New Polyfunctional Phragmalin Limonoids from Neobeguea mahafalensis.

Neobeguea mahafalensis is used as a medicinal plant in Madagascar. A decoction of the stem bark of this species is reported to treat back pain. Recently, it was reported that a decoction of the root bark, containing two novel phragmalin limonoids as identified active constituents, exhibited an extraordinarily high potency and remarkably long duration in augmenting sexual activity in male rodents.From the dichloromethane extract of the root barks of N. mahafalensis, nine phragmalin limonoids were isolated, of which eight were novel compounds. The structures were established mainly by extensive use of 2D NMR spectroscopic techniques and high-resolution mass spectrometry. One of the new compounds named dodoguin displayed sleep-inducing activity in Swiss albino mice. The amount of 3-10 mg/kg of this compound induced sleep 18-22 min after its administration with a duration of 16-18 min.