The polymerization of acrylic acid (AA) was performed under 60 Co irradiation in the presence of dibenzyl trithiocarbonate at room temperature, and welldefined poly(acrylic acid) (PAA) with a low polydispersity index was successfully prepared. The gel permeation chromatographic and 1 H NMR data showed that this polymerization displays living free-radical polymerization characteristics: a narrow molecular weight distribution (M w /M n ϭ 1.07-1.22), controlled molecular weight, and constant chain-radical concentration during the polymerization. Using PAAOSO C(AS)OSOPAA as an initiator, the extension reaction of PAA with fresh AA was carried out under 60 Co irradiation, and the results indicated that this extension polymerization displayed controlled polymerization behavior.

6‐Amino‐6‐deoxy‐(1→3)‐β‐D‐curdlan sulfate was synthesized in three steps. First, curdlan was azidized by lithium azide (LiN3) and carbon tetrabromide (CBr4) with triphenylphosphine (Ph3P) in dimethylformamide (DMF). Second, the azido group was reduced to an amino group with sodium borohydride (NaBH4) in dimethyl sulfoxide (DMSO) to afford 6‐amino‐6‐deoxy‐(1→3)‐β‐D‐curdlan. Third, sulfation of the amino‐group‐containing curdlan with a sulfur trioxide‐pyridine complex produced a 6‐amino‐6‐deoxy‐(1→3)‐β‐D‐curdlan sufate exhibiting high anti‐HIV (human immunodeficiency virus) activity (EC50 = 0.912 µg/ml) and low cytotoxicity (CC50 = 2512 µg/ml). Copyright © 2003 John Wiley & Sons, Ltd.

A bioassay-guided isolation of an ethanol extract of the fruit of Piper longum L. yielded piperlonguminine, piperine and pipernonaline, as the main antihyperlipidemic constituents. They exhibit appreciable antihyperlipidemic activity in vivo, which is comparable to that of the commercial antihyperlipidemic drug, simvastatin.

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Sulfated astragalus polysaccharide (sulfated astragalan, SA) was prepared by chemical modification of astragalus polysaccharide abstracted from an astragalus menbranceus used as a Mongolia herbal medicine. Anti‐HIV activity of SA was assayed in vitro and the results indicated that the SA showing high anti‐HIV activity and lower cytotoxity. Sulfation of astragalan was carried out by using sulfur trioxide‐pyridine complex in a mixture of dimethylsulfoxide (DMSO) to give sulfated astragalan with degree of substitution (DS) of 1.14–1.20 and a number average molecular weight (Mn) of 1.27–1.46 × 104. Copyright © 2003 John Wiley & Sons, Ltd.

A simple and convenient method was established for simultaneous quantitative determination of piperine and piperlonguminine in dried fruits of Piper longum and allied plants. The average content of piperine in P. longum (18.26 mg/g, range 12.05-33.23 mg/g) was about one half that of P. nigrum (40.09 mg/g, range 29.57-54.23 mg/g), but the content of piperlonguminine in P. longum was in the range of 0.42-1.82 mg/g, and the average content of piperlonguminne (0.91 mg/g) was about seven times higher than that in P. nigrum (0.13 mg/g). A sample of P. longum from Vietnam and a sample of P. retrofractum collected in Ishigaki, Japan, showed high contents of piperine and piperlonguminine. On the other hand, a sample of P. betle collected in Taiwan showed low content of piperine, and piperlonguminine was not detected.

A novel cellobiose-polylysine dendrimer with reducing sugar terminals was synthesized in which the reactive reducing end of a disaccharide cellobiose was directing outward. Hexa-O-benzyl-4Ј-(1-carboxyethyl)-cellobioside (HBCEC) was synthesized through the reaction of a 4Ј-hydroxyl group of benzyl hexa-O-benzyl-cellobioside with methyl 2-chloropropionate, followed by the removal of the methyl ester group. HBCEC was reacted with polylysine dendrimer generation 3 (G3) to produce benzylated cellobiose-polylysine dendrimer G3. After debenzylation, a cellobiose-polylysine dendrimer G3 was obtained in which the reducing end of the cellobiose was the terminal group of the dendrimer. For the preparation of a dendrimer-type acquired immunodeficiency syndrome vaccine, the cellobiose-polylysine dendrimer was reacted with a tripeptide (glycyl-prolyl-leucine) and a cyclic oligopeptide from the human immunodeficiency virus by reductive amination; this produced a tripeptide-bound cellobiose-polylysine dendrimer and an insoluble compound, respectively. The structure analysis was carried out with NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. 13 (36 mg, 8.7 mol) and Gly-Pro-Leu (20 mg, 70 mol) were dissolved in a 0.1 M borate buffer (pH 9.0, 5 mL). After BH 3 /pyridine (80 mL, 800 mmol) was added, the solution was stirred at 37°C for 5 days. The resulting compound was purified by dialysis and then freeze-dried from water to produce Gly-Pro-Leu-cellobiose-polylysine dendrimer G3 (14; 32 mg) as a white powder. Preparation of Cyclic V3 Loop-Cellobiose-Polylysine Dendrimer G3The cyclic V3 loop (10 mg, 3 mmol) was suspended in 5 mL of a 0.1 M borate buffer (pH 9.0). After cellobiose-polylysine dendrimer (12 mg, 3 mmol) and BH 3 /pyridine (12 mL, 118 mmol) were added, the suspension was stirred at 37°C for 5 days. OLIGOSACCHARIDE-POLYLYSINE DENDRIMER

Piper longum L. is a well-known traditional antihyperlipidemic medicine in China, containing medicinal constituents of piperine, pipernonaline and piperlonguminine in its fruit. However, the antitumor properties of these constituents have not yet been studied. We found that potassium piperate (GBK), a derivative of piperine, inhibited proliferation of cancer cells. GBK selectively inhibited the G1-S-phase transition in breast cancer cells and the G1 arrest was correlated with induction of p27 expression, which is an inhibitor for cyclin-dependent kinases, and inhibition of cyclin A, cyclin E and cyclin B expression. Moreover, GBK treatment led to a downregulation of the mini-chromosome maintenance protein expression and induction of mitochondrial-dependent cell apoptosis in breast cancer cells. Our results also suggested that GBK might also inhibit cancer cell proliferation through epigenetic signaling pathways. A synergistic effect in inhibition of cancer cell proliferation was found when GBK was combined with chemotherapy medicines etoposide phosphate or cisplatin at middle or low doses in vitro. These results show that GBK is a novel potential anti-breast cancer drug that inhibits cell proliferation and promotes cell apoptosis.