Abstract
Angelica keiskei Koidzumi (A. keiskei), as a Japanese edible herbal plant, enjoys a variety of biological activities due to the presence of numerous active compounds, especially flavonoids. This study aims for the optimization of ultrasound-assisted extraction (UAE) for flavonoids in A. keiskei and their antioxidant activity by using the response surface methodology (RSM). Single-factor experiments and a four-factor three-level Box–Behnken design (BBD) were performed to explore the effects of the following parameters on flavonoid extraction and antioxidant activity evaluation: ultrasonic temperature (X1), ultrasonic time (X2), ethanol concentration (X3) and liquid–solid ratio (X4). The optimum conditions of the combination of total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (DPPH-RSC) and ferric-reducing antioxidant power (FRAP) were as follows: X1 = 80 °C, X2 = 4 min, X3 = 78%, X4 = 35 mL/g, respectively. The experimental results provide a theoretical basis for the extensive utilization of A. keiskei and flavonoids extraction from A. keiskei as a potential source of antioxidants.
Highlights
Angelica keiskei Koidzumi (A. keiskei), a clumping perennial herb member of the Umbelliferae family, has been described as “Ashitaba” or “Japanese angelica” in Japan [1,2], “Shin-sun cho” or “Myeong-ilyeob” in Korea [3] and “Ming-ri-ye” in China [4]
It is generally accepted that the speed of molecular motion, diffusion speed, penetration and dissolution rise rapidly when ultrasonic temperature increases, which contributes to the improvement of total flavonoid content (TFC)
Similar phenomena were found for the extraction of flavonoid compounds from Sophora flavescens [33], Fagopyrum tataricum [34]
Summary
Angelica keiskei Koidzumi (A. keiskei), a clumping perennial herb member of the Umbelliferae family, has been described as “Ashitaba” or “Japanese angelica” in Japan [1,2], “Shin-sun cho” or “Myeong-ilyeob” in Korea [3] and “Ming-ri-ye” in China [4]. As a native plant to the island of Hachijojima, the herb is mainly located in the Izu Islands of Japan [5,6], but it has been cultivated in other Asian countries, including China and South Korea [7]. The aerial parts of A. keiskei has been initially used as ordinary food, especially as vegetables and pickles [9]. It has been reported to possess properties of anti-oxidative [13], anti-bacterial [14], anti-virus [15], anti-osteoporosis [16], Molecules 2019, 24, 3461; doi:10.3390/molecules24193461 www.mdpi.com/journal/molecules
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