Kaempferol rhamnosides from Bryophyllum pinnatum, a medicinal plant used against infectious diseases and as analgesic in Mbouda, Cameroon

An ethnobotanical survey was made on plants used in the treatment of infectious diseases in Mbouda subdivision, Cameroon. According to our survey, one of the most important medicinal plants in that area is Bryophyllum pinnatum (Lank.) Oken (Crassulaceae), a succulent plant native to Africa. B. pinnatum (leaves or whole plant) was found to be well known and was used against blennorrhoea, syphilis, jaundice, candidiasis and for the treatment of others ailments such as dysmenorrhoea, external ulcers, burns, convulsions and as analgesic. In order to identify the biologically active compounds of the plant and to confirm or infirm its ethnopharmacological claims, phytochemical study of ethyl acetate extract of the whole plant was carried out. As a result of this kaempferol rhamnosides, kaempferol 3,7-O-bis-α-L-rhamnopyranoside (kaempferitrin) [1], kaempferol 3-O-α-L-(3-acetyl)rhamnoside-7-O-α-L-rhamnopyranoside [2], kaempferol 3-O-α-L-rhamnoside (afzelin) [1] and kaempferol 7-O-α-L-rhamnoside (α-rhamnoisorobin) [1] were isolated and identified by extensive NMR and MS studies. All compounds were described for the first time in this species. These isolates are reported in other plant species to possess antioxidant, antinociceptive and anti-inflammatory activities [3, 4], therefore the kaempferol rhamnosides of B. pinnatum may account for the medicinal use of the plant against pain and inflammatory disorders.

Acknowledgements: AUF (Agence Universitaire de la Francophonie)

References: 1. Nakano, A. et al. (1983) Phytochemistry 22:2831–2833.

2. Pérez-Castorena, A-L. et al. (1997) Phytochemistry 46:297–1299.

3. De Melo, G.O. et al. (2009)J Ethnopharmacol 124:228–232.

4. Fang, S.H. et al. (2005) Bioorg Med Chem 13:2381–2388.