Planta Med 2013; 79 - PI97
DOI: 10.1055/s-0033-1352186

Novel anti-inflammatory neolignans and dineolignans from the fruit of Magnolia obovata

K Seo 1, D Lee 2, D Lee 3, Y Kim 3, N Baek 1
  • 1Graduate School of Biotechnology & Department of Oriental Medicinal Materials and Processing, Kyung Hee University, Yongin 446 – 701, Korea
  • 2Department of Herbal Crop Research, National Institute of Horticultural and Herbal Science, RDA, Eumseong 369 – 873, Korea
  • 3Standardized Material Bank for New Botanical Drugs, College of Pharmacy, WonKwang Universtiy, Iksan 570 – 749, Korea

Introduction and Objective:

Magnolia obovata (Magnoliaceae), a deciduous tree, growing up to 20 m high and is widely distributed in Korea, China, and Japan. It contains many kinds of secondary metabolites such as neolignans, sesquiterpene-neolignans and flavonoids. These compounds were reported to show anti-gastric, anti-platelet, and anti-complement activities However, studies on the fruits of M. obovata barely investigated for its chemical constituents and biological activities. Therefore, the present study focused on isolation and identification of active constituents in the fruit of this plant, as well as examination of the pharmacological activities of the isolated compounds.

Methods:

The fruit of M. obovata were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtoAc, n-BuOH, and H2O, successively. From the EtOAc fraction, four new neolignans and 6 new dineolignans along with six known ones were isolated through the repeated SiO2, ODS column chromatografies.

Results:

Our phytochemical study on the fruit of M. obovata led to isolation and identification of four new neolignans 3, 7, 8, 10 as well six known ones 1, 2, 4-7, 9 and six new dineolignans 11-16 by spectroscopic analysis including 1H and 13C-NMR, DEPT, and 2D-NMR. These ten neolignans and six dineolignans were identified as magnolol (1), honokiol (2), isoobovatol (3), isomagnolol (4), obovatol (5), obovatal (6), 9-methoxyobovatol (7), magnobovatol (8), obovaaldehyde (9), 2-hydroxyobovaaldehyde (10), and new dineolignan (11-16).

Conclusion:

All isolated compounds 1, 2, 4, 5, 7, 8, and 10 inhibited nitric oxide production in RAW 264.7 cells with IC50 values of 15.8 0.3, 3.3 1.2, 12.9 2.0, 6.2 1.2, 14.8 2.3, 14.2 1.2, and 14.8 3.2µM, respectively, without obvious toxic effect.