Simultaneous Determination of Eight Components in Leonuri Herba from Different Habitats by HPLC-DAD.

A HPLC-DAD method was established for the simultaneous determination of eight components in Leonuri Herba from different habitats, as well as providing methodological reference for quality control of Leonuri Herba. In this study, absolute ethanol extracts of the medicinal material were considered as the sample solutions to be analyzed. Agilent ZORBAX SB-C18 column (250 mm × 4.6 mm, 5 µm) was used for determination maintained at the temperature of 30°C. Gradient elution was performed with a mobile phase of methanol (B)-0.1% phosphoric acid solution (A) at the flow rate of 1.0 mL·min-1. The analysis was carried out at the wavelength of 225, 280 and 320 nm. The measured eight components showed good linear relationships within their own concentration range. Average recoveries ranged from 98.83 to 100.36% with RSDs of 1.14~1.97%. The proposed method was found to be simple, accurate and reproducible, which provided an effective quantitative analytical method for quality control of Leonuri Herba from different habitats.

Expression of a novel small antimicrobial protein from the seeds of motherwort (Leonurus japonicus) confers disease resistance in tobacco.

Medicinal plants are valuable resources of natural antimicrobial materials. A novel small protein with antimicrobial activities, designated LJAMP1, was purified from the seeds of a medicinal herb, motherwort (Leonurus japonicus Houtt). LJAMP1 is a heat-stable protein with a molecular mass of 7.8 kDa and a determined isoelectric point of 8.2. In vitro assays showed that LJAMP1 inhibits the growth of an array of fungi and bacteria. The hyphal growth inhibition by LJAMP1 was more evident against hyphomycete fungi, such as Alternaria alternata, Cercospora personata, and Aspergillus niger. The N-terminal amino acid sequence of LJAMP1 was determined, and its coding gene was consequently cloned by the rapid amplification of cDNA ends. The gene LJAMP1 has no intron and encodes a polypeptide of 95 amino acids, in which the first 27 residues was deduced as a signal peptide. The mature LJAMP1 shows relatively low identity to plant napin-like storage proteins. Northern blot assays revealed that LJAMP1 is expressed preferentially in seeds. Bioassays in transgenic tobacco demonstrated that that overexpression of LJAMP1 significantly enhanced the resistance of tobacco against not only the fungal pathogen A. alternata but also the bacterial pathogen Ralstonia solanacearum, while no visible alteration in plant growth and development was observed.

[Regulation on growth and accumulation of total alkaloid in Leonurus artemisia (Lour.)S.Y. Hu by various microfertilizers].

OBJECTIVE: To trace the effects of various microfertilizers on the growth and accumulation of total alkaloid in Leonurus artemisia. METHOD: The total alkaloid was determined by spectrophotometry. RESULT: Microfertilizers of different concentrations could facilitate the growth of L. artemisia in various degrees and Mn-fertilizer of standard concentration and Cu-fertilizer of excessive concentration could help raise the output of the plant markedly by up to 43.6% and 55.2% respectively. Microfertilizers of different concentrations could improve the content of total alkaloid in L. artemisia: Mn-fertilizer of standard concentration and B-fertilizer of excessive concentration could enhance the contents of total alkaloid up to 2.15% and 2.09% respectively. Mn-fertilizer and Cu-fertilizer of standard concentration have been proved very useful in improving the resistibility and ability of the plant to survive summer safely, and Fe-fertilizer of standard concentration could bring the plant an obvious increase of output after surviving summer. CONCLUSION: Application of Mn-fertilizer of standard concentration is very important for cultivating L. artemisia of excellent quality and high output.