A recent study shows organic compounds found in several African plants, including a common seaweed, caused cell death in human carcinoma cell lines, including malignant mesothelioma.
Dr. Victor Kuete of the University of Dschang in Cameroon led the research team that investigated 14 naturally occurring quinones, a class of organic compounds, they isolated from African medicinal plants.
Researchers tested these compounds against six types of carcinoma cell lines, including breast, colon and small-cell lung cancer.
One quinone in particular, rapanone, had promising results against mesothelioma cancer cells.
“We found that rapanone likely induced apoptosis [cell death] via loss of mitochondrial membrane potential,” Kuete told Asbestos.com.
Mitochondrial functions, including producing energy for a cell and regulating its metabolism, are essential for carcinoma cells to grow and spread.
By limiting mitochondrial functions, rapanone triggered cell death in a human mesothelioma culture.
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Cancer Fighting Power of Quinones
Cancer is the leading cause of death worldwide, according to the World Health Organization.
Despite this, Kuete noted cancer is a low public health priority in Africa, where communicable diseases, such as AIDS, malaria and tuberculosis, are more pressing issues.
Kuete and his team have dedicated years of research to finding and investigating antineoplastic compounds, or natural agents that prevent, inhibit or halt the development of tumors.
“Many investigations are being carried out to identify new drugs or to find new lead structures from the flora of Africa to develop novel therapeutic agents for the treatment of human diseases such as cancer,” Kuete wrote in the study.
Kuete’s study involved a species of seaweed, a tree already used in alternative treatments and a flowering shrub.
Researchers used the neutral red uptake assay to evaluate the cytotoxicity (toxicity to living cells) of the quinones. The Caspase-Glo assay allowed researchers to detect the activation of caspases, which are enzymes known for playing essential roles in programmed cell death.
Quinones exhibit numerous biological activities including:
- Antiplasmodial and trypanocidal (counters parasites)
“Amongst plant secondary metabolites, quinones comprise the second largest class of anti-cancer agents,” Kuete said.
In addition to rapanone, two other compounds in the study demonstrated significant cytotoxicity against mesothelioma cells. Kuete suggested these three compounds “can be useful in the management” of malignant mesothelioma.
Using Plant-Based Compounds to Fight Cancer
The quinones in the African study are the latest naturally derived compounds researchers analyzed to find a cure for mesothelioma.
Scientists in South Korea discovered that resveratrol, a compound found in wine and red grapes, enhanced the platinum-based chemotherapy drug cisplatin.
A 2014 study showed PEITC, an anti-cancer compound found in cruciferous vegetables (arugula, broccoli, kale, etc.), can kill mesothelioma cells on its own, and it’s even more effective when combined with cisplatin.
Mesothelioma is a rare cancer with a long latency period. The cancer develops in the body decades after asbestos exposure takes place. Symptoms of mesothelioma develop after the cancer spreads beyond the lungs, making it very difficult to treat by the time it is diagnosed. While some chemotherapy drugs successfully kill and reduce the spread of cancer cells, finding methods to enhance these treatments are essential for aggressive cancers such as mesothelioma.
Using rapanone and other quinones to treat mesothelioma is a novel therapy at this point, but Kuete didn’t rule out the possibility of future research, noting the need for more investigations to develop novel cytotoxic drugs.
“We don’t have funds for clinical trials but we will be happy to welcome any financial support in that way,” he said.