Natural Products as a Vital Source for the Discovery of Cancer Chemotherapeutic and Chemopreventive Agents

Abstract

Throughout history, natural products have played a dominant role in the treatment of human ailments. For example, the legendary discovery of penicillin transformed global existence. Presently, natural products comprise a large portion of current-day pharmaceutical agents, most notably in the area of cancer therapy. Examples include Taxol, vinblastine, and camptothecin. These structurally unique agents function by novel mechanisms of action; isolation from natural sources is the only plausible method that could have led to their discovery. In addition to terrestrial plants as sources for starting materials, the marine environment (e.g., ecteinascidin 743, halichondrin B, and dolastatins), microbes (e.g., bleomycin, doxorubicin, and staurosporin), and slime molds (e.g., epothilone B) have yielded remarkable cancer chemotherapeutic agents. Irrespective of these advances, cancer remains a leading cause of death worldwide. Undoubtedly, the prevention of human cancer is highly preferable to treatment. Cancer chemoprevention, the use of vaccines or pharmaceutical agents to inhibit, retard, or reverse the process of carcinogenesis, is another important approach for easing this formidable public health burden. Similar to cancer chemotherapeutic agents, natural products play an important role in this field. There are many examples, including dietary phytochemicals such as sulforaphane and phenethyl isothiocyanate (cruciferous vegetables) and resveratrol (grapes and grape products). Overall, natural product research is a powerful approach for discovering biologically active compounds with unique structures and mechanisms of action. Given the unfathomable diversity of nature, it is reasonable to suggest that chemical leads can be generated that are capable of interacting with most or possibly all therapeutic targets.

Transferrin‐bearing liposomes entrapping plumbagin for targeted cancer therapy

“…For example, paclitaxel (from the Pacific yew tree), doxorubicin (from Streptomyces peucetius bacterium), vincristine (from the periwinkle plant), topotecan (from the Camptotheca acuminate tree), and etoposide (from the mayapple plant Podophyllum peltatum ) are well‐established drugs available in the market for cancer treatment. In addition, several natural‐derived compounds, such as isoflavones (from soy bean), curcumin oils (from turmeric), and resveratrol (from grape seed) are currently being investigated in clinical trials (Cragg & Pezzuto, ). Natural products are therefore an important channel for the discovery of new anticancer agents.…”

Endophytic fungi associated withTaxus fuana(West Himalayan Yew) of Pakistan: potential bio-resources for cancer chemopreventive agents

“…It is well established that endophytes are capable of producing remarkable cancer chemotherapeutic agents (Tayung & Jha 2010;Cragg & Pezzuto 2015). This investigation of biological activities mediated by endophytic fungi isolated from Taxus fuana indicates their diverse potential for the generation of bioactive metabolites.…”

Natural Products & Complementary Medicines: where are we up to?

“…Furthermore, this chemical variety plays an important role in shaping the pharmacological diversity of compounds and interacting with multiple targets as cancer is known as a complex disease. In addition, the continuing discovery of natural lead is paving the way for medicinal chemists to synthesise modified substances with similar or even stronger effects (Cragg and Pezzuto 2016). Therefore, scientist focus on searching of new anti-tumour agents from natural sources as many plant and marine derived compounds are successfully used in the clinic for cancer therapy.…”

“…ecteinascidin 743 and halichondrin B) and microbes (e.g. bleomycin and doxorubicin), have also provided anti-tumour lead compounds (Cragg and Pezzuto 2016).…”