Changes in the Harpagide, Harpagoside, and Verbascoside Content of Field Grown Scrophularia lanceolata and Scrophularia marilandica in Response to Season and Shade

Scrophularia lanceolata Pursh and Scrophularia marilandica L. are two common species within the Scrophulariaceae family that are endemic to North America. Historically, these species were used by indigenous peoples and colonialists to treat sunburn, sunstroke, frostbite, edema, as well as for blood purification, and in women's health. Several iridoid and phenylethanoid/phenylpropanoid glycosides detected in these species, such as harpagoside and verbascoside, possess anti-inflammatory and anti-nociceptive properties. Due to the presence of anti-inflammatory metabolites and the historical uses of these species, we performed a two-year field study to determine the optimal production of these important compounds. We subjected the plants to shade treatment and analyzed differences in the metabolite composition between the two species and each of their leaves, stems, and roots at various times throughout the growing seasons. We determined that S. lanceolata plants grown in full sun produced 0.63% harpagoside per dried weight in their leaves compared to shade-grown plants (0.43%). Furthermore, S. lanceolata accumulated more harpagoside than S. marilandica (0.24%). We also found that verbascoside accumulated in the leaves of S. lanceolata and S. marilandica as the growing season progressed, while the production of this metabolite remained mostly seasonally unchanged in the roots of both species.

[Study on scrophulariaceae radix reference extract and its application in quality control of Scrophulariae Radix]

By establishing the preparation process of Scrophulariaceae Radix reference extract(SRRE) and calibrating it, we discussed its feasibility as a substitute for single reference substance in the quality control of Scrophulariae Radix. The SRREs were prepared by solvent extraction method and chromatographic separation technology, and then calibrated with the reference substances of harpagide, angoroside C and harpagoside. The HPLC content determination method of Scrophulariae Radixl was established with SRREs of the known content and the reference substances of harpagide, angoroside C and harpagoside respectively as the control ones. Then the content of three components in Scrophulariae Radix was determined, and the t-test method was used to compare the results of the two methods. With SRRE as references, harpagide, angoroside C and harpagoside were in a good linear relationship(r≥0.999 8) within each range, and the average recovery rate was 98.55% to 100.6%. The t-test results showed that the P values of two determination methods were 0.493, 0.155 and 0.171 for harpagide, angoroside C and harpagoside respectively, indicating no significant diffe-rence between the two methods of content determination. The SRRE can be used as a substitute for the reference in the quality control of Scrophulariaceae Radix. The SRRE can replace the corresponding reference substance for the quality control of Scrophulariae Radix. The results of this study provide new methods and new ideas for the quality evaluation of Scrophulariae Radix, and provide a scientific basis for the application of reference extracts in the quality research of traditional Chinese medicine.

[Isolation and identification of endophytic fungi producing harpagoside and harpagide from Scrophularia ningpoensis]

The endophytic fungi from root,main stem,branch and leaf of Scrophularia ningpoensis were isolated from Zhejiang,whether these strains could yield harpagide or harpagoside were tested by HPLC and LC-MS. According to the morphological characteristic and the similarity of the nucleotide sequence of internal transcribed spacer( ITS) between r DNAs,the strains producing harpagide or harpagoside were identified. The results showed that 210 strains were isolated from the samples,which were classified into 9 orders,13 families and 17 genera by morphological study. Harpagide was detected in endogenous fungi ZJ17 and harpagoside was detected in endogenous fungi ZJ25 by HPLC coupled with LC-MS. ZJ17 was identified as Alternaria alternate and ZJ25 was identified as A.gaisen by its morphology and authenticated by ITS( ITS4 and ITS5 regions and the intervening 5. 8 S rDNA region).

Validated LC-MS method for simultaneous quantitation of catalpol and harpagide in rat plasma: application to a comparative pharmacokinetic study in normal and diabetic rats after oral administration of Zeng-Ye-Decoction

A simple and efficient liquid chromatography-mass spectrometry (LC-MS) method was developed and validated for simultaneous quantitation of catalpol and harpagide in normal and diabetic rat plasma. Protein precipitation extraction with acetonitrile was carried out using salidroside as the internal standard (IS). The LC separation was performed on an Elite C18 column (150 × 4.6 mm, 5 µm) with the mobile phase consisting of acetonitrile and water within a runtime of 12.0 min. The analytes were detected without endogenous interference in the selected ion monitoring mode with positive electrospray ionization. Calibration curves offered satisfactory linearity (r > 0.99) at linear range of 0.05-50.0 µg/mL for catalpol and 0.025-5.0 µg/mL for harpagide with the lower limits of quantitation of 0.05 and 0.025 µg/mL, respectively. Intra- and inter-day precisions (RSD) were <9.4%, and accuracy (RE) was in the -6.6 to 4.9% range. The extraction efficiencies of catalpol, harpagide and IS were all >76.5% and the matrix effects of the analytes ranged from 86.5 to 106.0%. The method was successfully applied to the pharmacokinetic study of catalpol and harpagide after oral administration of Zeng-Ye-Decoction to normal and diabetic rats, respectively.