Undescribed C-Glycosylflavones from Corn Silk and Potential Anti-inflammatory Activity Evaluation of Isolates

Abstract

Phytochemical investigation of corn silk resulted in isolation and characterization of four flavone C-glycosides, chrysoeriol 6-C-β-oliopyranosyl-7-O-β-D-glucopyranoside (1), 3′-methoxycassiaoccidentalin A (2), chrysoeriol 6-C-β-boivinopyranosyl-7-O-β-D-glucopyranoside (3), and ax-4"-OH-3′-methoxymaysin (4), a triterpenoid, friedelin (5), two sterols, (22E)-5,8-epidioxyergosta-6,22-dien-3β-ol (6) and 6β-hydroxystigmasta-4,22-diene-3-one (7), and a mixture of β-sitosterol and stigmasterol. Compounds 1 and 2 were previously undescribed. Structure elucidation of the isolated compounds was attained using spectral data including 1D and 2D NMR and HRESIMS. Compounds 1, 2, 5, and 6 inhibited iNOS activity in LPS-induced macrophages and decreased nitrite levels by 68.64+4.46, 65.67 + 6.47, 88.50 + 0.50, and 94.00 + 4.00 %, respectively, at 50 µM. Compound 5 also showed inhibition of NF-κB (51.00+1.50 %). Compounds 1 and 2 induced NAG-1 activity in chondrocytes by 1.80 + 0.05 and 2.00 + 0.13 fold, respectively. The extract of corn silk, however, did not exhibit inhibition of iNOS or NF-κB but induced NAG-1 by 1.80+ 0.51 fold.

An Umbrella Insight into the Phytochemistry Features and Biological Activities of Corn Silk: A Narrative Review

“…Furthermore, in modern clinics, corn silk is applied to treat various diseases, such as nephritis, acute and chronic pneumonia, diabetes, hypertension, and edema [6]. In addition, many modern pharmacological activities, such as antihypertension activities [7], lowering blood lipids [8], anti-inflammatory activities [9], anti-urolithiasis activities [10], anti-oxidant activities [11], protecting the liver [12], and other effects [13] have been verified in previous studies.…”

Phytochemical study: Fragmentation patterns of flavonoid‐C‐glycosides in the enriched flavonoids from corn silk using high‐efficiency ultra‐high‐performance liquid chromatography combined with quadrupole time‐of‐flight mass spectrometry

“…Modern studies showed that corn silk owned diversiform ingredients, including flavonoids [17,18], polysaccharides [19,20], polyphenols [21], amino acids [22], and other components [23], among which flavonoids with antiinflammatory [24,25], antioxidant [26], and other helpful biological activities [27] were especially abundant. Our previous study has revealed that the main constituents absorbed into the blood of corn silk were flavonoids [28], indicating flavonoids may be the nominated material basis of pharmacological effects.…”