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A rapid sensitive analytical method was established and validated to investigate levistolide A in rat plasma by liquid chromatography-tandem mass spectrometry operated in the positive ion mode. Levistilide A (LA) and internal standard (IS) andrographolide (AD), mixed with the plasma sample, were separated on a reversed phase Spursil™ C18 5 µm column. The precursor/product transitions (m/z) were 398.5/381.3 for LA and (m/z) 368.0/351.1 for AD. The calibration curve was linear over the range from 5 to 1,250 ng/mL for oral administration and 10-4,000 for intravenous administration with a correlation coefficient (r) ≥0.9993. The lower limit of quantification was 5 ng/mL for LA in plasma. The inter- and intra-day accuracy and precision were less than ±15% of the relative standard deviation. In this study, the developed method is successfully applied to the comparative pharmacokinetic study of LA in rats after oral administration of LA alone, Rhizoma Chuanxiong, and Danggui-Shaoyao-San along with the bioavailability study of LA in rats. Our study shows that low bioavailability (7.5%) is observed after oral administration of LA. Traditional formula compatibility of Danggui-Shaoyao-San could significantly enhance LA bioavailability compared with LA alone and Rhizoma Chuanxiong.

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Poria cocos is a well-known medicinal plant widely used in China and other East Asian countries owing to its various therapeutic effects. Pachymic acid (PA) is a bioactive lanostrane-type triterpenoid from Poria cocos. In this paper, a method of high-performance liquid chromatographic (LC) coupled with triple quadrupole tandem mass spectrometry (QQQ-MS/MS) was developed and validated to investigate the concentration of PA in rat plasma. Samples were prepared by a liquid-liquid extraction, and chromatographic separation was achieved with a Phenomenex Gemini C 18 column (50 mm 2.0 mm i.d.) using a mobile phase consisting of acetonitrile and 0.05% formic acid (85 : 15, v/v) at a flow rate of 0.3 mL/min. The detection was performed on an Applied Bio-Systems API 4000 MS/MS with an electrospray ionization (ESI) inlet in negative multiple reaction monitoring (MRM) mode. Standard curves of samples in plasma were linear (R 2 0.9948) over the concentration range of 5-500 ng/mL, and acceptable accuracy and precision were achieved. The lower limit of quantification and detection were 5 and 0.5 ng/mL, respectively. The method was used successfully to study the pharmacokinetics of PA in rats for oral administration. The main pharmacokinetic parameters of elimination half-life (t 1/2 ), area under the plasma concentration-time curve from time zero to infinity (AUC 0→∞ ), plasma clearance (CL), and apparent volume of distribution (V d ) for the PA group were 4.96 1.33 h, 1466.9 361.7 ng·h/mL, 6.82 1.73 L/h, and 48.85 9.47 L, respectively. This LC-MS/MS method can be developed further for clinical investigation of PA-containing products. Key words Poria cocos; pachymic acid; quantitation; rat plasma; pharmacokinetics; LC-MS/MSBecause of their low toxicities and high levels of effectiveness against many diseases, traditional Chinese medicines (TCMs) have played an important role in the health of the Chinese people for thousands of years. In addition, they have gained ever-increasing global attention owing to the desirability of their bioactive compounds for the discovery of novel drug candidates. Poria cocos, which is also known as Fu Ling, is often used in TCM for its diuretic and sedative effects. 1) P. cocos alone or in combination with other herbs is often used to treat diabetes as well as other disorders. 2-4)The main ingredients of this herbal medicine include a group of triterpenoid compounds. Pachymic acid (PA) is one of the major components in P. cocos and plays an important role in various pharmacological effects. For example, PA has shown anti-inflammatory, 5)anti-apoptotic, and anti-immunologic rejection effects.6) In addition, it has exhibited cytotoxicity against a human colon carcinoma cell line.1,7) Furthermore, PA has been shown to induce apoptosis of human prostate cancer cells by reducing prostaglandin synthesis and AKT activity, 8,9) to stimulate glucose uptake, 10) and to inhibit the phospholipase A2 family of arachidonic acid-producing enzymes.11) Therefore, further pharmacodynamic and pharmacokinetic studie...

Peanut (Arachis hypogaea L.) is one of the most important crops produced worldwide. Peanut is the dominant crop in the typical upland red soil areas of China; however, phosphorus bioavailability in red soil is very low, which severely affects peanut production. To improve the phosphorus bioavailability, which substantially promotes the green development of peanut production, a peanut–green manure rotation field experiment was conducted with six treatments (milkvetch; radish; brassica rape; mustard rape; winter fallow and no-tillage), commencing in September 2017 in the red soil area of Jiangxi province, China. The results show that compared with no-tillage (NT) treatments, different green manure returning treatments had significant effects on soil pH, soil phosphorus components and available potassium content. The particulate phosphorus and soil available phosphorus contents in the green manure treatments were significantly higher than those in the winter fallow (WF) treatment. Compared with the WF treatment, the content of particulate phosphorous in brassica rape (BR), radish (R) and milkvetch (MV) treatments was significantly increased by 6.55%, 3.66% and 2.50%, respectively; the available phosphorus content in mustard rape (MR), BR, R and MV was significantly increased by 20.93%, 25.60%, 23.76% and 18.10%, respectively. In addition, the total phosphorus content of peanut shell in the MV and R treatment was significantly higher than that in the WF treatment, increasing by 33.47% and 60.66%, respectively. Compared with the WF treatment, the peanut biomass of MR, BR and R treatments increased significantly by 19.51%, 29.83% and 19.77%, respectively. The total phosphorus accumulation in all green manure treatments was higher than that in the WF treatment, and the MV treatment reached a significant level at 18.83%. Based on these results, the particulate phosphorus (PP) and available phosphorus were significantly affected by different green manure treatments; green manure amendment improves peanut phosphorus uptake. The use of green manure (especially milkvetch and brassica rape) can be recommended to improve phosphorus bioavailability and yield of peanut in red soil areas.