New Alkaloids from Forsythia suspensa and their Anti-Inflammatory Activities

Abstract

Two new alkaloids, named suspensine A (1) and (−)-7′-O-methylegenine (2), along with two known alkaloids, (−)-egenine (3) and (−)-bicuculline (4), were isolated from the ethanolic extract of the fruits of Forsythia suspensa. Their structures were established by means of chemical methods and spectroscopic analyses. In vitro, four alkaloids showed anti-inflammatory activities, with inhibition rates of release of β-glucuronidase from polymorphonuclear leukocytes of rats being in the range 34.8 % – 39.6 % at 10 μM.

Key words

Forsythia suspensa - Oleaceae - suspensine A - (−)-7′-O-methylegenine - anti-inflammatory activity

References

• 1 Seya K, Endo K, Hikino H. Structures of rengyosides A, B, and C, three glucosides of Forsythia suspense fruits.  Phytochemistry. 1989;  28 1495-8
• 2 Liu D L, Zhang Y, Xu S X, Xu Y, Wang Z X. Phenylethanoid glycosides from Forsythia suspense Vahl.  J Chin Pharm Sci. 1998;  7 103-5
• 3 Nie Z G, Wang W J. Effect of ginkgolide B on platelet-activating factor induced activation of rat polymorphonuclear leukocytes.  Acta Pharm Sin. 2003;  38 98-102
• 4 Kessar S V, Vohra R, Kaur N P. Lewis acid complexed heteroatom carbanions, a conventient route to α–hydroxybenzyltetrahydroisoquinoline alkaloids.  Tetrahedron Lett. 1991;  32 3221-4
• 5 Rein K S, Gawley R E. Synthesis of the phthalide isoquinoline alkaloids (−)-egenine, (−)-corytensine, and (−)-bicuculline by asymmetric carbonyl addition of chiral dipole-stabilized organometallics.  J Org Chem. 1991;  56 1564-9
• 6 Blasko G, Gula D J, Shamma M. The phthalideisoquinoline alkaloids.  J Nat Prod. 1982;  45 105-22
• 7 Rein K S, Gawley R E. Synthesis of (−)-egenine by asymmetric carbonyl addition.  Tetrahedron Lett. 1990;  31 3711-4