A study on the bioactive principles of Hedyotis diffusa Willd., led to the isolation of a new acyl flavonol di-glycoside which was characterized as kaempferol 3-O[2"-O-(E-6'"-O-feruloyl)-beta-D-glucopyranosyl]-beta-D-galactop yranoside by spectral and chemical methods from the methanolic extract. In addition, three known flavonol glycosides and six known iridoid glycosides were also obtained. The above-mentioned glycosides were tested for antioxidant effects on xanthine oxidase inhibition, xanthine-xanthine oxidase cytochrome c and TBA-MDA systems.

Sixteen constituents from Formosan Moraceous plants were tested for their antiplatelet activities in rabbit platelet suspension and human platelet-rich plasma. Cycloartocarpin A, cycloheterophyllin, broussochalcone A, kazinol A, broussoaurone A, and broussoflavonol F showed strong inhibition of arachidonic acid (AA)-induced platelet aggregation. Of the compounds tested, broussochalcone A exhibited the most potent inhibition of platelet aggregation induced by AA (IC50 = 6.8 microM). The antiplatelet effects of cycloheterophyllin, broussochalcone A, kazinol B, broussoaurone A, and broussoflavonol F are partially due to an inhibitory effect on cyclooxygenase.

In continuation of work on Solanum incanum a new steroidal alkaloid glycoside has been isolated from the fresh berries, which is named incanumine, and characterized as O(3)-[beta-D-xylopyranosyl-(1----3glu)-[beta-D-xylopyranosyl-(1--- -4rha)- alpha-L-rhamnopyranosyl-(1----4)]-beta-D-glucopyranosyl)-solasodine++ +. Solamargine, solasodine, ursolic acid, and ursolic acid derivatives (3-O-palmitoyl ursolic acid, 3-O-crotonyl ursolic acid, 3-O-propionyl ursolic acid) exhibited significant cytotoxic effects against human PLC/PRF/5 cells in vitro. Esterification of ursolic acid with aliphatic acids clearly enhanced the cytotoxic effects against human PLC/PRF/5 cells in vitro.

The anti-inflammatory activities of the isolated flavonoids, quercetin 3-O-methyl ether (1), kaempferol (2), and quercetin (3), of Rhamnus nakaharai, and anthraquinone, frangulin B (4), of Rhamnus formosana, were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells, neutrophils, macrophages, and microglial cells. Compounds 1 - 3 strongly inhibited the release of beta-glucuronidase and lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe/cytochalasin B (fMLP/CB). Compound 1 strongly inhibited superoxide anion formation in fMLP/CB or phorbol 12-myristate 13-acetate (PMA)-stimulated rat neutrophils. Compound 1 exhibited potent inhibitory effect on tumor-necrosis factor-alpha ( TNF-alpha) formation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells while 1 and 4 showed potent inhibitory effects on TNF-alpha formation in LPS/IFN-gamma (interferon-gamma)-stimulated murine microglial cell lines N9.

A new naphthalene derivative, isotorachrysone [1], was isolated from the stem bark of Rhamnus nakaharai along with several known compounds. The antiplatelet effects of isotorachrysone [1], isotorachrysone peracetate [2], 6-methoxysorigenin [3], quercetin 3-O-methyl ether [4], and quercetin 3-O-methyl ether peracetate [5] were studied using washed rabbit platelets. Of the compounds tested, 1, 2, 4, and 5 showed potent antiplatelet effects on arachidonic acid (AA-) and collagen-induced platelet aggregation. Compound 5 also showed potent antiplatelet effects on platelet-activating factor-(PAF-) induced platelet aggregation. Isotorachrysone [1] and its peracetate [2] were also studied for antiplatelet activity in human platelet-rich plasma (PRP) and both showed potent inhibition of the secondary aggregation induced by epinephrine. The antiplatelet effects of 1 and 2 are due partially to an inhibitory effect on thromboxane formation.