ABSTRACT
The traditional usage of noni fruit did not include any claims for lowering cholesterol levels in humans. However, recently a commercial noni fruit juice blend, Tahitian Noni Original® Bioactive (TNOB),was shown in a double blind, and placebo control clinical trial to significantly lower cholesterol levels in current smokers. But, its effect on cholesterol levels of nonsmokers with normal cholesterol levels, and its mechanisms of action, has not been fully elucidated. The current study evaluates the effects of various noni preparations (TNOB, NFJC (noni fruit juice concentrates), NFJME (noni fruit juice methanol extract)) on HMG-CoA Reductase and ACAThepatic/intestine enzymes in vitro. Further, TNOB was evaluated for its potential cholesterol-lowering effects in 10 non-smoking subjects with normal to mild cholesterol levels. TNOB and NFJC both inhibited HMG-CoA Reductase, and ACAT enzymes concentration-dependently in-vitro, and NFJC has a <1.0 mg/mL IC50 on HMG-CoA Reductase enzymes. NFJME, the active fraction from the noni fruit juice, in 100μg/mL, inhibited HMG-CoA reductase by 81%. TNOB showed a trend towards lowering total cholesterol and LDL levels while increasing HDL levels in nonsmokers. Noni fruit juice has the potential to lower cholesterol levels in nonsmokers perhaps via its inhibitory effects on HMGCoA reductase and ACAT enzymes as its possible mechanism of action. However, a larger clinical trial is warranted to assess its effects in non-smokers with higher cholesterol levels above 220 mg/dL to evaluate the nature of this cholesterol-lowering trend seen in this pilot study.
ABSTRACT
The aim of the present investigation was to evaluate whether extracts and preparations of noni fruit and leaf, a Polynesian traditional herbal medicine, inhibit MMP, COX-2 and Cat-G enzymes in vitro, as its mechanism of action for healing sun-burn known as fohia in Tonga. Noni leaf ethanolic extract (NLEE) inhibited MMP-1, -2, -3, and -9 enzymes concentration dependently with 0.517, 0.234, 0.184, and 0.302 mg/mL IC50, respectively. Noni fruit juice concentrates (NFJC) in 1 and 5 mg/mL concentrations, inhibited MMP-12 enzymes by 102, and 99%, respectively. NFJC and NLEE inhibited Cat-G enzymes concentration-dependently with 0.125, <0.1, and 0.41 mg/mL IC50, respectively. Noni fruit juice fractions 4 and 6 inhibited COX-2 and Cat-G enzymes by 85 and 89%, and 89 and 78%, respectively. Additionally, the noni fruit puree and noni leaf has 1.91 mg/g and 5.77 mg/g of ursolic acid, respectively. NFJC, and NLEE inhibitory effects on MMP, COX-2 and Cat-G enzymes might help explain the traditional usage of the noni fruits and leaves for treatment of fohia skin as alluded to by Polynesian traditional healers. These results warrant further studies into the skin health benefits of noni fruit and leaf to further assess their efficacies and dosages in human subjects suffering from photoaging.