W.W. Li

Effects of ginsenosides, lectins and Momordica charantia insulin-like peptide on corticosterone production by isolated rat adrenal cells

Ginsenosides Rb1, Rb2, Rc and Rg1 inhibited steroidogenesis induced by a maximally active dose of corticotropin in isolated rat adrenal cells. The galactose-binding lectins from Momordica charantia seeds and Trichosanthes kirilowii tubers and mannose-binding concanavalin A did not affect basal corticosterone production. The lectins potentiated steroidogenesis induced by a submaximal dose of corticotropin but were without effect on steroidogenesis induced by a maximally active dose of corticotropin. Momordica charantia insulin-like peptide did not affect steroidogenesis.

Isolation and Characterization of An Immunosuppressive Protein From Trichosanthes Kirilowii Root Tubers

An immunosuppressive protein was isolated from Trichosanthes kirilowii root tubers by a procedure involving acetone fractionation and ion exchange chromatography on CM-Sepharose. Homogeneity of the protein was demonstrated in immunoelectrophoresis, SDS-polyacrylamide gel electrophoresis, gel filtration, high performance liquid chromatography and a single NH2-terminal sequence. The protein had a molecular weight of 26,000, aspartic acid as the NH2-terminal amino acid and no cysteine or carbohydrates in its molecule. It inhibited ConA-induced transformation in lymphocytes isolated from spleens of CBA mice. The protein was also potent in inducing mid-term abortion in mice.

Improved isolation and further characterization of beta-trichosanthin, a ribosome-inactivating and abortifacient protein from tubers of trichosanthes cucumeroides (cucurbitaceae)

Abstract 1. 1. Beta-trichosanthin was isolated from root tubers of Trichosanthes cucumeroides with a procedure involving acetone fractionation, ion exchange chromatography on CM-Sepharose and DEAE-Sepharose and gel filtration on Sephadex G-50. 2. 2. The protein was homogeneous by SDS-polyacrylamide gel electrophoresis, polyacrylamide gel electrophoresis, immunodiffusion and immunoelectrophoresis. It possessed a molecular weight of 28,000 and was a strongly basic glycoprotein. 3. 3. It was immunochemically identical to trichosanthin but different from alpha- and beta-momorcharins. 4. 4. It possessed potent abortifacient and ribosome-inactivating activities. In the latter type of activity it was more potent than trichosanthin.

Crystals of α-momorcharin: A new ribosome-inactivating protein

Abstract Crystals of α-momorcharin were obtained by vapour phase diffusion. The crystal belongs to the space group R3, with unit cell constants a = b = 131.3 A , c = 39.5 A . There is one α-momorcharin molecule in the asymmetric unit; a data set at 3 A has been collected.

Peptides with antilipolytic and lipogenic activities from seeds of the bitter gourd Momordica charantia (family Cucurbitaceae).

Decorticated Momordica charantia seeds were extracted with acidic ethanol. The pH of the extract was adjusted to 8 and the resulting precipitate was chromatographed on CM Sepharose CL-6B and then desalted on Sephadex G-10. A number of factors which exhibited antilipolytic and lipogenic activities in rat adipocytes were isolated. Two of the factors were demonstrated to be peptides with similar amino acid compositions and a molecular weight of approximately 8000. However the peptides greatly differed in their chromatographic behavior on CM-Sepharose CL-6B and in their mobilities in agarose and polyacrylamide gel electrophoresis.

Effects of lectins with various carbohydrate binding specificities on lipid metabolism in isolated rat and hamster adipocytes

1. Mannose-binding and N-acetylglucosamine binding lectins exhibited potent antilipolytic and lipogenic activities. 2. Fucose-binding lectins had minimal lipogenic activity but possessed antilipolytic activity. 3. Most galactose-binding and N-acetylgalactosamine-binding lectins were devoid of significant antilipolytic and lipogenic activities. Notable exceptions were lectins from Momordica charantia, Wisteria floribunda, Vicia villosa, Codium fragile and the Siberian pine tree. lipogenic activity but lacked antilipolytic activity. 5. The galactose-binding horse gram and osage orange lectins exerted antilipolytic activity in hamster but not in rat adipocytes.

Investigation of ribosome inactivating protein-like activity in tissues of cucurbitaceae plants

1. 1. Extracts of roots, seeds and fruits of seventeen plant species belonging to Family Cucurbitaceae were examined for the ability to inhibit protein synthesis in rabbit reticulocyte lysate and induce mid-term abortion in mice. 2. 2. Out of the 22 tissue extracts examined, 16 were found to inhibit protein synthesis by >90%, three caused 65–85% inhibition and 3 caused <25% inhibition. 3. 3. In general, there was a close correlation between protein synthesis inhibiting activity and mid-term abortifacient activity of the tissue extracts. 4. 4. SDS-PAGE of the tissue extracts revealed the presence of a Coomassie Blue-stainable band with a mol. wt of ca 30,000. The data suggest that this band is responsible for the protein synthesis inhibiting and mid-term abortifacient activities.

Abortifacient activity in leaves, roots and seeds of Phytolacca acinosa

Fresh leaves, roots and seeds of Phytolacca acinosa were individually extracted with 0.9% saline and cold acetone was added to the supernatants. The resultant precipitates were dialyzed against distilled water and lyophilized to form acetone powders (AP). The relative potencies of abortifacient activity of the APs were: seed greater than root greater than leaf. The abortifacient activity in these APs was susceptible to destruction by heat and pepsin.

Trichosanthin, alpha-momorcharin and beta-momorcharin: identity of abortifacient and ribosome-inactivating proteins

The abortifacient proteins trichosanthin, alpha-momorcharin and beta-momorcharin at nM concentrations inhibit cell-free protein synthesis. The momorcharins and the ribosome-inactivating proteins isolated from Momordica charantia seeds cross-react with the respective antisera. The ribosome-inactivating proteins saporins, pokeweed antiviral protein (PAP) and, to a lesser extent, gelonin have abortifacient activity on pregnant mice.