ABSTRACT
Syzygium aromaticum (L.) Merr. & L.M. Perry, Myrtaceae, is an evergreen tree with anticarcinogenic, antimutagenic, aphrodisiac, antimicrobial, antioxidant and antiinflammatory properties. This study aims to investigate the anti-breast cancer effect of extracts from leaves, stem and bark of S. aromaticum and to develop a method for preparation of betulinic acid fraction from the leaves. Betulinic acid, ursolic acid and oleanolic acid contents of the extracts were determined by HPLC. A betulinic acid fraction was prepared by simple crystallization of leaves extract and was characterized by HPLC and mass analysis. Anti-breast cancer effects were studied on MCF-7 and MDA-MB-231 cells. The extracts were found to contain high levels of betulinic acid particularly the leaves extract which contained 17% wt/wt. The betulinic acid fraction contains 75% betulinic acid. Cytotoxicity testing reveals high and selective cytotoxic effect of the stem extract on MCF-7 cells with IC50 33±1.6 µg/mL. Cytotoxic effect of the stem extract was due to activation of apoptotic machinery of cell death. Combination studies of stem extract with tamoxifen reveals antagonistic effect at high concentration of tamoxifen and enhancement effect at low concentration. The selective cytotoxicity of the stem extract of S. aromaticum on MCF-7 is not due to betulinic acid but due to other constituents yet to be discovered.
ABSTRACT
This study aimed to investigate the antitumorigenicity of xanthones-rich extract from Garcinia mangostana L., Clusiaceae, fruit rinds which was obtained by a simple recrystallization of 75 percent ethanolic extract. α-Mangostin content of the extract was determined qualitatively by TLC and quantitatively by HPLC, and total xanthones content was quantified by UV spectrophotometry. The extract was evaluated for cytotoxicity, apoptosis and antitumorigenicity on HCT 116 human colorectal carcinoma cells. α-Mangostin was found to be the main constituent of the extract which was 71.2±0.1 percent, and the total xanthones content was 95±4.8 percent (wt/wt). The extract showed potent dose dependent cytotoxicity with IC50 value 9.2 μg/mL. Apoptosis studies revealed activation of caspases 3 and 7, DNA fragmentation, chromatin condensation and loss of mitochondrial membrane potential. Studies on cell migration and colony formation indicate reduced cell migration ability and clonogenicity of treated HCT 116 cells at sub-inhibitory concentrations. Taken together, the cytotoxic effect of the xanthones extract is mediated through the mitochondrial pathway of apoptosis. The reduced cell migration and clonogenicity of HCT 116 cells might prevent both primary and metastatic tumor growth in vivo which will be the topic of our future work using the metastatic orthotopic colon cancer model.