Pharmaceutical Properties and Phytochemical Profile of Extract Derived from Purple Leaf Graptophyllum pictum (L.) Griff.

Abstract

Graptophyllum pictum (L.) Griff is a medicinal shrub belonging to the Acanthaceae family and is traditionally used to treat various diseases. Therefore, this study aimed to evaluate the pharmaceutical properties and phytochemical profiles of the methanolic extract of G. pictum. G. pictum leaves was extracted using methanol. Antioxidant, cytotoxic on Michigan Cancer Foundation-7 (MCF-7) and HepG2, antidiabetic, and antibacterial properties were evaluated in vitro. Chemical profile of the extract was identified through qualitative (for phytochemicals), quantitative (for phenolic and flavonoid content), and gas chromatography-mass spectrometry (GC-MS) analysis. The results showed that the extract had potent antioxidant activity against 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picrylhydrazyl radicals with IC50 values of 49.00 ± 3.20 µg/mL and 70.18 ± 3.27 µg/mL, respectively. It also exhibited cytotoxic effects on human breast (MCF-7) and liver (HepG2) carcinoma cells with growth inhibition percentages of 74.29 ± 1.53% and 64.90 ± 1.94%, respectively. The antidiabetic assay showed that the extract had inhibitory effects on α-glucosidase activity with IC50 value 194.59 ± 15.59 µg/mL, indicating its potential to be developed as an antidiabetic agent. Furthermore, it had antibacterial properties against four test strains, and the highest activity was found against Bacillus subtilis American Type Culture Collection 19659, with minimum inhibitory concentration and minimum bactericidal concentration values of 625 µg/mL and 1250 µg/mL, respectively. Phytochemical tests indicated the presence of alkaloids, flavonoid and terpenoids in the extract, with total phenolic content and total flavonoid content of 41.17 ± 2.38 mg gallic acid equivalents/g and 26.52 ± 0.61 mg quercetin equivalent/g, respectively. GC-MS analysis revealed that it contained several active compounds, including eicosane, 2,4-Di-tert-butylphenol, hentriacontane, tetracosane, octacosane, sulfurous acid, 2-methylhexacosane, docosane, heneicosane, 1-propene-1,2,3-tricarboxylic acid, tributyl ester, and pentacosane. The extract derived from G. pictum leaves was a potential source of therapeutic compounds, particularly for antioxidant, antidiabetic, anticancer, and antibacterial agents.