Prieurianoside, a protolimonoid glucoside from the leaves of Trichilia prieuriana

Insights into the Mechanism of Action of the Degraded Limonoid Prieurianin

Limonoids are extremely diversified in plants, with many categories of products bearing an intact, rearranged or fragmented oxygenated scaffold. A specific subgroup of fragmented or degraded limonoids derives from the tetranortriterpenoid prieurianin, initially isolated from the tree Trichilia prieuriana but also found in other plants of the Meliaceae family, including the more abundant species Aphanamixis polystachya. Prieurianin-type limonoids include about seventy compounds, among which are dregeanin and rohitukin. Prieurianin and analogs exhibit insecticidal, antimicrobial, antiadipogenic and/or antiparasitic properties but their mechanism of action remains ill-defined at present. Previous studies have shown that prieurianin, initially known as endosidin 1, stabilizes the actin cytoskeleton in plant and mammalian cells via the modulation of the architecture and dynamic of the actin network, most likely via interference with actin-binding proteins. A new mechanistic hypothesis is advanced here based on the recent discovery of the targeting of the chaperone protein Hsp47 by the fragmented limonoid fraxinellone. Molecular modeling suggested that prieurianin and, to a lesser extent dregeanin, can form very stable complexes with Hsp47 at the protein-collagen interface. Hsp-binding may account for the insecticidal action of the product. The present review draws up a new mechanistic portrait of prieurianin and provides an overview of the pharmacological properties of this atypical limonoid and its chemical family.

Phragmalin-type limonoids from the roots of Trichilia sinensis

Twelve new limonoids were isolated from Trichilia sinensis. Some compounds exhibited cytotoxicity and acetylcholinesterase-inhibiting activity.

A New β-D-Glucopyranosyl 2-Oxo-urs-12-en-28-oate from the Cameroonian Plant Combretum bracteatum

From the Cameroonian plant Combretum bracteatum (Laws.) Engl. and Diels a new compound, β-D-glucopyranosyl 3β,19α-dihydroxy-2-oxo-urs-12-en-28-oate, was isolated along with three known ursane and oleane triterpenes and two galactopyranosyl lipids. This represents the first example of a naturally occurring 2-oxo-urs-12-enoic acid derivative.

An antiinflammatory galactolipid from rose hip (Rosa canina) that inhibits chemotaxis of human peripheral blood neutrophils in vitro

The galactolipid (2S)-1,2-di-O-[(9Z,12Z,15Z)-octadeca-9,12,15-trienoyl]-3-O-beta-d-galactopyranosyl glycerol (1) isolated from dried and milled fruits of Rosa canina by bioassay-guided fractionation is an antiinflammatory agent with inhibitory effects on chemotaxis of human peripheral blood neutrophils in vitro. The inhibition of cell migration is not related to toxicity. The presence of 1 in rose hips may explain the clinically observed antiinflammatory properties of rose hip herbal remedies.