Isolation of terrestribisamide from Peltophorum pterocarpum (DC.) Baker ex. K. Heyne and its antimicrobial, antioxidant, and cytotoxic activities

Peltophorum pterocarpum (DC.) Baker ex. K. Heyne (Caesalpiniaceae) is an ornamental tree distributed in the tropical regions of the world; it is attributed to have several medicinal properties. The bark of the tree is used to treat dysentery, for gargling, and as tooth powder; it is applied externally to treat eye diseases, muscular pains, and sores. Flowers possess antibacterial activity; they are used to treat insomnia and to induce good sleep. The cinnamic acid derived bisamide alkaloid (E, E)-terrestribisamide was isolated for the first time from the methanolic extract of the flower of P. pterocarpum. It was also quantified by HPLC and was shown to be the second major constituent (0.145 %) next to the coumarin bergenin (0.399 %). Terrestribisamide showed moderate antimicrobial activity against tested strains and exhibited potent antioxidant activity at 1 mg/mL concentration. The compound showed prominent cytotoxic activity in vitro against COLO320 colorectal adenocarcinoma cell line. It showed 83.22 % activity at the dose of 200 μg/mL with an IC₅₀ value of 50 μg/mL. Terrestribisamide can be probed further for its cytotoxic effect. This is the first report of the antibacterial, antifungal, antioxidant, and cytotoxic properties of terrestribisamide from this plant. Graphical Abstract: [Figure not available: see fulltext.].