Chemistry and Antiviral Activity of Arrabidaea pulchra (Bignoniaceae)

Geraldo Brandão,Alaíde Oliveira,Danielle Souza,Erna Kroon,José Filho

doi:10.3390/molecules18089919

Abstract

The aim of the present work was to carry out a bioguided isolation of antiviral chemical constituents from an ethanol extract of leaves from Arrabidaea pulchra (Cham.) Sandwith (EEAPL) that had shown in vitro activity in a previous screening using DNA and RNA viruses. The activity of EEPAL was evaluated against the DNA viruses Human herpesvirus 1 (HSV-1) and Vaccinia virus Western Reserve (VACV-WR) as well as against the RNA viruses Murine encephalomyocarditis virus (EMCV), and Dengue virus 2 (DENV-2) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. Cytotoxicity was determined in LLCMK2 and Vero cells and the Selectivity Indexes (SI) were calculated. The most potent effect was observed against DENV-2 (EC50 46.8 ± 1.6 µg mL−1; SI 2.7). For HSV-1 and VACV-WR EC50 values > 200 µg mL−1 were determined, while no inhibition of the cytopathic effect was observed with EMCV. Bioguided fractionation of EEAPL by partition between immiscible solvents followed by chromatography over a Sephadex LH20 column afforded two arylpropanoid glycosides, verbascoside (AP 1) and caffeoylcalleryanin (AP 2), along with a terpenoid, ursolic acid (AP 3). AP 1 and AP 3 exhibited similar anti-DENV-2 profiles, with SI values of 3.8 and 3.1, respectively, while AP 2 was the most effective anti-DENV-2 constituent, with a SI of 20.0. Our results show that A. pulchra leaves ethanol extract (EEAPL) affords compounds with antiviral activity, mainly against DENV-2.

Highlights

Viral infections represent a current problem in industrialized and developing countries, accounting for severe damages to human health and economic losses in livestock
Our results show that A. pulchra leaves ethanol extract (EEAPL) affords compounds with antiviral activity, mainly against Dengue virus 2 (DENV-2)
APEL was weakly active against herpesvirus 1 (HSV-1) (EC50 121.9 ± 9.8 μg/mL) and disclosed good activity against VACV (EC50 18.4 ± 1.9 μg/mL) and DENV-2 (EC50 12.2 ± 1.6 μg/mL), with Selectivity Indexes (SI) values > 10 in these two last viruses

Summary

Introduction

Viral infections represent a current problem in industrialized and developing countries, accounting for severe damages to human health and economic losses in livestock. Plants afford an extensive chemical diversity and represent rich and renewable sources of natural products with promising biological activities. Antivirals of ethnomedicinal origin are of great interest and have been widely explored [1]. Antiviral compounds can block or inhibit virus replication by interfering with virus attachment to cells, interfering with viral enzymes or suspending viral genome replication. Compounds working at each of these steps within the virus replication cycle must target the viral process, while avoiding similar ongoing cellular processes. Viruses of different families present different structures and replication schemes, and offer different potential molecular targets [2]

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