Antiproliferative Effects of Pterodon pubescens Extract and Isolated Diterpenes in HaCaT Cells

Pterodon pubescens fruits are popularly used because of their analgesic and anti-inflammatory actions, which are attributed to the isolated compounds with a vouacapan skeleton. This work aimed to evaluate the antiproliferative and anti-inflammatory effects of a P. pubescens fruit dichloromethane extract and the vouacapan diterpene furan isomer's mixture (1 : 1) (6α-hydroxy-7β-acetoxy-vouacapan-17β-oate methyl ester and 6α-acetoxy-7β-hydroxy-vouacapan-17β-oate methyl ester isomers) in HaCaT cells using the cell migration and the BrDU incorporation assay. Levels of IL-8 were measured by ELISA after TNF-α stimulation. HPLC/DAD analysis of the extract revealed the expressive presence of vouacapan diterpene furan isomer's mixture. P. pubescens extract (1.5625 - 25 µg/mL) and vouacapan diterpene furan isomer's mixture (3.125 - 50 µM) inhibited cell proliferation as indicated by a decreased BrdU-incorporation. For the evaluation of cell migration, time-lapse microscopy was used. P. pubescens presented inhibition on cell migration at all concentrations tested (3.125 - 12.5 µg/mL), whereas for the VDFI mixture, the inhibition was only observed at the highest concentrations (12.5 and 25 µM) tested. Furthermore P. pubescens extract and vouacapan diterpene furan isomer's mixture significantly decreased IL-8 levels. Our results showed antiproliferative and anti-inflammatory effects on HaCaT cells treated with the extract and the vouacapan isomer's mixture, without affecting cell viability. These activities could be attributed to the voucapan molecular structures. In conclusion, topical products developed of P. pubescens extract or the voucapan isomer's mixture should be further studied as a potential product for local treatment against hyperproliferative lesions as in psoriasis vulgaris, representing an alternative treatment approach.