Comparative antioxidant, antibacterial, and GC-MS analysis of methanol extract's fractions and isolation of luteolin from leaves of trans-Himalayan Codonopsis clematidea

Codonopsis clematidea, is a trans-Himalayan cold desert medicinal plant species, traditionally used by local tribal communities for the cure of various ailments. On this basis in present study the phytochemical composition and biological potential (antibacterial and antioxidant) of various fractions (n-hexane, chloroform, ethyl acetate, and n-butanol) of methanol extract obtained by soxhlet extraction technique from leaves of Codonopsis clematidea were investigated. Different fractions were accessed for their yield percentage, total polyphenol content (TPC), total flavonoid content (TFC), antioxidant potential (DPPH - 1,1-diphenyl-2-picrylhydrazyl; ABTS - 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), reducing power assay (FRAP - ferric reducing antioxidant power activity), and antibacterial activity (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli). Further, different fractions were also subjected to gas chromatography - mass spectrometry (GC-MS) analysis in order to assess the composition of various volatile phytoconstituents. In antioxidant assays, ethyl acetate fractions (EF) showed the strongest DPPH and ABTS antioxidant (IC50: 0.082 and 0.004 mg/mL) and FRAP potential, which significantly correlate to its high content of polyphenolics and flavonoids. However, EF has also demonstrated similar response in antibacterial activity. Further, luteolin was isolated and identified in EF using chromatography techniques and nuclear magnetic resonance (NMR) spectroscopy. The present results support the possible use of the ethyl acetate fraction from Codonopsis clematidea in food, pharmaceutical, and cosmetic industries.