Antibacteria, Antiurease, and Antiproliferative Abruquinones from Abrus precatorius Roots

Phytochemical studies of methanol soluble fractions of Abrus precatorius Linn (Fabaceae) led to the isolation of four abruquinones (abruquinones M, A, E, and B). Structures of the compounds were elucidated using spectroscopic analyses - 1D, 2D NMR, HRESI-MS. Evaluation of the therapeutic effects of A. precatorius fractions showed significant (p < 0.05) antibacterial and antiurease activities. Further therapeutic evaluation of the compounds showed that abruquinones M, A, E, and B demonstrated antibacterial activities by inhibiting significantly (p < 0.05) the growth of multidrug resistant S. aureus (MIC values ranged from 20 - 30 μg/mL) (µM) via induction of morphological damages with concomitant membrane segmentation. Abruquinones A and B showed significant (p < 0.05) urease inhibiting activity (IC₅₀ values 35.2 and 37.7 µM, respectively), docked tightly to the side chains of urease enzyme active site via π-cation interactions, as well as showed cytotoxicity against AU565 and MDA-MB231 breast cancer cells (IC₅₀ values 23.13 and 9.05 μM, respectively). These findings suggest abruquinones (isoflavanquinones) from A. precatorius roots as viable candidates for further mechanistic studies on possible antibacterial, antiurease, and anticancer drug development.