Bonabiline A, a Monoterpenoid 3α-Acyloxytropane from the Roots of Bonamia spectabilis showing M₃ Receptor Antagonist Activity

Abstract

Two 3alpha-acyloxytropanes with unique monoterpenoic acyl moieties, bonabiline A and its anhydro derivative bonabiline B, have been isolated from the roots of Bonamia spectabilis. Their structures were elucidated by detailed spectroscopic analysis. Due to the structural similarity of bonabiline A to atropine/hyoscyamine, the affinity of both bonabilines to the muscarinic M (3) receptor was studied in the isolated guinea-pig ileum. Bonabiline A (pA (2) 6.65 +/- 0.03) proved to be a more potent antagonist than bonabiline B (pA (2) 5.50 +/- 0.03).

Ipvelutine, 7β-Acetoxy-2α-(tigloyloxy)tropane, an Unusual Tropane Alkaloid from Ipomoea velutina R. Br. (Convolvulaceae)

“…During our continuous studies on secondary metabolites of the Convolvulaceae, this plant family has been shown to produce a plethora of tropane alkaloids, especially 3-tropanols and their esters (e. g. [1, 2]), as well as some 3,6-disubstituted tropanes [3] or the polyhydroxylated calystegines [4]. This underlines the chemotaxonomic relationship with their sister family Solanaceae where the biosynthetic pathway of tropane alkaloids is well investigated.…”

A Synthetic Butenolide Diterpene is now a Natural Product Isolated from Metaporana sericosepala, a Plant from the Madagascar Dry Forest [1a]

“…Another similar genus from the Convolvulaceae family, Bonamia (not to be confused with the parasite) has been shown in the literature to produce monoterpenes and lignans [5]. The isolation, structure elucidation, and antiproliferative properties of 1 are reported herein.…”