This study was conducted in order to investigate the antioxidant and antimicrobial activity of Solanum nigrum L. fruit powder after undergoing different extraction solvent processes. The total phenolic content of Solanum nigrum L. fruit powder measured a 14.66 GAE mg/g after undergoing ethanol extraction, and the total flavonoid content measured at 201.23 mg CE/g when undergoing ethanol extraction. The ABTS radical scavenging activity was 160.38~209.53 TEAC umol/g, and the DPPH radical scavenging activity was 53.99~90.76 TEAC umol/g, which indicated a higher level of antioxidant power in the ethanol extract as opposed to in the water extract. The FRAP (ferric reducing antioxidant power) of Solanum nigrum L. fruit powder was 115.58~194.58 TEAC umol/g, and B. subtilis KCTC 2189 showed greater antimicrobial activity in the ethanol extract (concentration 200 ug/uL) as opposed to the water extract. Solanum nigrum L. fruit powder revealed differences in antioxidant and antimicrobial activity between the different extraction solvents. In particular, ethanol extract had higher antioxidant and antibacterial activity, meaning it is more favorable for usage as a functional food material.

In this study, we investigated the variation in free sugars, organic acids, antioxidant activity and anti-inflammatory effect of Solanum nigrum Linne fruits according to harvest time. Four kinds of free sugars (fructose, glucose, sucrose, maltose) were detected in S. nigrum fruit, and the free sugar contents varied significantly with harvest time. Organic acid content of S. nigrum fruit showed the highest in malic acid and acetic acid, and the highest content of total organic acids was found in S. nigrum fruit harvested on October 18th and October 25th. For the total polyphenol content, S. nigrum fruit harvested on October 18th was the highest. The strongest DPPH and ABTS radical scavenging activity was showed in S. nigrum fruit harvested on October 11th and October 18th. The anti-inflammatory activity and antioxidant effects were the highest in the ethanol extract from S. nigrum fruit collected on October 18th and October 11th. Thus, it seems the best to harvest of S. nigrum fruit harvested on October 11th and October 18th.