Chestnut (Castanea sativa Miller.) Burs Extracts and Functional Compounds: UHPLC-UV-HRMS Profiling, Antioxidant Activity, and Inhibitory Effects on Phytopathogenic Fungi

Abstract

Chestnut (Castanea sativa Miller.) burs (CSB) represent a solid waste produced during the edible fruit harvesting. Their usual disposal in the field increases the environmental and economic impact of the agricultural process. HPLC-UV-HRMS profiling revealed that CSB organic and aqueous extracts (CSB-M, CSB-H, CSB-A) contain several hydrolyzable tannins, mainly ellagitannins, and glycoside flavonols. Ellagic acid (EA) and chestanin are predominant components (5–79 and 1–13 mg/g dry extract, respectively). NMR analysis confirmed the chemical structures of the major constituents from CSB-M. The extracts displayed a significant scavenging activity against DPPH• (EC50 12.64–24.94 µg/mL) and ABTS•+ radicals (TEAC value 2.71–3.52 mM Trolox/mg extract). They were effective in inhibiting the mycelial growth (EC50 6.04–15.51 mg/mL) and spore germination (EC50 2.22–11.17 mg/mL) of Alternaria alternata and Fusarium solani. At the highest concentration, CSB-M was also active against Botrytis cinerea both in mycelium and spore form (EC50 64.98 and 16.33 mg/mL). The EA contributed to the antifungal activity of extracts (EC50 on spore germination 13.33–112.64 µg/mL). Our results can support the upgrading of chestnut burs from agricultural wastes to a resource of natural fungicides for managing fruit and vegetable diseases.

Evaluation of the Phenolic Profile of Castanea sativa Mill. By-Products and Their Antioxidant and Antimicrobial Activity against Multiresistant Bacteria

“…For this reason, some farmers choose to gather and burn the burs and leaves, which has a negative impact on the environment. Despite the fact that several food processing by-products and/or agriculture wastes are being discarded, numerous studies have been demonstrating that they can be an attractive and cheap source of bioactive compounds with high interest for the food, cosmetic, and pharmaceutical industries [6][7][8]. In this way, the use of agro-industry residues to obtain added-value molecules or products is increasingly being suggested as part of the concept of a circular economy [9,10].…”

Allelochemicals from Castanea Sativa Mill.: Plant-Root Environment Interactions

“…However, secondary metabolites, including phenolic nature, from different tree organs can also be released into the rhizosphere soil of C. sativa through root exudates, leaching, and decay. C. sativa contains a significant pool of phenolic compounds, in particular tannins and flavonoids (Chiarini et al, 2013;Fuente-Maqueda, 2018;Esposito et al, 2019). Tannins and phenolic compounds characterized in C. sativa bark, including ellagic acid, gallic acid, and ellagitannins (vescalin, castalin, vescalagin, and castalagin), were reported (Chiarini et al, 2013).…”

“…Other minor compounds from C. sativa bark, detected in trace levels, 5-o-galloylhamamelose (3.5-dimethoxy-4hydroxyphenol)-1-o-b-D-(6-o-galloyl)-glucoside isomer, m-digallic acid, kurigalin isomer, and chestanin were reported (Chiarini et al, 2013). Glucose esters with gallic acid (-mono, -di, and -trigalloylglucose), ellagitannins (vescalagin/castalagin), phenolic acids (gallic, ellagic, protocatechuic, chlorogenic acid), flavonoids (apigenin, quercetin, and quercetin 3-O-glucoside) has been identified in chestnut burs (Esposito et al, 2019). A methanol extract of the leaves of C. sativa contained as main compounds crenatin, chestanin, gallic acid, cretanin, 5-O-p-coumaroylquinic acid, p-methyl gallic acid and quercetin-3-O-glucoside (Cerulli et al, 2018).…”

“…Sweet chestnut (Castanea sativa Mill., Fagaceae family) is a valuable food, ornamental, honey and medicinal plant. C. sativa is a rich source of broad-spectrum bioactive compounds and nutrients, that give it medicinal properties (Leonardi et al, 1996;Chiarini et al, 2013;Fuente-Maqueda, 2018;Grygorieva et al, 2018;Cerulli et al, 2018;Esposito et al, 2019). C. sativa exhibits antibacterial, antifungal, antioxidant and cardioprotective effects (Basile et al, 2000;Chiarini et al, 2013;Esposito et al, 2019).…”

Design and Development of Spray-Dried Microsystems to Improve Technological and Functional Properties of Bioactive Compounds from Hazelnut Shells

“…By-products of agro-food manufacturing chains contain polysaccharides, proteins, vitamins, fats, and phytochemicals. The recovery of bioactive components with health-promoting benefits suggests the exploitation of vegetable residues as functional ingredients in developing nutraceuticals, functional or novel foods, and pharmaceutical products [1][2][3]. Today, there is an increasing interest in the use of nutraceuticals, based on plant extracts or food by-products, as potential chemopreventive agents, to be used in combination with chemotherapeutics, as a new strategy in cancer control [4][5][6].…”