Glycobiology Advance Access originally published online on September 22, 2008
Glycobiology 2008 18(12):1074-1084; doi:10.1093/glycob/cwn090
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Pectic polysaccharides from Biophytum petersianum Klotzsch, and their activation of macrophages and dendritic cells
2 Department of Pharmaceutical Chemistry, School of Pharmacy, P.O. Box 1068, Blindern, N-0316 Oslo
3 Institute of Immunology, Rikshospitalet-Radiumhospitalet Medical Centre, University of Oslo, N-0027 Oslo, Norway
4 National Centre for Macromolecular Hydrodynamics, School of Biosciences, Sutton Bonington Campus, Sutton Bonington, LE12 5RD
5 Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, NG7 2RD, UK
6 Department of Anatomy, Institute of Basic Medical Science, University of Oslo, P.O. Box 1105, Blindern, N-0317 Oslo
7 The Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
8 Department of Traditional Medicine, B.P. 1746, Bamako, Mali
9 Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
1 To whom correspondence should be addressed: Tel: +47-23-07-30-12; Fax: +47-23-07-35-10; e-mail: marit.inngjerdingen{at}rr-research.no
Received on May 2, 2008; revised on August 14, 2008; accepted on September 16, 2008
The Malian medicinal plant Biophytum petersianum Klotzsch (Oxalidaceae) is used as a treatment against various types of illnesses related to the immune system, such as joint pains, inflammations, fever, malaria, and wounds. A pectic polysaccharide obtained from a hot water extract of the aerial parts of B. petersianum has previously been reported to consist of arabinogalactans types I and II (AG-I and AG-II), probably linked to a rhamnogalacturonan backbone. We describe here further structural characteristics of the main polysaccharide fraction (BP1002) and fractions obtained by enzymatic degradations using endo-
-D-(1
4)-polygalacturonase (BP1002-I to IV). The results indicate that in addition to previously reported structures, rhamnogalacturan type II and xylogalacturonan areas appear to be present in the pectic polymer isolated from the plant. Atomic force microscopy confirmed the presence of branched structures, as well as a polydisperse nature. We further tested whether the BP1002 main fraction or the enzymatically degraded products could induce immunomodulating activity through stimulation of subsets of leukocytes. We found that macrophages and dendritic cells were activated by BP1002 fractions, while there was little response of T cells, B cells, and NK cells. The enzymatic treatment of the BP1002 main fraction gave important information on the structure–activity relations. It seems that the presence of rhamnogalacturonan type I is important for the bioactivity, as the bioactivity decreases with the decreased amounts of rhamnose, galactose, and arabinose. The demonstration of bioactivity by the plant extracts might indicate the mechanisms behind the traditional medical use of the plant.
Key words: Biophytum petersianum Klotzsch / dendritic cells / macrophages / pectin / rhamnogalacturonan