**1. Introduction**

Cancer is defined as the abnormal proliferation of cells in our bodies, which can result in death. As a result, there is currently no effective cancer therapy available, and the disease has the potential to spread globally. Plants are a rich source of novel bioactive compounds. This is because of their innate biological capabilities, which have the potential to be used in medicine and other disciplines of human health promotion. There is a significant need for new anticancer medications that are more effective and less damaging to healthy cells, such as plant-derived substances. The preliminary strategy for identifying active chemicals in plants is cytotoxic screening [1–3].

*Chromolaena odorata* is a tropical and subtropical flowering shrub widely distributed in various parts of the world. Fresh leaves or a decoction of *C. odorata* have been used for folk medicine in Vietnam. In other traditional medicine, it is useful for burn wounds, leech bites, skin infections, soft tissue wounds, and dento-alveolitis.

In Myanmar, local people are used for stomachache, cancer, and urinary tract infection. Chemical components of this plant have been discovered as chalcones, flavonoids, glycosides, anthraquinones, triterpenoids, fatty acids, coumarino lignoids, and phenolic compounds [4–12].

*Croton oblongifolius* is a medium-size tree and is widely distributed throughout Asia and Myanmar. In folk medicine, this plant is useful for dysmenorrhea, purgative, dyspepsia, and dysentery. In Myanmar, it is used to treat diarrhea (seeds) and liver disorders (barks). Phytochemical studies of *C. oblongifolius* have been reported in several different types of research and many clerodane diterpenes, cembranoid diterpenes, halimane-type diterpenoids, labdane diterpenoids, furanocembranoids, and megastigmane glycosides have been isolated from the stem barks, leaves, and roots [5–21].

*Tinospora cordifolia* is a huge evergreen and annual climbing plant distributed throughout the world. The plant is used to treat skin diseases, allergic conditions, jaundice, urinary disorders, anaemia, rheumatism, inflammation, and diabetes in both traditional and homeopathic medicine. In Myanmar, this plant is used for diabetes and hypertension. An important phytoconstituents reported from this plant were clerodane furano diterpene glucosides, phenylpropene disaccharides, phenylpropanoids, clerodane diterpenoid, steroids, terpenoids, and alkaloids [22–31].

*Melastoma malabathricum* is an evergreen shrub that belongs to the family Melastomataceae. In Malaysia, India, and Indonesia, this plant has traditionally been used to treat a variety of symptoms and disorders. In Myanmar, this plant is used to treat various kinds of cancer, toothache, diabetes, asthma, and lung disorders. Chemical constituents reported from *M. malabathricum* were flavonoids, triterpenes, alkaloids, steroids, lipids, phenolic compounds, and tannins [32–37].

*Dioscorea bulbifera* is a perennial vine widely distributed throughout tropical and temperate areas. It is commonly known as air potato. This herb is used in the treatment of leprosy and cancer by triple people in Bangladesh. In China, this herb is utilized for cancer and thyroid diseases. In Myanmar, this plant is used for various cancer diseases such as breast cancer, cervix cancer, etc. Phytochemical studies revealed the presence of alkaloids, anthraquinones, norclerodane diterpenoids, clerodane diterpenoids, flavonoids, phenolic compounds, steroidal saponins, steroidal sapogenins, and glycosides [38–49].

Our main focus for this chapter is secondary metabolites derived from the plant's kingdom, i.e., *C. odorata*, *C. oblongifolius*, *Tinospora cordifolia*, *M. malabathricum*, and *D. bulbifera*, and cytotoxic compounds obtained from them (**Table 1**).


#### **Table 1.**

*Myanmar medicinal plants and their traditional (or) local uses.*

*Cytotoxic Activity of Secondary Metabolite Compounds from Myanmar Medicinal Plants DOI: http://dx.doi.org/10.5772/intechopen.105153*
