Cytotoxic Alkaloids fromHippeastrum solandriflorumLindl.

Kaline R Carvalho,Alison B Silva,Letícia V Costa-Lotufo,Maria Conceição M Torres,Larissa A Guimarães,Danilo D Rocha,Edilberto R Silveira,Raimundo Braz-Filho,Otília Deusdênia L Pessoa,Francisco Chagas L Pinto

doi:10.5935/0103-5053.20150176

Abstract

One new alkaloid, 2α-10bα-dihydroxy-9-O-demethylhomolycorine, in addition to seven others known alkaloids, and 5-(hydroxymethyl)furfural, piscidic acid and eucomic acid, were isolated from the bulbs of Hippeastrum solandriflorum. The structures of all compounds were determined using nuclear magnetic resonance (NMR) spectroscopic techniques: 1H NMR and 13C NMR, heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear Overhauser effect spectroscopy (NOESY), and also the high-resolution electrospray ionization mass spectrometry (EI-HRMS). The cytotoxic activity of all alkaloids was evaluated against three human cancer cell lines (HCT-116, HL-60, OVCAR8 and SF-295) showing IC50 values ranging from 0.01 to 35.7 µM.

Highlights

We report the isolation and characterization of a new homolycorine type alkaloid [1] (Figure 1) from the bulbs of H. solandriflorum, a species widely found in Ceará State
The chemical characterization was performed by analysis of their nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopies and high-resolution electrospray ionisation mass spectrometry (EI-HRMS) spectral data
Compound 1, isolated as an optically active white powder, was determined to have the molecular formula as C17H19NO6 (9 degrees of unsaturation) by analysis of its EI-HRMS (m/z: 334.1272 for [M + H]+, calcd.: 334.1285) and the 13C NMR spectra

Summary

Introduction

The Amaryllidaceae, the 4th of the 20 most important alkaloid-containing plant families, comprising approximately 1100 perennial bulbous species, represented by 85 genera.1 Known for their beautiful flowers, Amaryllidaceae plants have been extensively investigated, due to the structural diversity of their compounds and the broad spectrum of biological activities.2 The main particularity of the plants from this family is the production of a large and peculiar group of isoquinoline alkaloids, most of which have never been found in any other plant family.1 So far, more than 500 alkaloids have been isolated and evaluated through their pharmacological properties, as: antiviral, antitumor, antioxidant, antimalarial, anti-inflammatory and cytotoxic.3-5 Two of these alkaloids, lycorine and narciclasine, which were isolated from several Amaryllidaceae genera including Hipeastrum, have been extensively investigated due their anticancer properties.6-8Hippeastrum is a known ornamental genus, consisting of approximately 70 species, predominantly distributed in Latin America, especially in Brazil, with ca. 30 cataloged species.9 Previous investigations carried out with Hippeastrum species have shown that this genus is a prolific source of alkaloids, of the lycorine (pyrrolo[de]phenanthridine) and tazettine (2-benzopyrano[3,4-c] indole) types.10. We report the isolation and characterization of a new homolycorine type alkaloid [1] (Figure 1) from the bulbs of H. solandriflorum, a species widely found in Ceará State.

Results

Conclusion