In vitro antispasmodic effects of Mallotus oppositifolium leaves extracts
Authors:   Animal Physiology Laboratory, Department of Biology and Animal Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon., Zintchem Roger , Noubissi Paul Aimé ,   Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon., Archange Fokam Tagne Michel ,   Department of Biological Science, Faculty of Science, University of Ngaoundéré, Ngaoundéré, Cameroon., Njiaza Joseph ,   Animal Physiology Laboratory, Department of Biology and Animal Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon., Fankem Gaétan Olivier ,   Animal Physiology Laboratory, Department of Biology and Animal Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon., Mukam Joseph Ngakou ,   Animal Physiology Laboratory, Department of Biology and Animal Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon., Fondjo Foyet Angèle ,   Department of Applied Sciences for Health, Higher Institute of Applied Sciences, University Institute of Gulf of Guinea, Douala, Cameroon., Bernard Bidias Claude ,   VIPOD, Medical Research Departement, Yaoundé Cameroon., Fokunang Charles ,   Department of Pharmacotoxicology and Pharmacokinetics, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon., Kamgang René ,   Laboratory of Endocrinology and Radioisotopes, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaoundé, Cameroon.
Published: August 2022

Mallotus oppositifolium is a plant traditionally used in many African countries to treat diarrhea and other gastrointestinal tract disorders. This study was undertaken to evaluate in vitro antispasmodic effects of decoction, hexane and methanolic leaves extracts of this plant. Antispasmodic activities of Mallotus oppositifolium leaves decoction, hexane and methanolic extracts were assessed on spontaneous contractions, on acetylcholine or potassium chloride (KCl) induced contractions of isolated rat duodenum strips. Mallotus oppositifolium decoction, hexane or methanolic extracts increasing cumulative concentrations relaxed duodenum strips and at 1 mg/mL, they respectively decreased contraction amplitudes by 77.84 ± 2.25, 55.81 ± 2.14, and 51.67 ± 0.95% compared to the initial values. Decoction, hexane, and methanolic extracts decreased contraction tensions respectively from 3.00 to 2.5 gF, 3.40 to 2.80 gF and from 3.10 to 2.50 gF. At 0.25 mg/mL, they significantly (p <0.05) decreased contraction tension. Emax were 186.89 ± 34.05, 116.30 ± 10.92 and 91.57 ± 4.70% respectively with decoction, methanolic, and hexane extracts with EC50 of 0.610 ± 0.184; 0.146 ± 0.011 and 0.237 ± 0.105 mg/mL (p <0.05). Acetylcholine increased contraction amplitudes. Cumulative administration of Mallotus oppositifolium decoction at 0.05 to 2.00 mg/mL significantly (p <0.05) decreased tension, from 4.00 to 2.60 g.F. At these concentrations, tension variation was concentration-dependent, it increased from 13.39 ± 1.72 to 77.59 ± 1.10%. EC50 and Emax were respectively 1.311 ± 0.340 mg/mL and 99.29 ± 24.80%. KCl produced only little variations of contractions amplitude. Emax was 0.65%. Cumulative administration of Mallotus oppositifolium decoction from 0.05 to 2.00 mg/mL significantly (p <0.05) decreased KCl induced contraction tension, from 3.70 to 2.30 gF (p <0.05). Emax was 133.30 ± 34.29% and EC50 = 2.140 ± 0.231 mg/mL. The antispasmodic effects of Mallotus oppositifolium extracts obtained in this study could therefore justify its traditional use against gastrointestinal tract ailments. Keywords: mallotus oppositifolium; acetylcholine; potassium chloride; antispasmodic effects; gastrointestinal tract disorders.