This article has been patterned by a substantial review of the scientific ethnobotanical composition of the most recent time by the authors. We have developed some protocols in this systematic review, to collect data, different combinations of keywords medicinal plants, anticancer, cell line, cytotoxicity and phytochemical compounds are entered into databases of Google Scholar, Scopus, PubMed, etc. By collecting some data from different papers and presented in the table form. Here, fourteen Bangladeshi medicinal plants are described briefly which already showed potential anticancer effects. Another twenty more medicinal plants included in a table. The articles only in the English language published between 1981 and 2019 were selected for writing the review. ChemDraw software has been used to draw the chemical metabolites found in different anticancer plants.
Medicinal Plants As Anticancer Agents Several medicinal plants are mentioned below which possess anticancer agents.
1. Phyllanthus emblica Phyllanthus emblica is commonly known as ‘amloki’ or ‘amla’ in Bangladesh. It is a medium-sized tree with long compound leaves, bunches of small pale green flowers, and astringent round “small green” or “yellow fruits” in the axils. It grows naturally and is planted in many areas of our country. Chemically, it contains ellagic acid, tannins, gallic acid, lipids, emblicol etc. The Phyllanthus emblica has been substantially used, both as edible plants and for its therapeutic potentials, for example fruit extract from this plant is utilized in traditional medicine for generations to treat indications differing from constipation to the treatment of tumors. However, the prospective of Phyllanthus emblica extracts to be employed as an anticancer agent has been studied availing of contemporary medical approaches over the past two decades. Both in vitro and in vivo methods, these plant extracts have been dominated malignancy oppressive properties against some cancer forms for example, simple aqueous extracts of Phyllanthus emblica have been exhibited cytotoxic activity against ovarian and cervical malignant cells. Besides, the flavonoid quercetin has been indicated to depress tumor growth in numerous animal models. Drew on the comprehensible mechanism of action and upholding data using murine models, quercetin was processed in a phase 1 clinical trial where it exhibited antityrosine kinase activity in vivo. Analogues of quercetin outlined as more specific PI3K inhibitors also demonstrate potent anticancer activities. It becomes relevant clinically imperative for Phyllanthus emblica that molecules mediating the antitumor effects of these plants are being identified and potent, patentable derivatives also synthesized.
2. Terminalia chebula Terminalia chebula is frequently known as ‘hartaki’ or ‘haritaki’ in Bangladesh. It belongs to the white flowers in terminal spikes, and small 5-ridged fruits. It grows in Dhaka, Mymensingh, Tangail, and Chattogram districts. This plant consists of significant biochemicals as amino acids, flavonoids, glycosides, resins, minerals, reducing sugars, tannins, steroidal triterpenoids etc. Terminalia chebula is a source of hydrolyzable tannins that possess anti-mutagenic activity in Salmonella typhimurium. From acetone extract of bark of Terminalia chebula, promising anti-mutagenic and anti-carcinogenic activity has been reported. This flora also uses in the treatment of indigestion, constipation, dysentery, jaundice, etc. Alcoholic extract of Terminalia chebula fruit is being reported to be effective in human (MCF7) and mouse (S115) breast cancer cell lines as well as in Ehrlich Ascites Carcinoma induced in breast cancer model in mice.
3. Withania somnifera Withania somnifera is usually recognized as ‘ashwagandha’ and found to grow wild in the northern districts in Bangladesh. It derives from the family Solanaceae. This plant is very rich in tropane alkaloids, steroidal lactones, and withanolides. This plant is mostly recognized in ayurvedic for treating cancer. It is made using of a traditional remedy for combating cancer-like conditions. The roots of this plant contain tropine, pseudotropine, tigloyloxytropine, choline, anaferine, somniferine, somniferinine, etc. Withanolides from these plants lessened the progress of cancer cells in human lung, breast and colon cancer cell lines similar to doxorubicin that used as a standard drug in-vitro study. Research on animal cell cultures has shown that the herb decreases the levels of the nuclear factor kappa B, suppresses the intracellular tumor necrosis factor, and potentiates apoptotic signaling in cancerous cell lines. The leaves of Withania somnifera have also been shown to inhibit the growth of human cancer cell lines equivalent to that produced by adriamycin. The leaf extract produced anti-cancer activity on NCI-H460 (lung), HCT-116 (colon), SF-268(central nervous system) and MCF-7(breast) human tumor cell lines. These are some indicative observations of the protective effect of Withania somnifera is a cancer-causing agent.
4. Azadirachta indica Azadirachta indica is commonly known as ‘neem’ in Bangladesh. This plant belongs to the Meliaceae family. Every part of this plant is used medicinally important. It composes of biologically active compounds as nimbin, nimbidin, nimbidol, nimbolide, etc. All of those compounds engage in cancer development and management through anticancer activity, antioxidant activity, and the inhibitory effect exerted on the incident of malignant cells by modulation of cellular proliferation, tumor suppressor genes and apoptosis. Besides, gedunin is a tetranortriterpenoid isolated from neem seed oil with a D lactone ring, this also demonstrated its anticancer activity as a preventive and therapeutic agent in breast cancer. This bioactive molecule exerts its function through inhibition of tumoral cells, modulating several heat shock proteins. Another study made in vitro regarding anticancer activity of ethanolic neem leaves extract on HeLa viability. After treatment with ethanolic neem leaf extract on normal and HeLa cells, cellular growth was differentially suppressed by apoptosis. The mechanism through which ethanolic neem leaf extract induced cell apoptosis was represented by the modulation of bax, cyclin D1 and cytochrome P450 monooxygenases expression. The prospective anticancer competence of this plant has been shown against tumor cells in the colon, prostate and ovaries through regulation of cardinal signaling pathways in recent investigations. These plant extracts are convenient as chemo preventive agents but their effects merged with calibrating cytotoxic therapies also dominant to illuminate.
5. Zingiber officinale Zingiber officinale is frequently known as ‘ada’ in Bangladesh. It is widely used all over the world as a spice and condiment for food. Zingiber officinale contains gingerol-6, an active phenolic compound among various composites that are considered superior in combating cancer. Gingerol-6 has two modes of anticancer activities that suppress the cancer cell growth progression and block the supply of nutrients to the cancer cells by maturation. The laboratory experiment with the leaf extract from these plant shows that it is effective in reducing the cell viability in human colorectal cells. Other hands, the ginger extract may have a chemotherapeutic effect in the treatment of liver cancer cell as NF-κB is activated and that blocking NF-κB activation with ginger resulted in suppressed production of NF-κB and TNF-α. This is in line with findings that many of the pathways that mediate adaptive survival strategies in cancer cells are under the transcriptional control of NF-κB.