Extraction and Evaluation of Bioactive Compounds from Immature and Mature Corn Silk

Abstract

The purpose of this research was to assess the mineral content, bioactive compounds, α-glucosidase inhibitory activity, and antioxidant of two-maturity stages of corn silks, i.e., immature and mature with standard methods. Corn silks have been dried with sun and oven-drying methods and extracted through methanol and water, two individual solvents. The results revealed that both corn silks were good sources of mineral content. The higher calcium (13.37 ± 0.06) and magnesium (890.00 ± 0.00) were found in the sun-dried immature corn silk. The sun-dried mature corn silk also exhibited a higher content of iron, zinc, and manganese. The results also revealed that all the extraction systems yielded significant amounts of TPC, TFC, β-carotene, and anthocyanin content; ABTS and DPPH radical scavenging activity; and α-glucosidase inhibitory activity. Moreover, sun-dried methanolic extracts exhibited the highest levels of TFC (127.58 ± 7.95 mg QE/100 g DM), β-carotene (0.28 ± 0.00 mg/100 mL), TAC (42.53 ± 1.02 mg C3GE/kg DM), DPPH (75.65 ± 2.38%), and ABTS (94.22 ± 0.00%), showcasing their superior antioxidant potential. Conversely, oven-dried methanolic extracts demonstrated a higher TPC of 20.82 ± 0.62 mg GAE/g DM, while water extracts showed maximum α-glucosidase inhibitory activity of 76.19 ± 0.00%. Therefore, the obtained results demonstrated that sun-dried methanolic extracts from corn silks might be a good source of therapeutic agents and natural ingredients for manufacturing food, feed, and pharmaceutical products. It could also encourage researchers to carry out more studies to commercialize corn silk.