A new steroidal glycoside from the fruits of Solanum myriacanthum.

A new cholestane-type steroidal glycoside, solamyriaside A (1), was isolated from the fruits of Solanum myriacanthum Dunal (Solanaceae), along with two known steroidal glycosides, namely, solaviaside A (2) and aculeatiside A (3), and three known steroidal alkaloid glycosides, namely, solamargine (4), khasianine (5) and solasonine (6), which were isolated for the first time from this plant. Based on spectroscopic data as well as chemical evidence, 1 was determined to be 3-O-α-L-rhamnopyranosyl-(1→2)-O-[α-L-rhamnopyranosyl-(1→4)]-ß-D-glucopyranosyl-22R,25R-cholest-5-ene-3ß,16α,22,26-tetraol 26-O-ß-D-glucopyranoside. The cytotoxic activity of 1-6 against HL-60 human promyelocytic leukaemia cells was examined. Compounds 4-6 showed cytotoxic activity. Among them, 4 exhibited the strongest activity with an IC50 value of 4.64 ± 0.17 µM, similar to the activity of cisplatin, a positive control.

Two new triterpenoids from the leaves and stems of Lantana camara.

Two new oleanane-type triterpenoids with an epoxy bridge between C-3 and C-25, named lantacamaric acids A and B, were isolated from the leaves and stems of Lantana camara L. (Verbenaceae). In addition, seven known triterpenoids, two known iridoid glycosides, four known phenylethanoid glycosides, one known flavonoid glycoside, and one known cyanogenic glycoside were isolated. Their structures were determined based on the spectroscopic data. Furthermore, the cytotoxic activities of the isolated triterpenoids toward HL-60 cells were examined. The IC50 values of all compounds were obtained and ranged from 1.16 to 68.4 µM, with three compounds exhibiting stronger activities than the positive control, cisplatin. In addition, the structure-activity relationship was investigated.

Effects of indole and indoxyl on the intracellular oxidation level and phagocytic activity of differentiated HL-60 human macrophage cells.

Indoxyl, a derivative of indole originating from tryptophan, may undergo phase-II sulfate-conjugation pathway, thereby forming indoxyl sulfate (IS) in vivo. We previously reported that IS, a well-known uremic toxin, can increase the intracellular oxidation level and decrease the phagocytic activity in a differentiated HL-60 human macrophage cell model. Using the same cell model, the current study aimed to investigate whether indole and indoxyl (the metabolic precursors of indoxyl and IS, respectively) may cause macrophage immune dysfunction. Results obtained indicated that intracellular oxidation level and cytotoxicity markedly increased upon treatment with indole and indoxyl, in comparison with IS. Incubation of the cells with indole and indoxyl also resulted in attenuated phagocytic activity. Human serum albumin (HSA)-binding assay confirmed that tryptophan and IS, but not indole and indoxyl, could selectively bind to the site II in HSA. Collectively, the results indicated that indole and indoxyl may strongly down-regulate the phagocytic immune function of macrophages, whereas IS, formed upon sulfate conjugation of indoxyl, may exhibit enhanced HSA-binding capability, thereby reducing the adverse effects of indoxyl.

Investigation of the effects of indoxyl sulfate, a uremic toxin, on the intracellular oxidation level and phagocytic activity using an HL-60-differentiated human macrophage cell model.

Indoxyl sulfate (IS), a uremic toxin, is a sulfate-conjugated metabolite originated from tryptophan. Accumulating uremic toxins may worsen renal diseases and further complicate related disorders including impaired immune functions under oxidative stress conditions. However, it has remained unclear whether or not IS can directly cause the cellular immune dysfunction. We investigated the effects of IS on the intracellular oxidation level and phagocytic activity in a HL-60-differantiated human macrophage cell model. Incubation of the cells in the presence of IS resulted in increasing intracellular oxidation level and decreasing phagocytic activity. In addition to inhibitors for NADH oxidase (NOX), organic anion transporting polypeptide2B1 (OATP2B1), protein kinase C (PKC), and phosphoinositide 3-kinase (PI3K), a representative antioxidant Trolox, was also shown to significantly relieve the IS-induced oxidation and restore weakened phagocytosis. Collectively, IS may directly down-regulate the phagocytic immune function of macrophages through the oxidation mechanisms including OATP2B1, PKC, PI3K, and NOX pathways. Abbreviations: CKD: Chronic kidney disease; IS: Indoxyl sulfate; ROS: Reactive oxygen species; NOX: NADH oxidase; OATP2B1: Organic anion transporting polypeptide2B1; PKC: Protein kinase C; PI3K: Phosphoinositide 3-kinase; 2-APT: 2-acetylphenothiazine.

