Antimammary Tumour Effects of Calliandra portoricensis Fraction Via Pro-Apoptotic and Anti-Inflammatory Actions in Female Wistar Rats

Calliandra portoricensis (CP) is used in ethnomedicine to manage breast inflammation. We investigated the anti-mammary tumour effects of fraction from CP in rat model of mammary tumorigenesis induced with N methyl N nitrosourea (NMU) and benzo (a)pyrene (BaP) and MCF-7 cells. In vivo, thirty-two female Wistar rats were assigned into four equal groups: Group 1 (control), group 2 received [NMU (50 mg/kg) +BaP (50 mg/kg)], group 3 received [NMU (50 mg/kg) +BaP (50 mg/kg) + CP (100 mg/kg)] and group 4 received [NMU (50 mg/kg) +BaP (50 mg/kg) + vincristine (VIN) (500 μg/kg)]. The NMU and BaP was injected intraperitoneally to rats at age 7, 10 and 13 weeks for twelve weeks. Thereafter, CP (orally) and vincristine (i.p) was administered for two weeks. In vitro, CP and VIN concentration-dependently inhibited the growth of MCF-7 cells by over 80% at 100 µg/mL. The CP and VIN elevated Bax by 4.2 and 1.5 folds, and decreased myeloperoxidase by 75% and 82%, respectively, while CP alone decreased interleukin-1β by 34% in vitro. In vivo, [NMU+BaP] increased weight and organo somatic weight of mammary gland by 3 and 2.9 folds; total bilirubin, nitric oxide and malondialdehyde by 23%, 51% and 52%, respectively. In [NMU+BaP] rats, weak expression of caspase-3, Bax, and strong expression of iNOS and NF-kB activities were observed, with histological alteration. The GC-MS fingerprint of CP fraction revealed the presence of hexadecanoic acid methyl ester as the most abundant constituent. Treatment with CP ameliorates mammary tumour through mechanisms that involve anti-inflammatory and pro-apoptotic reactions.