ABSTRACT
OBJECTIVE@#Kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone (DTMC) are two major flavonoids found in Chromolaena odorata Linn. leaf extract. The aim of this study was to elucidate the mechanism by which these two flavonoids exerted their effect on adipogenesis. The inhibitory effect of kaempferide and DTMC on adipocyte differentiation and their mechanisms involving mitotic clonal expansion (MCE) and apoptosis during the early stage of adipogenesis were investigated.@*METHODS@#Confluent 3T3-L1 preadipocytes were induced to differentiate and exposed to the flavonoids during various phases of differentiation. Intracellular lipid accumulation, cell density and expression of the transcription factors peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins α were assessed using AdipoRed, Oil red O and Western blot assays. Effects of both flavonoids on cell proliferation and apoptosis were also determined by carboxyfluorescein diacetate succinimidyl ester and annexin V-fluorescein isothiocyanate/propidium iodide-staining assays, respectively.@*RESULTS@#Kaempferide and DTMC showed significant, concentration-dependent anti-adipogenic activity and effect on cell density in the early phase of adipogenesis. The expression of the transcription factors seemed to be reduced when the treatment was prolonged or in the early phase of adipogenesis. These flavonoids interrupted MCE via inhibition of preadipocyte proliferation and induction of apoptosis. DTMC was nearly three times more potent than kaempferide in inducing apoptosis.@*CONCLUSION@#Kaempferide and DTMC exerted their anti-adipogenic activity through inhibition of MCE, either by suppressing cell proliferation or by inducing apoptosis during the early phase of differentiation.
ABSTRACT
<p><b>OBJECTIVE</b>The roots of two Thai medicinal plants, Clerodendrum indicum and Clerodendrum villosum are found in traditional medicine practices. The aim of this research was to preliminarily study the cytotoxicity of extracts of their roots, and the parts that possessed cytotoxic activity were separated on a chromatograph to identify their active compounds.</p><p><b>METHODS</b>The extracts of both plants were screened for cytotoxicity on the SW620 cell line and the compounds isolated from the active extracts were further evaluated for their cytotoxic activity against five human cancer cell lines, including SW620, ChaGo-K-1, HepG2, KATO-III and BT-474 using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay.</p><p><b>RESULTS</b>Dichloromethane extracts of C. indicum and C. villosum were active against the SW620 cell line. Triterpenoids were mostly obtained from the extracts of these plants (0.28% and 1.02%, respectively) and exhibited varying degrees of cytotoxicity and specificity against the tested cell lines. Two triterpenoids, oleanolic acid 3-acetate and betulinic acid, displayed moderate to strong cytotoxicity toward all cancer cell lines, with 50% inhibitory concentration (IC) values of 1.66-20.49 µmol/L, whereas 3β-hydroxy-D:B-friedo-olean-5-ene and taraxerol were cytotoxic to only the SW620 cell line (IC = 23.39 and 2.09 µmol/L, respectively). Triterpenoid, lupeol, showed potent cytotoxicity on both SW620 (IC = 1.99 µmol/L) and KATO-III cell lines (IC = 1.95 µmol/L), while a flavonoid, pectolinarigenin, displayed moderate cytotoxicity against these cells (IC = 13.05 and 24.31 µmol/L, respectively). Although the widely distributed steroid, stigmasterol, was effective against the SW620 cell line (IC = 2.79 µmol/L) and β-sitosterol was also active against SW620 (IC = 11.26 µmol/L), BT-474 (IC = 14.11 µmol/L) and HepG2 cancer cells (IC = 20.47 µmol/L), none of the characteristic 24β-ethylsteroids of either Clerodendrum species were shown to be cytotoxic.</p><p><b>CONCLUSION</b>This study is the first report on the presence of cytotoxic triterpenoids from the roots of these medicinal plants, which have been used in herbal formulas as an antipyretic. Our findings support further in-depth study of this pharmacological activity as an anticancer agent.</p>
ABSTRACT
<p><b>OBJECTIVE</b>The leaves of Chromolaena odorata, a highly invasive shrub found growing wild worldwide, are traditionally used for wound healing. Due to its high flavonoid contents, we aimed to find a new application for this plant. Preliminary tests using its ethanolic leaf extract showed that it could suppress the accumulation of lipids in adipocytes. We therefore studied the anti-adipogenic effect of several C. odorata leaf extracts and the relationship between molecular structure and bio-activity of its isolated flavonoid constituents using 3T3-L1 preadipocytes/adipocytes as a model.</p><p><b>METHODS</b>Three leaf extracts and thirteen flavonoids isolated from C. odorata were tested for their effect on lipid accumulation in 3T3-L1 adipocytes using AdipoRed reagent, with quercetin as the positive control. The effects of active flavonoids on the adipocytes were confirmed by oil red O staining and visualized under a light microscope.</p><p><b>RESULTS</b>n-Hexane and ethyl acetate extracts of C. odorata leaves displayed anti-adipogenic activity. The latter extract was the more potent one, especially at 40 µg/mL. Four flavonoids, pectolinarigenin, kaempferide, 4,2'-dihydroxy-4',5',6'-trimethoxychalcone and dillenetin, exhibited significant, concentration-dependent inhibitory effects on lipid accumulation in 3T3-L1 adipocytes. The most potent flavonoid obtained in this study was 4,2'-dihydroxy-4',5',6'-trimethoxychalcone, which caused 75% and 90% inhibition of cellular lipid accumulation at 30 and 50 µmol/L, respectively. Both kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone were major constituents in the ethyl acetate extract of this plant.</p><p><b>CONCLUSION</b>C. odorata leaves contained several flavonoids with anti-adipogenic effects against lipid accumulation in 3T3-L1 adipocytes. The plant, normally considered a useless weed, may actually provide an abundant source of biologically active flavonoids.</p>