Transcriptome of primary adipocytes from obese women in response to a novel hydroxycitric acid-based dietary supplement.

BACKGROUND: Obesity is a global public health problem. Traditional herbal medicines may have some potential in managing obesity. The dried fruit rind of Garcinia cambogia, also known as Malabar tamarind, is a unique source of (-)-hydroxycitric acid (HCA), which exhibits a distinct sour taste and has been safely used for centuries in Southeastern Asia to make meals more filling. Recently it has been demonstrated that when taken orally, a novel, highly soluble calcium/potassium salt of HCA (HCA-SX) is safe and bioavailable in the human plasma. Although HCA-SX seems to be conditionally effective in weight management in experimental animals and in humans, its mechanism of action remains unclear.

METHODS: In this study, subcutaneous preadipocytes collected from obese women with body mass index>25 kg/m2 were differentiated to adipocytes for 2 weeks in culture. The effects of low-dose HCA-SX on lipid metabolism and on the adipocyte transcriptome were tested. HCA-SX augmented isoproterenol- and 3-isobutyryl-1-methylxanthine-induced lipolysis. Using oil red O, the production of lipid storage droplets by the cultured mature human adipocytes was visualized and enumerated.

RESULTS: HCA-SX caused droplet dispersion facilitating lipase action on the lipids. HCA-SX markedly induced leptin expression in the adipocytes. In the microarray analyses, a total of 54,676 probe sets were screened. HCA-SX resulted in significant down-regulation of 348, and induction of 366 fat- and obesity-related genes. HCA-SX induced transactivation of hypoxia inducible factor (HIF), a novel approach in the management of obesity.

CONCLUSION: Taken together, the net effects support the antilipolytic and antiadipogenic effects of HCA-SX. Further human studies are warranted.