Natural products-based: Synthesis and antifungal activity evaluation of novel L-pyroglutamic acid analogues

Abstract

Botanical pesticides are one of the sources of third-generation pesticides, which have received much attention at home and abroad in recent years due to their degradable and pollution-free advantages in nature. This article explored a concise approach toward synthesizing a series of novel L-pyroglutamic acid analogues from L-hydroxyproline. Furthermore, bioassay studies of these sulfonyl ester derivatives against Pyricularia oryzae, Fusarium graminearum, Alternaria brassicae, Valsa mali, and Alternaria alternariae showed moderate antifungal activity. For instance, C08a and C08l provide potential lead agents for controlling Fusarium graminearum because of their inhibitory activity.

Characterization of tea (Camellia sinensis L.) flower extract and insights into its antifungal susceptibilities of Aspergillus flavus

“…Catechin, caffeine, epigallocatechin gallate, salicylic acid, scopoletin, and pyroglutamic acid, which were identified in TFE, have antimicrobial capacity [ 28 – 32 ]. Therefore, other compounds including L-phenylalanine, L-isoleucine, astragalin, 2-keto-glutaramic acid, L-tyrosine, and 2-ketobutyric acid were analyzed to confirm whether they can inhibit A. flavus .…”

“…In addition, the increase in the electrical conductivity in the fungal broth treated with TFE implied the damages to the cell wall and cell membrane, leading to cytoplasm leakage and fungal death [ 26 ]. Several antimicrobial agents were identified, such as catechin, caffeine, epigallocatechin gallate, salicylic acid, scopoletin, and pyroglutamic acid, according to the chemical composition of TFE [ 28 – 31 ]. In the present work, L-phenylalanine, L-isoleucine, astragalin, 2-keto-glutaramic acid, L-tyrosine, and 2-ketobutyric acid were further explored for antifungal activity.…”

Various Biomimetics as Antifungals

“…The use of the created biomimetics is aimed at their competition with the substituted molecules, which affects the metabolic activity and growth of fungal cells [105]. The well-known metabolomics of fungi enable developing of approaches to the decrease in fungal resistance and adaptation to various stress conditions (ionizing radiation, pH change, hypoxic stress, solar ultraviolet radiation, presence of toxic compounds, nutrient stress, oxidative stress, cold-heat stress) (Table 5) [17,89,[106][107][108][109][110][111][112][113].…”

“…Among the 31 synthesized compounds at a concentration of 100 mg/L, the maximum inhibition level (61.6%) of the fungal growth of F. graminearum, comparable to the commercial fungicide chlorothalonil, were derivatives obtained by the introduction of naphthalene or alkane by hydroxyl group. The electron-withdrawing groups on the aromatic ring facilitated the inhibitory effect [17].…”

“…In addition to AFPs, the synthesis of a number of other compounds and materials forming various surfaces imitating natural analogues that can be attributed to biomimetics is also interesting from scientific and practical point of view. The antifungal effect of these compounds and materials is not limited to the destruction of the cell wall and membranes of fungi, but affects their various metabolically important pathways, growth and spore formation [15][16][17]. Of great interest is the possible synergistic effect among such biomimetics with antifungal drugs, which allows to reduce the doses of individual substances used [18,19].…”