Isolation and characterization of undescribed flavonoid from Abrus precatorius L. based on HPTLC-DPPH bioautography and its cytotoxicity evaluation

Abstract

Background

Naturally derived compounds play a tremendous role as a drug as well as lead structure for the development of APIs. Therefore, isolation and characterization of compounds from nature are needed to alleviate life-threatening diseases. A. precatorius L. belongs to the family Leguminosae and is valued for its medicinal properties. Therefore, in this study, efforts are being made to isolate bioactive entity based on HPTLC-DPPH bioautography from APHA extract. Among all the separated compounds on TLC plate, the one (APSP-3) at R_f = 0.67 showed significant antioxidant activity, and hence, APSP-3 was further subjected to isolation, purification, and structural characterization using diverse analytical modus operandi such as 1D and 2D NMR, FTIR, HPLC–MS/MS, and elemental analysis. In addition, antioxidant and cytotoxicity evaluation of APHA extract and APSP-3 was pursued by standard DPPH and colorimetric MTT assays, respectively.

Results

Antioxidative isolated compound APSP-3 was scrutinized based on HPTLC-DPPH bioautography. The APSP-3 was found novel and spectroscopic data revealed the plausible structure; 7-hydroxy-3,5-dimethoxy-2-(4-((3,4,5-trihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-2-yl)oxy) phenyl)-4H-chromen-4-one. Moreover, APSP-3 ascribed higher free radical scavenging activity with IC₅₀ = 38.70 ± 3.5 µg/mL than standard ascorbic acid (75.19 ± 1.5 µg/mL). Cytotoxicity evaluation of APHA extract exhibited IC₅₀ value 122.09 µg/mL for HepG2, 122.61 µg/mL for MCF-7, and 48.08 µg/mL for HCT116 cell lines, while APSP-3 displayed IC₅₀ values 96.75 for HepG2, 61.67 for MCF-7, and 47.61 µg/mL for HCT116 cell lines.

Conclusions

In a nutshell, HPTLC-directed bioautography leads to the capturing of new flavonoid entity having antioxidant potency from APHA extract. The IC₅₀ values obtained from cytotoxicity establish a dose–response relationship helping to determine the concentration at which a substance begins to exhibit toxic effects. This fundamental information is crucial for establishing safe dosage level in medical and pharmaceutical applications. Further, research engrossed in assessing other bioactivities involving in silico and in vivo studies obliged to offer a promising and secure portrayal for clinical implications.

Graphical abstract