Phytochemical Composition and Anti-Motility Effects of Napoleonae imperialis Methanol Crude Leaf Extract and Fractions in Rats

Abstract

Background: Extracts from that Napoleonae imperialis leaves have traditionally been used to treat wounds and diarrhoea in south east Nigeria. Aim: The present study was carried out to evaluate following scientific principles, the phytochemical composition and anti-motility effect of leaf extract and fractions prepared from the plants in experimental rats. Methods: Crude extract was prepared from the plant’s leaves and was subjected to phytochemical and acute toxicity tests. Thereafter, the extract was fractionated using column and thin layer chromatographic techniques. Anti-motility effect of the crude extract and fractions was evaluated using 80 rats assigned to 16 groups of 5 rats each. While group 1 served as control and group 2 was treated with Loperamide (0.5 mg/kg), groups 3-16 were treated with specific dose levels of the crude extract or fraction before charcoal meal 30 minutes after treatments. The animals were sacrificed in a further 30 minutes to assess the extents of movement of the charcoal meal along the gastrointestinal tract. Results: Alkaloids (31.09 +0.44 mg/100 g) were the most abundant phytochemical identified in the crude extract and was followed by flavonoids (17.19± 0.90 mg/100 g). Others were saponins (9.61±0.12 mg/100 g), tannins, (3.23±0.06 mg/100 g), phenolics (8.83±0.41 mg/100 g), steroids (5.24±0.10 mg/100 g), terpenoids (2.58±0.11 mg/100 g) and cardiac glycosides (4.95±0.08 mg/100 g). Results of acute toxicity (LD50) test showed no mortality nor obvious signs of toxicity, even at an oral dose of 5000 mg/kg in rats. Results of the anti-motility studies showed that Napoleonae imperialis crude extract and fractions significantly inhibited charcoal meal transit in rat’s gastrointestinal tract with 500 mg/kg of the extract producing an inhibitory effect of 51.44±3.53%. A repeat of the test on chromatographic fractions of the extract showed that fraction 5 had the highest anti-motility effect having produced an inhibitory effect of 87.70±6.04% on intestinal motility. Conclusion: Our findings have shown that Napoleonae imperialis leaves contain pharmacologically active components with antidiarrhoeal activities and may be the reason for its antidiarrheoal application in traditional medicine. The observed effects of the extract may be due to its flavonoids and tannins contents and may be via the anticholinergic and osmotic pathway. Solvent combination for fraction 5 may be the most ideal for higher anti-motility effects. More work is required to further establish these findings.