In summary, the three natural xanthone compounds tested,
especially a-mangostin, have great potential to be anti-skin cancer
agents, associated with their capacity to induce significant apoptosis
and cell cycle arrest in G1 phase in melanoma cells. The results
demonstrate that SK-MEL-28 melanoma cell line responds differently
in both cell cycle arrest and apoptosis induction pathway
from other types of cancer cell lines reported in the literature. This
new knowledge specific to anti-cancer effect and modes of action
of melanoma cell line provides a strong foundation for further
investigation on the molecular mechanisms of the three xanthone
compounds and their in vivo therapeutic efficacy.