Synthesis and Fungicidal Activity of β-Carboline Alkaloids and Their Derivatives.

Zhibin Li,Shaohua Chen,Yaomou Zhang,Qunfang Weng,Shaowen Zhu,Jianjun Luo

doi:10.3390/molecules200813941

Zhibin Li, Shaohua Chen + Show 4 more

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https://doi.org/10.3390/molecules200813941

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Abstract

A series of β-Carboline derivatives were designed, synthesized, and evaluated for their fungicidal activities in this study. Several derivatives electively exhibited fungicidal activities against some fungi. Especially, compound F5 exhibited higher fungicidal activity against Rhizoctonia solani(53.35%) than commercial antiviral agent validamycin (36.4%); compound F16 exhibited high fungicidal activity against Oospora citriaurantii ex Persoon(43.28%). Some of the alkaloids and their derivatives (compounds F4 and F25) exhibited broad-spectrum fungicidal activity. Specifically, compound F4 exhibited excellent high broad-spectrum fungicidal activity in vitro, and the curative and protection activities against P. litchi in vivo reached 92.59% and 59.26%, respectively. The new derivative, F4, with optimized physicochemical properties, obviously exhibited higher activities both in vitro and in vivo; therefore, F4 may be used as a new lead structure for the development of fungicidal drugs.

Highlights

Plant pathogenic microorganisms can infect crops, causing local or whole plant disease and leading to significant economic losses
Previous structure–activity relationship studies had demonstrated the influence of substituents in positions-1, -3, and -9 of the β-carboline skeleton for a variety of synthetic β-carboline derivatives [21,22,23,24]
In order to study the effect of main structure and the substituent groups at position 1 and 3 on their herbicidal activity, we synthesized a series of 30 novel β-carboline derivatives bearing a substituted amide group at C-3 and substituted groups at C-1 (Figure 2 and Scheme 1)

Summary

Introduction

Plant pathogenic microorganisms can infect crops, causing local or whole plant disease and leading to significant economic losses. Many kinds of fungicides are used to prevent and cure the diseases caused by fungi; these chemical agents cannot fully protect the crops or completely cure the crops’ tissues from fungal infection under field conditions. Harman, harmol, harmaline, and harmalol, which are β-carboline and dihydro-β-carboline alkaloids, are four representative harmala alkaloids. Harmane has DNA intercalation ability, leading to intercalation into DNA [6,7] and formation DNA adducts [8], and inhibition of Topo I [7,9], Topo II [9], and MAO-A activity [10,11]. Harmalol is able to induce melanogenesis through p38 MAPK signaling [18] and can act as an agent for preventing dioxin-mediated effects [19]

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