Antispasmodic and antioxidant activities of fractions and bioactive constituent davidigenin isolated from Mascarenhasia arborescens.
BACKGROUND
Mascarenhasia arborescens A. DC. (Apocynaceae) is used in traditional medicine in the North of Madagascar to treat intestinal disorders, intestinal spasms and diarrhoea.


OBJECTIVE
The main objective of this work was to evaluate the antispasmodic activity of the crude methanolic extract of Mascarenhasia arborescens and of its four partitions and to identify the effective compound responsible for this effect.


METHODS
Isolation and structure elucidation techniques were performed in order to identify the bioactive constituent of Mascarenhasia arborescens and HPLC analysis was used for its quantification. Total phenolic content (TPC) of crude extracts and partitions were determined using the Folin-Ciocalteu method. Crude methanolic extract, partitions and the bioactive compound were investigated for their spasmolytic activity on several isolated organs. Their antiradical activity was also investigated by the DPPH test.


RESULTS
Bioassay-guided fractionation using isolated guinea pig ileum pre-contracted with histamine 3x10(-6) M led to the isolation of davidigenin (DG), a dihydrochalcone, as the main active constituent from the most promising methylene chloride partition (McP). This partition was effective on isolated guinea pig ileum pre-contracted with 3x10(-6) M histamine, with a median effective concentration (EC(50)) of 41.19+/-3.74 microg/ml. The DG content of this partition was shown to be 26.5% by HPLC. DG induced a concentration-dependent relaxation of the histamine pre-contracted guinea pig ileum with an EC(50) of 8.04+/-0.81 microg/ml and a concentration-dependent relaxation of the acetylcholine pre-contracted rat duodenum with an EC(50) of 9.35+/-0.30 microg/ml. It inhibited in a non-competitive manner histamine-induced isolated ileum contraction and the acetylcholine-induced isolated duodenum contraction. Moreover, DG does not have any antiradical activity.


CONCLUSIONS
We demonstrated for the first time antispasmodic and antioxidant effects of Mascarenhasia arborescens. This study supports its use in traditional medicine. Furthermore, we highlighted the crucial role of davidigenin in the antispasmodic activity of this plant.
Desire
Odile
O
Laboratoire de Chimie, Faculté des Sciences, Université Nord d'Antsiranana, Antsiranana 201, Madagascar.
Rivière
Céline
C
Razafindrazaka
René
R
Goossens
Laurence
L
Moreau
Stéphane
S
Guillon
Jean
J
Uverg-Ratsimamanga
Suzanne
S
Andriamadio
Pascal
P
Moore
Nicholas
N
Randriantsoa
Adolphe
A
Raharisololalao
Amélie
A
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D029062:Apocynaceae; D001713:Biphenyl Compounds / Q000737:chemistry; D002599:Chalcone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D047188:Chalcones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000187:drug effects; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D015394:Molecular Structure; D009126:Muscle Relaxation / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology*; D010636:Phenols / Q000302:isolation & purification; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
D000975:Antioxidants; D001713:Biphenyl Compounds; D047188:Chalcones; D010276:Parasympatholytics; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; C553221:davidigenin; D002599:Chalcone; C004931:1,1-diphenyl-2-picrylhydrazyl