Phytochemical Investigation of Equisetum arvense and Evaluation of Their Anti-Inflammatory Potential in TNFα/INFγ-Stimulated Keratinocytes

Abstract

Equisetum arvense L. (Equisetaceae), widely known as ‘horsetail’, is a perennial plant found extensively across Asia. Extracts of E. arvense have been used in traditional medicine, particularly for the treatment of inflammatory disorders. This study aimed to determine the phytochemical compounds in E. arvense ethanolic extract and their anti-inflammatory properties. Subsequently, we isolated and identified nine secondary metabolites, including kaempferol 3,7-di-O-β-D-glucopyranoside (1), icariside B2 (2), (Z)-3-hexenyl β-D-glucopyranoside (3), luteolin 5-O-β-D-glucopyranoside (4), 4-O-β-D-glucopyranosyl caffeic acid (5), clemastanin B (6), 4-O-caffeoylshikimic acid (7), (7S,8S)-threo-7,9,9′-trihydroxy-3,3′-dimethoxy-8-O-4′-neolignan-4-O-β-D-glucopyranoside (8), and 3-O-caffeoylshikimic acid (9). The chemical structures of the isolated compounds (1–9) were elucidated using HR-ESI-MS data, NMR spectra, and ECD data. Next, the anti-inflammatory effects of the isolates were evaluated in tumor necrosis factor (TNF)α/interferon (IFN)γ-induced HaCaT, a human keratinocyte cell line. Among the isolates, compound 3 showed the highest inhibitory effect on the expression of pro-inflammatory chemokines, followed by compounds 6 and 8. Correspondingly, the preceding isolates inhibited TNFα/IFNγ-induced activation of pro-inflammatory transcription factors, signal transducer and activator of transcription 1, and nuclear factor-κB. Collectively, E. arvense could be employed for the development of prophylactic or therapeutic agents for improving dermatitis.

Cycloolivil Isolated from Nardostachys jatamansi Inhibits TNF-α/IFN-γ-Induced Chemokine Production by Blocking NF-κB and JAK/STAT Activation in HaCaT Keratinocytes

“…In this study, 14 compounds were isolated from N. jatamansi, which is traditionally used to treat various diseases, including liver diseases. The isolated compounds were structurally identified as olivil (1), cycloolivil (2), 2-(3'-hydroxy-5'-ethoxyphenyl)-3-hydroxylmethyl-7-methoxy-2,3-dihydrobenzofuran-5-carboxylic acid (3), teuclatriol (4), bullatantriol (5), 1β,4β,7α-trihydroxyeudesmane (6), nardoeudesmol A (7), debilon (8), nardonoxide (9), nardosinone (10), 4β-hydroxy-8β-methoxy-10-methylene-2,9-dioxatricyclo[4.3.1.0 3,7 ]decane (11), jatamanins A (12), 4α,5-dimethyl-1,3-dioxo1,2,3,4,4α,5,6,7-octahydronaphthalene (13), and kanshone M (14) through 1D and 2D NMR. Among the isolated compounds, cycloolivil (2) and 2-(3'-hydroxy-5'-ethoxyphenyl)-3-hydroxylmethyl-7-methoxy-2,3-dihydrobenzofuran-5-carboxylic acid (3) are the first to be discovered in N. jatamansi.…”

“…Fourteen compounds were isolated from the ethyl acetate fraction partitioned from the methanol extracts of N. jatamansi through various chromatographic techniques, and their chemical structures were elucidated using nuclear magnetic resonance (NMR) analysis and mass spectrometry. The identified compounds included olivil (1), cycloolivil (2), 2-(3 ′ -hydroxy-5 ′ -ethoxyphenyl)-3-hydroxylmethyl-7-methoxy-2,3-dihydrobenzofuran-5-carboxylic acid (3), teuclatriol (4), bullatantriol (5), 1β,4β,7α-trihydroxyeudesmane (6), nardoeudesmol A (7), debilon (8), nardonoxide (9), nardosinone (10), 4β-hydroxy-8βmethoxy-10-methylene-2,9-dioxatricyclo[4.3.1.0 3,7 ]decane (11), jatamanins A (12), 4α,5dimethyl-1,3-dioxo1,2,3,4,4α,5,6,7-octahydronaphthalene (13), and kanshone M (14) (Figure 1). Notably, this is the first report of compounds 2 and 3 being isolated from N. jatamansi.…”

“…Tumor necrosis factor (TNF)-α and interferon (IFN)-γ promote the production of inflammatory cytokines in human keratinocyte cell lines, such as HaCaT keratinocytes [ 8 ]. The overproduction of these inflammatory cytokines damages keratinocytes and reduces the rate of cell proliferation, contributing to the development of various inflammatory skin diseases, such as atopy and psoriasis [ 9 ].…”

“…Tumor necrosis factor (TNF)-α and interferon (IFN)-γ promote the production of inflammatory cytokines in human keratinocyte cell lines, such as HaCaT keratinocytes [8].…”