Out of the leaf extracts of the seven plants researchers tested, they found the sabah snake grass (bottom right) had weak effects or no effect against almost all the cell lines they tested. (Credit: NUS
The leaves of a variety of medicinal plants can stop the growth of breast, cervical, colon, leukemia, liver, ovarian, and uterine cancer, a new study shows.
Researchers found the effects in leaves of the bandicoot berry (Leea indica), South African leaf (Vernonia amygdalina), and simpleleaf chastetree (Vitex trifolia). Three other medicinal plants also demonstrated anti-cancer properties.
“Medicinal plants have been used for the treatment of diverse ailments since ancient times, but their anti-cancer properties have not been well studied,” says Koh Hwee Ling, associate professor from the National University of Singapore’s pharmacy department.
“Our findings provide new scientific evidence for the use of traditional herbs for cancer treatment, and pave the way for the development of new therapeutic agents.”
The findings, which appear in the Journal of Ethnopharmacology, highlight the importance of conserving these indigenous plants as resources for drug discovery and understanding these natural resources.
While modern medicine is the primary form of healthcare in Southeast Asian countries such as Singapore and Malaysia, there remains a tradition of using local medicinal plants for health promotion and the treatment of diseases.
“Given the scarcity of land due to rapid urbanization and the dearth of records on herbal knowledge, there is a pressing need to document and investigate how indigenous medicinal plants were used before the knowledge is lost,” says Siew Yin Yin, who did the research as part of her doctoral thesis under Koh’s supervision.
For the study, conducted between 2010 and 2013, researchers documented the different types of medicinal plants that grow in Singapore and the region. They found that the top three reasons for using medicinal plants included general health promotion, detoxification, and boosting the immune system. Among the medicinal plants documented, people also used some to treat cancer.
The researchers reviewed the pharmacological properties of the tropical plants reportedly used for cancer, and selected seven promising plant species for further investigation: bandicoot berry, sabah snake grass, fool’s curry leaf, seven star needle, black face general, South African leaf, and simpleleaf chastetree.
The experiments involved preparing extracts of fresh, healthy and mature leaves of the seven plants, and testing the extracts with the cell lines of seven different types of cancers—breast, cervical, colon, leukemia, liver, ovarian, and uterine. The team opted to examine leaves as they can regrow without harming the plants—making it a sustainable choice, unlike using the bark or roots.
Among the seven plants, the researchers found the extracts of the leaves of the bandicoot berry, South African Leaf, and simpleleaf chastetree promising in fighting against the seven types of cancers. The leaf extracts of the seven star needle performed well against cervical, colon, liver, ovarian, and uterine cancer cells. The leaf extracts of two other plants—fool’s curry leaf and black face general—demonstrated efficacy against some cancer cell lines, too.
“What we did not expect is that the leaf extract of the sabah snake grass was not very effective in inhibiting growth of cancer cells. In our earlier study, this plant was frequently reported to be used by cancer patients in the region. One possibility could be that it may be helping cancer patients in other ways, rather than killing the cancer cells directly,” Koh says.
While the results of this study provide a scientific basis for the traditional practice of using tropical medicinal plants to fight cancer, the researchers stress that people should not self-medicate without consulting qualified practitioners.
“More research is required to identify the active components responsible for the anti-cancer effects. Meanwhile, conservation of these medicinal plants is highly crucial so that there is a rich and sustainable source that could be tapped [into] for the discovery of anti-cancer drugs,” Koh says.
Source: National University of Singapore