Structure-activity relationships for saponins from Allium hirtifolium and Allium elburzense and their antispasmodic activity.
A phytochemical study of Allium hirtifolium Boiss flowers has led to the isolation of high amounts of six new furostanol and spirostanol saponins, named hirtifoliosides A1/A2 (1a/ 1b), B (2), C1/C2 ( 3a/ 3b), and D(4) along with three known spirostanol saponins, alliogenin 3- O-beta-D-glucopyranoside, gitogenin 3- O-beta-D-glucopyranosyl-(1-->4)- O-beta-D-glucopyranoside, and agapanthagenin 3- O-beta-D-glucopyranoside. High concentrations of the following known flavonol glycosides have been isolated from both flowers and bulbs: kaempferol 3- O-beta-D-rhamnopyranosyl-(1-->2)-glucopyranoside, kaempferol 3- O-beta-D-glucopyranosyl-(1-->4)-glucopyranoside, kaempferol 3-O-glucopyranoside, kaempferol 7-O-glucopyranoside. The isolated saponins along with the four saponins elburzensosides A1/A2 and C1/C2 and the sapogenin agapanthagenin, previously described from A. elburzense, have been subjected to biological assays for evaluating possible antispasmodic activity in the guinea-pig isolated ileum. The obtained results served as a basis for the establishment of structure-activity relationships within this class of antispasmodic agents. They highlight the positive effects of a hydroxyl group at position 5 and of a glucose unit at position 26 and demonstrate the detrimental effects of both a hydroxyl group at position 6 and of a glucose unit at position 3. Among the tested compounds, elburzensosides C1/C2 and agapanthagenin showed the highest activity in reducing induced contractions as measured by the reduction of histamine release by about 50 %. The observed effect therefore contributes to the explanation of the traditional use of onion and garlic in the treatment of disturbances of the gastrointestinal tract.
Barile
Elisa
E
DISTAAM, Università degli Studi del Molise, Campobasso, Italy.
Capasso
Raffaele
R
Izzo
Angelo A
AA
Lanzotti
Virginia
V
Sajjadi
S Ebrahim
SE
Zolfaghari
Behzad
B
D000490:Allium / Q000737:chemistry*; D000818:Animals; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D015394:Molecular Structure; D009119:Muscle Contraction / Q000187:drug effects; D010276:Parasympatholytics / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D010276:Parasympatholytics; D012503:Saponins