## 1 Introduction  
Carnosic acid (CA), carnosol (CS), 12-O-methylcarnosic acid (12 MCA), rosamanol (RO) and 7-O-methyl-_epi_-rosmanol (7 MER) are highly interesting abietane-type diterpenes due to their anti-inflammatory, anti-oxidant, anti-tumor, anti-human immunodeficiency virus (HIV), anti-microbial, anti-Alzheimer, anti-adipogenic and neuroprotective properties [1]. All these metabolites have been identified uniquely in specific plants in the Lamiaceae family [2]. Indeed, CA accounts for about 30% of phytochemical studies and is the most studied bioactive metabolite of _Salvia rosmarinus_, followed by CS with 17%, while both rosmarinic acid and unsolic acid add up to 18% of research studies [3].  
In our previous study, we showed that rosmarinus officinalis L. syn. _Salvia rosmarinus_) extract and its metabolites, carnosic acid (CA), carnosol (CS), 7-O-methyl-_epi_-rosmanol (7 MER), 4',7-O-dimethylapigenin (DMA) and betulinic acid (BA), were able to antagonize in vitro the action of 2,3,7,8-tetrachlorophenoxy-p-dioxin (TCDD) on the aryl hydrocarbon receptor (AhR), while its methanolic extract antagonized the activity of dioxin (TCDD), 6-formyl-indolocbarazole (FICZ), pityriazepin and indirubin in AhR in human keratinocytes [4]. After that, we focused on the optimization of the extraction process in infusions, decoctions, turbulent flow extracts, timcures and oleolites from three _Salvia_ species, _Salvia officinalis_ L. (common sage, _SO_), _Salvia fruticosa_ Mill. (Greek sage, _SF_) and _Salvia rosmarinus_ Spenn. (rosemary, _SR_), regarding 12 MCA, CA, CS, 7 MER and RO using 1H-qNMR [5].  
In the present study, the purpose was the quantitative and qualitative evaluation of 61 plants from the Lamiaceae family growing (as native and/or cultivated) in Greece from the following genera: _Ballota_, _Hysopus_, _Lavandula_, _Marrubium_, _Nepeta_, _Phlomis_, _Ocimum_, _Origanum_, _Salvia_, _Stachys_, _Thymbra_, _Mentha_, _Melissa_, _Teiderium_, _Satureja_, and _Betonica_. They were assessed regarding their content of selected abietane-type diterpenes, CA, CS, 7 MER, 12 MCA, and RO, with 1H-qNMR spectroscopy using isolated and fully structurally determined metabolites as standards [4; 5]. The overall target was the identification of new sources of the target analytes that could be used for wider practical applications, e.g., as natural food additives, as functional food ingredients and as raw materials for the isolation of the studied substances. To our knowledge, 37 out of 61 (60%) Lamiaceae species were examined herein for the presence of CA and CS for the first time, and 57/61 (93%) for 12 MCA.  
The measurement of the aforementioned substances was usually carried out with high-performance liquid chromatography-ultraviolet (HPLC-UV) or liquid chromatography-mass spectrometry (LC-MS) methods (reviewed by [PERSON] et al., 2023 [6]), which have greater sensitivity than NMR spectroscopy. However, in our study, we used 1H-NMR spectroscopy for the qualitative and quantitative analyses because it presents many advantages compared to the previously mentioned methods, such as being much quicker, exhibiting high repeatability and accuracy, providing the possibility of comparing spectra between different instruments without the need for internal standardization or calibration, allowing the simultaneous identification and quantification of a large number of compounds, being a non-destructive technique for the sample since it remains unchanged and can be used again, and also being of lower cost and eco-friendly. Moreover, from our previous experience [4; 5], CA and CS are vulnerable to structural transformation in polar solvents like water and methanol, while with 1H-NMR we have more inert conditions. For all these reasons, we considered 1H-NMR more useful in our work, especially in the case of screening a large number of samples.