Hake et al visited tribes near the Malaysian rain forest and selected 50 medicinal plants in coordination with the Universiti Kebangsaan Malaysia. They conducted cellular assays on each of these and chose the plant Knema laurina as having the most anti-inflammatory potential as well as the least neurotoxity for further analysis.
The results were pretty astounding. No neurotoxic effects were found in hippocampal cell cultures, although there was some glia damage at very high concentrations. In hippocampal slice cultures, it reduced the neuron damage from excitotoxicity dose-dependently. At 30 µg/ml and 75 µg/ml, the neuron damage was reduced to levels near the controls.
In addition, the plant was found to stimulate neurogenesis after oxygen-glucose deprivation. In vehicle treated brain tissue, higher concentrations of extract from the plant led to a 1.8 +/- 0.2 increase in BrdU/DXC-positive cells, which are both indicators of proliferating cells. The authors claim that this is similar to the neurogenic effects of other pharmaceutical agents, without the neurotoxic side effects. It is cool to see modern science piggybacking on ancient wisdom.
Hake I, Schonenberger S, Neumann J, Franke K, Paulsen-Merker K, Reymann K, Ismail G, bin Din L, Said IM, Latiff A, Wessjohann L, Zipp J, Ullrich O. 2009 Neuroprotection and enhanced neurogenesis by extract from the tropical plant Knema laurina after inflammatory damage in living brain tissue. Journal of Neuroimmunology 206:91-99. doi:10.1016/j.jneuroim.2008.10.007.