New Insights toward Colorectal Cancer Chemotherapy Using Natural Bioactive Compounds

Abstract

Combination therapy consists in the simultaneous administration of a conventional chemotherapy drug (or sometimes, a radiotherapy protocol) together with one or more natural bioactives (usually from plant or fungal origin) of small molecular weight. This combination of anticancer drugs may be applied to cell cultures of tumor cells, or to an animal model for a cancer type (or its xenograft), or to a clinical trial in patients. In this review, we summarize current knowledge describing diverse synergistic effects on colorectal cancer cell cultures, animal models, and clinical trials of various natural bioactives (stilbenes, flavonoids, terpenes, curcumin, and other structural families), which may be important with respect to diminish final doses of the chemotherapy drug, although maintaining its biological effect. This is important as these approaches may help reduce side effects in patients under conventional chemotherapy. Also, these molecules may exerts their synergistic effects via different cell cycle pathways, including different ones to those responsible of resistance phenotypes: transcription factors, membrane receptors, adhesion and structural molecules, cell cycle regulatory components, and apoptosis pathways.

Herbal melanin inhibits colorectal cancer cell proliferation by altering redox balance, inducing apoptosis, and modulating MAPK signaling

“…Numerous studies have reported the anticancer effects of herbal medicines or phytochemicals for the treatment of CRC. Herbal medicines may have improved efficacy and safety compared to other regimens as well as the potential to be used as a complementary therapy for advanced colorectal adenocarcinoma and mCRC [10][11][12]. Examples of current clinically used phytochemicals include Catharanthus alkaloids (Vinca rosea) [13] and Camptotheca (happy tree, cancer tree) [14], while others are currently in clinical trials such as curcumin, green tea and soybeans [15].…”

Cost Effective Use of a Thiosulfinate-Enriched Allium sativum Extract in Combination with Chemotherapy in Colon Cancer

“…As allicin targets multiple signal transduction pathways, it is also conceivable that this lyophilized garlic extract may prove useful in combination with mechanistically distinct chemotherapeutic agents, such as the ones that we propose. In fact, the use of natural compounds for combinatorial therapy in cancer treatment is a new promising line of research [39][40][41]. Moreover, because of its pharmacological safety, this garlic extract has been proposed to be used alone to prevent cancer and in combination with chemotherapy to treat cancer [42].…”

Phytotherapeutics in cancer invasion and metastasis

“…Flavonoids possess a documented anticancer activity toward a number of cancer cell lines (Redondo‐Blanco, Fernández, Gutiérrez‐del‐Río, Villar, & Lombó, ). Unfortunately, these activities have not always been confirmed in humans (Iriti & Varoni, ).…”