A traditional process used by farmers in Chad consists in soaking slices of taro (Colocasia esculenta L. SCHOTT) in tamarind infusion, or in corn solution or in water over a 24-hour period to reduce the acridity of taro and facilitate cooking. The aim of this study was to assess the effect of traditional soaking on the in vitro digestibility of taro flour using or not using an α-amylase enzyme. The digestion without the enzyme has shown that the soaking processes improve the digestibility of taro flour (from 39.30% for the control sample to 75.11% (after tamarind infusion) and 78.67% (treatment with water) after 24 hours of soaking). Soaking over a 6-hour period and preferentially in tamarind infusion or in corn solution obtains highly digestible flour (around 95% of digestibility rate after 3 hours of enzymatic digestion).

Constipation is a condition in which a person or animal has difficulty in eliminating solid waste from the body and the faeces are hard and dry. It is mainly characterized by a difficulty in defecation. The aim of the study is to assess the laxative effect of some plants such as Adansonia digitata, Ziziphus mauritiana and Psidium guayava traditionally used in Chad to treat the problems of constipation. The Microdynamometer method (Biomecatronics) is used to carry out this study. The outcomes show that the extracts' leaves of Psidium guayava and barks of Ziziphus mauritiana did not lead a significant contraction of duodenum of rabbit until a maximum concentration of 1000 µg, but the extracts' leaves of Adansonia digitata had a significant effect (P < 0.05) on the intestinal motility of rabbit. This effect of the extract of Adansonia digitata varies with the increase of its concentration (dose dependent) with a maximum of 500 µg and the minimal effect is inferior to 10 µg. On the other hand, the extract of Adansonia digitata has a musculotrope effect because the results have shown that inhibitive molecules such as the atropine and the naloxone do not have to inhibit the action of Adansonia digitata on the intestinal motility of rabbit. Thus, the extract of this plant would reduce significantly the time of intestinal transit and it will be an important laxative drug candidate as described traditionally in Chad.