Phytochemical investigation, and biological evaluation of roots and aerial parts extract of Ranunculus multifidus and in silico study of the interaction of some of its constituents with selected protein targets

Abstract

Medicinal plants contain a wide range of secondary metabolites that can be used to treat chronic and infectious diseases. Infectious and inflammation diseases are still a growing public health concern, especially with the emerging challenge of drug resistance to the current drugs. Ranunculus multifidus, commonly known as Etse siol (in Amharic) was a perennial herb, traditionally used treating malaria, asthma and healing of wound etc. In view of its medicinal uses, the powdered root was successively extracted with n-hexane, dichloromethane and methanol yield 1.125, 1.58, and 6.096%, respectively. The powdered aerial part was extracted with methanol and successively fractionated with n-hexane, chloroform, ethyl acetate, n-butanol and afford 4.54,10.87,26.27,15.15,38.08%, respectively. Phytochemical test revealed the presence of flavonoids, phenols, tannins, saponins, and steroids in both extract of the plant. The silica gel column chromatography has led to the isolation of four compounds from methanol extract designated as RMR01, RMR02, RMR08 and F59 and three compounds from ethyl acetate fraction coded as RML01, RML02, and RML03. The structures were elucidated using spectroscopic methods such as 1H-NMR,13C-NMR and DEPT-135. The extracts and isolated compounds were evaluated in vitro antibacterial activities using disc diffusion method against B. subtilis, S. aureus, E. coli, and P. aeruginosa. Strong inhibition zone (13±0.82 mm, 12.5±1.5 mm,12±0.34 mm, and 11±0.45 mm) and (11.5± 0.5 mm ,11±0.45 mm, 10±0.98 mm, 10±0.26 mm) against B. subtilis, S. aureus, E. coli, and P. aerugin osa compared to standard ciprofloxacin (24±0.15 mm,23±0.34 mm, 22.5±0.52 mm,22±0.00m m) for compound RML02 and RML 01, respectively. The antifungal activities of extracts and isolated compounds were done using disc diffusion methods against two fungal strains. RMR02 and RMR08 shows inter mediate inhibitory with inhibition zone of (5.33±0.58 mm, and 7.33 ±0.42mm) to C. albicans and (9.12±0.76mm, and 5.77±0.68 mm) for A. niger at concentration of 3 mg/ml respectively. RML01, RML02 and RML03 shows good inhibitory zone with (14.43±0.40mm ,11.33 ±0. 58 mm, and 9.93±0.13 mm) against C. albicans and (15.17±0.76 mm, 14.67±0.59 mm, and 16.1± 0.27mm) to A. niger compared to standard fluconazole (21±1.5 mm) and ketoconazole (23.43 ±0.65 mm) at 1mg/ml respectively. The antiradical activities of extracts and pure compounds were done using DPPH assay and MeOH, and n-hexane root extracts shows 97.57%, 71. 95%, and n-butanol and ethyl acetate fraction shows (9 4.187%) and (90.78 %) respectively, which was comparable to ascorbic acid (98.59%) at 100 µg/mL. The pure com pounds also have promising anti-radical activities with maximum inhibition for RML03 (90.13%), RML02 (89.91%) and RMR08 (90.02 %). The Insilico molecular docking of some isolated compounds was done using AutoDock vina with some selected protein (tyrosyl-tRNA synthetase and human peroxiredoxin 5). The result shows compound RML03 and RML01 had the highest binding affinity (-9.8 kcal/mol) and (-8.7 kcal/mol) relative to CPFX (-8.8 kcal /mol). Insilico antioxidant molecular docking revealed RML01 and RML03 showed highest bin ding affinities -6.2 and -5.9 kcal/mol, respectively. The present finding of these pharmacologic ally important secondary metabolites from R. multifidus extracts brings the future attention of experts to look more on the medicinal importance of the plant.