# Relationship between Total Antioxidant Capacity, Cannabinoids and Terpenoids in Hops and Cannabis
Hops cannot synthesize cannabinoids as they lack the oxidoreductase enzymes needed to convert cannabigerolic acid (CBGA) to various cannabinoids [40]. Other antioxidant compounds of interest produced by hops and cannabis are terpen and phenols [9]. Terpenes, or isoprenoids, are one of the largest and most diverse groups in plants [41]. Although terpenes and volatile phenols are mostly responsible for their characteristic aroma, they possess beneficial health benefits such as anticancer, antimicrobial, antifungal, antiviral, analgesic, anti-inflammatory, and antiparasitic activities [42; 43; 44]. In vitro studies by [PERSON] et al. (2015) showed that myrcene, one of the most abundant terpenes in hops and cannabis, has significant anti-inflammatory and anti-catabolic properties, and is useful for halting or slowing down cartilage destruction and osteoarthritis progression. Phenolic compounds, including terpenes, are reportedly powerful antioxidants with high scavenging properties [8]. Plant secondary metabolite biosynthesis and antioxidant activity can be disrupted and altered during postharvest storage and drying [45; 46; 47]. Storage studies by [PERSON] et al. (2019) over four years showed that CBD is not prone to oxidative degradation and is stable over time, while decarboxylation of THCA to THC which occurs in stored plant material is increased by the presence of oxygen and higher temperatures [48; 49]. Specifically, THC concentrations markedly increase from 1.5% to 2.1%, 12.3% and 12.8% when stored at 50 \({}^{\circ}\)C, 100 \({}^{\circ}\)C, and 150 \({}^{\circ}\)C, respectively, due to THCA decarboxylation [45]. Hop buds stored at 20 \({}^{\circ}\)C in a dark room showed decreased \(\alpha\)-acid concentrations from 186.9 \(\upmu\)mol g\({}^{-1}\) to 37.0 \(\upmu\)mol g\({}^{-1}\) and \(\beta\)-acids from 107.7 \(\upmu\)mol g\({}^{-1}\) to 50.9 \(\upmu\)mol g\({}^{-1}\). Both \(\alpha\)-acids and \(\beta\)-acids are oxidized rapidly during hop storage [50]. Decreases in \(\alpha\)-acids and \(\beta\)-acids can decrease the antioxidant capacity of hops. The effects of pre-freezing and drying on hop terpene content has been reported and the optimal conditions for freeze-drying and microwave assisted hot air drying (MAHD) were explored [51]. This previous study showed that the low temperature used during freeze-drying preserved 16.6% to 68.3% of the major terpen present in hops compared to hot air and MAHD systems, respectively. Pre-freezing caused significant structural damage to hops and this was similarly observed for cannabis in a related trial [51]. The main objective of this follow-up study was to investigate the effects of pre-freezing, prior to drying hops and cannabis, on antioxidant capacity using pre-optimal drying conditions. The suitability and efficiency of 2,2-diphenyl-1-picrylhydrazine (DPPH) and ferric reducing antioxidant power (FRAP) assays were examined and compared for estimating total antioxidant activity (TAC) in hops and cannabis extracts from biomass subjected to these postharvest methods. Given the legislative focus on documenting scientific literature that scrutinizes the therapeutical potential of cannabis for medical use, the relationship between antioxidant capacity and valued secondary metabolites in these two crops was examined.