Planta Med 2014; 80 - P1L24
DOI: 10.1055/s-0034-1394682

Effects of Leonurus japonicus Houtt. and its N-containing constituents leonurine and stachydrine on the activity of PPARα, β/δ, and γ in a newly developed in vitro luciferase reporter gene assay

K Kuchta 1, N Matsuura 2, HW Rauwald 3, M Iinuma 4
  • 1Natural Products Research, Department of Nutrition, Sanyo Gakuen University-College, 703 – 8501 Okayama, Naka, Hirai 1 – 14 – 1, Japan
  • 2Department of Life Science, Okayama University of Science, 700 – 0005 Okayama, Kita, Ridai 1 – 1, Japan
  • 3Department of Pharmaceutical Biology, Leipzig University, Johannisallee 23, 04103 Leipzig, Germany
  • 4Department of Pharmacognosy, Gifu Pharmaceutical University, 501 – 1196 Gifu, Daigaku-nishi 1 – 25 – 4, Japan

Leonurus japonicus (Yimucao; Chin.Ph., DAB) has been used in TCM since earliest times [1] for conditions presently referred to as the “metabolic syndrome”. Here, the agonistic activity of aqueous Yimucao extracts – both from China and from German TCM plant cultivation – and their dominant constituents leonurine and stachydrine [2, 3] on the metabolic syndrome related peroxisome proliferator-activated receptors (PPAR) α, β/δ, and γ was investigated using a novel luciferase reporter gene assay [4]. COS-1 cells were co-transfected with the luciferase reporter plasmid p17m2G, containing a GAL4 upstream activating sequence in the promoter region, an expression vector for the human PPARβ/δ ligand-binding domain fused to the GAL4 DNA-binding domain pPPARβ/δ-GAL4, and the secreted alkaline phosphatase control vector pSEAP. The results are relative to the luciferase expression levels, which were normalized using secreted alkaline phosphatase (SEAP) activity. The two L. japonicus extracts and the two isolated constituents (all at 6.25, 25, and 100 µg/ml), and GW0742 (positive control, 0.1 nM) were dissolved in DMSO and added to the medium of the transfected cells. The same approach was used for PPARα and PPARγ in which case the COS-1 cells were transfected with pPPARα or γ-GAL4 and p17m2G, respectively (positive controls 50µM WY14643/10µM troglitazone). Whereas significant activity was measured for the Chinese Yimucao extract in all three PPAR assays at both 100 and to a lesser extent 25 µg/ml, no activity above DMSO vehicle negative control levels could be detected for the sample from German cultivation or for the two N-containing compounds. Thus, the agonistic activity of Chinese Yimucao in all three PPARs indicates its potential for diabetes and metabolic syndrome therapy. However, the still unidentified active constituents seem to be absent from the German cultivated drug.

Keywords: Leonurus japonicus Houtt., leonurine, stachydrine, diabetes, PPARα, PPARβ/δ, PPARγ, luciferase reporter gene assay

References:

[1] Yang SZ (1998) The Divine Farmer's Materia Medica. Blue Poppy Press, Boulder, p. 30. A translation of the “Shennong Bencao Jing”, first published before 200 AD.

[2] Kuchta K, Ortwein J, Rauwald HW (2012) Leonurus japonicus, Leonurus cardiaca, Leonotis leonurus: A novel HPLC study on the occurrence and content of the pharmacologically active guanidino derivative leonurine. Pharmazie 67: 973 – 979.

[3] Kuchta K, Ortwein J, Hennig L, Rauwald HW (2014) 1 H-qNMR for Direct Quantification of Stachydrine in Leonurus japonicus and L. cardiaca. Fitoterapia 96: 8 – 17.

[4] Matsuura N, Gamo K, Miyachi H, Iinuma M, Kawada T, Takahashi N, Akao Y, Tosa H (2013) γ-Mangostin from Garcinia mangostana pericarps as a dual agonist that activates both PPARα and PPARδ. Biosci Biotechnol Biochem 77(12): 2430 – 2435.