Adipogenesis and therapeutic potentials of antiobesogenic phytochemicals: Insights from preclinical studies

Profiling of antioxidant properties and identification of potential analgesic inhibitory activities of Allophylus villosus and Mycetia sinensis employing in vivo, in vitro, and computational techniques

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional use of plants for medicinal purposes, called phytomedicine, has been known to provide relief from pain. In Bangladesh, the Chakma indigenous community has been using Allophylus villosus and Mycetia sinensis to treat various types of pain and inflammation.

AIM OF THE STUDY

The object of this research is to evaluate the effectiveness of these plants in relieving pain and their antioxidant properties using various approaches such as in vitro, in vivo, and computational techniques. Additionally, the investigation will also analyse the phytochemicals present in these plants.

MATERIALS AND METHODS

We conducted in vivo analgesic experiment on Swiss albino mice and in-silico inhibitory activities on COX-2 & 15-LOX-2 enzymes. Assessment of DPPH, Anti Radical Activities (ARA), FRAP, H2O2 Free Radical Scavenging, Reducing the power of both plants performed significant % inhibition with tolerable IC50. Qualitative screening of functional groups of phytochemicals was précised by FTIR and GC-MS analysis demonstrated phytochemical investigations.

RESULTS

The ethyl acetate (EtOAc) fractioned Mycetia sinensis extract as well as the ethanoic extract and all fractioned extracts of Allophylus villosus have reported a significant percentage (%) of writhing inhibition (p < 0.05) with the concentrated doses 250 mg as well as 500 mg among the Swiss albino mice for writhing observation of analgesic effect. In the silico observation, a molecular-docking investigation has performed according to GC-MS generated 43 phyto-compounds of both plants to screen their binding affinity by targeting COX-2 and 15-LOX-2 enzymes. Consequently, in order to assess and ascertain the effectiveness of the sorted phytocompounds, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) investigation, DFT (Density-functional theory) by QM (Quantum mechanics), and MDS (Molecular dynamics simulation) were carried out. As the outcome, compounds like 5-(2,4-ditert-butylphenoxy)-5-oxopentanoic acid; 2,4-ditert-butylphenyl 5-hydroxypentanoate; 3,3-diphenyl-5-methyl-3H-pyrazole; 2-O-(6-methylheptan-2-yl) 1-O-octyl benzene-1,2-dicarboxylate and dioctan-3-yl benzene-1,2-dicarboxylate derived from the ethnic plant A. villosus and another ethnic plant M. sinensis extracts enchants magnificent analgesic inhibitions and performed more significant drug like activities with the targeted enzymes.

CONCLUSIONS

Phytocompounds from A. villosus & M. sinensis exhibited potential antagonist activity against human 15-lipoxygenase-2 and cyclooxygenase-2 proteins. The effective ester compounds from these plants performed more potential anti-nociceptive activity which could be used as a drug in future.

Sesamolin suppresses adipocyte differentiation through Keap1-dependent Nrf2 activation in adipocytes

Sesamolin, a lignan isolated from sesame oils, has been found to possess neuroprotective, anticancer, and free radical scavenging properties. We hypothesized that sesamolin could stimulate the activity of nuclear factor erythroid-derived 2-like 2 (Nrf2) and inhibit adipocyte differentiation of preadipocytes. The objective of this study was to investigate effects of sesamolin on adipocyte differentiation and its underlying molecular mechanisms. In this study, we determined the effects of treatment with 25 to 100 µM sesamolin on adipogenesis in cell culture systems. Sesamolin inhibited lipid accumulation and suppressed the expression of adipocyte markers during adipocyte differentiation of C3H10T1/2, 3T3-L1, and primary preadipocytes. Mechanism studies revealed that sesamolin increased Nrf2 protein expression without inducing its mRNA, leading to an increase in the expression of Nrf2 target genes such as heme oxygenase 1 and NAD(P)H:quinone oxidoreductase 1 (Nqo1) in C3H10T1/2 adipocytes and mouse embryonic fibroblasts. These effects were significantly attenuated in Nrf2 knockout (KO) mouse embryonic fibroblasts, indicating that effects of sesamolin were dependent on Nrf2. In H1299 human lung cancer cells with KO of Kelch like-ECH-associated protein 1 (Keap1), a negative regulator of Nrf2, sesamolin failed to further increase Nrf2 protein expression. However, upon reexpressing Keap1 in Keap1 KO cells, the ability of sesamolin to elevate Nrf2 protein expression was restored, highlighting the crucial role of Keap1 in sesamolin-induced Nrf2 activation. Taken together, these findings show that sesamolin can inhibit adipocyte differentiation through Keap1-mediated Nrf2 activation.

The effect of quercetin on adipogenesis, lipolysis, and apoptosis in 3T3-L1 adipocytes: The role of SIRT1 pathways

Background

Lipotoxicity, caused by adipocyte triglyceride over-accumulation, contributes to obesity-related comorbidities such as hypertension, type 2 diabetes, coronary heart disease, respiratory dysfunction, and osteoarthritis. This study focuses on determining how sirtuin-1 (SIRT-1) mediates quercetin's (QCT) effect on 3T3-L1 adipocytes. Key aspects of this study include preventing adipogenesis, inducing lipolysis, and stimulating adipocyte apoptosis.

Methods

3T3-L1 adipocytes underwent treatment with varying QCT doses, lipopolysaccharide (LPS), and the SIRT-1 inhibitor EX-527, followed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide [MTT] assay for cell viability assessment. Furthermore, quantitative real-time polymerase chain reaction measured mRNA expression levels of adipogenesis markers (fatty acid synthase [FASN] and peroxisome proliferator-activated receptor gamma [PPARγ]), lipolysis markers (adipose triglyceride lipase [ATGL] and hormone-sensitive lipase [HSL]), and apoptosis markers (B-cell lymphoma2 [Bcl-2], Bcl-2 Associated -X-protein [BAX] and Caspase-3).

Results

The data showed that LPS + QCT significantly reduced cell viability in a dose- and time-dependent manner, unaffected by LPS + QCT + EX-527. Treatment with LPS + QCT did not affect FASN and PPARγ expression but significantly increased ATGL and HSL mRNA expression compared with LPS alone. Interestingly, EX-527 reversed the effects of LPS + QCT on lipogenesis and lipolysis markers completely. QCT enhanced apoptosis in a SIRT-1 independent pattern.

Conclusion

The data suggest that QCT suppresses adipogenesis while increasing lipolysis via SIRT-1. However, QCT's effects on apoptosis appear to be independent of SIRT-1. These findings provide further evidence for QCT's effects on adipocytes, particularly its interaction with SIRT-1.

Cinnamyl Alcohol Attenuates Adipogenesis in 3T3-L1 Cells by Arresting the Cell Cycle

Cinnamyl alcohol (CA) is an aromatic compound found in several plant-based resources and has been shown to exert anti-inflammatory and anti-microbial activities. However, the anti-adipogenic mechanism of CA has not been sufficiently studied. The present study aimed to investigate the effect and mechanism of CA on the regulation of adipogenesis. As evidenced by Oil Red O staining, Western blotting, and real-time PCR (RT-PCR) analyses, CA treatment (6.25-25 μM) for 8 d significantly inhibited lipid accumulation in a concentration-dependent manner and downregulated adipogenesis-related markers (peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), fatty acid binding protein 4 (FABP4), adiponectin, fatty acid synthase (FAS)) in 3-isobutyl-1-methylxanthine, dexamethasone, and insulin(MDI)-treated 3T3-L1 adipocytes. In particular, among the various differentiation stages, the early stage of adipogenesis was critical for the inhibitory effect of CA. Cell cycle analysis using flow cytometry and Western blotting showed that CA effectively inhibited MDI-induced initiation of mitotic clonal expansion (MCE) by arresting the cell cycle in the G0/G1 phase and downregulating the expression of C/EBPβ, C/EBPδ, and cell cycle markers (cyclin D1, cyclin-dependent kinase 6 (CDK6), cyclin E1, CDK2, and cyclin B1). Moreover, AMP-activated protein kinase α (AMPKα), acetyl-CoA carboxylase (ACC), and extracellular signal-regulated kinase 1/2 (ERK1/2), markers of upstream signaling pathways, were phosphorylated during MCE by CA. In conclusion, CA can act as an anti-adipogenic agent by inhibiting the AMPKα and ERK1/2 signaling pathways and the cell cycle and may also act as a potential therapeutic agent for obesity.

Inhibitory Effects of Sesquiterpenoids Isolated from Artemisia scoparia on Adipogenic Differentiation of 3T3-L1 Preadipocytes

Obesity and related complications are significant health issues in modern society, largely attributed to a sedentary lifestyle and a carbohydrate-rich diet. Since anti-obesity drugs often come with severe side effects, preventative measures are being sought globally, including dietary changes and functional foods that can counteract weight gain. In this context, plant-based metabolites are extensively studied for their advantageous biological effects against obesity. Several plants within the Artemisia genus have been reported to possess anti-adipogenic properties, preventing adipocytes from maturing and accumulating lipids. The present study investigated the anti-adipogenic potential of two sesquiterpenoids, reynosin and santamarine, isolated from A. scoparia in adipose-induced 3T3-L1 preadipocytes. Differentiating 3T3-L1 adipocytes treated with these isolated compounds displayed fewer adipogenic characteristics compared to untreated mature adipocytes. The results indicated that cells treated with reynosin and santamarine accumulated 55.0% and 52.5% fewer intracellular lipids compared to untreated control adipocytes, respectively. Additionally, the mRNA expression of the key adipogenic marker, transcription factor PPARγ, was suppressed by 87.2% and 91.7% following 60 μM reynosin and santamarine treatment, respectively, in differentiated adipocytes. Protein expression was also suppressed in a similar manner, at 92.7% and 82.5% by 60 μM reynosin and santamarine treatment, respectively. Likewise, SERBP1c and C/EBPα were also downregulated at both gene and protein levels in adipocytes treated with samples during differentiation. Further analysis suggested that the anti-adipogenic effect of the compounds might be a result of AMPK activation and the subsequent suppression of MAPK phosphorylation. Overall, the present study suggested that sesquiterpenoids, reynosin, and santamarine were two potential bioactive compounds with anti-adipogenic properties. Further research is needed to explore other bioactive agents within A. scoparia and elucidate the in vivo action mechanisms of reynosin and santamarine.

Association between dietary phytochemical index, cardiometabolic risk factors and metabolic syndrome in Switzerland. The CoLaus study

BACKGROUND AND AIMS

Plant-based diets are associated with reduced cardiometabolic risk factors (CRFs) and lower risk of metabolic syndrome (MetS), probably via phytochemicals acting synergistically. However, dietary phytochemical content estimation is challenging; therefore, the dietary phytochemical index (DPI) was proposed as a practical way to assess total dietary phytochemical content from phytochemical-rich foods (PRFs). We evaluated the association between DPI with CRFs and MetS and its components.

METHODS AND RESULTS

Cross-sectional analysis of 2009-2012 data of Colaus cohort study (Lausanne, Switzerland), including 3879 participants (mean age 57.6 ± 10.4 years, 53.5% women). Dietary intake was assessed via a validated food frequency questionnaire. DPI was calculated as the total energy intake percentage obtained from PRFs consumption and assessed as quartiles. Associations were determined using multivariable linear and logistic regression for CRFs and MetS, respectively. Median DPI value was 25.5 (interquartile range: 17.7-34.6). After multivariable-adjusted analyses, significant inverse associations were observed between the last two highest DPI quartiles and waist circumference (WC), body mass index (BMI), insulin, leptin, and hs-CRP. No significant associations were observed for MetS or its components except for central obesity, as subjects in the highest DPI quartile had lower odds (OR: 0.78; 95% CI: 0.62, 0.97) than those in lowest quartile.

CONCLUSION

A diet high in PRFs assessed via DPI is associated with lower WC, BMI, insulin, leptin, hs-CRP values, and lower odds of central obesity, indicating a potential protective effect of phytochemical intake on these CRFs and highlighting the importance of high PRFs intake in promoting cardiometabolic health.

Effects of allicin on human Simpson-Golabi-Behmel syndrome cells in mediating browning phenotype

INTRODUCTION

Obesity is a major health problem because it is associated with increased risk of cardiovascular disease, diabetes, hypertension, and some cancers. Strategies to prevent or reduce obesity focus mainly on the possible effects of natural compounds that can induce a phenotype of browning adipocytes capable of releasing energy in the form of heat. Allicin, a bioactive component of garlic with numerous pharmacological functions, is known to stimulate energy metabolism.

METHODS

In the present study, the effects of allicin on human Simpson-Golabi-Behmel Syndrome (SGBS) cells were investigated by quantifying the dynamics of lipid droplets (LDs) and mitochondria, as well as transcriptomic changes after six days of differentiation.

RESULTS

Allicin significantly promoted the reduction in the surface area and size of LDs, leading to the formation of multilocular adipocytes, which was confirmed by the upregulation of genes related to lipolysis. The increase in the number and decrease in the mean aspect ratio of mitochondria in allicin-treated cells indicate a shift in mitochondrial dynamics toward fission. The structural results are confirmed by transcriptomic analysis showing a significant arrangement of gene expression associated with beige adipocytes, in particular increased expression of T-box transcription factor 1 (TBX1), uncoupling protein 1 (UCP1), PPARG coactivator 1 alpha (PPARGC1A), peroxisome proliferator-activated receptor alpha (PPARA), and OXPHOS-related genes. The most promising targets are nuclear genes such as retinoid X receptor alpha (RXRA), retinoid X receptor gamma (RXRG), nuclear receptor subfamily 1 group H member 3 (NR1H3), nuclear receptor subfamily 1 group H member 4 (NR1H4), PPARA, and oestrogen receptor 1 (ESR1).

DISCUSSION

Transcriptomic data and the network pharmacology-based approach revealed that genes and potential targets of allicin are involved in ligand-activated transcription factor activity, intracellular receptor signalling, regulation of cold-induced thermogenesis, and positive regulation of lipid metabolism. The present study highlights the potential role of allicin in triggering browning in human SGBS cells by affecting the LD dynamics, mitochondrial morphology, and expression of brown marker genes. Understanding the potential targets through which allicin promotes this effect may reveal the underlying signalling pathways and support these findings.

Libanoridin Isolated from Corydalis heterocarpa Inhibits Adipogenic Differentiation of Bone Marrow-Derived Mesenchymal Stromal Cells

Bone marrow adiposity is a complication in osteoporotic patients. It is a result of the imbalance between adipogenic and osteogenic differentiation of bone marrow cells. Phytochemicals can alleviate osteoporotic complications by hindering bone loss and decreasing bone marrow adiposity. Corydalis heterocarpa is a biennial halophyte with reported bioactivities, and it is a source of different coumarin derivatives. Libanoridin is a coumarin isolated from C. heterocarpa, and the effect of libanoridin on adipogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) was evaluated in the present study. Cells were induced to undergo adipogenesis, and their intracellular lipid accumulation and expression of adipogenic markers were observed under libanoridin treatment. Results showed that 10 μM libanoridin-treated adipocytes accumulated 44.94% less lipid compared to untreated adipocytes. In addition, mRNA levels of PPARγ, C/EBPα, and SREBP1c were dose-dependently suppressed with libanoridin treatment, whereas only protein levels of PPARγ were decreased in the presence of libanoridin. Fluorescence staining of adipocytes also revealed that cells treated with 10 μM libanoridin expressed less PPARγ compared to untreated adipocytes. Protein levels of perilipin and leptin, markers of mature adipocytes, were also suppressed in adipocytes treated with 10 μM libanoridin. Analysis of MAPK phosphorylation levels showed that treatment with libanoridin inhibited the activation of p38 and JNK MAPKs observed by decreased levels of phosphorylated p38 and JNK protein. It was suggested that libanoridin inhibited adipogenic differentiation of hBM-MSCs via suppressing MAPK-mediated PPARγ signaling. Future studies revealing the anti-adipogenic effects of libanoridin in vivo and elucidating its action mechanism will pave the way for libanoridin to be utilized as a nutraceutical with anti-osteoporotic properties.

The evolving view of thermogenic fat and its implications in cancer and metabolic diseases

The incidence of metabolism-related diseases like obesity and type 2 diabetes mellitus has reached pandemic levels worldwide and increased gradually. Most of them are listed on the table of high-risk factors for malignancy, and metabolic disorders systematically or locally contribute to cancer progression and poor prognosis of patients. Importantly, adipose tissue is fundamental to the occurrence and development of these metabolic disorders. White adipose tissue stores excessive energy, while thermogenic fat including brown and beige adipose tissue dissipates energy to generate heat. In addition to thermogenesis, beige and brown adipocytes also function as dynamic secretory cells and a metabolic sink of nutrients, like glucose, fatty acids, and amino acids. Accordingly, strategies that activate and expand thermogenic adipose tissue offer therapeutic promise to combat overweight, diabetes, and other metabolic disorders through increasing energy expenditure and enhancing glucose tolerance. With a better understanding of its origins and biological functions and the advances in imaging techniques detecting thermogenesis, the roles of thermogenic adipose tissue in tumors have been revealed gradually. On the one hand, enhanced browning of subcutaneous fatty tissue results in weight loss and cancer-associated cachexia. On the other hand, locally activated thermogenic adipocytes in the tumor microenvironment accelerate cancer progression by offering fuel sources and is likely to develop resistance to chemotherapy. Here, we enumerate current knowledge about the significant advances made in the origin and physiological functions of thermogenic fat. In addition, we discuss the multiple roles of thermogenic adipocytes in different tumors. Ultimately, we summarize imaging technologies for identifying thermogenic adipose tissue and pharmacologic agents via modulating thermogenesis in preclinical experiments and clinical trials.

Characterization of Plocamium telfairiae Extract-Functionalized Au Nanostructures and Their Anti-Adipogenic Activity through PLD1

Here, Au nanostructure (AuNS) biosynthesis was mediated through ethanolic extract of Plocamium telfairiae (PT) without the use of stabilizers or surfactants. PT-functionalized AuNSs (PT-AuNSs) were analyzed using ultraviolet–visible spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, and Fourier-transform infrared spectroscopy. Stable monodisperse PT-AuNSs were synthesized, with a mean size of 15.36 ± 0.10 nm and zeta potential of −35.85 ± 1.36 mV. Moreover, biosynthetic AuNPs with a face-centered structure of PT-AuNS exhibited crystalline characteristics. In addition, many functional groups playing important roles in the biological reduction of PT extracts were adsorbed on the surface of PT-AuNSs. Furthermore, the effects of PT-AuNSs on adipogenesis in immature adipocytes were investigated. PT-AuNSs reduced morphological changes, lowered triglyceride content, and increased lipid accumulation by approximately 78.6% in immature adipocytes compared with the values in mature adipocytes (MDI-induced). PT-AuNS suppressed lipid accumulation by downregulating the transcript and protein expression of C/EBPα, PPARγ, SREBP 1, FAS, and aP2. Finally, PT-AuNS induced the transcript and protein expression of UCP1, PRDM16, and PGC1a, thereby increasing mitochondrial biogenesis in mature adipocytes and effectively inducing brown adipogenesis. In this study, the biosynthesized PT-AuNS was used as a potential therapeutic candidate because it conferred a potent anti-lipogenic effect. As a result, it can be used in various scientific fields such as medicine and the environment.

Dracunculin Inhibits Adipogenesis in Human Bone Marrow-Derived Mesenchymal Stromal Cells by Activating AMPK and Wnt/β-Catenin Signaling

Increased bone marrow adiposity is widely observed in patients with obesity and osteoporosis and reported to have deleterious effects on bone formation. Dracunculin (DCC) is a coumarin isolated from Artemisia spp. but, until now, has not been studied for its bioactive potential except antitrypanosomal activity. In this context, current study has reported the anti-adipogenic effect of DCC in human bone marrow-derived mesenchymal stromal cells (hBM-MSCs). DCC dose-dependently inhibited the lipid accumulation and expression of adipogenic transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) in hBM-MSCs induced to undergo adipogenesis. To elucidate its action mechanism, the effect of DCC on Wnt/β-catenin and AMPK pathways was examined. Results showed that DCC treatment activated Wnt/β-catenin signaling pathway via AMPK evidenced by increased levels of AMPK phosphorylation and Wnt10b expression after DCC treatment. In addition, DCC treated adipo-induced hBM-MSCs exhibited significantly increased nuclear levels of β-catenin compared with diminished nuclear PPARγ levels. In conclusion, DCC was shown to be able to hinder adipogenesis by activating the β-catenin via AMPK, providing potential utilization of DCC as a nutraceutical against bone marrow adiposity.

Flavonoid Phloretin Inhibits Adipogenesis and Increases OPG Expression in Adipocytes Derived from Human Bone-Marrow Mesenchymal Stromal-Cells

Phloretin (a flavonoid abundant in apple), has antioxidant, anti-inflammatory, and glucose-transporter inhibitory properties. Thus, it has interesting pharmacological and nutraceutical potential. Bone-marrow mesenchymal stem cells (MSC) have high differentiation capacity, being essential for maintaining homeostasis and regenerative capacity in the organism. Yet, they preferentially differentiate into adipocytes instead of osteoblasts with aging. This has a negative impact on bone turnover, remodeling, and formation. We have evaluated the effects of phloretin on human adipogenesis, analyzing MSC induced to differentiate into adipocytes. Expression of adipogenic genes, as well as genes encoding OPG and RANKL (involved in osteoclastogenesis), protein synthesis, lipid-droplets formation, and apoptosis, were studied. Results showed that 10 and 20 µM phloretin inhibited adipogenesis. This effect was mediated by increasing beta-catenin, as well as increasing apoptosis in adipocytes, at late stages of differentiation. In addition, this chemical increased OPG gene expression and OPG/RANKL ratio in adipocytes. These results suggest that this flavonoid (including phloretin-rich foods) has interesting potential for clinical and regenerative-medicine applications. Thus, such chemicals could be used to counteract obesity and prevent bone-marrow adiposity. That is particularly useful to protect bone mass and treat diseases like osteoporosis, which is an epidemic worldwide.