Biomedical subjects

Yuan Jiang Pan

Publications and source records attributed to Yuan Jiang Pan.

6 recordsLinked to original sources

PubMed2006

Synthesis and cytotoxicity of racemic isodeoxypodophyllotoxin analogues with isoprene-derived side chains.

A series of isodeoxypodophyllotoxin (5) analogues, 26-38, with various isoprene-derived side chains at the E-ring were designed and synthesized. For comparison, compound 39, with a benzyloxy group on the E-ring, and six D-ring opened analogues, 40-45, were also prepared. All the synthetic compounds were evaluated for their cytotoxic activities in vitro against seven cultured human tumor cell lines. Compounds 27, 43, and 44 were more cytotoxic than etoposide on BEL-7404, A549, and HL-60 cell lines, respectively. However, none of the synthetic isodeoxypodophyllotoxins were more cytotoxic than podophyllotoxin (1).

Antineoplastic Agents, Phytogenic↗

PubMed2005

The nisin-controlled gene expression system: construction, application and improvements.

Lactic acid bacteria are widely used in industrial fermentation. The potential use of these bacteria as homologous and heterologous protein expression hosts has been investigated extensively. The NIsin-Controlled gene Expression system (the NICE system) is an efficient and promising gene expression system based on the autoregulation mechanism of nisin biosynthesis in the Lactococcus lactis. In the NICE system, the membrane-located histidine kinase NisK senses the inducing signal nisin and autophosphorylates, then transfers phosphorous group to intracellular response regulator protein NisR which activates nisA promoter to express the downstream gene(s). The NICE system allows regulated overproduction of a variety of interest proteins by several Gram-positive bacteria, especially L. lactis. The essential elements for system construction, its application for expression of some biotechnologically important proteins and further improvements of this system are discussed.

Gene Expression↗

PubMed2004

3beta,6beta-dihydroxyolean-12-en-27-oic acid: a cytotoxic and apoptosis-inducing oleanane triterpenoid from the rhizome of Astilbe chinensis.

3beta,6beta-dihydroxyolean-12-en-27-oic acid, C(30)H(48)O(4), a cytotoxic and apoptosis-inducing oleanane triterpenoid, which was isolated from the rhizome of Astilbe chinensis, consists of a linear array of five fused six-membered rings. The central ring has a slightly distorted half-chair conformation, while the four outer rings adopt chair conformations. Two hydroxy groups and one carboxy group serve simultaneously as hydrogen-bond donors and acceptors, forming molecular chains.

Antineoplastic Agents↗

PubMed2003

Crystal structure of the 1:2:2 adduct of piperazine, o-phthalic acid and water.

The adduct of piperazine, o-phthalic acid and water (1:2:2), C20H26N2O10, crystallizes in the monoclinic space group P21/c with a = 6.129(1), b = 12.810(2), c = 13.137(2)A, beta = 95.87(1) degrees, V = 1026.0(3)A3, Z = 2. The piperazinium adopts a chair comformer, and is tied with the hydrogen orthophthalate via a hydrogen bond of the N-H...O type. Because of bifurcated hydrogen bonding of C(sp3)H-O [3.0801(17) and 3.1408(18)A] and the shortest hydrogen bond of C(sp3)H-O [2.9758(17)A], C(sp3)H-O hydrogen bonds play important roles in stablizing the title adduct.

Journal Article↗

PubMed2002

The natural diterpenoid kamebanin.

Kamebanin, alternatively called rel-(-)-(1R,4R,8S,9R,10S,13S,16R)-2,8,16-trihydroxy-5,5,9-trimethyl-14-methylenetetracyclo[11.2.1.0(1,10).0(4,9)]hexadecan-15-one, C(20)H(30)O(4), is a natural diterpenoid which has cytotoxic and antibacterial activity. The molecule is composed of three six-membered rings, which all adopt chair conformations, and one five-membered ring, which adopts an envelope conformation. The conjugated alpha-methylenecyclopentanone ring is the active part in the molecule due to the ring strain. All three hydroxy groups serve as hydrogen-bond donors and acceptors, forming a continuous two-dimensional network.

Journal Article↗

PubMed2001

Macrocalyxin I.

The title compound, 2-[1,2,3,4,4a,4b,5,6,7,8,8a,9-dodecahydro-7-hydroxy-4b,8,8-trimethylphenanthren-2-yl]propenoic acid, C20H30O3, is a naturally occurring diterpenoid which was isolated from Rabdosia macrocalyx. The hydroxy and carboxy groups, which are located at the two ends of the molecule, both serve as simultaneous hydrogen-bond donors and acceptors. Two intermolecular O-H...O hydrogen bonds are present and link each molecule to four neighbours, thus forming an extensive hydrogen-bond network within the crystal.

Crystallography, X-Ray↗