antioxidant characteristics of cinnamon, citrus aurantium, and green tea leaves by dpph and total phenol tests

Oxidation is an important factor causing food spoilage. it changes the smell, taste, and color of the fatty foods when they are exposed to environmental factors such as light, temperature, and oxygen, a process ultimately leading to food deterioration. natural or synthetic antioxidants with phenol construction are used to increase food quality and shelf life and prevent oil oxidation but some studies showed that synthetic antioxidants may have adverse effects on human health, causing mutagenic and carcinogenic problems. due to the antioxidant properties of herbs and spices and consumer interest in natural preservatives, this study examined the antioxidant properties of cinnamon, citrus aurantium, and green tea leaves by 2, 2-diphenyl-1-picrylhydrazyl (dpph) and total phenol tests. determination of main constituents of extracts' components were performed by a gas chromatograph with a mass spectrometer (gc/ms). the antioxidant properties of cinnamon, citrus aurantium, and green tea leave extracts were examined individually and using a mixture of two or three extracts (with different percentages) by dpph and total phenol tests. total phenol was determined using folin-ciocalteu reagents with analytical grade. 200 μl of extracts, prepared in methanol at the ratio of 1:10, was added to 1mm folin-ciocalteu reagents diluted with distilled water at the ratio of 1:10. after 4 min, 800 ml of 20% sodium carbonate was added to the mixture. the absorbance at 756 nm was measured after more than 1 h in darkness. next, the standard curve of ga (700-1100 μg/ml) was plotted. the concentration of total phenols was expressed based on the below formula. the blank for this research was a combination of 2 ml of methanol, 1 ml of folin reagent, and 800 μl of saturated sodium carbonate. the absorbance was read against this solution. for dpph test, 50 ml of various dilutions of the extracts was mixed with 5 ml of a 0.004% methanol solution of dpph. after an incubation period of 30 min, the absorbance of the samples was read at 517 nm using a spectrophotometer. the resulting number is known as the scavenging percentage of free radicals. to obtain 50% free radical scavenging, this was performed for different concentrations of the extract and calculated using the following equation. butylhydroxytoluene (bht) was the positive control and the blank was the dpph solution in 0.004% methanol. e. cinnamaldehyde (32.41%), linalool (65.08%), and kaempferol-3-0-glucoside (84%) were the most important combinations of cinnamon, citrus aurantium, and green tea leave extracts, respectively. examination of the antioxidant activity of extracts by total phenol test showed that treatments with a higher percentage of green tea leaves and cinnamon extracts had the highest (28.98±.12 µg/gr ga) and those with the highest amount of citrus aurantium had the lowest (15.56 ±.06 µg/gr ga) amount of phenolic content. also, the dpph test revealed that the lowest ic50 was related to the mixture of three extracts (307.62 µg/ml) where the highest belonged to citrus aurantium extract treatment (2100.3 µg/ml). although these three extracts had radical scavenging capacity, butylated hydroxytoluene (bht) and butylated hydroxyanisole (bha) were most powerful.