Antimicrobial Effect, Antioxidant and Tyrosinase Inhibitory Activity of the Extract from Different Parts of Phytolacca americana L.

Abstract

This study was conducted to clarify the anti- microbial effect, antioxidant and tyrosinase inhibitory activities of the biological composition having the Phytolacca americana, and to enhance the natural materials utilization of foods and cosmetics. The antimicrobial activities of the different parts of P. americana were evaluated using the agar diffusion test. The antimicrobial activity of P. americana was relatively high in Malassezia furfur known as a skin fungi and Vibrio parahaemolyticus compared to Escherichia coli and Staphy- lococcus epidermidis. However, the antimicrobial activity in Vibrio parahaemolyticus did not show at all parts of P. americana. Both the DPPH radical scavenging activity and ABTS radical scavenging activity have been increased with the higher concentration of methanol extract. In particular, leaf extract of P. americana exhibited the highest activity both ABTS radical scavenging activity and DPPH radical scavenging activity. The nitrite scavenging activity was decreased when the pH was changed from pH 1.2 to pH 6.0. The highest nitrite scavenging activity was exhibited from the methanol extract of fruit, followed by root, stem, and leaf at pH 1.2. However, the nitrite scavenging activity at pH of 6.0 was not almost detected. All plant parts of P. americana showed tyrosinase inhibitory activity. The highest activity was found in the stem, and followed by root, leaf, and fruit in order. These tyrosinase inhibitory activity was progressively increased in a concentration-dependent manner. In this experiment on the methanol extracts of different organ from P. americana, we confirmed that the extract of P. americana showed potent tyrosinase inhibitory activity. Taken together, we conjectured that the P. americana had the potent biological activities, therefore this plant having various functional components could be a good material for development into source of natural food additives and cosmetics. Phytolacca americana L. is a perennial plant belonging to the family Phytolaccaceae and is a native plant of North America. This plant was introduced to Korea from the native country, now found in both grassland and forest. P. americana have a toxic in all parts of stem, leaf, fruit, and root. Especially, the root has the highest toxic, but ripe fruit is known to have relatively low toxicity. In addition, its root has been used as a traditional crude diuretic drug, therapeutic purposes of rheumatoid arthritis and swelling in spite of having a strong toxicity. And the pigment extracted from the fruit has been used as additive material of foods and coloring material on the nails of women. P. americana poisoning is a benign plant intoxication that causes gastrointestinal symptoms, including abdominal cramps, vomiting, diarrhea, and gastrointestinal bleeding (Kim et al., 2008). The biological activities of P. americana have been investigated by many researchers with their substance research (Shao et al., 1999; Bylka and Matlawska, 2001; Wang et al., 2008). Recently, plant and plant-derived products are treated a part of the healthcare system by applying the bioactive phytochemicals. Medicinal plants, including P. americana are good sources of antimicrobial agents. Many infectious diseases have been known to be treated with herbal extracts. The clinical efficacy of many existing antibiotics is being threatened by the emergence of multidrug-resistant pathogens (Goveas and Abraham, 2013). The evaluation of antimicrobial property of P. americana is of great interest and importance. Antioxidant compounds in food play an important role as a health protecting factor. Scientific evidence suggests that antioxidants reduce the risk for chronic diseases, including cancer and heart disease. Most of the antioxidant compounds in a typical diet are derived from plant sources and belong to various classes of compounds with a wide variety of physical and chemical properties. The main characteristic of an