Drug development efforts to find new selective and safe drugs for cancer from natural resources are promising ones. The natural products are obtained in the multiple or single compounds. One of them is a sinensetin found in ethanol extract of Orthosiphon stamineus Benth. Sinensetin could inhibit cancer cell proliferation. However, it has a poor solubility so the absorption is low and then it impacts on the low bioavailability. The solubility problem in conventional drug could be solved by pharmaceutical manipulation. In the previous research, the manipulation was tried although there was no single compound found in the material tested. We found an optimal formula of a manipulation using solid disperse system of polyethylene glycol (PEG 6000) 15 times higher than sinensetin weight. This research was focused on observing the effect of the optimal formula of solid disperse system to inhibit cancer cell cycle. The cell lines used were T47D cells. The method used was flow cytometry. The result showed that the optimum formula has a consistent effect on the concentration of 40 and 60µg/mL. The sinensetin increase cell accumulation on S phase at the percentage of 18.80% (40µg/mL) and 22.21% (60µg/mL) compared to T47D normal cells. It reflects the S phase as the longest time experienced by the cells. Inhibition on S phase (S arrest) resulted from a DNA elongation. It causes an inhibition of DNA synthesis process. It could be concluded that the solid disperse of sinensetin was active to inhibit cancer cells proliferation on phase S.
Keywords: cell cycle; sinensetin; solid disperse; poor solubility