Introduction and Experimental Background
Houttuynia cordata is a perennial herb native to China, Japan, and South Korea. It is 25–30 cm tall, its stems are thin and reddish violet, its leaves are heart-shaped and its tips are pointed, and its juices smell very similar to 'fishy smell' in its leaves and stems . According to the Publication and Bibliographical Characteristics of Hyangyak, Houttuynia cordata is known to have inflammation, detoxification, hemorrhoids, gonorrhea, uterine inflammation, pneumonia, bronchitis, athlete's foot, and diuretic effects, and to relieve symptoms such as vitiligo, bronchitis, and hepatitis . In Japan, it is known as a herbal medicine that has excellent effects on many diseases, such as being nicknamed Chinese medicine or Houttuyniae Herba. In China, it is also known as a Pulmonary plant, walnut plant, and guza, but it is also called Chuyeongdan or Phyllanthus urinaris because it is a reverse drug that gives off a strong smell such as fishy smell when injured in any part of the outpost .
Houttuynia cordata is a traditional medicinal plant that has been reported to have a wide range of therapeutic effects such as aquatic species, syphilis, bladder inflammation, uterine inflammation, pulmonary inflammation, and mesenchymal wind , and that contains antioxidant materials such as quercetin, quercitrin, rutin, and myricetin. Experiments on acne-causing bacteria and inflammation in Houttuynia cordata extracts reported increased NO production inhibition and increased DPPH radical elimination , and anti-allergic effects significantly inhibited passive skin anaphylaxis reactions PCA and systemic anaphylaxis shock in Houttuynia cordata [Histamine and IgE]. Until now, studies of Houttuynia cordata have reported antimicrobial activity , antioxidant , anti-tumor , anti-leukemia and hyperlipid blood inhibitory effects , and quercitrin, the main physiological activity of Houttuynia cordata, has been reported to have various physiological activation functions .
Research details and experimental results
The antioxidant and whitening effects of Houttuynia cordata extracts were analyzed as raw materials for natural cosmetics of resource plants in Namwon and Mt.Jiri areas. First, the DPPH radical erasing activity was investigated to save antioxidant effects. The DPPH radical erasability of Houttuynia cordata ethanol extract was measured by modifying the Blois method  for 2,2-diphenyl-1-dicrylhydrazyl (DPPH) radical erasivity. A mixture of 400㎕ of 200 mM DPPH (Sigma Aldrich Co., St. Louis, MO, USA) solution and 100㎕ of ethanol in 100㎕ diluted samples at a certain concentration was measured at room temperature for 30 minutes and then measured at ELISA reader at 517㎚(Spark 10M, Tecan, Mandorf, Switzerland). As shown in Figure 1, the measurement of Houttuynia cordata ethanol extracts showed excellent radical erasure activity of 79% at the concentration of 1000㎍/ml of DPPH radical erasure, and the SC50 value was 85㎍/mL. In addition, the total polyphenol content was 40mg/g and the total flavonoid content was 34mg/g, showing excellent antioxidant effects.
Experiments on whitening effects of Houttuynia cordata extract showed that in Figure 2. The method of measuring melanin pigment production capability was inoculated with 0.5×105 cell water in a 6well culture plate and incubated at 37℃ for 24 hours in a CO2 culture medium. Alpha-melanocyte-stimulating hormone (α-MSH) was used to induce hyperpigmentation, and the specimen was treated for 72 hours. The cells that were cultivated were separated and cleaned with trypsin/EDTA, measured at 402 nm absorbance, and treated with 150 μM of 4BR (Rucinol) as a positive control. After calculating and collecting the same number of cells per group, the color change of cell sediment was observed visually. Cells were collected and the amount of melanin finally produced was measured, resulting in approximately 28% inhibition at 100㎍/ml treatment compared to α-MSH treatment. Tyrosinase active inhibitors were also experimented in the same way, and cells dissolved with Lysis buffer were reacted with LDOPA and absorbance was measured at 475 nM. Measurements of tyrosinase inhibitory activity of Houttuynia cordata extracts show approximately 30% inhibition at 100㎍/ml treatment zones compared to controls. Based on these findings, it is expected that the extract of Houttuynia cordata in Namwon and Jirisan areas will be highly valuable as a raw material for natural cosmetics and will be able to utilize it with excellent antioxidant and whitening effects.