Effect of Morinda citrifolia Linn. Leaf Extracts on in vitro Lipase Activity

Leaves of the Morinda citrifolia Linn. (Rubiaceae) have been used as folklore medicinal plants for various pharmacological activities including abdominal disorders and health benefits. They have been cooked with curries containing coconut milk and might help reduce fat absorption. This study aims to investigate the effect of M citrifolia leaf extracts on lipase activity. Four extracts were prepared by maceration of fresh leaves with ethanol (FMC_CE), boiling in water (FMC_HW), and freeze-drying fresh leaves juice (FMC_CF) whereas the dried-leaves were extracted to make herbal tea (DMC_TW). The activity of the bovine milk lipoprotein lipase (LPL) and porcine pancreatic lipase (PPL) were assayed using simple titration and spectrophotometric methods. Orlistat and green tea extract (GTE) were used as positive controls. HPLC analysis revealed that rutin was the major phytocompound present in all extracts, whereas quercetin and kaempferol were detected in small amounts. Titration revealed that all extracts exhibited potent anti-PPL activity. DMC_TW and FMC_HW extracts exhibited the maximum enzymatic inhibition (75%) which was higher than orlistat (68.29%) but lower than GTE (96.32%). Only FMC_CF and DMC_TW extracts presented moderate inhibition on LPL activity. Spectrophotometry based assays demonstrated only the DMC_TW extract had mild inhibition on PPL activity whereas orlistat exhibited moderate anti-PPL activity (66.20%) and mild activation of LPL activity. Rutin might not be predominantly accountable for anti-lipase activity and kaempferol may responsible for anti-PPL activity. Our investigations suggested that M citrifolia extract had anti-lipase activity. FMC_CF and DMC_TW extracts, which were effective for both anti-PPL and anti-LPL activity, could be an effective anti-obesity agent candidate to manage body weight.