3.4 Sterols
Analysis of the trimethylsilyl derivatives of phytosterols, applying GC–MS, led to identify nine compounds in both varieties ofCannabis sativa L. such campesterol, campestanol, stigmasterol, clerosterol, β-sitosterol, sitostanol, Δ5- avenasterol, Δ5-24-stigmastadienol and Δ7-stigmasterol (Table 4). The total sterols content showed different trend in the two varieties of Cannabis sativa L. considered; in fact, it significantly increased (p<0.05) in Futura 75 during maturation (642.8, 679.1 and 913.4 mg/100 g of oil in F1, F2 and F3, respectively) and, on the other hand, significantly decreased in Carmagnola (532.7, 518.7 and 456.1 mg/100 g of oil in C1, C2 and C3, respectively). These trends reflect the β-sitosterol trends, the predominant sterol detected. In fact, it represented the 63% of the total content in both varieties, but its concentration significantly increased and decreased inFutura 75 and Carmagnola , respectively, with maturation (Table 4). In Futura 75 it had an initial increase about 5% from F1 to F2 and about 36% between F2 and F3; in Carmagnola , on the other hand, β-sitosterol decrease about 6% from first to second harvest stage and then, again about 10%, between second and third harvest.
In Futura 75 campesterol, campestanol, stigmasterol and clerosterol had the same trend reported for β-sitosterol; instead the other sterols detected decreased between the first and the second harvest stage and then increased at full maturity (Table 4). InCarmagnola , instead, campesterol and clerosterol decreased significantly (p < 0.05) during the maturation; campestanol and stigmasterol did not show significant differences during the three harvesting stages.
To the best of our knowledge, only Montserrat-de la Paz et al. (2014) reported a study of sterols in hemp seed oil. Our results were higher than what is reported by these authors for Spanish hempseed oil (total content of 279.4 mg/100 g of oil) but β-sitosterol (190.5 mg/100 g of oil) and campesterol (50.6 mg/100 g of oil) were the same predominant sterols. Comparing sterols composition of HSO with other oils it is possible to see some differences. Considering other vegetable oils, olive oil, linseed oil and hazelnut oil contain an higher amount of campesterol, β-sitosterol and Δ5-avenasterol than HSO. Campesterol reachs values of 40, 50-95, 785 mg/kg; stigmasterol values of 20, 10-18, 343 mg/kg; β-sitosterol values of 750, 1050-1700, 1600 mg/kg and Δ5-avenasterol value of 40-140, 20-80, 369 mg/kg in olive oil, hazelnut oil (Azadmard-Damirchi & Torbati, 2015) and linseed oil (Matthäus & Özcan, 2017), respectively. In addition, linseed oil contains cholesterol, brassicasterol and 5,24-stigmasterol that are not present in HSO. On the other hand, HSO is richer in sterols that sunflower oil, in fact campesterol, stigmasterol, β-sitosterol and Δ5-avenasterol report value of 20, 28, 186 and 20 mg/100g, respectively (Yilmaz & Erden, 2019). Corn oil has the same stigmasterol content of HSO (about 33 mg/100g); is poorer in β-sitosterol than HSO (266 mg/100 g) and, on the other hand, is richer in campesterol (191mg/100g) (Yang et al., 2018).
In general, even if sterols are minor constituents of vegetable oils and are present in the unsaponifiable fraction (Gusakova, Sagdullaev & Khushbaktova, 1998), it is well known that they have a lot of beneficial effects on human health. In fact, they can reduce the serum level of cholesterol concentration, atherosclerotic risk (Ntanios, van de Kooij, de Deckere, Duchateau & Trautwein et al., 2003; Patel & Thompson, 2006), low-density lipoprotein cholesterol and they are related to a lower risk of myocardial infarction (Klingberg et al., 2013).