The Effect of Graviola Leaves Extract (Annona muricata L.) on Pharmacokinetic of Metformin in Rats’ Plasma and Pharmacological Activity of their Combination on Breast and Prostate Cancer Cell Lines

Abstract

Objectives: Metformin is the most widely given medication for type 2 diabetes mellitus (T2DM). Annona muricata L. is a medicinal plant that belongs to the family Annonaceae, popularly known as graviola. Graviola leaves extract was found useful against diabetes, headache, insomnia, cystitis, inflammation, cancer, and other health benefits. The objectives of the current study are to investigate the effect of graviola leaves extract on metformin pharmacokinetics in rat plasma by applying high performance liquid chromatography (HPLC) method as well as its pharmacological effects on breast cancer (MCF-7) cells and prostate cancer (DU-145) cells. Methods: Wistar rats were classified into two groups; the first group (control group) received metformin (20 mg/kg) alone by oral gavage, while the second group, was administered a combination of metformin (20 mg/kg) and graviola leaves extract (20 mg/kg). Blood samples were collected at different time intervals to be analyzed using a validated HPLC method. Plasma profile and pharmacokinetic parameters were determined for each group. In addition, blood glucose levels at 0 hours and after 2 hours of metformin administration were measured in both groups. Breast cancer (MCF-7) cells and prostate cancer (DU-145) cells were used to investigate the anticancer effect of metformin (40 mg/ml), graviola leaves extract (20 mg/ml) and their combination by the standard MTT assay. Results: In the first group, metformin maximum plasma concentration (Cmax) and the area under the curve (AUC0-last) were (1509.25 ng/ml and 8705.59 h*ng/ml) respectively. In the second group, Pre-administration of graviola leaves extract significantly reduced MET (Cmax) and (AUC0-last), (701.88 ng/ml and 3467.72 h*ng/ml), respectively (P ≤0.05). Further, the use of metformin and graviola leaves extract separately showed strong anticancer activity on (MCF-7) cell lines with IC50 values of (10 and 20 mg/ml), respectively as well as on (DU-145) cell lines with IC50 value of (0.3125 and 5 mg/ml), respectively. In addition, the combination of metformin and graviola leaves extract showed a synergistic effect on (MCF-7) cells since the fractional inhibitory concentration value (FIC = 0.375) was less than 0.5, while it showed an additive effect on (DU-145) cells since the fractional inhibitory concentration value (FIC = 1.5) was between (0.5 and 4). Conclusion: In the current study, pre-administration of graviola leaves extract significantly reduced efficacy of metformin In vivo. The combination of metformin and graviola leaves extract showed a synergistic anticancer effect on breast cancer in vitro, while the combination has an additive effect on prostate cancer. The combination could be a potential therapeutic option to help treat breast cancer. The result achieved in this study is very encouraging to be considered for further investigation.