Background : Kenaf (Hibiscus cannabinus L.) is a member of the malvaceae family and has been prescribed in traditional folk medicine in Africa and India. It showed broad biologicas activities such as hepatoprotective activity, antioxidative activity and haematinic activity. Kenaf leaves contain a lot of vegetable calcium, protein, iron and vitamins, so have high potential as functional food. Thus, the present study purposed to analyze useful substances contained in kenaf leaves and their activities and look for their possibilities as the materials of food and medicine. Methods and Results :　We sowed the seeds of three varieties of kenaf, namely, Dowling, Everglade-41 and Tainung-2 at planting space of 20 × 20㎝ on the field and collected plants on the 98th , 127th and 141st days from sowing. The total polyphenol content was measured using a slightly modified Folin-Denis method, which uses the phenomenon that a phenolic substance turns blue by reaction with phosphomolybdate. Conclusion : We analyzed SOD enzyme activity related to the scavenging of superoxide anion radical (․O2-) through NBT reduction. As for the SOD activity of leaf extract by variety, the activity was 92.6%, 91.0% and 92.6%, respectively, in Tainung-2 on day 98, 127 and 141 from sowing, slightly higher than those in the other two varieties but not significantly different. The activity was slightly higher in the middle period of growth than in the harvest period, but not much different according to harvest time. As for the DPPH radical scavenging activity of leaf extract by variety, the activity was 80.87% and 80.71%, respectively, in Tainung-2 on day 98 (30th of October)and day127 (28th of September), slightly higher than the other two varieties.

Background : Buckwheat (Fagopyrum spp.) is an annual crop belonging to the polygonaceae family and cultivated in most of Asian and European countries. Nowadays, many people take interest in the utilization of buckwheat seed because of its high nutritional and pharmaceutical values. Especially, tartary buckwheat is drawing attention for its high rutin content, which is beneficial to health. Methods and Results :　Tartary buckwheat sprout (TBS) was powdered and two grams of powder was mixed with 4 ㎖ H2O in a glass petri disc (100 x 20 ㎜) and exposed to far infrared irradiation (FIR) at different temperature (80, 100, 120, 140, 160℃) for an hour each. Further, the FIR treated powdered sprout samples were suspended in 200 ㎖ of 80% ethanol (v/v) and kept overnight in a shaker at room temperature. The extracts were filtered through Advantec 5B Tokyo Roshi Kaisha Ltd., Japan and dried using a vacuum rotatory evaporator (EYLA N-1000, Tokyo, Japan) in a 40℃ water bath. Dried samples were weighed and kept at 4℃ for further analysis. Conclusion : Total polyphenol was evaluated by Folin-Ciocalteau assay and total flavonoid by aluminum nitrate colorimetric assay, while antioxidant properties were evaluated based on DPPH free radical scavenging activity, metal chelating property and total antioxidant capacity. This study showed that FIR treatment to TBS caused a decrease in total antioxidant capacity and metal chelation property. However, there was a slight increase in total polyphenol and total flavonoid content from 80 to 120℃. Similarly, DPPH free radical scavenging activity also increased in the same way as TP and TF in TBS. The HPLC result revealed that quercetin production was directly proportional to temperature, and the production (average 14.87 ㎎/g dw) of quercetin was highest at 120℃ (an hour’s treatment), which was 13.54 times higher than the control in TBS.

Background : Kenaf (Hibiscus cannabinus L.) is a member of the malvaceae family and has been prescribed in traditional folk medicine in Africa and India. It showed broad biologicas activities such as hepatoprotective activity, antioxidative activity and haematinic activity, Recently, immunomodulatory effect of kenaf extract has been elucidated. However, depigmenting activity from kenaf extract has not been evaluated. In the present study, the tyrosinase inhibitory effect of kenaf leaf extract was investigated before and after subjecting the extract to together with infrared(FIR) irradiation. Methods and Results :　FIR irradiation involves electromagnetic waves with wavelengths ranging from 4 to 15 μM. It has been hypothesized that FIR treatment during extraction of polyphenols from plant cells stimulates exudation of chemical components in cells without destroying the cells by radiant heat and breaks covalent bonds of polymerized polyphenols resulting in the release of active, natural antioxidants with a low molecular weight. The purpose of this study was to evaluate not only the changes in antityrosinase activity but also the chemical transformation of kenaf extract exposed to FIR(Scheme 1). Conclusion: The tyrosinase inhibitory activity of kenaf xtract was evaluated after far-infrared (FIR) irradiation. The ethanol extract of kenaf was prepared and its main component was analyzed as a kaempferitrin (kaempferol-3,7-O-a-dirhamnoside). Inhibitory activity of kenaf extract was not detected in tyrosinase assay. However, tyrosinase inhibitory activity was observed in kenaf extract treated with FIR irradiation. After 60 min of FIR irradiation onto kenaf extract at 60oC, a ethanolic extract was prepared and it showed significant tyrosinase inhibitory activity (IC50=3500ppm). According to HPLC analysis, kaempferol, afzelin and minor product were detected(. The inhibitory activity may be due to the existence of kaemperol, afzelin and minor product. This study showed that FIR irradiation method can be used as a convenient tool for deglycosylation of flavonoid glycoside.