**4. Flavonoids in pigmented corn**

for the free acids, they performed an extraction with 80% ethanol using a high-performance disperser, then the residue was assisted by adding an enzyme cocktail (pectinases, amylases and cellulases). To the residue of this, they made a thermal hydrolysis doing another extraction with methanol and 70°C. Finally, to the solid residue of this extraction, they added NaOH

In the case of phenolic acids present in corn silk, they only report extractions with organic solvents; for example, performing a direct extraction of the silk, using 95% methanol, centrifuging and using the supernatant for quantification and characterization [35]; other studies use 50% ethanol [21]. In the same way, for the case of the phenolic acids of the cob where they

To carry out the characterization and quantification of each of the phenolic acids perform

The phenolic acids present in the pigmented corns are of great importance due to the biological effects on human health [56], such as anticancer properties, antimutagenic, anti-inflammatory and cardiovascular diseases [56]. **Table 6** shows the biological properties of each of the

The biological activity that most report is as antioxidant, with phenolic acids having the capacity to reduce the free radical formation and elimination of ROS, inhibition and repair of lesions caused by the oxidation and degradation of other molecules and biomolecules [57].

> Anticancer properties [57] Against cardiovascular diseases [56]

Reduce visceral adiposity index [21, 35]

[52]

[32]

**Phenolic acid Biological activity Ref.** Ferulic acid Potential antioxidant [24, 52]

Coumaric acid Reduction of blood glucose [21]

Allelopathic effects

Caffeic acid Immunostimulatory properties [58] *p*-Hydroxybenzoic acid Immunostimulatory properties [58] Vanillic acid Reduction of blood glucose [21] Chlorogenic acid Potential antioxidant [58]

Antihypertensive

describe a simple extraction using methanol and centrifugation [32].

chromatography techniques: such as HPLC and HPLC-MS [52–55].

**3.5. Biological activity of pigmented corn phenolic acids**

phenolic acids present in the pigmented corn plant.

Diferulic acid Potential antioxidant

Syringic acid Effect against cerebral ischemia

**Table 6.** Phenolic acids present in pigmented maize and their biological properties.

to carry out a basic hydrolysis [55].

82 Corn - Production and Human Health in Changing Climate

Other import group of the bioactive compounds that contain the pigmented corns are of flavonoids; with>4000 compounds, these molecules are most abundant polyphenols present in plant foods. They are characterized by a 15-carbon skeleton, organized as C6-C3-C6, with different substitutions making up the different subclasses. The major groups of the flavonoids of nutritional interest are the flavonols or catechins [59].

The most common chemical structures of flavonoids in corn are shown in **Figure 6**, and the composition of flavonoids in different parts of is presented in **Table 7**.
