Structure and spasmolytic activity of eucalyptanoic acid from Eucalyptus camaldulensis var. obtusa and synthesis of its active derivative from oleanolic acid.
A new triterpenoid acid named eucalyptanoic acid (1) has been isolated from the fresh uncrushed leaves of Eucalyptus camaldulensis var. obtusa along with two known constituents, beta-sitosterol (2) and betulinic acid (3). The structure of 1 has been established as 3beta-hydroxyolean-9(11),12-dien-28-oic acid through spectral studies including 1D and 2D NMR. 1 and its acetyl (1a) and acetylmethyl (1b) derivatives were tested for spasmolytic activity. 1b was found to be the most active spasmolytic, mediated through blockade of calcium influx at 1 mg/mL. In the present study 1b was also prepared starting from oleanolic acid (4). Acetylation of 4 gave 4a, which on methylation afforded 4b. Reaction of 4b with N-bromosuccinimide (NBS) furnished 1b. Hence 4 may be regarded as the biogenetic precursor of 1. Compounds 4 and 4a were found inactive at 1 mg/mL, while 4b was moderately active in showing spasmolytic activity.
Begum
Sabira
S
H. E. J. Research Institute of Chemistry, University of Karachi, Karachi-75270, Pakistan. sabira@khi.comsats.net.pk
Sultana
Ishrat
I
Siddiqui
Bina S
BS
Shaheen
Farhana
F
Gilani
Anwar H
AH
D000107:Acetylation; D000818:Animals; D002855:Chromatography, Thin Layer; D005052:Eucalyptus / Q000737:chemistry*; D007583:Jejunum / Q000187:drug effects; D008745:Methylation; D015394:Molecular Structure; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D019906:Nuclear Magnetic Resonance, Biomolecular; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology; D010154:Pakistan; D010276:Parasympatholytics / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
D010276:Parasympatholytics; D014315:Triterpenes; C473446:eucalyptanoic acid; D009828:Oleanolic Acid