Researchers at the Salk Institute for Biological Studies, researched the plant’s properties and isolated a compound from Voacanga africana. The compound was found to protect cells from altered molecular pathways linked to Alzheimer’s disease, Parkinson’s disease and the neurodegeneration that often follows a stroke.
“What this provides us with is a source of potential new drug targets,” said senior author Pamela Maher, a senior staff scientist in Salk’s Cellular Neurobiology Laboratory.
The scientists studied analyzed seven different extracts collected from five species of plants in São Tomé e Príncipe by putting each sample through different assays. Three of the five were used widely by local healers who reported effects on the nervous system and two were used as controls.
One assay tested the ability of the plant extracts to protect cells against oxidative stress, a byproduct of metabolism that can cause DNA damage and has been linked to age-related neurodegeneration. Another tested anti-inflammatory properties of the compounds. A third test measured whether the samples could block the build-up of beta-amyloid peptides in neurons, which has been linked to Alzheimer’s disease.
“I was surprised at how potent they were,” says Maher. “I thought maybe we’d see a little bit of activity in some of the assays and then have to separate out individual components to see a more profound effect.” But one sample in particular — Voacanga africana — performed exceptionally on all assays, even in its most dilute form.
Isolation of specific compounds revealed that vocamine caused the anti-inflammatory and neuroprotective effects.
“There are still a lot of potential sources of drugs in plants that are native to countries around the world and most of them haven’t been tested to any extent,” says Maher. “You can’t test everything, so the best way to approach plant research for drugs is to use the knowledge that’s been around for thousands of years to help you pick and choose what to study with modern techniques. That way you’re not just shooting in the dark.”
Antonio Currais, Chandramouli Chiruta, Marie Goujon-Svrzic, Gustavo Costa, Tânia Santos, Maria Teresa Batista, Jorge Paiva, Maria do Céu Madureira, Pamela Maher. Screening and identification of neuroprotective compounds relevant to Alzheimer׳s disease from medicinal plants of S. Tomé e Príncipe. Journal of Ethnopharmacology, 2014; 155 (1): 830 DOI: 10.1016/j.jep.2014.06.046