## 3 Results and Discussion
somalensis_ Vatke by \({}^{1}\)H-NMR using CD\({}_{3}\)OD, where the qualitative and quantitative results were the same. _S. microphylla_ Kunth is of particular interest as it showed the highest amount of 12 MCA among all the plants studied (Figure 5). This makes it an excellent raw material for isolating the latter. High CA and CS were also identified. [PERSON] et al. (2006) [29] detected 12 MCA and CA, but not carnosol. Figure 5: \({}^{1}\)H-NMR spectrum of _S. microphylla_ Kunth in CDCl\({}_{3}\). In _S. argentea_ L., CA, CS, and 12 MCA were identified. [PERSON] et al. (2013) [30] identified CA but not CS, and they did not provide any information about 12 MCA. It should be noted that they extracted the plant material with a Soxhlet device for 2 h in methanol. CA, CS, and 12 MCA were identified in _S. glutinosa_ L. This contrasts with the work by [PERSON] et al. (2008) [14], who detected only the presence of CA. The difference between the two results may lie in the extraction time with methanol. [PERSON] et al. (2017) [17], in an aqueous extract of _S. glutinosa_ L., detected \(\sim\)350 \(\upmu\)g/g of dry carnosic acid drug, while in ethanolic solution, they detected only traces. CA, CS, and 12 MCA were detected in _S. darcyi_ [PERSON]. In the work by [PERSON] et al. (2008) [14], only 12 MCA and CS were identified. CA was detected in _S. aurita_ L. but not 12 MCA and CS. CA and CS have previously been identified without information about 12 MCA ([PERSON] 2006 [31]). In _S. virgata_ Jacq., carnosic acid and carnosol were detected. In the work by [PERSON] et al. (2019) [18], CA had been identified in leaves and roots of the plant. CA and CS were identified in _S. canariensis_ L. and _S. verticillata_ L., as in the work by [PERSON] et al. (2008) [14] and [PERSON] et al. (2019) [18]. Only CA was identified in _Salvia pratensis_ L. This result is the same as the work by [PERSON] et al. (2017) [17] and [PERSON] et al. (2008) [14]. The presence of carnosic acid and/or carnosol in an extract does not imply the presence of 12-\(O\)-methyl-carnosic acid. A typical example is the methanolic extract of the leaves of _S. somalensis_ Vatke, which has high amounts of carnosic acid and carnosol but does not contain 12-\(O\)-methyl-carnosic acid. However, the opposite is not true, because whenever the latter was identified, there was always one or both of the former substances. Another observation that emerges is that high CA levels are not necessarily associated with high CS levels in the species studied. Since CS is derived from the conversion of CA, it is reasonable to assume the following:  
* A decrease in the amount of CA implies an even transient increase in carnosol. * The presence of high amounts of both substances in a plant extract is due to an even greater initial amount of CA. Regarding qualitative and quantitative analyses using \({}^{1}\)H-NMR spectroscopy, the method offers several advantages, including the short analysis time, the high repeatability and accuracy, no requirement for internal calibration or standardization for spectral comparison across different instruments, the capability to simultaneously investigate numerous compounds, and the non-destructive nature of the analysis, which allows sample reuse. It is worth noting that the \({}^{1}\)H-NMR spectrum of the methanolic extract from each examined plant exhibited a unique sequence of peaks, which can serve as a \"fingerprint\" for the purpose of botanical differentiation or plant identification, particularly in cases where classification is challenging. _Betonica officinalis_ L. and _Stachys officinalis_ (L.) Trevis.