Abstract
BACKGROUND: S. guineense DC. var. macrocarpum (Engl.) F. White. plant has been a traditional Cameroonian spice used as medicine to treat several health conditions such as liver cirrhosis, vaginal infections, and cancer. OBJECTIVE: This study aims to investigate the anti-cancer effects of Syzygium guineense plant parts on leukemia preclinical models. MATERIAL AND METHODS: Crude extracts and fractions of S. guineense were tested to inhibit the proliferation of human leukemia cells and reduce tumor volume in leukemia xenograft KG1 in immunodeficient mice. Further active fractions were evaluated for the mechanism of action using cell cycle analysis. Inflammasome markers, key targets of chronic inflammation, were screened from phytoconstituents obtained by LC-MS analysis. Of these, putative compounds having potential anticancer efficacy were assessed for kinetic binding with Molecular docking using PyRx-Python Prescription 0.8, and molecular dynamics simulations were performed by GROMACS 22.04. RESULTS: Bark extract B(2) and leaf fractions L(4)/L(5) exhibited significant (P < 0.001) anticancer activity against leukemia cells in a dose-dependent manner. Mechanistically, in L(4)/L(5) arrested HL-60 cells at G2/M phase (population increased to >25 % at drug concentration up to 80 μg/ml compared to 8.8 % in control cells), while B(2) caused S phase arrest (population increased to 56.2 % at drug concentration up to 100 μg/ml compared to 45.8 % in control) in HL60 cells. L(4)/L(5) treatment led to apoptosis induction in these cells. B(2) (P=0.035) and L(4) (P=0.096) significantly reduced the tumor xenograft KG1 in the animal model. HRMS allowed the identification of Betulinic Acid/Oleanolic Acid in L(4). Computational prediction and GROMACS simulations of these compounds revealed stable binding patterns between the component and target proteins NLRP3 and NEK-7 over 100 ns. CONCLUSION: Our study has provided interesting leads that Cameroonian spice S. guineense fractions/extract exhibited anti-leukemia activity, which could be mediated by inhibiting the innate immune inflammasome pathway. The study emphasizes the importance of S. guineense plant parts that have the potential to be developed for novel targeted therapeutics for leukemia.