Antiviral and anti-proliferative glycoproteins from the rhizome of Smilax glabra Roxb (Liliaceae).
The glycoproteins possessing antiviral and anti-proliferative activities were isolated from the Chinese medicinal herb Smilax glabra (known as tufuling), by extraction with 0.2 M NaCl, ammonium sulfate precipitation, fetuin-agarose affinity chromatography and gel filtration. The molecular mass of the fetuin-binding glycoprotein (designated SGPF2) was estimated to be about 58 kDa, with a major protein subunit of 26 kDa. The non-fetuin binding glycoproteins (in the unadsorbed fraction) were further separated into 5 different subfractions (SGPF1a-SGPF1e) with anion-exchange chromatography, all of which also contained the major band at 26 kDa. All the isolated proteins of 26 kDa had similar N-terminal amino acid sequences, implying that they were probably the isoforms originated putatively from a multigene family with different binding affinity and ionic strength. The glycoprotein SGPF2 exhibited antiviral activity against respiratory syncytial virus (RSV) with a median inhibitory concentration (IC(50)) of 62.5 microg/ml and Herpes simplex virus type 1 (HSV-1) had an IC(50) of 31.3 microg/ml. The glycoprotein potencies for antiviral activity appeared to depend on the molecules' binding affinity for fetuin, that is, the fetuin-binding protein was more potent than the non-fetuin binding proteins. Further examination revealed that these glycoproteins also had the ability to suppress the proliferation of MCF-7 cells. The possible mechanism of anti-proliferative action as analyzed by DNA flow cytometry indicated that they could induce apoptosis mediated via sub-G(1) phase of the MCF-7 cell cycle. For example, there was an increase by 75.8% of the control level of apoptosis after incubation with SGPF1a.
Ooi
Linda S M
LS
Department of Biology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Wong
Elaine Y L
EY
Chiu
Lawrence C M
LC
Sun
Samuel S M
SS
Ooi
Vincent E C
VE
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D005260:Female; D006023:Glycoproteins / Q000302:isolation & purification / Q000494:pharmacology*; D000882:Haplorhini; D006801:Humans; D010936:Plant Extracts / Q000494:pharmacology*; D010940:Plant Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots; D032281:Smilax; D014709:Vero Cells / Q000187:drug effects
D000998:Antiviral Agents; D006023:Glycoproteins; D010936:Plant Extracts; D010940:Plant Proteins