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. 2023 Feb 2:2023:5685174.
doi: 10.1155/2023/5685174. eCollection 2023.

Extraction Optimization, Preliminary Identification, and Bioactivities in Corn Silk

Ping Li  1 , Guangxi Ren  1 , Yifan Sun  1 , Dan Jiang  1 , Chunsheng Liu  1
Affiliations

Extraction Optimization, Preliminary Identification, and Bioactivities in Corn Silk

Ping Li et al. Evid Based Complement Alternat Med. .

Abstract

For thousands of years, corn silk has been widely used as an antidiabetic, antioxidant, and antihyperlipidemic and for other effects, but there is a lack of studies that correlate the extracts of flavonoid composition with their biological activities. Thus, the objectives of this study were to optimize the conditions for extracting flavonoids, identify flavonoids, and correlate the flavonoid composition with the biological activities in corn silk. The response surface experiments showed that the highest flavonoid content was predicted at 45.321 min, 57.349°C, 26.089 mL/g, and 71.269%, respectively. The verification experiment results under these optimized conditions showed an ultrasonic time of 45 min, an ultrasonic temperature of 57°C, a liquid-to-material ratio of 26, and an ethanol volume fraction of 70%. No significant differences (the relative error is 4.378%) were observed between the theoretical and experimental TFC values, indicating that the developed models were accurate. Under these optimum extraction conditions, 20 major compounds were identified and quantified by UPLC-LTQ/Orbitrap MS. Furthermore, these optimum ethanol extracts of corn silk are effective against Bacillus subtilis and hypoglycemic activity compared with the traditional heating reflux extraction method. Six corn silk components seem to be the main contributors to the inhibitory effect against Bacillus subtilis and hyperglycemia activities. These results are useful for the application of corn silk in the food or pharmaceutical industry.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
The standard curve of rutin in the range of 0.016 mg/ml–0.08 mg/ml.
Figure 2
Figure 2
Variation of the total flavonoid yield of corn silk with different single factors. (a) Ultrasonic power, (b) ultrasonic time, (c) ultrasonic temperature, (d) liquid-solid ratio, and (e) ethanol concentration.
Figure 3
Figure 3
The effect of the interaction of two factors on the yield of corn silk flavonoids. (a) The 3-dimensional model of the interaction of ultrasonic time and ultrasonic temperature on the yield of corn silk flavonoids. (b) The 2-dimensional model of the interaction of ultrasonic time and ultrasonic temperature on the yield of corn silk flavonoids. (c) The 3-dimensional model of the interaction of ultrasonic time and liquid-solid ratio on the yield of corn silk flavonoids. (d) The 2-dimensional model of the interaction of ultrasonic time and liquid-solid ratio on the yield of corn silk flavonoids. (e) The 3-dimensional model of the interaction of ultrasonic time and ethanol concentration on the yield of corn silk flavonoids. (f) The 2-dimensional model of the interaction of ultrasonic time and ethanol concentration on the yield of corn silk flavonoids. (g) The 3-dimensional model of the interaction of ultrasonic temperature and liquid-solid ratio on the yield of corn silk flavonoids. (h) The 2-dimensional model of the interaction of ultrasonic temperature and liquid-solid ratio on the yield of corn silk flavonoids. (i) The 3-dimensional model of the interaction of ultrasonic temperature and liquid-solid ratio on the yield of corn silk flavonoids. (j) The 2-dimensional model of the interaction of ultrasonic temperature and liquid-solid ratio on the yield of corn silk flavonoids. (k) The 3-dimensional model of the interaction of liquid-solid ratio and ethanol concentration on the yield of corn silk flavonoids. (l) The 2-dimensional model of the interaction of liquid-solid ratio and ethanol concentration on the yield of corn silk flavonoids. Meaning of coordinate axis: (A) ultrasonic time (min), (B) ultrasonic temperature (°C), (C) liquid-solid ratio (mL/g), and (D) ethanol concentration (%).
Figure 4
Figure 4
Different concentrations of corn silk ethanol extracts had different inhibitory effects on Bacillus subtilis. The criteria for antibacterial effects are as follows: diameter >20 mm means extremely effective, 15∼20 mm means highly effective, 10∼15 mm means moderately effective, 7∼9 mm means slightly effective, and absence of inhibition zones means ineffective.
Figure 5
Figure 5
The results of qualitative analysis. (a) TIC of the ethanol extract of corn silk in a negative ion mode. (b) The chromatograms of 20 compounds. (c) The secondary fragment ion patterns of 20 compounds.
Figure 6
Figure 6
Typical fragmentation pathways of two main chemical components. (a) The fragmentation pathway of rutin. (b) The fragmentation pathway of linoleic acid.
Figure 7
Figure 7
Targets related to 6 components with Bacillus subtilis and hyperglycemia. (a) 22 common targets related to 6 components and Bacillus subtilis. (b) 20 common targets related to 6 components and hyperglycemia.
Figure 8
Figure 8
PPI network of related targets. (a) PPI of common targets related to 6 components and Bacillus subtilis. (b) PPI network of common targets related to 6 components and hyperglycemia.
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