Plantagiolides I and J, Two New Withanolide Glucosides from Tacca plantaginea with Nuclear Factor-kappaB Inhibitory and Peroxisome Proliferator-Activated Receptor Transactivational Activities

Abstract

A novel withanolide glucoside, plantagiolide I (1), a new withanolide glucoside, plantagiolide J (2), and six known compounds (3–8) were isolated from the whole plant of Tacca plantaginea. Their structures were determined by spectroscopic and chemical methods. Compound 3 significantly inhibited tumor necrosis factor alpha (TNFα)-induced nuclear factor-kappaB (NF-κB) transcriptional activity in HepG2 cells in a dose-dependent manner, with IC₅₀ values of 9.0 µM. Compounds 1–8 enhanced the transcriptional activity of peroxisome proliferator-activated receptors (PPARs) in a dose-dependent manner, with EC₅₀ values ranging from 1.6 to 49.7 µM. In addition, the transactivational effects of compounds 1–8 on three individual PPAR subtypes, including PPARα, β(δ), and γ were evaluated. Compounds 1–8 significantly activated the transcriptional activity of PPARβ(δ), with EC₅₀ values in a ranging from 4.1 to 29.6 µM. These results provide scientific support for the use of T. plantaginea and its components for the prevention and treatment of inflammatory and metabolic diseases.