A rich source for cancer cure is natural products, which is anticipated to become the most important causes of death in this century.
But, there is a current need for improvement of new drugs for anticancer, chemotherapy strategies and drug combination via scientific search of vast pond of synthetic and methodical, biological and natural products. Highly effective conventional drugs that used in treatments of many forms of cancer are plant based anticancer drugs, which is the primary source.
After cardiovascular disease, second major cause of death is cancer. Cancer is raising public problem whose value worldwide new rate is about 6 million cases each year. A great number of microbial and marine of plants have been tested. These are more than 100 different types of cancer.
There are many anticancer drugs that are killing the cancer cells. More than 1000 plants out of 250,000 plants species that have important anticancer properties. Plant-derived compounds have been a vital cause of numerous clinically useful anti-cancer agents.
These contain vincristine, topotecan, vinblastine, irinotecan, derivatives of camptothecin, etoposide, derived from pactitaxel and epipodophyllotoxin.
Tumor and its type
An abnormal growth or lump of cell is tumor. There are two type of tumor cell (i) benign (ii) malignant tumor.
A stage when uncontrolled growth normal cell is benign tumor, then higher production of cell cause of abnormal lump and it grow slowly. Benign is not a cancerous and it removed by surgery. It is less problematic and present near blood, vessel, tissue, nerves and cause damage but not spread other part of body.
It is cancerous cell and it moves into lymph node and blood stream. It spread other part of body, called metastasis. Any place in the body, cancer arises with reproductive organ, skin lungs, blood, intestines and breast. It is grow fast.
Types of cancer
- A cancer that starts in tissue that line other organ or skin is carcinoma.
- A cancer of bones, cartilages, muscles and vessels is sarcoma.
- Bone marrow cancer is leukemia.
- Immune system cancer is myeloma and lymphoma.
How can cancer rises
Change in genes that control the function of cell particularly, how cell divide and grow, a genetic disease. Cancer that cause change in genetic change can be congenital from our parents.
They can also rise throughout a man’s life as a result of errors that’s arise as a division of cell or as a damage of DNA began via certain conversational exposures.
Cancer causing of ecological experience contain substance, such as radiation, such as ultraviolet rays coming from sun and chemicals using in tobacco smoke.
Factor of risk
Change in DNA of cells that direct cause of cancer. Change in genes can be inherited. After birth as an environmental force, they can cause a cancer. Certain of these forces include irradiations exposure, non-protective sun irradiation, smoking, carcinogens chemicals, human papilloma virus and type of physical activity and diet and many others.
- Radiation therapy
Types of anticancer drugs
Plants based anticancer drugs are
- Alkylation agent
- Plants alkaloids
- Topoisomerase inhibitors.
Pattern of DNA methylation is vital in improvement and can be changed in tumors of human. Alkylation agent forms covalent bond by nucleophilic substance and attacks on the alkyl group on DNA. Tumor cells are considered through specific variations in epigenetic and genetic that stimulates uncontrolled cellular production.
On the foundation base through repetition and gene demethylation, hypermethylation induced gene silencing could be exposed and as tools to treatments of cancer in the characterization and identifications of DNA methylation inhibitors, many efforts have been placed.
Numerous studies submitted that green tea have potential of therapeutic and chemopreventive against cells of tumor. large amount of the cancer or/and anticancer green tea chemopreventive effects are mediated via its most rich epigallocatechin-3-gallate (EGCG), catechin.
EGCG has been shown to have strong effects of anti-tumor and anti-proliferation both in vitro and in animal models. Activity of DNA methyltransferase inhibited by EGCG with repetition of epigenetically silenced tumor suppressor genes.
Normal DNA and antimetabolites is structurally related and methotrexate is widely used antimetabolites. Hydroxyurea is antineoplastic drug. It decrease DNA production over formation of inhibitor ribonuclotide enzyme from ribonuclotide of thymine and pyrimidine, nucleosides need the DNA replication.
By using two main classes of antimitotic drugs for cancer treatments are (i) vinca alkaloids and (ii) taxanes. Since the pink periwinkle plant (Catharantus roseus; formerly vinca rosea Linn), vinca alkaloids were primarily isolated. β tubulin nearby the GTP-binding site binds with vinca alkaloids.
While the several vinca alkaloids structures differ only slightly, they have different positions as chemotherapeutic agents. As microtubule-targeting agents, taxanes are bind to polymerized microtubules, microtubule stabilize and inhibit its disassembly leading finally to death of cells via apoptosis.
In variation of solid and haematological tumors, anticancer drugs active are topoisomerase inhibitors I and II. Plant derived component camptothecins (e.g. topotecan, irinotecan) act similarly as topoisomerase inhibitor I and microbial-derived anthracyclines (e.g. epirubicin, doxorubicin) and plant derived topoisomerase epopodophyllotoxins (e.g. teniposide and etoposide) act similarly as inhibitor II.
Mode of action
Mode of action of different plants based anticancer drugs is different
Table: Some cytotoxic drugs and plant sources
|Drug s name||Source of plant||Mechanism of action|
|Flavopiridol||Amoora rohituka; Dysoxylum binectariferum (Maliaceae)||Inhibition of cyclin-dependent kinases|
|4-Ipomeanol||Ipomoeca batatas (Convolvulaceae)||
Cytochrome P-450-mediated conversion
into DNA-binding metabolites
|Elliptinium||Bleekeria vitensis(Apocynaceae)||Inhibition of topoisomerase II|
|Homoharringtonine||(Apocynaceae) (Cephalotaxaceae)||Inhibition of DNA polymerase ∝|
Recent advancements of natural anticancer agents is MOA, have low toxicity that acts on intercalation of DNA, proteinkinases and topoisomerases. Many new species are studies for cancer treatment.