Absolute Quantification of Isoflavones in the Flowers of Pueraria lobata by qHNMR.

Pueraria lobata (Willd.) Ohwi. is a widely used medicinal plant in Korea, China, and Japan. The flower of P. lobata (Puerariae Flos) contains various bioactive substances such as triterpenoidal saponins and isoflavonoids. In this study, we developed a quantitative analysis of the isoflavones of Puerariae Flos by quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy using the internal calibrant (IC). From the qHNMR results, the isoflavone content was found to be 7.99% and 10.57% for the MeOH sonication extract (PLs) and the MeOH reflux extract (PLr) of Puerariae Flos, respectively. The quantified isoflavone content was validated using the conventional analytical method, high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The present study shows that validated qHNMR spectroscopy is a reliable method for quantifying and standardizing the isoflavone content in Puerariae Flos.

Eudesmane and Eremophilane Sesquiterpenes from the Fruits of Alpinia oxyphylla with Protective Effects against Oxidative Stress in Adipose-Derived Mesenchymal Stem Cells.

Alpinia oxyphylla Miquel (Zingiberaceae) has been reported to show antioxidant, anti-inflammatory, and neuroprotective effects. In this study, two new eudesmane sesquiterpenes, 7α-hydroperoxy eudesma-3,11-diene-2-one (1) and 7ß-hydroperoxy eudesma-3,11-diene-2-one (2), and a new eremophilane sesquiterpene, 3α-hydroxynootkatone (3), were isolated from the MeOH extract of dried fruits of A. oxyphylla along with eleven known sesquiterpenes (4-14). The structures were elucidated by the analysis of 1D/2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and optical rotation data. Compounds (1-3, 5-14) were evaluated for their protective effects against tert-butyl hydroperoxide (tBHP)-induced oxidative stress in adipose-derived mesenchymal stem cells (ADMSCs). As a result, treatment with isolated compounds, especially compounds 11 and 12, effectively reverted the damage of tBHP on ADMSCs in a dose-dependent manner. In particular, 11 and 12 at 50 µM improved the viability of tBHP-toxified ADMSCs by 1.69 ± 0.05-fold and 1.61 ± 0.03-fold, respectively.

Purification of Phenylpropanoids from the Scaly Bulbs of Lilium Longiflorum by CPC and Determination of Their DPP-IV Inhibitory Potentials.

The scaly bulbs of Lilium longiflorum (Liliaceae) are used as a food ingredient and a traditional medicine in East Asia. A preliminary study revealed that treatment with 100 µg/mL of the ethyl acetate fraction of this plant material inhibited dipeptidyl peptidase IV (DPP-IV) to 58.99%. Phytochemical studies were conducted to identify the active ingredient, and five compounds, namely, 1 (2.9 mg, 75.8% purity at 320 nm), 2 (12.2 mg, 97.9% purity at 320 nm), 3 (3.1 mg, 66.5% purity at 320 nm), 4 (6.8 mg, 96.9% purity at 320 nm), and 5 (6.2 mg, 90.2% purity at 320 nm) were purified from 200 mg of the ethyl acetate fraction of L. longiflorum via centrifugal partition chromatography (CPC) with a two-phase solvent system composed of chloroform/methanol/isopropanol/water (5:2:2:4, v/v/v/v) in an ascending mode. Their structures were identified as 1-O-p-coumaroyl-2-O-ß-glucopyranosylglycerol (regaloside D, 1), 3,6'-O-diferuloylsucrose (2), 1-O-p-coumaroyl-2-O-ß-glucopyranosyl-3-O-acetylglycerol (regaloside B, 3), 1-O-p-coumaroylglycerol (4), and 4-O-acetyl-3,6'-O-diferuloylsucrose (5), respectively, by 1H and 13C NMR and MS analysis. Compounds 2 and 5 exhibited DPP-IV inhibitory activities with IC50 values of 46.19 and 63.26 µM, respectively. Compounds 1, 3, and 4 did not show activities, indicating that biphenylpropanoids linked via the sugar moiety are more effective than phenylpropanoids with glycerol or glyceryl glucoside. This is the first report of simultaneous separation of five phenylpropanoids from L. longiflorum by CPC and evaluation of their DPP-IV inhibitory activities.