Effects of noni fruit extract on intestinal contractility in rats

Noni (Morinda citrifolia, Rubiaceae) fruits have been wildly used for health benefits. They have been found effective in reducing blood cholesterol levels [1] and may be effective against breast cancer [2] and have antioxidant properties [3]. However, the effects of noni fruit extract on intestinal contractility have never been investigated. The aims of the study were to investigate the effects of noni fruit extract on intestinal contractility in male rats. We particularly examined the effects of the extract on contractions arising spontaneously and by acetylcholine stimulation and investigated the underlying mechanisms. Noni fruits were collected from local gardens and extracted using methanol. The extract was then analyzed by GC/MS. Rats were killed by asphyxiation with CO₂ and longitudinal duodenal smooth muscles isolated. Isometric force was measured and the effects of the extract studied. Several agents, previously reported to decrease contraction in other smooth muscles, were found in noni fruit extract. When the extract was applied to spontaneously duodenal contractions, it significantly decreased the contractions. Its effect was dose dependent. The half maximal effect of the extract was observed at the dose of 50mg/100ml (20–100mg/100ml). An elevation of extracellular Ca²⁺ concentration could not reverse the inhibitory effects of the extract. The extract (100mg/100ml) also inhibited the phasic, but not tonic components of acetylcholine-induced contractions. In conclusion, noni fruit extract has inhibitory effects on intestinal contractility. These may involve contractile machinery that regulates phasic components of contraction.

References: 1. Henley, E. et al. (2006) 46^th AHA Annual Conference.

2. Hornick, C.A. et al. (2003) Angiogenesis 6:143–9.

3. Wang, M.Y. & Su, C. (2001) Annals of the New York Academy of Sciences 952:161–8.