The samples of Turmeric (Curcuma longa) were collected from the local market in Erode, Sweet Flag (Acoruscalamus) and Tea (Camellia sinensis) was collected from the local field at Kotagiri, Nilgiris district.

Ethanolic extracts were prepared by adding 20 g of samples (Figure 1) to 80 mL of ethanol at 90˚C. The obtained mixture was filtered with a 200-mesh sieve, and the filtrate contained in a beaker was cooled to 10˚C in an ice water bath, then centrifugated with a centrifuge for 15 min to remove impurities. The upper layer was collected and concentrated in a vacuum at 60˚C and then dried powdered extract was stored in airtight bottles and refrigerated at 40˚C until use.

The total phenolic content of the sample was determined by using Folin-Ciocalteu reagent following a slightly modified method by Ainsworth and Gillespie [18] . Gallic acid was used as a reference standard for plotting calibration curve (25 to 500 μg/mL). A volume of 0.1 mL of the sample was mixed with 2 mL of the Folin-Ciocalteu reagent (diluted 1:10 with de-ionized water) and neutralized with 4 mL of sodium carbonate solution (7.5%, w/v). The reaction mixture was incubated at room temperature for 30 min with intermittent shaking for color development. The absorbance of the resulting blue color was measured at 765 nm using double beam UV/VIS SPECTROPHOTOMETER LMSP-UV-1200-PC (LABMAN SCIENTIFICS, India). The total phenolic contents were determined from the linear equation of a standard curve prepared with gallic acid. The content of total phenolic compounds is expressed as mg/L gallic acid equivalent (GAE) of a sample.

Total flavonoid content was measured spectrophotometrically by using Aluminium chloride colorimetric method [19] . 0.1 ml of the extract was mixed with 1.5 ml of ethanol, 0.1 ml of 10% aluminium chloride, 0.1 ml of 1M sodium acetate and 2.8 ml of distilled water. It was kept at room temperature for 30 min and absorbance of the reaction mixture was measured at 415 nm with a double beam UV spectrophotometer. The calibration curve was prepared by preparing

Quercetin solutions at concentrations 6.25, 12.5, 25, 50 and 100 μg/ml in methanol. The total flavonoid content was expressed as mg/g Quercetin equivalents (QE).

DPPH radical scavenging activity of the extract was determined according to the method reported by Blois [20] . An aliquot of 0.5 ml of the sample solution in methanol was mixed with 2.5 ml of 0.5 mM methanolic solution of DPPH. The mixture was shaken vigorously and incubated for 30 min in the dark at room temperature. The absorbance was measured at 517 nm using UV spectrophotometer. Ascorbic acid was used as a positive control. DPPH free radical scavenging ability (%) was calculated by using the formula.

% of inhibition = absorbance of control − absorbance of sample/absorbance of control × 100.

TPC and TFC of the extracts were calculated on the basis of a standard gallic acid curve and the results were expressed as mg/L gallic acid equivalent (GAE) of sample extractives. TPC of Curcuma longa, Acorus calamus and Camellia sinensis ethanolic extracts were found to be 15.53% ± 0.53%, 12.22% ± 0.68% and 17.20 ± 0.70 mg of GAE/g of Curcuma longa, Acorus calamus and Camellia sinensis ethanolic extracts, respectively (Figure 2). From the data, it was shown that the phenolic content of Camellia sinensis as well as Curcuma longa was higher than Acorus calamus extract. Hence these extracts might serve as a good source for phenolics as well as antioxidants. The TFC of Curcuma longa, Acorus calamus and Camellia sinensis ethanolic extracts were 13.67% ± 1.63%, 12.07% ± 0.23% and 13.92% ± 0.76% mg/g Quercetin equivalents (QE), respectively (Figure 3). The data indicates that Camellia sinensis, as well as Curcuma longa, contained higher amounts of flavonoids than that of Acorus calamus extract, the results demonstrated that these extracts are a significant source of flavonoids.

From Table 1 % inhibition of free radicals by ascorbic acid at various concentrations (5, 10, 20, 40 and 50 µg/ml) can be determined. Ascorbic acid is taken as the positive control for the DPPH assay of scavenging free radicals. From the IC₅₀ graph (Figure 4), the value 41.21% ± 1.56% µg/ml for IC₅₀ is obtained. Ascorbic acid at various concentrations (5, 10, 20, 40 and 50 µg/ml) showed an inhibition percentage of 3.35%, 8.64%, 13.52%, 43.45% and 82.54% respectively. Two graphs were plotted between the concentration of the sample and log values for the concentration of the sample and % inhibition as shown in Figure 4. The

IC₅₀ value above 42% of ascorbic acid shows very strong inhibition of the free radicals.

From Table 2 % inhibition of free radicals by Curcuma longa ethanolic extracts at various concentrations (25, 50, 100, 250 and 500 µg/ml) can be determined. Curcuma longa ethanolic extracts at various concentrations showed less inhibition of free radicals than the positive control ascorbic acid taken for the DPPH assay of scavenging free radicals. From the IC₅₀ graph (Figure 4) the value 123.20% ± 0.06% µg/ml for IC₅₀ is obtained. Curcuma longa ethanolic extracts at various concentrations (500, 250, 100, 50 and 25 µg/ml) showed an inhibition percentage of 83.89%, 73.54%, 38.92%, 24.55% and 18.69% respectively. Two graphs were plotted between the concentration of the sample and log values for the concentration of the sample and % inhibition as shown in Figure 5. The IC₅₀ value above 123% of Curcuma longa ethanolic extract shows very strong inhibition of the free radicals [21] .

From Table 3 % inhibition of free radicals by Acorus calamus ethanolic extracts at various concentrations (25, 50, 100, 250 and 500 µg/ml) can be determined. Acorus calamus ethanolic extracts at various concentrations showed less inhibition of free radicals than the positive control ascorbic acid taken for the DPPH assay of scavenging free radicals. From the IC₅₀ graph (Figure 6) the value 129.9%

± 21.47% µg/ml for IC₅₀ is obtained. Acorus calamus ethanolic extracts at various concentrations (500, 250, 100, 50 and 25 µg/ml) showed an inhibition percentage of 32.51%, 19.64%, 9.41%, 7.76% and 6.06% respectively. Two graphs were plotted between the concentration of the sample and log values for the concentration of the sample and % inhibition as shown in Figure 6. The IC₅₀ value above 129.9% µg/ml of Acorus calamus ethanolic extract should be used to have a very strong inhibition of the free radicals [22] .

From Table 4 % inhibition of free radicals by Camellia sinensis ethanolic extracts at various concentrations (25, 50, 100, 250 and 500 µg/ml) can be determined. Camellia sinensis ethanolic extracts at various concentrations showed better inhibition of free radicals than the positive control ascorbic acid taken for the DPPH assay of scavenging free radicals. From the IC₅₀ graph (Figure 4) the value 24.74% ± 0.1% µg/ml for IC₅₀ is obtained. Camellia sinensis ethanolic extracts at various concentrations (500, 250, 100, 50 and 25 µg/ml) showed an inhibition percentage of 92%, 87.95%, 85.19%, 67.90% and 48.56% respectively. Two graphs were plotted between the concentration of the sample and log values for the concentration of the sample and % inhibition as shown in Figure 7. The IC₅₀ value above 25% of Camellia sinensis ethanolic extracts shows very strong inhibition of the free radicals [23] .