Phytochemical characterization and evaluation of the antimicrobial and antioxidant activity of various fractions of Malva sylvestris (Pick-cheese) leaf extracts

The methanolic extract fractions of Malva sylvestris, collected from Bahawalpur district, were subjected to study the total phenolic contents, total flavonoid contents, antioxidant and antimicrobial activity. The antioxidant activity was measured using the linoleic acid system, DPPH scavenging assay, and determination of reducing power. The antimicrobial activity was evaluated through the Disc diffusion method. The partition fractionation of the methanolic extract of M. sylvestris was performed using ethanol, acetic acid, acetone, ethyl acetate, and n-hexane. Yields of polar solvent fractions were higher than other fractions in these plants. HPLC analysis presented three major phenolics, gallic acid (141.51-192.03 μg/g), coumaric acid (112.21-172.11 μg/g), and Ellagic acid (110.31-159.18 μg/g) in M. sylvestris with maximum yield in methanol fractions. The total phenolic contents analyzed using Folin- Ciocalteu reagent of the samples varied from 5.58- 17.1g/100g, 2.66-7.41g/100g dry weight expressed as gallic acid equivalents (GAE). The determined total flavonoid contents in the fractions ranged from 11.50-32.4g/100g and 24.91-36.36g/100g dry weight expressed as catechin equivalents. The percentage of inhibition of linoleic acid peroxidation and reducing potential was more significant in M. sylvestris methanol fractions, i.e., 47.6% and 3.3 mg/100mL, respectively. M. sylvestris plants also demonstrated remarkable antimicrobial activity against various pathogens (E.coli, P.multocida, S.aureus, B. subtillus, A. niger, A. flavus, A, fusarium, F. Solani). The chemical screening of crude extracts constitutes an efficient complementary approach allowing localization and targeted isolation of new types of constituents with potential activities.