Pot marigold (Calendula officinalis) and Cancer (anticancer research): evidence and sources

A continuous challenge in cancer management is to improve treatment efficacy and to diminish its side effects. Consequently, new conventional and unconventional drugs and bioactive compounds from plants are constantly developed, characterized, and used for in vitro and in vivo models. This review focuses on the antitumor properties of Calendula officinalis, its biological and molecular effects in tumor cells and animal models, as well as its role in cancer palliative care. A systematic review of studies describing the cytotoxic role of C officinalis and its therapeutic role on cancer cells were carried out using the PubMed database. Albeit C officinalis extracts have cytotoxic activity toward different cancer cell lines, a high grade of variation between studies was observed, depending on plant organ subjected to extraction, extraction method, and the cancer cell lines used for each study. Nevertheless, its cytotoxic activity is related to a few bioactive compounds, presenting multiple roles in both activation of proapoptotic proteins and decreasing the expression of the proteins that inhibit cell death. Moreover, due to its anti-genotoxic/protective as well as antitumor and antimetastatic effects proven in animal models, C officinalis could have important future implications in developing novel cancer treatment strategies, while until now it has been used especially for diminishing the side effects of radiotherapy.

Background Phytopharmacological studies of different Calendula extracts have shown anti-inflammatory, anti-viral and anti-genotoxic properties of therapeutic interest. In this study, we evaluated the in vitro cytotoxic anti-tumor and immunomodulatory activities and in vivo anti-tumor effect of Laser Activated Calendula Extract (LACE), a novel extract of the plant Calendula Officinalis (Asteraceae). Methods An aqueous extract of Calendula Officinalis was obtained by a novel extraction method in order to measure its anti-tumor and immunomodulatory activities in vitro. Tumor cell lines derived from leukemias, melanomas, fibrosarcomas and cancers of breast, prostate, cervix, lung, pancreas and colorectal were used and tumor cell proliferation in vitro was measured by BrdU incorporation and viable cell count. Effect of LACE on human peripheral blood lymphocyte (PBL) proliferation in vitro was also analyzed. Studies of cell cycle and apoptosis were performed in LACE-treated cells. In vivo anti-tumor activity was evaluated in nude mice bearing subcutaneously human Ando-2 melanoma cells. Results The LACE extract showed a potent in vitro inhibition of tumor cell proliferation when tested on a wide variety of human and murine tumor cell lines. The inhibition ranged from 70 to 100%. Mechanisms of inhibition were identified as cell cycle arrest in G0/G1 phase and Caspase-3-induced apoptosis. Interestingly, the same extract showed an opposite effect when tested on PBLs and NKL cell line, in which in vitro induction of proliferation and activation of these cells was observed. The intraperitoneal injection or oral administration of LACE extract in nude mice inhibits in vivo tumor growth of Ando-2 melanoma cells and prolongs the survival day of the mice. Conclusion These results indicate that LACE aqueous extract has two complementary activities in vitro with potential anti-tumor therapeutic effect: cytotoxic tumor cell activity and lymphocyte activation. The LACE extract presented in vivo anti-tumoral activity in nude mice against tumor growth of Ando-2 melanoma cells.

Calendula officinalis Linn. (CO) is a popular medicinal plant from the plant kingdom's Asteraceae family that has been used for millennia. This plant contains flavonoids, triterpenoids, glycosides, saponins, carotenoids, volatile oil, amino acids, steroids, sterols, and quinines. These chemical constituents confer multifaceted biological effects such as anti-inflammatory, anti-cancer, antihelminthic, antidiabetes, wound healing, hepatoprotective, and antioxidant activities. Additionally, it is employed in cases of certain burns and gastrointestinal, gynecological, ocular, and skin conditions. In this review, we have discussed recent research from the last five years on the therapeutic applications of CO and emphasized its myriad capabilities as a traditional medicine. We have also elucidated CO's molecular mechanisms and recent clinical studies. Overall, this review intends to summarize, fill in the gaps in the existing research, and provide a wealth of possibilities for researchers working to validate traditional claims and advance the safe and effective use of CO in treating various ailments.