Anticancer medicinal plants used by Moroccan people: Ethnobotanical, preclinical, phytochemical and clinical evidence

Ethnopharmacological relevance: Cancer is a major health problem worldwide. Drugs' side effects and high cost of treatment remain the main limitations of conventional therapy. Nowadays, developing new therapeutic strategies is necessary. Therefore, medicinal plants can be used to promote novel, safe, and potent anticancer drugs through their natural compounds. Aim of the study: This review aims to provide scientific evidence related to the anticancer activities of medicinal plants used by Moroccan people as well as approving their efficiency as an alternative cancer therapy. Methods: An ethnopharmacological review approach was conducted by analyzing Moroccan published ethnobotanical surveys from 1991 to 2019 and consulting peer-reviewed articles worldwide to investigate the pharmacological, phytochemical, and clinical effects related to the anticancer activities. Plants with anticancer proprieties were classified into four groups: (a) plants only cited as anticancer, (b) plants pharmacologically investigated, (c) plants with bioactive compounds tested as anticancer, and (d) plants clinically investigated. Results: A total of 103 plant species belonging to 47 botanical families used by Moroccans to treat cancer have been recorded. Aristolochia fontanesii Boiss. & Reut, Marrubium vulgare L., and Allium sativum L. are the most referred species in Morocco. Medicinal plants used for cancer treatment were classified into four groups: 48 species were used traditionally as anticancer (group a), 41 species pharmacologically investigated for their anticancer activities (group b), 32 plants with bioactive compounds tested against cancer (group c), and eight plants were clinically investigated for their anticancer effects (group d). Out of 82 plants' extracts pharmacologically tested (from plants of group b), only 24 ones show a significant cytotoxic effect. A total of seventy-seven compounds are isolated from plants of group (c). However, only six ones were clinically evaluated, and most of them exhibit a beneficial effect on cancerous patients with few side effects. Conclusion: Medicinal plants can be a promising candidate for alternative cancer therapy. Nevertheless, it is critical to increasing the clinical trials to confirm their beneficial effect on patients with cancer. Overall, this review can serve as a database for further studies.