Antioxidant, urobactericidal and antibiotic modulating activity of the methanolic extract of the stem and resin of Acacia catechu (L.f.) Willd.

Abstract

Background: Emergence of multidrug resistant pathogens has opened new vistas for novel drug discovery or combinatorial drug surveillance, often in form of some natural products, which is considered to be cheap and safe. In this study, the urobactericidal activity of the methanolic extract of the stem and resin of Acacia catechu (L.f.) Willd (Fabaceae) was explored against five uropathogenic bacterial strains i.e. Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris and Staphylococcus aureus.

Methods: Varieties of antibacterial (disc diffusion, agar well diffusion, modified agar well diffusion) and antioxidant assays (DPPH and OH free radical scavenging assay) were tried to prove the efficacy of stem and resin extracts of A. catechu and to compare their urobactericidal and free radical scavenging properties.

Results: Phytochemical analysis envisaged that the stem and resin contained phytoconstituents like alkaloids, phenols, tannins, proteins, glycosides, flavonoids, steroids and terpenoids, which were reported to have excellent antioxidant and antibacterial activities. The total phenolic contents of the methanolic extract of A. catechu stem (ACs) and A. catechu resin (ACr) were calculated as 37.74 ± 0.023 and 51.98 ± 0.011 mg/g Gallic Acid equivalents. The total flavonoid contents of methanolic extract of ACs and ACr were calculated to be 71.33 ± 0.004 and119.6 ± 0.010 mg/g Rutin equivalent. ACs had IC₅₀ value of 93.68 ± 0.71; 90.92 ± 0.54 µg/mL and ACr had 79.21 ± 0.54; 85.74 ± 0.61 µg/mL in comparison to an IC₅₀ value of 72.33 ± 1.20; 66.96 ± 0.61 µg/mL for standard Ascorbic acid in the DPPH and hydroxyl free radical scavenging assay. Phytocompounds present in both ACs and ACr were proved to have improved the urobactericidal efficacies of conventional antibiotics especially against the E. faecalis and E. coli, the prime etiological agents of uropathogenesis.

Conclusion: Our results indicated the excellent urobactericidal effects of the stem and resin extracts of a least explored natural remedy against uropathogens, which will be beneficial for treating urinary tract infections and augmenting the quest for novel therapies in future for uropathogenesis.