Fucoidans from Thelenota ananas with 182.4 kDa Exhibited Optimal Anti-Adipogenic Activities by Modulating the Wnt/β-Catenin Pathway

In this study,fucoidans were extracted from the sea cucumber Thelenota ananas(Ta-FUCs)by enzymatic degradation.Four products with molecular weights of 1380.3,524.0,182.4,and 110.3 kDa were obtained,and the Ta-FUC showing optimal anti-adipogenic activities was determined.Results of MTT and Oil red O staining analyses showed that the Ta-FUCs inhibited the proliferation and differentiation of 3T3-L1 adipocytes.Futhermore,Ta-FUCs significantly downregulated the key transcriptional factors,such as SREBP-1c,PPARγ,and C/EBPαof adipocytes.The Ta-FUCs also activated Wnt/β-catenin pathway-related genes,such asβ-catenin,LRP5,and FrZ.The Ta-FUCs suppressed lipid accumulation in 3T3-L1 adipocytes possibly by decreasing the expression of genes ACC,FAS,ME,GPAT,DGAT,and PILN,which are important in the synthesis of fatty acids and triglycerides;and by increasing the expression of genes PPARα,CPT-1α,and ACOX,which are crucial in fatty acidβ-oxidation.The anti-adipogenic activities initially increased and then declined with decreasing molecular weight.Among the Ta-FUCs,the 182.4 kDa Ta-FUC exhibited optimal bioactivities.This study reports for the first time that Ta-FUCs can prevent obesity by regulating the differentiation and lipid accumulation of adipocytes.

Anti-adipogenic effect of flavonoids from Chromolaena odorata leaves in 3T3-L1 adipocytes

Objective： 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 appli- cation 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-LI preadipocytes/adipocytes as a model. Methods： 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 con- trol. The effects of active flavonoids on the adipocytes were confirmed by oil red O staining and visualized under a light microscope.Results： 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, kaemp- feride, 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% inhi- bition of cellular lipid accumulation at 30 and 50μmol/L, respectively. Both kaempferide and 4,2＇-dihy droxy-4＇,5＇,6＇-trimethoxychalcone were major constituents in the ethyl acetate extract of this plant.Conclusion： C odorata leaves contained several flavonoids with anti-adipogenic effects against lipid accu- mulation in 3T3-L1 adipocytes. The plant, normally considered a useless weed, may actually provide an abundant source of biologically active flavonoids.

Characterization of two chimeric sesterterpene synthases from a fungal symbiont isolated from a sesterterpenoid-producing Lamiaceae plant Leucosceptrum canum

Two chimeric sesterterpene synthases(Aa TPS1 and Aa TPS2)were functionally characterized from Alternaria alternata MB-30 isolated from the leaves of a sesterterpenoid-producing Lamiaceae plant Leucosceptrum canum.Aa TPS1 generated a 5/8/6/5 tetracyclic sesteraltererol(1)and its absolute stereochemistry was determined by X-ray crystallographic analysis of its derivative 10,11-epoxysesteraltererol(2),which enabled revision of the absolute configuration of C7 of sesterfisherol produced by Nf SS and PTTS014 characterized previously and its derivative 10,11-epoxysesterfisherol.Aa TPS2 produced a 5/15 bicyclic preterpestacin I(3).Site-directed mutagenesis suggested that F192 in Aa TPS1 was likely involved in controlling of the hydroxylation of C12,and eight amino acids were important for the enzyme activity of Aa TPS1 and Aa TPS2.The engineered Escherichia coli and Saccharomyces cerevisiae strains were constructed for the productions of compounds 1 and 3,and the highest titer of compound 1 reached 62.3 mg/L in shake-flask culture.Both compounds 1 and 2 showed anti-adipogenic activity.

Flavonoids kaempferide and 4,2’-dihydroxy-4’,5’,6’-trimethoxychalcone inhibit mitotic clonal expansion and induce apoptosis during the early phase of adipogenesis in 3T3-L1 cells

Objective: Kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone (DTMC) are two major flavonoids found in Chromolaena odoraia 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 difTerentiaiion. Intracellular lipid accumulation, cell density and expression of the transcription factors peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding pro-teins a were assessed using AdipoRed, Oil red 0 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.