Pharmacokinetic study comparing pure desoxo-narchinol A and nardosinonediol with extracts from Nardostachys jatamansi.

Nardostachyos Radix et Rhizoma (NR) is a valuable medicinal herb widely used in Korea, India, and China for the treatment of many diseases. Desoxo-narchinol A (DA) and nardosinonediol (ND) are the two main bioactive compounds belonging to the sesquiterpene group. Desoxo-narchinol A possesses anti-inflammatory activity while ND exhibits anti-depressant and cardioprotective activities. A pharmacokinetic study is important to decide whether the isolated compounds or the NR extract have better pharmacological activity. Hence, we developed an analytical method for studying the pharmacokinetics of DA and ND after oral administration of the pure compounds and herbal extract. An optimized liquid chromatography-mass spectrometry method (LC-MS/MS) with solid-phase extraction (SPE) for sample preparation was developed. A ZORBAX Extend C18 column (2.1 × 50 mm, 3.5 µm) was used under gradient elution with acetonitrile and 0.1% formic acid in water as the mobile phase. Validation experiments assessing accuracy, precision, and stability were satisfactory; the lower limit of quantification was 5 ng/mL. For the pharmacokinetic study, three groups of rats were administrated pure DA, pure ND, or NR extract orally. Concentrations of DA and ND in their plasma were determined by the developed method. Pharmacokinetic parameters, including the time to achieve maximum plasma concentration (Tmax) and the area under the plasma concentration curve from time zero to infinity (AUC0-∞), were compared for the herbal extract and pure compounds. The Tmax of the pure compound and the NR extract for DA was 7.50 and 8.33 min, respectively, compared to 5.00 and 5.83 min for the pure compound and the NR extract for ND, respectively. The AUC0-∞ of the pure compound and the NR extract for DA was 156.34 and 133.90 µg min/mL, respectively, and that for the NR extract for ND was 6.42 and 4.15 µg min/mL, respectively. LC-MS/MS was used to determine DA and ND in rat plasma. The pharmacokinetic profile of each pure compound and those in the extract were characterized and compared.

An optimized HPLC-UV method for quantitatively determining sesquiterpenes in Nardostachyos Radix et Rhizoma.

Nardostachyos Radix et Rhizoma (NR), the root and rhizome from either Nardostachys jatamansi Batal or Nardostachys jatamansi DC, is known to have biological functions including neuro-protective and anti-pancreatitis activity. The main bioactive compounds within NR are all classified as sesquiterpenes, and include desoxo-narchinol A, nardosinonediol, and nardosinone. Although NR is a valuable herb that is widely used in many Asian countries, robust quality control protocols for NR are still in question, especially those that can analyze the three main active compounds. Current quantitative methods within the Chinese Pharmacopoeic use nardosinone as a marker compounds. One compound cannot represent a complicated matrix, and is thus insufficient to control the quality of this herbal medicine. Moreover, there are no high-performance liquid chromatography (HPLC) methods that can simultaneously analyze desoxo-narchinol A (DA), nardosinonediol (NE), and nardosinone (ND) within NR. This study aimed to establish an efficient quality control protocol by developing an analytical method that simultaneously detects the three sesquiterpenes with HPLC using response surface methodology (RSM) to optimize sample preparation. Optimized HPLC conditions included a mobile phase of 0.1% formic acid in water (A), and a 0.1% formic acid in acetonitrile (B) under an elution program of 20% B-80% B for 30min at 254nm. The method was well validated, demonstrating satisfactory linearity, accuracy, precision, recovery, repeatability, and stability. Optimized conditions for creating the analytical sample were predicted by RSM using a Box-Behnken design. These conditions included reflux at 70°C for 3h using 24.98% ethanol as the extraction solvent (solvent: solid ratio=78.81mL/g). The relationship between the results between predicted and experimental conditions was well correlated, and varied between 96.48%-102.11%. Thus, our developed HPLC method, paired with optimized sample preparation conditions, accurately quantified all three sesquiterpenes, and may thus be a prospective means of controlling the quality of NR.