Identification and evaluation of antioxidants in Japanese parsley

A Smart Advanced Chemiluminescence-Sensing Platform for Determination and Imaging of the Tissue Distribution of Natural Antioxidants

Antioxidants have gained marked attention owing to their ability to prevent the oxidation of biological components and to protect the body from reactive oxygen species, thereby maintaining human health. Thus, antioxidant-rich dietary supplements and natural foods can be effective against oxidative stress and can even act as chemopreventive agents. Therefore, a simple and rapid assay for evaluation of antioxidant capacity and assessment of their distribution profile in natural sources is vital. Herein, we report a rapid, innovative chemiluminescence (CL) platform for evaluation and visualization of antioxidant capacity. We found that intense and long-lasting CL was formed upon the redox reaction of quinones, e.g., menadione, with antioxidants, e.g., l-ascorbic acid, in the presence of luminol. The produced CL intensities were proportional to the antioxidants' concentrations with a detection limit of 0.18 μM for the model antioxidant, l-ascorbic acid. As the formed CL was long-lasting, it could be easily captured and detected with a charge-coupled device (CCD) camera. To evaluate the quantification ability of the CCD camera, we developed a smart and fast microplate-based assay based on photographing the generated CL with a cooled CCD camera. The photographed CL intensities were linearly proportional with the antioxidant concentrations, and then the method was applied for photographing multiple food sample extracts. Ultimately, we utilized our method for the distribution profiling of antioxidant capacity in food cut sections. Samples were dipped in luminol and then in quinone, followed by CCD camera photography, without the need for any pulverization/extraction procedure, giving precise antioxidant distribution information.

Antioxidant Capacities of Plant-Derived Foods Commonly Consumed in Japan

To provide reliable data for high quality epidemiological studies examining the relationship between health and antioxidant intake from daily foods, 107 plant-derived food items (12 rice, bread and noodles, 5 potatoes and starches, 9 pulses, 6 nuts/seeds, 29 vegetables, 22 fruits, 5 mushrooms, 7 algae, and 12 beverages) were selected as commonly consumed foods in Japan based on dietary records, and their antioxidant capacities were evaluated by validated hydrophilic- and lipophilic-oxygen radical absorbance capacity (H-ORAC and L-ORAC) methods. The food items covered more than 60% of total food intake for each category on a weight basis. The H-ORAC and L-ORAC values were widely distributed at 0-210 and 0-30 μmol-Trolox equivalent/g, respectively. The foods possessing potent antioxidant capacities were found in vegetables and fruits as well as other plant-derived foods. In most foods measured, the H-ORAC values were much larger than the L-ORAC values, except for certain kinds of pulses, nuts/seeds, mushrooms, and algae. The ORAC data shown here is sufficient to accurately estimate the antioxidant intake from plant-derived foods in Japan, and should be useful in future epidemiological studies aiming to clarify the biological significance of ORAC values.

The Major Source of Antioxidants Intake From Typical Diet Among Rural Farmers in North-eastern Japan in the 1990s

Background

Previous Japanese studies have led to the erroneous conclusion of antioxidant capacity (AOC) intakes of the overall Japanese diet due to limitations in the number and types of food measured, especially in rice and seafood intake. The aims of the study were to construct an AOC database of foods representative of the typical Japanese diet and to clarify the high contributors to AOC intake from the overall diet of the Japanese population.

Methods

Commonly consumed foods were estimated using 3-day dietary records (DRs) over the four seasons among 55 men and 58 women in Japan. To generate an AOC database suitable for the typical Japanese diet, hydrophilic (H-)/lipophilic (L-) oxygen radical absorbance capacity (ORAC) values of foods in each food group were measured via validated methods using the food intake rankings. Subsequently, we estimated the AOC intake and the AOC characteristics of a typical Japanese diet.

Results

Of 989 food items consumed by the participants, 189 food items were measured, which covered 78.8% of the total food intake. The most commonly consumed types of antioxidant-containing food were tea, soybean products, coffee, and rice according to H-ORAC, and soybean products, fish and shellfish, vegetables, and algae according to L-ORAC.

Conclusions

The characteristics of high AOC intake in rice and seafood more appropriately reflected the Japanese-style diet. Further studies are expected to clarify the association between food-derived AOC and its role in preventing or ameliorating lifestyle-related diseases.