Artepillin C and Other Herbal PAK1-Blockers: Effects on Hair Cell Proliferation and Related PAK1-Dependent Biological Function in Cell Culture

The study from 2015 examined the impact of herbal PAK1-inhibitors on cancer cells, hair follicle cells, and melanogenesis in cell culture. Cucurbitacin I, from bitter melon, was the most effective, inhibiting lung cancer cell growth with an IC50 of 140 nM and promoting hair cell growth at 10 nM, which is 1000 times more effective than minoxidil. Hispidin and artepillin C also inhibited cancer cell growth with an IC50 of 25 µM, while mimosine tetrapeptides and hispidin derivatives showed strong anti-cancer activity and suppressed melanogenesis with IC50 values between 16 to 30 µM. Artepillin C from Brazilian green propolis promoted hair cell growth with an effective dose of 20 µM. The study suggests these compounds' effects on hair cell growth are due to their PAK1-blocking action, but notes that non-CBI compounds had poor cell-permeability, leading to high IC50 values. The conclusion points to the need for future research on highly cell-permeable PAK1-blockers and improving the cell-permeability of these compounds.