Screening of antioxidant, anti-tyrosinase, antibacterial, alpha-glucosidase inhibitory activities and chemical profile from roots of Indigofera suffruticosa

Indigofera suffruticosa is a source of indigo dye, the aerial part of this plant was used to prepare the indigo, except for the roots that have not yet been used and a lack of information is available about its roots. The roots of I. suffruticosa was studied for antioxidant, anti-tyrosinase, antibacterial, and anti-a-glucosidase activities for the first time, as well as phytochemical compounds screened by LC-MS. The roots of I. suffruticosa were successfully extracted with hexane, ethyl acetate, and methanol to yield 3.11 %, 13.51 %, and 24.79 %, respectively. Crude ethyl acetate extract shows a higher antioxidant effect in DPPH assay (IC50 value of 351.69 ± 8.43) µg/mL and ABTS assay (IC50 value of 154.52 ± 17.34 µg/mL) than crude hexane and methanol extract. Crude methanol extract shows the highest antioxidant activity in the FRAP assay with a value of 352.96 ± 8.69 mg TE/g crude extract. Interestingly, all three crude extracts show anti-a-glucosidase activity higher than acarbose with %inhibition values were 99.51 ± 0.49, 97.85 ± 1.39, 77.95 ± 0.76, and 73.26 ± 1.94, respectively. Furthermore, every crude extract had potent inhibitory effects on S. aureus. Phytochemical compounds from the roots of I. suffruticosa analyses by LC-MS revealed that crude hexane, ethyl acetate, and methanol extracts as a source of phenolic compounds. This information provides an important biological potential that may be considered a high-value commercial and therapeutic. Also, every part from this plant should be used, and there should be zero waste in the preparation of indigo dye.