Antioxidant activity, cytotoxicity assay, and evaluation of bioactive compounds using GC-MS and HPTLC-based bioassay in the extracts of Osbeckia stellata var. crinita (Benth. ex Naudin) grown in Manipur, India

In the present study, we aimed to investigate the antioxidant, cytotoxicity activities, and phytochemical profiling of O. stellata extracts. Qualitative phytochemical tests showed the presence of different groups of phytochemicals, mainly in polar solvents. Methanolic and hydroalcoholic extracts showed high total phenolic and flavonoid contents. The antioxidant activity was determined by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), metal chelating, and reducing power assay where methanolic (IC50: 24.76 ± 2.78 μg/mL), hydroalcoholic (IC50: 29.59 ± 3.44 μg/mL), and aqueous (IC50: 33.72 ± 1.97 μg/mL) extracts showed significantly antioxidant potential. Significant cytotoxicity activity was observed in the methanolic extract. As methanolic extract showed better activities, gas chromatography–mass spectrometry (GC-MS) analysis of methanolic extract identified 41 bioactive compounds, where 17 major compounds had medicinal value. High-performance thin layer chromatography (HPTLC) bioassay-guided assay combined with Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and nuclear magnetic resonance (NMR) spectroscopy characterized gallic and caffeic acid as free radical scavengers. This study evidences that the methanolic extract of O. stellata has potent antioxidant and anti-cancer properties, which may render oxidative stress-related disease and may be used for drug development for human health benefits.