Inhibitors of aldose reductase and advanced glycation end-products formation from the leaves of Stelechocarpus cauliflorus R.E. Fr.

Two dihydroflavonol glycosides, engeletin and astilbin, were isolated from an EtOAc extract of the leaves of Stelechocarpus cauliflorus R.E. Fr. (Annonaceae). The inhibitory activity of engeletin against a recombinant human aldose reductase (IC50 value=1.16 microM) was twice that of quercetin as a positive control (2.48 microM), and 23 times greater than that of astilbin (26.7 microM). Engeletin inhibited the enzyme uncompetitively. Astilbin was about as potent as the positive control, quercetin, in its inhibition of advanced glycation end-products formation. These flavonoids displayed therapeutic potential in the prevention and treatment of diabetic complications.

Two new pimarane diterpenoids from Strychnos vanprukii Craib.

Two new pimarane diterpenoids, 7beta,12beta-dihydroxypimara-8,15-dien-14-one (1) and 14-hydroxy-15,16-dinorpimara-8,11,13-trien-7-one (2), were isolated from the n-hexane extract of the stem of Strychnos vanprukii Craib and their structures were elucidated based on spectroscopic evidences.

Survival of neutralizing antibody in previously rabies vaccinated subjects: a prospective study showing long lasting immunity.

Physicians dealing with potential rabies exposures and travel medicine are frequently asked how long previous pre- or post-exposure rabies vaccination induced immunity persists. We therefore carried out a prospective study on 118 rabies vaccine recipients who had received pre- or post-exposure regimens with tissue culture rabies vaccines by intramuscular or intradermal schedules 5-21 years previously. Rabies neutralizing antibody was detectable in the sera of all subjects on day 0. They then received one intradermal 0.1 mL booster injection on days 0 and 3. Neutralizing antibody determination was carried out on days 5, 7 and 14. All except one subject showed an accelerated antibody response following the two booster injections. Vaccination with a WHO recognized tissue culture rabies vaccine evokes long lasting immunity. This study supports current recommendations that immunity is long lasting and that boosters without immunoglobulin are sufficient even when prior vaccination was longer than 5 years previously.

A new 3,4-seco-ursane triterpenoid from Glyptopetalum sclerocarpum.

A new ursane-type triterpene, glyptopetolide, was isolated along with two known triterpenoids, isoarborinol and cangoronine, from the stem bark of Glyptopetalum sclerocarpum LAWS. (Celastraceae). The structure of glyptopetolide was elucidated as 3,4-seco-14alpha,27-cyclo-urs-4(23)-en-3,11alpha-ol ide by spectroscopic analysis.

Antimicrobial activity and stability of tingenone derivatives.

Quinone-methide triterpenes of the tingenone series were evaluated for their antimicrobial activity. These compounds were effective against Bacillus cereus, B. subtilis, Sarcina lutea, Staphylococcus aureus, Microsporum gypseum and a Gram-negative bacterium, Klebsiella pneumoniae. Under acidic conditions, the quinone-methide part of these compounds rearranged into the divinyl-phenolic system, and the antimicrobial activity was thus lost.

A new antiviral and antimicrobial sesquiterpene from Glyptopetalum sclerocarpum.

Sclerocarpic acid, a new sesquiterpene with a novel carbon skeleton, was isolated from the stem bark of Glyptopetalum sclerocarpum Laws. (Celastraceae). The compound exhibited antiviral activity against herpes simplex virus types 1 and 2, and antimicrobial activity against Gram-positive bacteria and a fungus.

Norpregnane glycosides from a Thai soft coral, Scleronephthya pallida.

Two new norpregnane glycosides, 19-norpregna-1,3,5(10), 20-tetraen-3-O-alpha-fucopyranoside (3) and 19-norpregna-1,3,5(10), 20-tetraen-3-O-beta-arabinopyranoside (4), were isolated from the soft coral Scleronephthya pallida, along with two known steroids, pregna-1,20-dien-3-one (1) and 19-norpregna-1,3,5(10), 20-tetraen-3-ol (2). 19-Norpregna-1,3,5(10), 20-tetraen-3-O-alpha-fucopyranoside (3) exhibits moderate antimalarial and cytotoxic activities. The chemical structures of 1-4 were elucidated from spectroscopic data.

Bisamides from Aglaia edulis.

The leaves of Aglaia edulis afforded a new bisamide, aglaiduline, and two new sulfur-containing bisamides, aglaithioduline and aglaidithioduline. Their structures were established from spectroscopic studies. The sulfur-containing amides exhibited slight antiviral activity against herpes simplex virus types 1 and 2.

New orthoquinones from the roots of Salvia lanigera.

A chloroform extract of the roots of the Egyptian Salvia lanigera Poir. afforded two new orthoquinones, lanigerone (8-hydroxy-3-isopropyl-7-methyl-1,2-naphthoquinone) and salvigerone (methyl 1,10-seco-5(10),6,8,13-abietatetraene-11,12-dion-1-oate) together with two known diterpenoids, arucadiol and pisiferal. Structural assignments of the new compounds were based on spectroscopic methods (UV, IR, MS, ID- and 2D-NMR).

Plant-derived triterpenoid sweetness inhibitors.

Considerable recent attention has been focused on naturally occurring compounds with taste-modifying activity, which are of potential use in both dietary sweetness management and in gaining a better understanding of the sweet taste sensation. This review summarizes information on the phytochemistry and biological activity of more than 40 triterpenoid sweetness inhibitors that have been isolated from the leaves of three medicinal plants, namely, Gymnema sylvestre R.Br. (Asclepiadaceae), Ziziphus jujuba P. Miller (Rhamnaceae), and Hovenia dulcis Thunb. (Rhamnaceae).

Periandrin V, a further sweet triterpene glycoside from Periandra dulcis.

A new sweet triterpene glycoside, periandrin V, was isolated from the roots of Periandra dulcis and identified as 3 beta-O-[beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl]-25 -al-olean-18(19)-en-30-oic acid on the basis of chemical and spectral evidence. The structure of an acid-rearranged product of periandrin V and the parent compound, periandrin I, was determined as 1(10-->25) abeo-3 alpha, 25 alpha-epoxy-olean-5(10), 18-dien-30-oic acid methyl ester.