Analgesic and antioxidant activity of mangiferin and its derivatives: the structure activity relationship.
Mangiferin, 2-beta-D-glucopyranosyl-1,3,6,7-tetrahydroxy-9H-xanthen-9-one, obtained directly from methanolic extracts of Bombax ceiba leaves in substantial amounts demonstrated strong antioxidant activity (EC(50) 5.8+/-0.96 mug/ml or 13.74 muM) using DPPH assay comparable to rutin, commonly used as antioxidant for medical purposes. The acetyl and cinnamoyl derivatives were found to be less active than mangiferin whereas, methyl and 3,6,7-trimethylether tetraacetate derivatives were inactive implying that for antioxidant activity, free hydroxyl groups and catechol moiety are essential. Moreover, mangiferin showed hepatoprotective activity against carbon tetrachloride induced liver injury further supporting the free radical scavenging property in the in vivo system. Additionally, plant extracts and mangiferin failed to exhibit acute anti-inflammatory activity whereas, it displayed significant analgesic effect in acetic acid-induced writhing and hot plate tests in mice. Using naloxone, it was revealed that plant extracts induced analgesia was independent of opioid receptor, whereas, mangiferin demonstrated significant interaction with it at peripheral site with a slight contribution at the neuronal level.
Dar
Ahsana
A
H.E.J. Research Institute of Chemistry, University of Karachi, Pakistan. dar@khi.comsats.net.pk
Faizi
Shaheen
S
Naqvi
Sabira
S
Roome
Talat
T
Zikr-ur-Rehman
Sadia
S
Ali
Muhammad
M
Firdous
Sadiqa
S
Moin
Syed Tarique
ST
D000700:Analgesics / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D035163:Bombax / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D015394:Molecular Structure; D009020:Morphine / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D013329:Structure-Activity Relationship; D044004:Xanthones / Q000737:chemistry / Q000494:pharmacology*
D000700:Analgesics; D016166:Free Radical Scavengers; D010936:Plant Extracts; D044004:Xanthones; C013592:mangiferin; D009020:Morphine; D001241:Aspirin