Flavokawains B and C, melanogenesis inhibitors, isolated from the root of Piper methysticum and synthesis of analogs.

The ethanolic extract of the root of Piper methysticum was found to inhibit melanogenesis in MSH-activated B16 melanoma cells. Flavokawains B and C were isolated from this extract based on their anti-melanogenesis activity and found to inhibit melanogenesis with IC50 values of 7.7µM and 6.9µM, respectively. Flavokawain analogs were synthesized through a Claisen-Schmidt condensation of their corresponding acetophenones and benzaldehydes and were evaluated in terms of their tyrosinase inhibitory and anti-melanogenesis activities. Compound 1b was the most potent of these with an IC50 value of 2.3µM in melanogenesis inhibition assays using MSH-activated B16 melanoma cells.

Curcumin protects against regional myocardial ischemia/reperfusion injury through activation of RISK/GSK-3ß and inhibition of p38 MAPK and JNK.

BACKGROUND: Curcumin, the active ingredient of turmeric (Curcuma longa), is known to have anti-inflammatory and antioxidative properties. The present study was aimed to determine the effect of curcumin in regional myocardial ischemia/reperfusion (I/R) injury and its underlying mechanisms involving the role of prosurvival kinases and apoptotic kinases. METHODS: Sprague-Dawley rats (n = 109) subjected to a 30-minute left anterior descending coronary artery (LAD) occlusion followed by reperfusion were assigned to receive saline (control), curcumin (100 mg/kg), wortmannin (inhibitor of phosphatidylinositol-3-OH kinase [PI3K]-Akt), wortmannin + curcumin, U0126 (inhibitor of extracellular signal-regulated kinase [ERK1/2]), U0126 + curcumin, SB216763 (inhibitor of glycogen synthase kinase [GSK-3ß]), and SB216763 + curcumin 20 minutes before LAD occlusion. Infarct size was measured after 2 hours of reperfusion by triphenyl tetrazolium chloride staining. The phosphorylation of Akt, ERK1/2, GSK-3ß, p38, and c-Jun N-terminal kinases (JNK) was determined by immunoblotting after 10 minutes of reperfusion. RESULTS: Curcumin significantly reduced the infarct size compared with the control (33.1% ± 6.2% vs 50.1% ± 3.9%; P < .05). Wortmannin or U0126 alone did not affect the infarct size but abolished the curcumin-induced cardioprotective effect. Curcumin significantly enhanced the phosphorylation of Akt, ERK1/2, and GSK-3ß, while it reduced that of p38 and JNK. Wortmannin or U0126 abolished enhanced phosphorylation of GSK-3ß induced by curcumin. SB216763 alone or combined with curcumin reduced the infarct size and enhanced phosphorylation of GSK-3ß compared with the control. CONCLUSIONS: Preconditioning by curcumin effectively protects against regional myocardial I/R injury through the activation of prosurvival kinases involving PI3K-Akt, ERK1/2, and GSK-3ß, and attenuation of p38 and JNK.

Pharmacokinetic study of ginsenoside Re with pure ginsenoside Re and ginseng berry extracts in mouse using ultra performance liquid chromatography/mass spectrometric method.

Ginsenoside Re is the major ginsenoside in ginseng berry(GB) extract and its pharmacokinetics were studied following the intravenous and oral administration of pure Re or ginseng berry extract in mouse with doses of 10 and 50 mg/kg using ultra performance liquid chromatography mass spectrometric (UPLC/MS) method which can simultaneously determine ginsenoside Re, Rg1 and Rh1 in mouse serum. The serum samples were pretreated by protein precipitation and chromatographic separation was performed on AQUITY UPLC BEH C(18) column using gradient elution with the mobile phase of 5 mM ammonium formate and acetonitrile. Analytes and digoxin (I.S.) were analyzed and identified using an electrospray negative ionization mass spectrometry in the selected ion monitoring mode with the linear concentration range of 5.0-5000 ng/mL and lower limits of detection (LLOD) under 2.5 ng/mL. Ginsenoside Re was rapidly cleared from the body with a short half-life (0.2+/-0.03 h for male and 0.5+/-0.08 h for female mice after i.v.) and oral absorption was generally poor (F% 0.19-0.28). Notably, GB extract showed a superior oral absorption of ginsenoside Re (F% 0.33-0.75) at equivalent ginsenoside Re dose to pure ginsenoside Re, indicating that GB extract might be a good form for ginsenoside Re intake.

Simultaneous determination of two Amadori compounds in Korean red ginseng (Panax ginseng) extracts and rat plasma by high-performance anion-exchange chromatography with pulsed amperometric detection.

A new simple, rapid and sensitive high-performance anion-exchange chromatography method with pulsed amperometric detection (HPAEC-PAD) was developed and validated for the simultaneous determination of two Amadori compounds, arginyl-fructose and arginyl-fructosyl-glucose in Korean red ginseng (Panax ginseng) extracts, rat plasma. Separation of the two target analytes was efficiently undertaken on CarboPac PA1 anion-exchange column with isocratic elution (400 mM sodium hydroxide and deionized water (90:10, v/v)) at flow rate 0.7 mL/min within 15 min of single chromatographic run. Under optimized conditions, the detection limits (signal-to-noise ratio equal to 3) were 20 and 25 ng/mL for arginyl-fructose and arginyl-fructosyl-glucose, respectively. Calibration curves of peak area for the two analytes were linear over three orders of magnitude with a correlation coefficients greater than 0.999. The accuracy of the method was tested by recovery measurement of the spiked samples which yielded good results of 94.15-102.62%. This method was successfully applied to the quantification of arginyl-fructose and arginyl-fructosyl-glucose in herbal extracts and in the plasma samples from rat.