# Antioxidants
###### Abstract  
The ability of hemp (_Camabis sativa_ L.) inflorescence extract to counteract lipid oxidation was studied in stripped linesed oil. The ethanolic extract was characterized in terms of terpenes (6.00 mg/mL), cannabidiol (4.99% _w/w_), phenolic compounds (1.80 mg gallic acid equivalents (GAE)/mL), antiradical, and metal ion-chelating activities (50% effective concentration (EC\({}_{50}\)) of 2.47 mg/mL and 0.39 mg/mL, respectively). The stripped linesed oil, used as control (CO), was mixed with hemp extract (HO) or \(\alpha\)-tocopherol (EO) at a ratio of 0.6% (_w/w_) and stored for 7 days in darkness at 40 \({}^{\circ}\)C. Hemp extract reduced the oxidation and lipolysis processes. At the end of the storage, HO showed a significantly higher level of \(\alpha\)-linolenic acid (ALA; 26.64 g/100 g), lower peroxide value (PV) (21.19 meg O\({}_{2}\)/kg oil), and lower hexanal content (7.67 mmol/kg oil) than those found in the control. In contrast, EO showed a marked lipolysis (the free fatty acids increased by 42.57%) and a noticeable oxidation, since the ALA content decreased by 2.10% and a PV of 50 meg O\({}_{2}\)/kg oil was observed. This study demonstrates that hemp infloresences can be used as a source of natural antioxidants in vegetable oils and lipid products to retard their oxidation, especially those characterized by a high degree of unsaturation. C 20202012 November 20202014 November 20202021 October 20202012 November  
oxidation products exert negative effects on human health, as well as impacting their sensory properties [8]. Many factors impact lipid oxidation, such as fatty acid composition and their degree of unsaturation [9], presence of pro-oxidant or antioxidant species, their solubility/lipophilicity, and storage conditions [10; 11]. In order to counteract lipid oxidation in edible oils, different strategies have been employed. In particular, use of antioxidants capable of neutralizing free radicals and/or chelating metal ions represents an efficient strategy to extend the shelf life of vegetable oils, especially those characterized by a high degree of unsaturation. Butylated hydroxyanisole (BHA), _tert_-butylhydroquinone (TBHQ), and butylated hydroxytoluene (BHT) are the predominant synthetic antioxidants. However, since they can promote DNA damage [12; 13] and due to health concerns from consumers, the use of natural antioxidants is preferred [8; 14]. In addition, natural antioxidants may positively affect human health (e.g., cardioprotective effect, anticancer, etc.) giving added value to the edible oils [15]. Recently, greater interest has been addressed to hemp (_Camabis sativa_ L.), also called industrial cannabis (content of psychoactive cannabinoids <0.2%), mainly investigated due to the presence of more than 133 cannabinoids and terpenes [16; 17]. However, hemp produces other metabolites, which could demonstrate antioxidant activity. [PERSON] et al. [18] reported that hemp synthesizes characteristic molecules, such as preynylated flavonoids, stilbenoid derivatives, and lignamides, which require further investigations. Other studies [19; 20] reported high amounts of polyphenols in hempesed cultivars Finola, Futura, Felina, and Carmagnola (Italy) with antioxidant activity. A special role is attributed to flavonoids, acting as free-radical scavengers and chelators of metal ions. Thus, the seeds of hemp are widely employed in the food industry, while the remaining infloresences, considered as by-products, are mainly used for obtaining essential oils [21; 22]. The cultivar Carmagnola was regarded as the most promising, due to the highest amount of polyphenols (about 743.5 mg/kg) in its infloresences. They are an attractive source of natural antioxidants for nutraceutical purposes [23]. However, the hemp extracts were mainly chemically characterized and tested in vitro, while few data are available on their antioxidant role in bulk oil [16]. Therefore, the effect of the whole phyto-complex obtained from hemp infloresences on lipid oxidation requires further deep investigation.