Nitric Oxide Inhibitory Constituents from the Fruits of Amomum tsao-ko

Abstract

Bioactivity-guided fractionation of MeOH extract of the dried fruits of Amomum tsao-ko led to isolation of nine compounds (1 -9). Their structures were elucidated by spectroscopic methods including extensive 1D and 2D-NMR, as alpinetin (1), naringenin-5-O-methyl ether (2), naringenin (3), hesperetin (4), 2',4',6'trihydroxy-4-methoxy chalcone (5), tsaokoin (6), boesenbergin B (7), 4-hydroxyboesenbergin B (8), and tsaokoarylone (9). Of these, compound 8 was isolated from a natural source for the first time, which was previously reported as a synthetic product. The isolated compounds (1 -9) were tested for their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages. Among them, three chalcone derivatives (compounds 5, 7, and 8) and a diarylheptanoid (compound 9) exhibited significant inhibitory activity on the NO production with IC 50 values ranging from 10.9 to 22.5 µM.

Metabolomics and Transcriptomics Reveal that Diarylheptanoids Vary in Amomum tsao-ko Fruit Development

“…Besides, two olefinic protons at δ H 6.48 (H, s) and δ H 5.68 (H, s) and a methoxyl signal at δ H 3.88 (3H, s) were found. The 13 13 C NMR spectra data (Table 1) were similar to those of compound 2, except for single-bond protons at δ H 2.44 and 2.83 (H-4), δ H 4.73 (H-5), δ C 41.0 (C-4), and 78.5 (C-5). The single bond at C-4 and C-5 was verified by the 1 H− 1 H COSY correlations of H7/H-6, H-6/H-5, and H-5/H-4 and the HMBC correlations from H-5 to C-3 and C-7 (Figure 3C).…”

“…Water content (A) and dry-fresh ratio (Figure S1); heatmap of tentative identified darylheptanoids (Figure S2); correlated heatmap of FPKM gene expression of transcript from fruitdevelopment, n = 3 (Figure S3); base peak ion (BPI) chromatograms and mass spectra in negative ionization mode of A. tsao-ko extracts and reference standards (Figure S4); HR-MS, 1 H NMR, 13 Tentative identified diarylheptanoids (Table S1), information on isolated diarylheptanoids (Table S2), KEGG analysis of the turquoise module (Table S3), and functional annotation of candidate genes (Table S4) (XLSX)…”

“…Previous phytochemical investigations on A. tsao-ko fruit have shown that the main components are diarylheptanoids, flavonoids, phenols compounds, volatile oils, and terpenoids. ,− Among the structurally diverse metabolites in A. tsao-ko, diarylheptanoids are characteristic of the Amomum genus.…”

Pyranoflavanones and Pyranochalcones from the Fruits of Amomum tsao-ko

“…Nitrite concentration in the culture medium of RAW 264.7 cells was measured as an indicator of NO production according to the Griess reaction. Cell viability was determined by the MTT-based colorimetric assay. , …”

“…It is also a well-known and commercially important food additive and spice. In previous phytochemical investigations of A. tsao-ko , bicyclic nonanes, essential oils, diterpenoids, diarylheptanoids, flavonoids, and phenolic compounds have been reported. − This species has been documented as showing antioxidant, antiproliferative, antifungal, neuroprotective, anti-inflammatory, and lipase inhibitory activities. ,,,− As part of a research program focusing on the isolation of potential plant-derived anti-inflammatory agents, a MeOH extract of the fruits of A. tsao-ko was examined for inhibitory effects against LPS-induced nitric oxide (NO) production. Herein are described the bioassay-guided isolation and structure determination of eight new geranylated and farnesylated pyranoflavanones ( 1 – 8 ) and two new farnesylated pyranochalcones ( 9 and 10 ).…”