Trilobolide and its analogues belong to the guaianolide type of sesquiterpene lactones, which are characteristic and widely distributed within the families Asteraceae and Apiaceae. Certain guaianolides are receiving continuously increasing attention for their promising sarco-endoplasmic reticulum Ca2+-ATPase (SERCA)-inhibitory activity. However, because of their alkylation capabilities, they are generally toxic. Therefore, the search for compounds with significant immunobiological properties but with decreased cytotoxicities suitable for use in immune-based pharmacotherapy is ongoing. Therefore, we extended our previous investigation of the immunobiological effects of trilobolide to a series of structurally related guaianolides and germacranolides. To evaluate the relationship, we tested a series of selected derivatives containing α-methyl lactone or exomethylene lactone ring. For a wider comparison, we also included some of their glycosidic derivatives. We assessed the in vitro immunobiological effects of the tested compounds on nitric oxide (NO) production, cytokine secretion, and prostaglandin E2 (PGE2) release by mouse peritoneal cells, activated primarily by lipopolysaccharide (LPS), and evaluated their viability. The inhibitory effects of the apparently most active substance, 8-deoxylactucin, seem to be the most promising.

• Keywords
• 8-deoxylactucin, 8-epiisoamberboin, germacranolides, guaianolides, immune-modulatory effects,
• MeSH
• Butyrates MeSH
• Cytokines metabolism   MeSH
• Dinoprostone metabolism   biosynthesis   MeSH
• Furans MeSH
• Lactones * pharmacology   chemistry   MeSH
• Lipopolysaccharides pharmacology   MeSH
• Mice MeSH
• Nitric Oxide * metabolism   MeSH
• Macrophages, Peritoneal drug effects   metabolism   MeSH
• Sesquiterpenes, Germacrane * pharmacology   chemistry   MeSH
• Sesquiterpenes, Guaiane * pharmacology   chemistry   MeSH
• Sesquiterpenes pharmacology   chemistry   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Butyrates MeSH
• Cytokines MeSH
• Dinoprostone MeSH
• Furans MeSH
• germacranolide MeSH Browser
• Lactones * MeSH
• Lipopolysaccharides MeSH
• Nitric Oxide * MeSH
• Sesquiterpenes, Germacrane * MeSH
• Sesquiterpenes, Guaiane * MeSH
• Sesquiterpenes MeSH
• trilobolide MeSH Browser

Saponins, a diverse group of natural compounds, offer an interesting pool of derivatives with biomedical application. In this study, three structurally related spirostanol saponins were isolated and identified from the leek flowers of Allium porrum L. (garden leek). Two of them were identical with the already known leek plant constituents: aginoside (1) and 6-deoxyaginoside (2). The third one was identified as new component of A. porrum; however, it was found identical with yayoisaponin A (3) obtained earlier from a mutant of elephant garlic Allium ampeloprasun L. It is a derivative of the aginoside (1) with additional glucose in its glycosidic chain, identified by MS and NMR analysis as (2α, 3β, 6β, 25R)-2,6-dihydroxyspirostan-3-yl β-D-glucopyranosyl-(1 → 3)-β-D-glucopranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl]-(1 → 4)-β-D-galactopyranoside, previously reported also under the name alliporin. The leek native saponins were tested together with other known and structurally related saponins (tomatonin and digitonin) and with their related aglycones (agigenin and diosgenin) for in vitro cytotoxicity and for effects on NO production in mouse peritoneal cells. The highest inhibitory effects were exhibited by 6-deoxyaginoside. The obtained toxicity data, however, closely correlated with the suppression of NO production. Therefore, an unambiguous linking of obtained bioactivities of saponins with their expected immunobiological properties remained uncertain.

• Keywords
• Allium porrum, NO production, aginoside, alliporin, cytotoxicity, leek flowers, steroid saponins,
• MeSH
• Allium chemistry   MeSH
• Cell Line MeSH
• Flowers chemistry   MeSH
• Lipopolysaccharides antagonists & inhibitors   pharmacology   MeSH
• Molecular Conformation MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Nitric Oxide antagonists & inhibitors   biosynthesis   MeSH
• Macrophages, Peritoneal drug effects   metabolism   MeSH
• Saponins chemistry   isolation & purification   pharmacology   MeSH
• Spirostans chemistry   isolation & purification   pharmacology   MeSH
• Cell Survival drug effects   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Lipopolysaccharides MeSH
• Nitric Oxide MeSH
• Saponins MeSH
• Spirostans MeSH

