Could compounds found in African plants hold the key to fighting intractable malignant mesothelioma?
That is the suggestion of a new study conducted by an international team of researchers including scientists in Cameroon and Kenya.
The study published in a recent issue of BMC Pharmacology and Toxicology, focused on naturally occurring quinones, organic compounds found in bacteria, certain fungi, and in various plants, including some found in Kenya.
Quinones as Cancer Fighters
The new study focused on 14 different naturally occurring quinones including three in the group anthraquinones, one naphthoquinone and ten benzoquinones.
The substances were tested on six types of cancer cells, including malignant mesothelioma, as well as on normal connective tissue cells called fibroblasts.
Specifically, the researchers were looking for the impact of quinones on the release of caspases, enzymes that play essential roles in programmed cell death or apoptosis.
Triggering Mesothelioma Cell Death
While different quinones impacted the various cancer cells in different ways, the quinone with the greatest impact on pleural mesothelioma cells was rapanone, a compound isolated from a particular evergreen shrub.
The researchers note that all of the 14 tested compounds “displayed interesting activities” in the cancer cell lines tested. In addition to malignant mesothelioma, those cell lines included colorectal cancer and cancers of the breast, liver, and lungs.
“The tested natural products…are potential cytotoxic compounds that deserve more investigations towards developing novel antiproliferative drugs against human carcinoma,” writes researcher and the study’s first author Victor Kuete, PhD, a biochemist with the Universite de Dschang.
Alternative to Chemotherapy Needed
Currently, chemotherapy is the primary first-line treatment for patients diagnosed with mesothelioma. But even the gold standard chemotherapy drug Alimta (pemetrexed) is only marginally effective against this aggressive cancer and can cause life-threatening side effects.
Alternative mesothelioma treatments are urgently needed.
In addition to quinones, other naturally-derived compounds that have shown promise in the fight against mesothelioma include curcumin from the spice turmeric, polyphenols found in tea and leafy greens, and resveratrol in red wine.
Kuete, V, et al, “Cytotoxicity of Plumbagin, Rapanone and 12 other naturally occurring Quinones from Kenyan Flora towards human carcinoma cells”, December 21, 2016, BMC Pharmacology and Toxicology