Hydroethanolic extract of Juglans regia L. green husks: A source of bioactive phytochemicals

Abstract

Juglans regia L. (walnut) green husks are an important fraction of waste resulting from the walnut production, thus representing an interesting natural matrix to explore as a source of bioactive compounds. In this work, the hydroethanolic extract of walnut green husks was studied considering the phytochemical composition and the biological activity using different cell model assays, most of them evaluated for the first time for this matrix. From the HPLC-DAD-ESI/MS n analysis, sixteen compounds were identified, being the extract mostly composed of naphthalene derivatives (including tetralone derivatives) and less abundant in phenolic compounds (hydroxycinnamic acids and flavonols). The cytotoxic potential of the extract was assessed against tumour (MCF-7, NCI-H460, HeLa and HepG2) and non-tumour (PLP2) cell lines. Moreover, the antioxidant activity of the extract was evaluated by inhibition of the oxidative haemolysis (OxHLIA) and the formation of thiobarbituric acid reactive substances (TBARS), and the anti-inflammatory potential by the inhibition of the NO production by the RAW264.7 cell culture. The antibacterial effects of the extract were also evaluated against Gram-negative and Gram-positive bacteria. The results obtained represent a stepping stone for the development of future applications using walnut green husks as a source of added value compounds with bioactive potential.

Walnut (Juglans regia L.) Septum: Assessment of Bioactive Molecules and In Vitro Biological Effects

“…The hydroethanolic extract of Juglans regia green husks has been shown to mitigate nitric oxide (NO) production in immune cells (RAW264.7) in response to LPS stimulation. Regarding the phytochemical profile of the above-mentioned extract, the authors reported the presence of phenolic acids, flavonoids, as well as tetralone and naphthalene derivatives, compounds usually described in the phytochemical profile of walnut [ 56 ]. Similarly, pretreatment of HaCaT cells with a methanolic extract of male flowers of walnut significantly prevented the secretion of ultraviolet B (UVB) activated inflammatory markers like IL-1, IL-6, tumor necrosis factor- α (TNF-α) and COX-2 [ 42 ].…”

Antitussive, Antioxidant, and Anti-Inflammatory Effects of a Walnut (Juglans regia L.) Septum Extract Rich in Bioactive Compounds

“…Walnuts are considered nutraceuticals, as they contain proteins and essential unsaturated fatty acids, as well as tocopherols, sterols, and polyphenols with recognized antioxidant, anti-inflammatory, and antibacterial properties [9]. In addition to kernel, walnut by-products including leaves, green husk or septum represent important sources of nutraceutical compounds [10,11].…”

Neuroprotective potential of hydroethanolic hull extract of Juglans regia L. on isoprenaline induced oxidative damage in brain of Wistar rats

“…Walnut ( Juglans regia L.) belongs to family Juglandaceae, and is extensively used in Indian Ayurvedic and other traditional systems of medicine for the treatment of various disorders [ 7 , 8 ]. It is a rich and cholesterol-free source of nutrients including quality proteins, high concentrations of alpha linolenic acid, phenolic acids, flavonoids, tetralones and naphthoquinone, are the main components [ 8 , 9 ]. Presence of pharmacological properties such as antifungal, astringent action, hepatoprotective, cardioprotective, neuroprotective, laxative action, antioxidant potential make it an ideal food for consumption [ 10 , 11 ].…”

“…Addition of walnut in diets has been also found to be beneficial against development and progression of Alzheimer's disease [ 13 ]. The basic mechanisms behind the curative effects rely on the action of the phytonutrients in safeguarding pathways associated with protein folding and neuroinflammation in vitro [ 9 , 14 ]. Hull is the outermost green covering of the fruit and loss during the extract of walnut seed from fruits.…”

“…Qualitative and quantitative studies indicate that hull is rich in polyphenolic compounds and alkaloids having various pharmacological properties. To maximize the utilization of hull as a feed and fodder supplement in animals and humans [ [7] , [8] , [9] , [10] ]. Therefore, present study was under taken to determine the possible antioxidant and neuroprotective potential of J. regia hull extract against ISO induced oxidative damage in brain of Wistar rats.…”