Role of ginsenosides and quercetin in anterograde transport of melanosomes
(English)Manuscript (preprint) (Other academic)
Panax ginseng is a traditional herb that has been used in the Orient for several thousands of years as a tonic and restorative. Active components of ginseng include ginsenosides, polysaccharides, flavonoids, polyacetylenes, peptides, vitamins, phenols and enzymes, of which the ginsenosides are considered to be the major bioactive constituents. In spite of extensive use, the exact mechanisms of ginseng and its components are still unknown. In the present study we use melanophores from Xenopus laevis to investigate the effects of Panax ginseng extract G115, ginsenosides and the flavonoid quercetin on pigment organelle transport and signalling. Through coordinated transport of their black pigmented granules (melanosomes), melanophores are capable of fast colour changes. The movement is regulated by changes in cyclic adenosine 3’:5’-monophosphate (cAMP) concentration, where a high or low level induce anterograde (dispersion) or retrograde (aggregation) transport respectively, leaving a dark or light cell. Previously we have shown that Panax ginseng induces dispersion of melanosomes. Here, ginsenoside Rc and Rd and the flavonoid quercetin are shown to stimulate an anterograde transport of pigment organelles. When Rc or Rd and quercetin were combined, a significant synergistic increase in dispersion could be seen. Protein kinase C (PKC) inhibitor Myristoylated EGF-R Fragment (651-658) (M-EGF) decreased the anterograde movement stimulated by ginseng and ginsenoside Rc and Rd. We also demonstrate that ginseng, but not ginsenosides or quercetin, induce a concentration-dependent activation of 44/42-mitogen activated protein kinase (MAPK). PKC-inhibition did not affect the MAPK-activation, suggesting a role for PKC in the ginseng- and ginsenoside-induced anterograde transport but not in the activation of MAPK.
melanophore, pigment organelle transport, Panax ginseng, ginsenosides, quercetin, PKC, MAPK
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-19970OAI: oai:DiVA.org:liu-19970DiVA: diva2:232369