The present study aimed to evaluate the effects of roasting temperature on the quality characteristics and biological activity of quinoa. Quinoa was roasted at 160, 200, and 220oC for 20 min. The lightness (L*) of quinoa decreased, however, the redness (a*) increased as the roasting temperature increased. The yellowness (b*) was the highest at 160oC and decreased at 200 and 220oC. The highest contents of total polyphenol, flavonoid, and quercetin were observed at 220oC, the highest roasting temperature. The highest radical scavenging activities of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (73.65%) and α,α-diphenyl-β-picrylhydrazyl free radicals (47.82%) were found in roasted quinoa at 220oC. The α- glucosidase activity was inhibited by 62.13% at this temperature. The roasted quinoa at 220oC also showed a significant cytoprotective effect against oxidative stress in HepG2 cells. These results could be useful in the development of food products using quinoa.

This study evaluated the biological activity and cytoprotective effect of guava (Psidium guajava L.) branch against oxidative stress. The contents of vitamin C, beta-carotene, total carotenoids, quercetin and catechin determined were 26.783, 43.676, 65.083, 58.245, and 8.309 mg/100 g, respectively. To measure antioxidant activity, the guava branch was extracted using various concentrations of ethanol (60, 80, or 100%) and water. The highest content of polyphenols (0.245 mg gallic acid equivalent/mg residue) and flavonoids (0.128 mg cathechin equivalent/mg residue) was found in the 100% ethanol extract of the branch (E100). Moreover, E100 also possessed the highest radical scavenging activities and showed the highest inhibition rate of α-glucosidase (77.692%). E100 was the most effective extract to impart cytoprotectant activity against oxidative stress in HepG2 cells. Taken together, our results determine the promising antioxidant activity of guava branch, and indicate the potential to be applied as a natural antioxidant.

This study examined the bioactive compound content and the antioxidant activities of bitter melon (Momordica charantia Linn.) leaves. The content of vitamin C, beta-carotene, and total carotenoids was 69.77, 45.68, and 65.08 mg/100 g, respectively. To investigate the antioxidant capacity, bitter melon leaves were extracted using various concentrations of ethanol (60, 80, or 100%). Highest content of total polyphenols (18.07 mg gallic acid equivalent/g) and flavonoids (4.53 mg cathechin equivalent/g) was found in the 100% ethanolic extract of the leaves (E100). Also, the E100 extract showed the highest levels of 2,2'azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and α-α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging activities. Reducing power was also the highest (39.21 mg Trolox equivalent/g) in E100 extract. The E100 extract effectively inhibited lipid peroxidation by 91.45% compared to the control group. Also, the E100 extract showed a cytoprotective effect against oxidative stress in HepG2 cells and decreased the generation of intracellular reactive oxygen species. These results suggest that bitter melon leaves could be regarded as a potential source of natural antioxidants.

This study examined the contents of bioactive compounds and the biological activity of okra seed oil. Okra seed oil consisted mainly of linoleic acid (44.2%). The content of total phytosterols was 2.180 mg/g oil, with β-sitosterol being the highest (1.756 mg/g oil). The vitamin E content was 1.278 mg/g oil; the content of α-tocopherol was higher than γ- tocopherol. The total polyphenol and flavonoid contents were 2.463 mg gallic acid equivalent/g and 1.602 mg cathechin equivalent/g, respectively. The 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and α-α-diphenyl-β-picrylhydrazyl free radical scavenging activities were 15.297% and 22.265%, respectively, and the reducing power was 4.524 mg gallic acid equivalent/g. The okra seed oil inhibited 77.692% of the α-glucosidase activity. The present study showed that okra seed oil had a considerable amount of phytochemicals and exhibited biological activity. These results suggest that okra seed oil is a potential natural therapeutic for the management of metabolic syndromes.

Buckwheat sprouts are a vegetable; a functional food should provide health benefit and enhance performance as high nutritionally important substances. Buckwheat noodles are the major buckwheat food in Japan, Korea and China. In addition, Buckwheat as preventive medicine has undergone a great advancement in the last decade. Comparison of the functional properties distribution and utilization in tatary buckwheat is required of understanding the metabolites. The study was conducted to identify the sorts of phenolic compounds and metabolites in tatary buckwheat seedling at 4, 7, and 10 days seedling under the different combinations of lightemitting diode (LED) such as blue, red, mix (red, blue, and white), dark, and natural lights in stem and leaves. After breaking the dormancy, buckwheat seeds were grown in culture room under lights for 14 hrs and the dark condition for 10 hrs, at 25ºC for 10 days. Length of buckwheat was gradually increased under all of the conditions. Using HPLC, rutin was highest at 7 days under mix and natural light in stem and leaf, respectively. Quercetin was highest at 4 and 7 days under natural light in both. Chlorogenic acid was highest at 7 days under mix and natural in stem and leaf, respectively. Taken Together, this study indicates that phenolic compounds and metabolites present in those plants could be helpful for the human health and nutritional additive.