Toxicity profiling and HR-LCMS analysis of Indigofera longiracemosa leaf methanolic extract exhibiting anti-inflammatory activity.

Indigofera longiracemosa, a member of the Fabaceae family documented in traditional medicine for its therapeutic potential, holds promise as a viable natural indigo source. The dearth of reliable and coherent research on the safety and medicinal advantages of phytochemicals obtained from this specific plant species prompted us to examine therapeutic potential of extracts prepared from the leaf and stem of this dye yielding plant. The aerial parts (leaf and stem) of I. longiracemosa were extracted separately using solvents of increasing polarity. In vitro anti-inflammatory studies such as lipoxygenase inhibition, albumin denaturation, and protease inhibitory activity revealed leaf methanolic extract (LME) to show the best anti-inflammatory property. Furthermore, short term toxicity studies (acute and sub-acute) were done in Balb/c mice to evaluate LME's toxicity. In acute toxicity study, LME administered at 2000 mg/kg body weight was found to be non-toxic. Consequently, sub-acute toxicity study was done in both male and female Balb/c mice at three doses (100, 200 and 400 mg/kg body weight, respectively). Following sub-acute toxicity study for 28 days, serum analysis and histological evaluation of tissues did not reveal any signs of toxicity at the administered doses, thereby indicating non-toxic nature of LME. Furthermore, to identify phytochemicals associated with LME, HRLCMS-QTOF untargeted metabolomics was done, and the predominant phytochemicals identified were phenols. The enhanced anti-inflammatory property observed in LME may be attributed to the predominance of phenols. Our studies have, therefore, illustrated the non-toxic nature and therapeutic potential of LME, an extract prepared from I. longiracemosa.