In vitro antioxidants and antihypertensive properties of corn silk–lemon infusion

Abstract

Abstract Background Agricultural waste generated annually results to environmental pollution; these wastes are rich sources of important bioactive compounds and could be used therapeutically in the management of some ailments. Corn silk, a by-product of sweet corn and whole lemon were processed separately into corn silk flour (CSF) and lemon flour (LF). Flour blends formulation used were as follows: 100% CSF (A), 95% CSF and 5% LF (B), 90% CSF and 10% LF (C), 85% CSF and 15% LF (D) and 80% CSF and 20% LF (E). Chemical compositions of the blends were investigated, while the total phenol content (TPC), total flavonoid contents (TFC), polyphenol profile, antioxidant activities, α-amylase, α-glucosidase inhibitory activities, nitric oxide, L-arginase, Angiotensin-I-Converting Enzyme (ACE) inhibitions as well as the colour and sensory attributes of the infusions were investigated using standard methods. Results The moisture and total ash contents increased proportionally with increased substitution of LF as moisture content ranged from 4.83 to 8.40% and the total ash content ranged from 2.32 to 3.25%. The calculated energy values decreased from 390.48 to 361.42 kcal, with increase in LF. Potassium (K) contents also increased with values ranging from 4.65 to 5.82 mg/100 g, increase in LF incorporation promoted a decrease in the Na/K ratio from 0.8 to 0.55; the Phy:Ca and Phy:Zn ratios ranged from 1.20 to 2.86 and 2.08 to 4.04, respectively. No significant difference was observed in consumer acceptability but there were total colour differences (ΔE) in the infusion as compared to the control samples. Samples A and B exhibited notable antioxidant properties, α-amylase, α-glucosidase inhibitory activities, nitric oxide, L-arginase and the ACE inhibitory activities compared favourably with the commercial samples. Conclusion This study revealed that corn silk–lemon infusion especially sample A (100% CSF) may be a therapeutic tool in lowering blood pressure because it possesses potent antihypertensive properties.