Antifungal activity and computational study of constituents from Piper divaricatum essential oil against Fusarium infection in black pepper.

Joyce Da Silva,José Silva,Shirlley Da Luz,Soelange Nascimento,José Maia,Cláudio Alves,Alessandra Ramos,Erisléia Meireles

doi:10.3390/molecules191117926

Abstract

Fusarium disease causes considerable losses in the cultivation of Piper nigrum, the black pepper used in the culinary world. Brazil was the largest producer of black pepper, but in recent years has lost this hegemony, with a significant reduction in its production, due to the ravages produced by the Fusarium solani f. sp. piperis, the fungus which causes this disease. Scientific research seeks new alternatives for the control and the existence of other Piper species in the Brazilian Amazon, resistant to disease, are being considered in this context. The main constituents of the oil of Piper divaricatum are methyleugenol (75.0%) and eugenol (10.0%). The oil and these two main constituents were tested individually at concentrations of 0.25 to 2.5 mg/mL against F. solani f. sp. piperis, exhibiting strong antifungal index, from 18.0% to 100.0%. The 3D structure of the β-glucosidase from Fusarium solani f. sp. piperis, obtained by homology modeling, was used for molecular docking and molecular electrostatic potential calculations in order to determine the binding energy of the natural substrates glucose, methyleugenol and eugenol. The results showed that β-glucosidase (Asp45, Arg113, Lys146, Tyr193, Asp225, Trp226 and Leu99) residues play an important role in the interactions that occur between the protein-substrate and the engenol and methyleugenol inhibitors, justifying the antifungal action of these two phenylpropenes against Fusarium solani f. sp. piperis.

Highlights

Piper nigrum L. (Piperaceae), commonly known as black pepper, is one of the most famous and oldest spices in the world, with culinary and food preservative uses [1]
Large amounts of phenylpropanoid compounds have been found in essential oils from Piper species occurring in the Brazilian Amazon: safrole in P. hispidinervum C
The Z-score value for the homologue model was −0.839 while the Z-score value for the template was −0.150. These results suggest that the structural quality of homologue model is better than template, model in some aspects

Summary

Introduction

Piper nigrum L. (Piperaceae), commonly known as black pepper, is one of the most famous and oldest spices in the world, with culinary and food preservative uses [1]. Piperis, a biotrophic phytopathogen that causes the Fusarium infection with vessels obstruction and reduction of the culture, bringing serious social and economic losses for the regional producers [3]. Control measures for the Fusarium infection were initiated with research on the resistant black pepper specimens against the phytopathogen. Studies with Piper species from the Amazon, which were previously infected with F. solani f. Tolerant species have been used as rootstock, but, later, these plants exhibit incompatibility, and they die in the fourth year after cultivation [4]. Another alternative use for the native Piper species is the employment of their secondary metabolites as a natural fungicide. Piper essential oils and extracts have a high metabolic diversity, as the terpenes, phenylpropanoids, amides, lignans, neolignans, steroids, pyrones, piperolides, chalcones and flavones, which were previously reported as having antifungal properties [5,6]

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