Sesquiterpene lactones are secondary plant metabolites with sundry biological effects. In plants, they are synthesized, among others, for pesticidal and antimicrobial effects. Two such compounds, archangelolide and trilobolide of the guaianolide type, are structurally similar to the well-known and clinically tested lactone thapsigargin. While trilobolide has already been studied by us and others, there are only scarce reports on the biological activity of archangelolide. Here we present the preparation of its fluorescent derivative based on a dansyl moiety using azide-alkyne Huisgen cycloaddition having obtained the two sesquiterpene lactones from the seeds of Laserpitium archangelica Wulfen using supercritical CO2 extraction. We show that dansyl-archangelolide localizes in the endoplasmic reticulum of living cells similarly to trilobolide; localization in mitochondria was also detected. This led us to a more detailed study of the anticancer potential of archangelolide. Interestingly, we found that neither archangelolide nor its dansyl conjugate did exhibit cytotoxic effects in contrast to the structurally closely related counterparts trilobolide and thapsigargin. We explain this observation by a molecular dynamics simulation, in which, in contrast to trilobolide, archangelolide did not bind into the sarco/endoplasmic reticular calcium ATPase cavity utilized by thapsigargin. Last, but not least, archangelolide exhibited anti-inflammatory activity, which makes it promising compound for medicinal purposes.

• Keywords
• anti-inflammatory properties, archangelolide, dansyl fluorescent conjugate, sarco/endoplasmic reticulum calcium ATPase, sesquiterpene lactone, trilobolide analogue,
• Publication type
• Journal Article MeSH

Like thapsigargin, which is undergoing clinical trials, trilobolide is a natural product with promising anticancer and anti-inflammatory properties. Similar to thapsigargin, it has limited aqueous solubility that strongly reduces its potential medicinal applications. The targeted delivery of hydrophobic drugs can be achieved using liposome-based carriers. Therefore, we designed a traceable liposomal drug delivery system for trilobolide. The fluorescent green-emitting dye BODIPY, cholesterol and trilobolide were used to create construct 6. The liposomes were composed of dipalmitoyl-3-trimethylammoniumpropane and phosphatidylethanolamine. The whole system was characterized by atomic force microscopy, the average size of the liposomes was 150 nm in width and 30 nm in height. We evaluated the biological activity of construct 6 and its liposomal formulation, both of which showed immunomodulatory properties in primary rat macrophages. The uptake and intracellular distribution of construct 6 and its liposomal formulation was monitored by means of live-cell fluorescence microscopy in two cancer cell lines. The encapsulation of construct 6 into the liposomes improved the drug distribution in cancer cells and was followed by cell death. This new liposomal trilobolide derivative not only retains the biological properties of pure trilobolide, but also enhances the bioavailability, and thus has potential for the use in theranostic applications.

• Keywords
• BODIPY conjugates, cancer targeting, drug delivery, liposomes, natural compounds, sesquiterpene lactone trilobolide,
• Publication type
• Journal Article MeSH

A series of 5-substituted 2-amino-4,6-dihydroxypyrimidines were prepared by a modified condensation of the corresponding monosubstituted malonic acid diesters with guanidine in an excess of sodium ethoxide. The optimized procedure using Vilsmeier-Haack-Arnold reagent, followed by immediate deprotection of the (dimethylamino)methylene protecting groups, has been developed to convert the 2-amino-4,6-dihydroxypyrimidine analogs to novel 5-substituted 2-amino-4,6-dichloropyrimidines in high yields. Pilot screening for biological properties of the prepared compounds was done in mouse peritoneal cells using the in vitro nitric oxide (NO) assay. Irrespective of the substituent at the 5 position, 2-amino-4,6-dichloropyrimidines inhibited immune-activated NO production. The most effective was 5-fluoro-2-amino-4,6-dichloropyrimidine with an IC 50 of 2 µM (higher activity than the most potent reference compound) while the IC 50s of other derivatives were within the range of 9-36 µM. The 2-amino-4,6-dihydroxypyrimidine counterparts were devoid of any NO-inhibitory activity. The compounds had no suppressive effects on the viability of cells. The Mechanism of action remains to be elucidated.

• Keywords
• Anti-inflammatory, NO, Nitric oxide, Pyrimidine,
• Publication type
• Journal Article MeSH