UPLC‒ESI‒MS/MS profiling of active polyphenolics in Morinda coreia leaf extract and in vitro antioxidant and antibacterial activity

Abstract

In this study, aqueous and methanol extracts of Morinda coreia (MC) leaves were tested for antioxidant and antibacterial activity under in vitro conditions. Phytochemical analysis using UPLC–ESI–MS revealed the presence of phenolics, flavonoids, alkaloids, glycosides, amino acids, proteins, saponins, and tannins. Under in vitro conditions, antioxidant test using DPPH, ABTS, and reducing power demonstrated that the plant leaves play a crucial role in antioxidant activity compared to the commercial antioxidant butylated hydroxytoluene (BHT). The ABTS and DPPH free radical scavenging activities showed that the IC50 values of the M. coreia methanol extract were 26.35 μg/mL and 200.23 μg/mL, respectively. The methanol extract of M. coreia contained higher levels of total phenols and flavonoids and higher free radical scavenging capacity than the aqueous extract. FTIR analysis of the methanol extract showed a substantial number of phenols in the functional groups of M. coreia leaves. The well diffusion assay using the methanolic extract of M. coreia (200 μg/mL) leaves showed antibacterial activity against Pseudomonas aeruginosa (19 ± 0.85 mm), Proteus sp. (20 ± 0.97 mm), Streptococcus sp. (21 ± 1.29 mm), and Enterobacter sp. (17 ± 0.2 mm). Thus, the present study revealed that the antibacterial and antioxidant activity of M. coreia leaf extract was due to the presence of 18 unknown and 15 primary known polyphenols.