Trema Orientalis (Linn) Blume stem bark: polyphenol profile, in-vitro antioxidant and anti-proliferative activities on the A549 cell line

Abstract

BACKGROUND: Trema orientalis (Linn) Blume is a plant that can be found in Australia, Asia, and Africa. Its stem bark is utilized in western Nigerian traditional medicine to cure a variety of illnesses. The study was designed to evaluate the polyphenol profile, antioxidant and anti-proliferative activity of methanol extract, butanol and aqueous fractions of T. orientalis. METHODS: Maceration was used to generate the methanol extract, and solvent-solvent partitioning was used to produce the butanol and aqueous fractions. DPPH, metal chelating, and various reducing power assays were used to evaluate the antioxidant activity of the extract/fractions. The anti-proliferative activity of the extract/fractions on the A549 cell line was investigated using MTT assay, DAPI (4’, 6-diamidine-2’-phenylindole) staining, and measurements of mitochondria membrane potential (MMP), intracellular reactive oxygen species (ROS), along with Western blot, and RT-qPCR studies. Using ultra-high performance liquid chromatography (U-HPLC) with a diode detector and a C18 column, the polyphenolic contents of the extract/fractions were identified. RESULTS: The antioxidant activity of methanol extract was higher than that of the fractions. Methanol extract (93.32.04 mg GAE/g) and butanol fraction (95.83.345 mg GAE/g) had higher total polyphenol content than aqueous fraction (136.14.05 mg GAE/g). Kaempferol was determined to be the most abundant polyphenol in T. orientalis extract/fractions, according to U-HPLC analysis and the highest concentration was found in aqueous fraction. When compared to butanol fraction (IC50=210 g/mL) and methanol extract (IC50=226 g/mL), MTT assay demonstrated that aqueous fraction was more potent against A549 cells (IC50=201 g/mL). After T. orientalis administration, DAPI stain revealed chromatin condensation and nuclear fragmentation, as well as a significant loss of MMP (P<0.01) and an increase in intracellular ROS (P<0.01) in A549 cells. Western blotting exhibited decreased p-NFκB and COX-2 expression, whereas upregulation of p53 expression of proteins. RT-qPCR studies showed downregulation of NFκB and CDK2 gene expression and upregulation in the expression of p53 genes. CONCLUSIONS: According to the findings, T. orientalis stem bark inhibited lung adenocarcinoma (A549) cell proliferation with mitochondria-mediated intrinsic pathway-induced A549 cell apoptosis.