1. Analysis of Anthocyanins

1.1 Online Product Statistics of Anthocyanins and Proanthocyanidins

Blueberries, cranberries, and purple corn are the main sources of anthocyanins; grape seeds are the main source of proanthocyanidins.

The average content of anthocyanins or proanthocyanidins in products is 22.71%.

Anthocyanin - related products:

They have the functions of improving eyesight (brightening eyes), enhancing eye defense, anti - fatigue, antioxidation, and improving nutrition and sleep.

1.2 Comparison of Anthocyanin Compositions from Different Sources

Plant anthocyanins include cyanidin, delphinidin, pelargonidin, peonidin, malvinidin, and petunidin. Their distributions in nature are approximately 50%, 12%, 12%, 12%, 7%, and 7%, respectively (Khoo et al. 2017). Among them, Cyanidin 3 - O - glucoside is the most common.

1.3 Mining of Stable Components of Anthocyanins in Purple Corn

Due to their ionic structure, anthocyanins in solution exist as different chemical substances depending on the pH value.

Extracts obtained from different plants show different hue changes at different pH values.

Anthocyanins are sensitive to light and oxygen; they are unstable at alkaline pH, high temperatures, and when exposed to light.

The color and stability of anthocyanins are greatly affected by modifications such as hydroxylation, methylation, glycosylation, and acylation. The more hydroxyl groups on the B - ring, the bluer the color becomes, while O - methylation and glycosylation cause a slight shift to red; acylation of the glycoside moiety can also cause a blue - shift and increased stability.

Anthocyanins have the ability to regulate the composition and diversity of the gut microbiota, thus contributing to potential health - promoting effects, including reducing insulin resistance, obesity, inflammation, and cardiovascular problems (Jamar et al. 2017; Park et al. 2021; Pemmari et al. 2022).

The mono - acylated anthocyanin petanin (Pt3R5G) alleviates inflammation and cell death caused by hypoxia and ischemia in neuroblastoma cells by enhancing autophagy (Cai et al. 2020). (Phenolic acid metabolism)

The caffeoyl flavonoid glycoside montbretin A has a strong inhibitory effect on amylase and shows promise as an anti - diabetic drug (Yuen et al. 2016).

1.4 Optimization of Anthocyanin Extraction Method from Purple Corn

Large - scale extraction techniques:

Maceration, soaking, heat - assisted extraction, etc.

Solvents: Methanol, ethanol, water, acetone, or their mixtures.

Precautions:

Acidic solutions (such as formic acid, citric acid, or acetic acid, pH ~ 3) stabilize the flavylium cation. Water can increase the yield. Optimization of powder particle size, solvent - to - solid ratio, extraction time, temperature, etc.

Potential technical key points and breakthroughs:

Increasing the yield >>> Cell - wall - breaking enzyme - assisted extraction.

Identification of anthocyanins and stable components in purple corn.

Identification of components in other extracts of purple corn >>> Proportion of sugars, flavonoids, and other small molecules.

1.5 Key points

2. Flavonoid C - Glycosides in Purple Corn

2.1 Flavonoid C - Glycosides in Purple Corn

Composition:

Maysin

isoorientin (ISO)

apimaysin

3' - methoxymaysin

Content: Maysin:

2.5% DW

Isoorientin ISO: 2% DW

2.2 Biological Activities of Flavonoid C - Glycosides in Purple Corn

Anticancer activity:

Maysin improves benign prostatic hyperplasia (Kim et al., 2017) and induces apoptosis of PC - 3 prostate cancer cells (Lee et al., 2014). ISO is effective against lung cancer, brain cancer, oral cancer, liver cancer, pancreatic cancer, and gastric cancer (Laurindo et al., 2025, Zhang et al., 2022, Liu et al., 2021).

Immunomodulatory activity:

Maysin activates macrophages and positively regulates the immune response, enhancing the early innate immunity (Lee et al., 2014).

Inhibitory effect on adipocyte function:

Maysin inhibits adipogenesis, differentiation, and the function of adipocytes, improving obesity in mice (Leea et al., 2017). ISO regulates lipid metabolism to inhibit obesity (Ziqubu et al., 2020).

Anti - inflammatory / antioxidant activity:

Dietary addition of ISO improves complications caused by metabolic diseases such as hyperglycemia, hyperlipidemia, and insulin resistance (Ziqubua et al., 2020).

Neuroprotective activity:

Maysin is used in the research of Parkinson's disease and has a protective effect against the damage caused by α - Syn amyloid aggregates, oligomers, and fibrils (Leri et al., 2020). ISO has antidepressant potential (Alves et al., 2020).

2.3 Development of Extraction Protocol for Flavonoid C - Glycosides in Purple Corn

Large - scale extraction techniques: Maceration, soaking, heat - assisted extraction, etc.

Solvents: Dichloromethane, benzene, ethyl acetate, diethyl ether, chloroform, or their mixtures.

Temperature:

3. Purification Capacity

Large - scale extraction:

Column - chromatography separation and preparation:

High - purity preparation: