Effects of coconut oil on lipid accumulation in 3T3-L1 cells

 

Consumption of medium-chain triglyceride as coconut (Cocos nucifera L., Arecaceae) oil was shown to reduce fat deposition both in human and animals [1, 2]. Since coconut oil (CO) consisted of 47% lauric acid (decanoate, LaA), mechanism of CO in comparison to LaA on fat deposition was verified in 3T3-L1 cells. Cell viability was assessed by tetrazolium/formazan assay. Density of Oil Red O stained material (OROSM) was observed. Both assays were expressed as % of control (1% ethanol and 1% dimethyl sulfoxide instead of CO and LaA, respectively). Relative gene expression of adipogenic nuclear factors, peroxisome proliferator activated receptor gamma (PPARγ) and CCAAT-enhancer-binding protein alpha (C/EBPα) were assessed by real-time quantitative PCR. The results showed that % cell viability was significantly (p < 0.05) lower than control when cells were treated with the highest dose of LaA (100 µg/mL) for 8 days indicating the potential toxicity. Both CO and LaA were significantly reduced mean ± SEM of the % OROSM density at day 8 (67.17 ± 4.40, 69.27 ± 3.89 and 74.66 ± 5.02 when cells were treated with 670, 1340 and 2012 µg CO/mL, respectively; 59.37 ± 3.22 and 65.96 ± 6.27 when cells were treated with 20 and 40 µg LaA/mL, respectively). Relative gene expressions were significantly reduced by both CO and LaA at day 8 (PPARγ: 0.54 ± 0.02 and 0.62 ± 0.02; C/EBPα: 0.37 ± 0.04 and 0.49 ± 0.09 when cells were treated with 670 and 1340 µg CO/mL or PPARγ: 0.38 ± 0.03 and 0.55 ± 0.03; C/EBPα: 0.49 ± 0.01 and 0.37 ± 0.03 when cells were treated with 20 and 40 µg LaA/mL, respectively). In conclusion, the medium-chain fatty acid both in CO and as LaA were able to reduce fat accumulation in adipocyte during its differentiation. It is worth, then, to study its effect on the ectopic fat deposition as well.

Acknowledgements: Two institutes were acknowledged for their funding: Research Unit, Faculty of Medicine, Thammasat University; Higher Education research Promotion and National Research Project of Thailand.

Keywords: Lauric acid, OROSM, PPARγ, C/EBPα.

References:

[1] Assunção ML, Ferreira HS, dos Santos AF. Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity. Lipids 2009; 44: 593 – 601

[2] Portillo MP, Serra F, Simon E, del Barrio AS, Palou A. Energy restriction with high-fat diet enriched with coconut oil gives higher UCP1 and lower white fat in rats. Int J Obesity 1998; 22: 974 – 979