Phytochemical Profile, Antioxidant Activity of Leaf of Hoslundia opposita Vahl and Docking of its Phytochemical Components with Uropathogenic Strain F11(ID:3NRP) and NFeoB from Escherichia coli BL21(ID:5FH9)

Abstract

Hoslundia opposita Vahl is a multi-purpose medicinal plant used traditionally to treat gonorrhea, cystitis, cough, fever, snake bites, convulsion in many parts of Africa. The objectives of this research are to evaluate the phytochemical profile, antioxidant activity of the leaves of Hoslundia opposita Vahl and to dock its phytochemical components with uropathogenic Escherichia coli strain F11(ID:3NRP) and NFeoB from Escherichia coli BL21(ID:5FH9). Harborne’s method was used for the identification of the class of phytochemicals while GC-MS was used to identify the type of phytochemicals. Folin-Ciocalteau method was used to determine the total phenolic content while aluminum colorimetric assay was used to estimate the total flavonoid content. 1, 1-diphenyl-2-picrylhydrazyl (DPPH) was used to evaluate the antioxidant activity. The molecular docking simulation method was used to investigate the interactions of the phytochemicals with the Escherichia coli receptors. In the phytochemical studies, flavonoids, terpenoids, cardiac glycosides and saponins were identified to be present in the methanolic leaf extract while steroids, alkaloids and anthraquinones were absent. The GC-MS analysis of the methanolic extract revealed presence of 17 compounds out of which 14 were identified. The compounds with appreciable quantity in the leaf extract were 1, 2, 3-benzetriol (38.11%), n-hexadacanoic acid (13.52%) and catechol (9.98%). Assessment of the antioxidant activity using DPPH gave a scavenging activity of 79.86% at 500ug/ml compared with ascorbic acid having a scavenging activity of 90.85% at the same concentration. Evaluation of the total phenolic and flavonoid contents at 500 ug/ml gave the values of 262.54 mg gallic acid equivalent/g extract and 6.24 mg quercetin equivalent/g extract respectively compared with gallic acid and quercetin with maximum concentrations of 385.12 and 12.46 respectively. This shows that the extract has significant antioxidant activity and can be explored as a valuable source of natural antioxidants. GC-MS analysis of the methanolic extract of Hoslundia opposita showed the presence of trans-3-(trifluoromethyl)cinnamic acid, octadecyl ester which was active against Escherichia coli. Docking results with 3NRP and 5FH9 showed binding affinities of -6.1, -6.6, 7.2and -7.0,7.4, 8.5 kJ/mol with the commercial drugs : ciprofloxacin, levofloxacin and tetracycline respectively while that of trans 3-(trifluoromethyl)cinnamic acid, octadecyl ester identified in the leaves were 5.6 and 5.9 kJ/mol.