**4. TOF-MS analysis**

The mass spectra of birthwort fractions: B1–B4 (acquired in positive ion mode, in a mass range of 100–3000 m/z) are presented in **Figure 1a–d**.

The results gained through mass spectrometry confirmed the presence of aristolochic acid in all four samples analyzed (m/z detected: 294, 293, 308, 355) among other secondary metabolites [86].

Further, thorough investigations are required to highlight:


#### **Figure 1.**

*Figure 1 a-d. Positive ion mode TOF-MS of of birthwort fraction B1-B4. (1a) Positive ion mode TOF-MS of of birthwort fraction B1. (1 b) Positive ion mode TOF-MS of of birthwort fraction B2. (1c)Positive ion mode TOF-MS of of birthwort fraction B3. (1d) Positive ion mode TOF-MS of of birthwort fraction B4.* 

### **5. Conclusions**

Natural compounds are essential for the existence of humanity; this assertion has been demonstrated by the most modern researches which once again highlights the particular curative properties of phytochemicals isolated from medicinal plants known and appreciated since the earliest times.

*Pharmacognosy - Medicinal Plants* 
