Evaluation of Antioxidant, Antimicrobial activity and GC-MS analysis of Phlomis stewartii

Abstract

The myths of curing several ailments related to Phlomis in different countries since centuries brought our attention to unveil one of its potent specie. The main target was to explore biological activities of this species and to investigate presence of chemical constituents. The present work consists of preliminary phytochemical analysis, Gas Chromatography-Mass Spectrometry (GC-MS) analysis, antioxidant, antibacterial and antifungal activities of the Phlomis stewartii. Qualitative phytochemical analysis deduced the presence of the alkaloids, terpenes, coumarins, saponins, cardiac glycosides, phlobatannins, flavonoids, quinone, steroids and tannins. The quantitative analysis showed that the highest percentage of phenolic compounds were present in methanolic extract that was 48% while 42% in n-hexane fraction. The GC-MS analysis of n-hexane fraction revealed the presence of fourteen compounds. The antioxidant activity was tested via 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical with butylated hydroxytoluene (BHT) as standard antioxidant. The 50% inhibitory concentration (IC50) value of methanolic extract (28.41±0.1) and n-hexane fraction (37.16±0.007) whereas BHT (16.83±0.03) were observed at same dilutions. The antibacterial activity of methanolic extract showed the inhibition zone (mm) against Bacillus subtilis (14±0.18) and Staphylococcus aureus (18±0.19) whereas n-hexane fraction inhibited former (12±0.18) and later (13±0.21).The antifungal activity resulted that n-hexane fraction inhibited Rhizoctonia solani (40±0.94), Alternaria alternate (25±0.81) and Fusarium oxysporum (12±0.67) whereas methanolic extract inhibited former (20±0.58). The present work recommended that Phlomis stewartii may be further explored for testing biological activities after the isolation of individual components. The mixture and various combinations of these chemicals may hint actual potent agent which may be novel against vast varieties of microbes.