Phytochemicals, Nutritional Analysis and In vitro Antioxidant Activities of Pickled Perilla frutescens Ethanolic Leaf Extract

Abstract

Aims: With pickled perilla leaves as raw materials, this paper proposed the optimal ethanol extraction conditions and made a profound analysis for extract in the compositions of major active ingredients, nutrients, mineral elements and amino acid to characterize the nutritional and biological properties of pickled perilla leaves, which could aid its finely processing and future application in the development of functional food. Methods: The optimum ethanol extraction process for preparing freeze-dried powder from pickled perilla was studied by means of orthogonal experiments, with the concentration of ethanol, extracting temperature and extracting time as factors. Meanwhile, the contents of the activity components, such as polysaccharide, flavones and rosmarinic acid, as well as the mineral elements and nutritional contents in the freeze-dried powder were determined according to the methods reported by relevant literatures without or with a few modifications. Results: The optimal extracting conditions as follows: 50ºC of temperature, 60 min of extraction time and 80% of ethanol concentration. Under the optimal extracting conditions, the extraction rate of the freeze-dried powder was 1.71%. Moreover, perilla leaf extract contained rich biological and nutritional ingredients, including 33.39% of flavonoids, 9.24% of polysaccharides, 22.79% of rosmarinic acid, 5.47% of protein, 7.61% of fat, 2354 mg/kg of Ca, 111.4 mg/kg of Fe, 5.045 mg/kg of Zn, 1817 mg/kg of K , 12.66 mg/kg of Mn and nine of essential amino acids. In addition, perilla leaf extract exhibited obvious scavenging effects on the DPPH•, •OH and O2-•. Conclusion: In summary, pickled perilla leaf ethanol extract was rich in biological ingredients as well as a variety of nutrients, and showed antioxidant activities in vitro, thus it is valuable and promising in the development of functional foods in the future.