Phytochemical profiling, molecular docking, and in vitro anti-hepatocellular carcinoid bioactivity of Suaeda vermiculata extracts

The ATP-binding cassette is the major class of transporters responsible for the efflux of chemotherapeutic agents from cancer cells, resulting in treatment failures of cancer's patients. Suaeda vermiculata Forssk. ex. J. F. Gmel. is traditionally known for its liver protective activity. The LC-MS based chemical profilings of the sequentially partitioned sub-extracts obtained from the alcoholic extract of S. vermiculata using n-hexane, chloroform, ethyl acetate, and n-butanol as fractionating solvents, identified a total of thirty six compounds. These sub-extracts were evaluated for their anti-hepatocarcinoma activity against the sensitive HepG2 and doxorubicin (DOX)-resistant, HepG-2/ADR cell lines. A mixture of doxorubicin and sub-extracts at 20 μg/ml doses were also tested for their anti-hepatocarcinoma activity. The exhibited IC₅₀ values for the chloroform, ethyl acetate, n-hexane, and n-butanol sub-extracts, and the doxorubicin against HepG2, and HepG-2/ADR cell lines were found at 64.5, 66.8, 81.25, 125, 1.3 μg/ml, and 110.1, 91.82, 138.2, 265.7, 4.77 μg/ml levels, respectively. However, the treatment of resistant cells with 20 μg/ml of different sub-extracts in combination with the doxorubicin showed significant improvements in the doxorubicin activity against the resistant cells, and the IC₅₀ values for DOX + chloroform, DOX + ethyl acetate, DOX + n-hexane, and DOX + n-butanol against resistant cells, were at 1.77, 2.05, 2.66, and 2.71 μg/ml levels, respectively. The IC₅₀ values exhibited 2.69x, 2.33x, 1.79x and 1.76x-folds reversal of the sensitivity in the resistant cancer cell lines. The molecular docking studies of the compounds identified in the LC-MS chemical profilings, against three ATP-binding cassette proteins i.e., ABCB1, ABCC1, and ABCG2, showed that flavonoids as the major class of compounds responsible for reversal of the resistant cells sensitivities. The predicted binding affinity for the flavonoids against the above mentioned three ATP-binding cassette proteins’ are in the ranges of ∼−8 to −11 kcal/mol. Our results clearly indicate that the presence of flavonoids, as the major class of compounds in the S. vermiculata is responsible for the chemosensitization of the resistant HCC-cell lines. Moreover, the structures, 21 (5-O-methyl visamminol), 22 (N-trans-feruloyl tyramine), 27 (atractylenolide-III), and 32 (ginsenoside-Rh2) were also identified among the potential ATP-binding cassette's modulators during the current study. These observations put the S. vermiculata in perspective with the traditionally claimed liver protective efficacy of the plant.