Anti-inflammatory activity of extracts and a saponin isolated from Melilotus elegans.
The crude methanol extract of Melilotus elegans Ser. (Fabaceae), a plant widely used in Ethiopian traditional medicine for the treatment of asthma, haemorrhoid and lacerated wounds showed a significant anti-inflammatory activity against carrageenin-induced rat paw oedema. At a dose corresponding to 333.3 mg per kg body weight of dry plant material, the methanol extract displayed a strong inhibitory effect that was comparable to the inhibitory effect of 1 mg/kg of indomethacin in the same test system. Bioassay guided fractionation of the alcoholic extract led to the isolation of an oleanene-type triterpene saponin identified as azukisaponin V (1) ((3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl(1 --> 2)-beta-D-glucuronopyranosyl]-soyasapogenol B). The structure of the compound was identified by using MS and extensive one- and two-dimensional NMR experiments (1H, 13C, COSY, HMQC, HMBC and NOESY). One hour after injection of carrageenin, inhibition of oedema exerted by 1 was approximately ten times higher than that of indomethacin on a molar basis.
Asres
K
K
Department of Pharmacognosy, School of Pharmacy, Addis Ababa University, Addis Ababa, Ethiopia.
Gibbons
S
S
Hana
E
E
Bucar
F
F
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D002240:Carbohydrate Sequence; D002351:Carrageenan; D002851:Chromatography, High Pressure Liquid; D004487:Edema / Q000139:chemically induced / Q000517:prevention & control; D005002:Ethiopia; D006868:Hydrolysis; D016488:Medicine, African Traditional; D029903:Melilotus / Q000737:chemistry*; D008969:Molecular Sequence Data; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D012503:Saponins / Q000302:isolation & purification* / Q000494:pharmacology*
D000893:Anti-Inflammatory Agents; D010936:Plant Extracts; D012503:Saponins; C500757:azukisaponin V; D002351:Carrageenan