Chemical fingerprinting of Nepeta L. species and antioxidant analysis of their leaves extract

The genus Nepeta L. is a member of the family Lamiaceae, commonly known as catmints or catnips. Nepeta L. has been used in traditional medicine to treat a variety of diseases. Additionally, it is sometimes used in herbal tea for its calming effects. Chemical fingerprinting of Nepeta species can help in determining the specific chemical constituents present in different species or varieties, and it can be useful for authentication, quality control, and phytochemical studies. This study provides comprehensive insights into the chemical composition of four Nepeta species including Nepeta erecta (Royle ex Benth.) Benth., Nepeta laevigata (D. Don) Hand.-Mazz., Nepeta nervosa Royle ex Benth. and Nepeta praetervisa Rech. f. using gas chromatography–mass spectrometry (GC–MS). The quantitative examination of phytochemicals such as phenols, flavonoids, alkaloids, and carbohydrates was done using different methods. The antioxidant activity of Nepeta species (methanolic extracts) was evaluated using free radical scavenging (FRSC) assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric reducing the ability of plasma (FRAP) assay. A total of 42 compounds belonging to different classes of natural products were identified in all species. All species exhibit high antioxidant activity. These findings contribute to understanding Nepeta species as a valuable source of natural products with potential therapeutic applications. Further investigations are warranted to explore their full pharmacological potential and develop novel drug candidates.