration, only 25.85% DPPH racial scavenging. Nevertheless, it was 75.32% in the presence of 100 mg/l BHA.

Figure 2

Table 1b: Antioxidant activity of Methanolic extract of

The % of DPPH racial scavenging activity of hexane extract of C. wallichii presented in Table 1(c). Like reducing power, the DPPH racial scavenging activity of the extract increases with increasing concentration, only 16.75% DPPH racial scavenging was present for 250 l. This result found to be lower than that of hexane extract of C. paniculata. Nevertheless, it was 75.32% in the presence of 100 mg/l BHA. Although this plant extract shows lower scavenging activity in comparison to BHA. Plant extract exhibited antioxidative potential and increased concentration of plant extract has shown increased antioxidative potential.

Figure 3

Table 1c: Antioxidant activity of hexane extract of

Figure 4

Table 1d: Antioxidant activity of methanolic extract of

The methanolic extract of Cordia wallichii was found to most effective than hexane extract (1 (d)). The DPPH racial scavenging activity of the extract increases with increasing concentration exhibited only 28.28% DPPH racial scavenging activity was noted. Nevertheless, it was 75.40% in the presence of 100 mg/l BHA. These results suggest that methanolic extracts of C. wallicii exhibited little better than other extracts.

Different extracts of Celastrus paniculata exhibited good reducing power. The reducing power of methanolic extract of Celastrus paniculata along with that of ascorbic acid at concentrations between 100-500 mg/ml. The reducing power of the plant extract was determined by the method of Ozaizu (1986). High absorbance indicates high reducing power. The reducing power of the plant hexane extract of C. paniculata leaf as the amount of extract increases Table 2(a). However, this reducing power is lower than that of ascorbic acid which was used as control. Therefore, the absorbance of ascorbic acid in a sample was (10 mg/l) 0.96 while at the 500mg/l methanolic extract concentration it was 0.44. Nevertheless the reducing power of methanolic extract of C. paniculata was 0.54 and it was considerably higher than those of hexane extract Table. 2(b).

Figure 5

Table 2a: Reducing power of hexane extract of

Figure 6

Table 2b: Reducing power of methanolic extract of

Figure 7

Table 2c: Reducing power of hexane extract of

The reducing power of Cordia wallichii leaf extract has shown good reducing power than celastrus paniculata. As the amount of extract increase, the reducing power also increases. Table 2(c). However, this reducing power is lower than that of ascorbic acid which was used as control. Therefore, the absorbance of ascorbic acid in a sample was (10 mg/l) 0.96 while at the 500mg/l methanolic extract concentration it was 0.52. Neverthless the reducing power of extract of C. wallichii was higher (0.61) Table 2(d) than those of C. paniculata (0.53). In both cases of C. paniculata and C. wallichii there is a remarkable concentration dependent reducing power was exhibited. This variation in reducing activity may be due to crude nature of plant extracts and availability of different phytochemicals in these plants.

Figure 8

Table 2d: Reducing power of methanol extract of