Co-formulation and therapeutic evaluation of bioactive plant compounds in Pheroid®

Abstract

Cancer is a global health burden; of which lung cancer is the most frequently diagnosed type and has the highest mortality. The survival profile of lung cancer patients at all stages is dismal despite the availability of various treatment options. This underscores the dire need for alternative treatment options that have better treatment modalities. In this regard, phytochemicals have been used as an emerging treatment strategy to combat all cancer types. Curcumin and ginger extract (GE) phenolics — particularly [6]-shogaol (6SG) — have been shown to have promising chemopreventive activity, the latter being the most potent one. A combination of phytochemicals often produces a more profound anticancer activity than single agent treatment. However, the clinical utility of phytochemicals is restricted owing to their poor physicochemical properties, which can be enhanced by using drug delivery systems such as the Pheroid® technology. In this study, the therapeutic activity of combined Meriva®; a curcumin phytosome, and GE Pheroid® formulations were investigated against the human lung cancer adenocarcinoma A549 cell line both in vitro and in vivo. The contents of curcumin in Meriva® and 6SG in GE were quantified. In the in vitro study, cellular uptake, cell viability, apoptosis, oxidative stress markers and mitochondrial health were assessed. Furthermore, the formulation administered to the animals was characterised in terms of particle size and distribution, zeta potential and compatibility assays. An in vivo study was conducted using an established athymic nude mice xenograft model. Accordingly, male and female athymic nude mice were inoculated with viable A549 cancer cells. Once the tumour volume reached a palpable size, mice were allocated into four groups and received a daily oral gavage of saline, Pheroid® only and phytochemical combination in Pheroid® for 14 days. Cisplatin was injected intraperitonially once a week. The amounts of principal actives — curcumin and 6SG — in Meriva® and GE were found to be 400 mg/g and 11 mg/g, respectively. Zeta potential and compatibility studies indicated that the phytochemicals were stable in Pheroid® and that no drug-excipient interactions were observed. Confocal microscopy revealed co-localisation of phytochemicals within the Pheroid® vesicles. In vitro results indicated that Pheroid® significantly enhanced cellular uptake, anti-proliferative and apoptotic effects of phytochemical combination compared to individual actives and the free active DMSO formulations. From the mitochondrial health assessment, it was noted that Meriva® but not GE was responsible for the mitochondrial dysfunction, and the effect was more pronounced in the Pheroid® formulation than in the free forms. In addition, the anticancer activity observed with combined phytochemicals in Pheroid® was without induction of oxidative stress, indicating the potential safe use of the formulation. The in vivo study demonstrated that daily oral gavage with the Pheroid® formulated phytochemical combination non-significantly reduced the tumour growth and burden in mice compared to the Pheroid® only treatment. However, cisplatin significantly reduced tumour growth compared to the saline negative control. The sub-therapeutic effect observed with the phytochemical combination treatment can be attributed to the suboptimal dose of curcumin and 6SG principal actives administered in the formulation. In addition, treatment with cisplatin was accompanied with a reduction in body mass. Research has indicated that the side effects of chemotherapeutic drugs such as cisplatin can be overcome by co-administration of phytochemicals. The present in vitro and in vivo study conclusively show the potential anticancer activity of combined Meriva® and ginger extract phenolic compounds. Pheroid® significantly improved the biological activity of the phytochemicals. In addition, the study opens an opportunity to further investigate the anticancer activity of cisplatin co-administered with therapeutic doses of curcumin and 6SG phytochemicals against lung cancer.