Anti-inflammatory and antioxidant effects of 2, 7-dihydroxy-4, 6-dimethoxy phenanthrene isolated from Dioscorea batatas Decne

Abstract

Our previous study showed that the ethanol extract of Dioscorea batatas Decne (Chinese yam) peel upregulated certain antioxidant enzymes and had the anti-inflammatory activity. In this study, 2, 7-dihydroxy-4, 6-dimethoxy phenanthrene (DDP) was isolated from yam peel extract as a potent antioxidative enzyme inducer through bioassay-guided fractionation using HepG2-ARE cells, and subjected to examination for its anti-inflammatory activity as well as antioxidant activity. DDP decreased the levels of inflammatory mediators in LPS-stimulated Raw 264.7 macrophage and reduced the level of reactive oxygen species in tert-butyl hydroperoxide-challenged Raw 264.7 cells. Moreover, DDP enhanced the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and its downstream heme oxygenase-1 proteins while it decreased the expression of iNOS, COX-2, proinflammatory cytokines via nuclear factor-κB pathway. However, the combinatorial treatment with DDP and the inhibitor of Nrf2 or HO-1 activity did not affect the levels of inflammatory biomarkers, suggesting that anti-inflammatory action by DDP is achieved by the mechanism independent of Nrf2 signaling pathway. In conclusion, DDP was found to be a strong antioxidant and anti-inflammatory agent and warrants further in vivo efficacy study for future use as a functional food ingredient.

Quantitative Analysis of Bioactive Phenanthrenes in Dioscorea batatas Decne Peel, a Discarded Biomass from Postharvest Processing

“…cultivated in Korea. Our previous study on the anti-inflammatory activity of D. batatas [18] also led to the isolation of Compound 1 as a responsible component for the bioactivity.…”

“…Phenanthrene Compounds 1 , 2 and 3 (Figure 1) were isolated from the peel of D. batatas following the method suggested by our previous studies [18,19]. The peel was extracted with 95% ethanol for 48 h, and solvents were removed in vacuo.…”

“…Compound 3 was isolated from the ninth fraction from LH20 column chromatography by using the same HPLC condition for the isolation of Compounds 1 and 2 . The structures of Compounds 1 and 2 were identified by our previous study [18,19] on the basis of 1 H- and 13 C-NMR spectra (Figures S1 and S2), and the structure of Compound 3 as identified as 6-hydroxy-2,4,7-trimethoxyphenanthrene (batatasin I) through a comparison of 1 H and 13 C NMR spectra (Figure S3) with a previous report [22]. NMR experiments were carried out using a Bruker Ascend ( 1 H-500 MHz, 13 C-125 MHz, Billerica, MA, USA) spectrometer.…”

“…Our previous studies on biological activities of D. batatas also revealed anti-inflammatory [18] and inhibitory effects on the particulate matter-induced pulmonary injury of phenanthrenes [19]. On the basis of cumulative research, phenanthrenes are putative medicinal components in D. batatas .…”

Coreolanceolins A–E, New Flavanones from the Flowers of Coreopsis lanceolate, and Their Antioxidant and Anti-Inflammatory Effects

“…All cell lines were sub-cultured when approximately 90% of the distribution was in the culture dish. To determine the non-toxic maximal concentration of compound 1-7, cytotoxicity was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction assay [18]. PC-12, Caco-2, and RAW 264.7 cells were seeded at a density of 2 × 10 4 cells/well in a 96-well plate in RPMI 1640 or DMEM medium containing FBS and left for 24 h. After removing the medium, cells were treated with a serum-free medium containing compound 1-7 at various concentrations.…”