Subcritical water extraction of phytochemicals from Phlomis umbrosa Turcz

Min Jung Ko, Jeong Hyun Lee, Hwa Hyun Nam, Myong Soo Chung

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21 Scopus citations


Subcritical water extraction (SWE) avoids the use of organic solvents when extracting active compounds. The SWE of phytochemicals from Phlomis umbrosa Turcz (PT) and the effect of antioxidant activity were investigated while varying the extraction temperature (from 100 °C to 200 °C) and time (from 5 to 25 min). The maximum yields of total polyphenols (142.02 ± 5.67 mg/g PT, mean ± SD) and flavonoids (33.69 ± 3.01 mg/g PT) were obtained for an extraction temperature and time of 200 °C and 20 min, respectively. The correlation of antioxidant activities in terms of their total phenolics and flavonoids contents suggest that the ABTS[rad]+ assay better reflects the antioxidant contents in SWE from PT than does the DPPH assay for extraction temperatures from 110 °C to 200 °C. At higher temperatures around 200 °C, SWE extracts affect the antioxidant activity due to the presence of not only flavonoids but also nonflavonoid phenolic compounds including prenylated flavonoids. Industrial relevance This study used subcritical water extraction (SWE) for the practical applications of the SWE process that extracts antioxidant compounds from medicinal herb such as Phlomis umbrosa Turcz. SWE is excellent technology to selectively extract bioactive compounds using temperature-dependent dielectric constant properties of water. As the temperature of water is increased, the polarity of water decreases. That's why it is selective extraction. The use of SWE in the present study was associated with high efficiency and antioxidant activities. These results indicate that SWE is an efficient and rapid method for extracting phytochemicals, and a safer product only using purified water. SWE has a potential to develop a commercial process for the extraction of phytochemicals. This method can be easily implemented on an industrial scale.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalInnovative Food Science and Emerging Technologies
StatePublished - Aug 2017

Bibliographical note

Funding Information:
The paper was supported by RP-Grant 2016 of Ewha Womans University. This research was also supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2016R1D1A1B03930300).

Publisher Copyright:
© 2017 Elsevier Ltd


  • Antioxidant activity
  • Flavonoids
  • Phenolics
  • Phlomis umbrosa Turcz
  • Shanzhiside methyl ester
  • Subcritical-water extraction


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