Identification and characterization of organic and glycosidic acids in crude resin glycoside fraction from Calystegia hederacea.

Resin glycosides are well known as the purgative ingredients, which are characteristic of convolvulaceous plants. Calystegia hederacea Wall. is a perennial herbaceous vine that is widespread throughout India and East Asia. All parts of this plant are used for the treatment of menoxenia, gonorrhea, etc. Alkaline hydrolysis of the crude resin glycoside fraction of the whole plants of C. hederacea yielded four new glycosidic acids, calyhedic acids A, B, C, and D, along with two known glycosidic acids, calysolic acids A and C, and three known organic acids, 2S-methylbutyric, tiglic, and 2R,3R-nilic acids. Their structures were characterized on the basis of spectroscopic data and chemical evidence. Calyhedic acids A, B, and D were penta-, hexa-, and hepta-glycosides of 12S-hydroxyhexadecanoic acid, respectively, and cayhedic acid C was an isomer of calyhedic acid D, in which the 12S-hydroxyhexadecanoyl residue of calyhedic acid D was replaced by a 11S-hydroxyhexadecanoyl residue. Additionally, cytotoxic activity toward HL-60 human promyelocytic leukemia cells of the crude resin glycoside fraction, the glycosidic acid fraction, calyhedic acid A, and calysolic acid A from C. hederacea was evaluated. Furthermore, to clarify the structure-activity relationship of resin glycosides, the activities of six genuine resin glycosides with calysolic acid A or calysolic acid C as the glycosidic acid, which were isolated from C. soldanella, were examined. Among them, the crude resin glycoside fraction and five genuine resin glycosides with macrolactone structures demonstrated clear cytotoxic activities, while the glycosidic acid fraction, calyhedric acid A, calysolic acid A, and a genuine non-macrolactone-type resin glycoside were either inactive or exhibited weaker activity than the tested macrolactone-type resin glycosides.

Seven new resin glycosides from the seeds of Quamoclit × multifida.

Seven new resin glycosides, multifidins III (1)-IX (7), were isolated from the seeds of Quamoclit × multifida (syn. Q. sloteri House) (Convolvulaceae), along with five known glycosides, quamoclinic acid B methyl ester (8), operculin XIII (9), quamoclin I (10), QM-10 (11), and QM-12 (12). Their structures were determined on the basis of spectroscopic data and chemical evidence. These compounds were of two different types, i.e., those with macrolactone structures and those with non-macrolactone structures. Additionally, cytotoxic activity towards HL-60 human leukemia cells of 1, 2, 5, 8, 9, 11, and 12 was evaluated. Among them, macrolactone-type resin glycosides (jalapins), 1, 2, and 9, specifically demonstrated clear cytotoxic activity with IC50 values of 3.46, 14.7, and 10.9 µM, respectively.

Radical scavenging effects of 1-naphthol, 2-naphthol, and their sulfate-conjugates.

1-Naphthol (1-Nap) and 2-naphthol (2-Nap) are phenolic isomers that may be subjected to sulfate conjugation in vivo. Phase-II sulfate conjugation of phenolic compounds is generally thought to result in their inactivation. This study aimed to investigate the antioxidative effects of 1-NapS and 2-NapS, in comparison with their unsulfated counterparts, using established free radical scavenging assays. Based on the calculated EC50 values, 1-NapS resulted in 5.60 to 7.35-times lower antioxidative activity than 1-Nap. In contrast, 2-NapS showed comparable activities as did the unsulfated 2-Nap. Collectively, the results obtained indicated that sulfate conjugation of the Nap isomers did not always result in the decrease of their antioxidant activity, and the antioxidant activity that remained appeared to depend on the position of sulfation.