Amaryllidaceae alkaloids from Rauhia multiflora (Kunth) Ravenna
The taxonomy of the American Amaryllidaceae subfamily Amaryllidoideae sensu APG (Amaryllidaceae s.s.) is currently undergoing revision based on molecular phylogenetic analyses . The genus Rauhia Traub comprises three to five species endemic to Northern Peru [1,2]. Rauhia resolves as sister to Phaedranassa Herb. in the primarily Andean tribe Stenomesseae Traub based on a combined nrITS and gap matrix .
Family specific alkaloids  with CNS activity such as galanthamine are phylogenetically constrained and have chemotaxonomic value [3,4]. However, the chemistry of the American Amaryllidaceae is sparsely investigated and the chemistry of the genus Rauhia has to our knowledge not previously been investigated.
In this first investigation of alkaloids from the genus Rauhia, galanthamine and sanguinine were isolated from Rauhia multiflora (Kunth) Ravenna. Dried bulbs of Rauhia multiflora (23.15g) were extracted following standard methods . The alkaloids were identified using 1H NMR and 13C NMR spectroscopy and optical rotation.
Galanthamine has been reported from several species of primarily Eurasian Amaryllidaceae, but also for example from South American Eucharis amazonica Linden . Sanguinine was first isolated from Lycoris sanguinea Maxim. and subsequently from other Eurasian Amaryllidaceae, as well as South American Phaedranassa dubia (Kunth.) J.F.Macbr. .
The finding of sanguinine in Rauhia multiflora may support the proposed sister relationship of Rauhia and Phaedranassa, but the taxonomic value of both galanthamine and sanguinine within American Amaryllidaceae in general is unknown.
Acknowledgement: We thank the Botanical Gardens of the University of Copenhagen for material of Rauhia multiflora (Voucher: Rønsted 374, Herbarium C). This research was supported by a Steno grant (N°272–07–0281) to NR from the Danish Council for Independent Research – Natural Sciences.
References: 1. Meerow AW (2010) Diversity, phylogeny and evolution in the monocotyledons, Aarhus University Press, Denmark, pp. 145–157.
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4. Jensen BS et al (2011) Biochem Syst Ecol 39: 153–155.