# Antioxidative and Photop Protective In Vitro Potential of Lavandula Angustifolium
## 4 Discussion
Similar observations can be made for flower extracts of _Lavandula angustifolium_. However, it should be noted that statistically significant differences were found between the SPF of herb and flower extracts evaluated both immediately and twelve months after their preparation (Table 2). Moreover, a very high correlation was observed between the SPF values obtained immediately and after twelve months, both for herb and flower extracts (r = 0.9526 and 0.8989, respectively). Studies on the in vitro determination of the SPF in plant extracts are rarely conducted. The results of the assessment of this parameter in lavender extracts obtained in our study are probably the first determinations of this parameter, taking into account the number of prepared and analysed extracts. Studies on the qualitative evaluation of _Lavandula angustifolia_ extracts have been performed by others. However, some of these studies have been focused on the analysis of essential oils isolated from this plant [30; 62; 63; 64]. The studies presented in this paper included GC-MS analysis of 24 extracts of both lavender flowers and herbs obtained in four solvents with three different concentrations. Based on the results obtained during the studies by the GC-MS method, it can be said that compounds present in the highest area percentages in alcoholic extracts of _Lavandula angustifolia_ include linalool, coumarin, 2H-1-benzopyran-2-one, 7-methoxy-, and linalyl acetate. The highest content of individual organic compounds mentioned above was observed in the following samples: flower 40% (\(v/v\)) nProOH-LIN 28.76 Area%, flower 40% (\(v/v\)) isoProOH-4-HEX 7.84 Area%, flower 40% (\(v/v\)) nProOH-\(\alpha\)-TER 6.48 Area%, flower 40% (\(v/v\)) MeOH-GER 2.22 Area%, herb 70% (\(v/v\)) EtOH-COU 16.25 Area%, herb 40% (\(v/v\)) EtOH-2H-1 30.43 Area%, flower 96% (\(v/v\)) EtOH-LIA 32.42 Area%, flower 99% (\(v/v\)) MeOH-4-HEA 10.05 Area%, herb 40% (\(v/v\)) isoProOH-\(\gamma\)-SIT 4.72 Area%, flower 99% (\(v/v\)) isoProOH-t-\(\delta\)-OCI 2.41 Area%, herb 40% (\(v/v\)) MeOH-4H-PYR 2.46 Area%, flower 99% (\(v/v\)) isoProOH-3,7-OCT 2.76 Area%,herb 99% (\(v/v\)) MeOH-D-ALL 2.88 Area%, herb 99% (\(v/v\)) nProOH-\(\tau\)-CAD 3.69 Area%, herb 40% (\(v/v\)) EtOH-2-MET 2.72 Area%, and herb 40% (\(v/v\)) nProOH-PHY 3.64 Area%. Moreover, a detailed analysis of Table 3 shows that linalool is the main component only in extracts obtained from _Lavandula angustifolia_ flowers. The lowest content of this compound (17.85%) was determined for the flower extract obtained using 99% (\(v/v\)) n-ProOH, and the highest (28.76%) was for the same solvent but at a concentration of 40% (\(v/v\)). It can be further assumed that in the extracts obtained from flowers using MeOH, EtOH, n-ProOH, and isoProOH, linalool plays a key role as an antioxidant compound. In addition, Table 3 shows that its concentration in extracts decreases with increasing concentrations of the solvent used. The linalool molecule contains a hydroxyl group (Figure 10), which is the main structural element responsible for the antioxidant activity of this compound, although this antioxidant activity is weaker than in phenols (e.g., flavonoids), due to the lack of the aromatic system and the lower stability of the radical after hydrogen donation. The hydroxyl group (-OH) allows hydrogen donation (H\(\bullet\)) in reaction with free radicals, which allows their neutralization. Thanks to this, linalool can act as a hydrogen donor and interrupt radical chain reactions. The free radical neutralization reactions involving linalool can be represented as follows:  
\[\text{ROO}\bullet+\text{R}-\text{OH}\rightarrow\text{ROOH}+\text{R}-\text{O}\bullet\]  
The resulting alkoxy radical (R-O\(\bullet\)) from linalool is relatively stable, which stops the oxidation reaction [65]. The extracts mentioned above also contain significant amounts of linalyl acetate (from 9 to 32%). In the case of this ester compound, unlike linalool, the content of linalyl acetate increases with the concentration of the solvent used for extraction.