Mariquit M. De Los Reyes

Cytotoxic Triterpenes and Sterols from Pipturus arborescens (Link) C.B. Rob.

The triterpenes, squalene (1), friedelin (2) and a mixture of ursolic acid (3a) and oleanolic acid (3b) in a 2:3 ratio, and a mixture of β-sitosterol (4a) and stigmasterol (4b) in a 2:1 ratio, obtained from the dichloromethane extract of Pipturus arborescens (Link) C.B. Rob., were evaluated for their anti-proliferative activities against three human cancer cell lines, breast (MCF-7) and colon (HT-29 and HCT-116), and a normal cell line, human dermal fibroblast- neonatal (HDFn) using the in vitro PrestoBlue� cell viability assay. The HCT-116 cell line was most susceptible to the compounds and mixtures tested. Triterpene 1 was most cytotoxic against HCT-116 and MCF-7 with IC50 values of 4.21 and 5.92 μg/mL, respectively. Triterpene 2 and the mixture of 3a and 3b were highly anti-proliferative against HCT-116 cells (IC50 of 1.22 and 1.66 μg/mL, respectively) and moderately inhibitory against MCF-7 cells (IC50 of 16.51 and 23.97 μg/mL, respectively). The mixture of 4a and 4b exhibited high cytotoxicity against HCT-116 cells (IC50 of 1.14 μg/mL). Compounds 1-4b showed the least activity against HT-29 cells (IC50 of 11.97 to 52.52 μg/mL). Cytotoxic effect was not observed against HDFn cells (>100 μg/mL). Comparing the effects of 1-4b on the two colon cancer cell lines, the IC50 values of 1-4b against HCT-116 were lower than those of HT-29.

Cytotoxic Compounds from Wrightia pubescens (R.Br.)

Background: Mixtures of ursolic acid (1) and oleanolic acid (2) (1:1 and 1:2), oleanolic acid (2), squalene (3), chlorophyll a (4), wrightiadione (5), and α-amyrin acetate (6) were isolated from the dichloromethane (CH2Cl2) extracts of the leaves and twigs of Wrightia pubescens (R.Br.). Objectives: To test for the cytotoxicity potentials of 1–6. Materials and Methods: The antiproliferative activities of 1–6 against three human cancer cell lines, breast (MCF-7) and colon (HT-29 and HCT-116), and a normal cell line, human dermal fibroblast neonatal (HDFn), were evaluated using the PrestoBlue® cell viability assay. Results: Compounds 4, 1 and 2 (1:2), 2, 1 and 2 (1:1), and 5 exhibited the most cytotoxic effects against HT-29 with half maximal inhibitory concentration (IC50) values of 0.68, 0.74, 0.89, 1.70, and 4.07 μg/mL, respectively. Comparing 2 with its 1:1 mixture with 1 (IC50 = 1.70 and 7.18 μg/mL for HT-29 and HCT-116, respectively) and 1:2 mixture with 1 (0.74 and 3.46 μg/mL for HT-29 and HCT-116, respectively), 2 also showed strong cytotoxic potential against HT-29 and HCT-116 (0.89 and 2.33 μg/mL, respectively). Unlike the mixtures which exhibited low effects on MCF-7 (IC50 = 20.75 and 30.06 μg/mL for 1:1 and 1:2, respectively), 2 showed moderate activity against MCF-7 (10.99 μg/mL). Compound 6 showed the highest cytotoxicity against HCT-116 (IC50 = 4.07 μg/mL). Conclusion: Mixtures of 1 and 2 (1:1 and 1:2), 2, 3, 4, 5, and 6 from the CH2Cl2extracts of the leaves and twigs of W. pubescens (R.Br.) exhibited varying cytotoxic activities. All the compounds except 6 exhibited the strongest cytotoxic effects against HT-29. On the other hand, 6 was most cytotoxic against HCT-116. Overall, the toxicities of 1–6 were highest against HT-29, followed by HCT-116 and MCF-7. All the compounds showed varying activities against HDFn (IC50 < 30 μg/mL). Abbreviation Used: IC50: Half maximal inhibitory concentration.

Cytotoxic Compounds from Kibatalia gitingensis (Elm.) Woodson

Ursolic acid (1), squalene (2), a mixture of α-amyrin acetate (3a) and lupeol acetate (3b), and isoscopoletin (4), isolated from the dichloromethane extracts of the leaves and twigs of Kibatalia gitingensis, were evaluated for their cytotoxic activities against three human cancer cell lines, breast (MCF-7) and colon (HT-29 and HCT-116), and a normal cell line, human dermal fibroblast-neonatal (HDFn), using the in vitro PrestoBlue® cell viability assay. Compounds 1-4 exhibited strong cytotoxic activities against HT-29 cells with IC50 values ranging from 0.6931 to 1.083 μg/mL. Furthermore, 1-4 were moderately cytotoxic against HCT-116 cells with IC50 values ranging from 4.065 to 11.09 μg/mL. These compounds were least cytotoxic against MCF-7 cells with IC50 values ranging from 8.642 to 25.87 μg/mL. The most cytotoxic against HT-29 cells, HCT-116 cells and MCF-7 cells are 2, 4 and 1, respectively.