## 3 Results and Discussion  
Aromatic and pharmaceutical plants belonging to the Lamiaceae family are well known for their culinary use as spices and their cosmetic and pharmacological properties, mostly associated with the carnisc acid (CA) and carnosol (CS) content. In medicine, they are known for their anti-oxidant, anti-microbial, anti-inflammatory, anti-ulcerogenic, and anti-nociceptive activities ([PERSON] et al., 2020 [10]). These properties are linked to many secondary metabolites that have been identified in their extracts [11,12]. CA and CS are among most valuable constituents due to their applications in the food industry as flavors and in the pharmaceutical sector as herbal medicine products. Carnisc acid and carnosol are the main non-volatile compounds found in the aerial parts of several \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Compounds** & **y = ax + b** & **R\({}^{2}\)** & **LOD** & **LOQ** \\ \hline CA & y = 0.4812x \(-\) 0.0067 & R\({}^{2}\) = 0.9999 & 0.04 & 0.1 \\ CS & y = 0.4565x \(-\) 0.0043 & R\({}^{2}\) = 0.9999 & 0.04 & 0.1 \\ RO & y = 0.4736x \(-\) 0.003 & R\({}^{2}\) = 0.9998 & 0.04 & 0.1 \\
7 MER & y = 0.4917x \(-\) 0.0025 & R\({}^{2}\) = 0.9999 & 0.04 & 0.1 \\
12 MCA & y = 0.4696x \(-\) 0.0021 & R\({}^{2}\) = 0.9999 & 0.04 & 0.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Calibration curves and LOD and LOQ values. Figure 1: The structures of the studied metabolites: Carnisc acid CA (**1**), carnosol CS (**2**), 12-O-methyl-carnisc acid 12 MCA (**3**), rosamanol RO (**4**), 7-O-methyl-_epi_-rosmanol 7 MER (**5**). Lamiaceae plants, mostly in the _Salvia_ genus, contributing to the overall anti-oxidant effect and pharmaceutical properties. Recently, [PERSON] et al. (2022) [13] showed the effect of CA/CS against prion diseases, highlighting the potential for prophylactic control against neurodegenerative diseases. This has led to a high demand for _S. rosmarinus_ genotypes rich in CA/CS. Significantly, some of the abietane triterpen isolated were evaluated in vitro and in vivo for neuroprotective activities, including anti-neuroinflammatory, neuronutrition, and protective effects against oxidative-induced damage. Carnosic acid and carnosol are the main active anti-oxidants in food additives in Europe (E392). Identification of carnosic acid as probably the key contributor to the anti-oxidant activity was an important milestone in the history of the use of rosmary extracts. In recognition of their efficiency and upon the request of the food industry, in 2010, rosmary extracts were classified as food additives by the European Commission and assigned the number E392 (Commission Directives 2010/67/EU and 2010/69/EU repealed in 2013 by EU regulation 231/2012 and 1333/2008). \"Antioxidant: extracts of rosmary\" are to be produced with one of the four extraction processes described in the regulation, by means of solvent extraction (ethanol, acetone or ethanol followed by hexane) or supercritical carbon dioxide extraction, paying respect to the purity criteria. According to the EU regulation, only deodorized rosmary extracts containing carnosic acid and carnosol are considered additives. Indeed, carnosic acid and its derivative carnosol are listed as key anti-oxidant compounds in rosmary extracts and the E392 dosage limitations are expressed as levels of carnosic acid and carnosol, rather than of the whole rosmary extract. The application areas are food matrices, including oils, animal fats, sauces, bakery wares, meat and fish products, etc. Based on the important applications of abietane dieterpenes from the Lamiaceae family, in this study, we performed the comparative qualitative and quantitative study of 12 MCA, 7 MER, RO, CA, and CS in 61 plant species among 18 plant genera from the Lamiaceae family growing in Greece by \({}^{1}\)H-qNMR. Using \({}^{1}\)H-NMR, the qualitative and quantitative analysis of specific substances in composite mixtures, such as plant extracts, was performed with a simple, fast and high-precision procedure.