Solasodine glycosides. In vitro preferential cytotoxicity for human cancer cells

Khasianine Affects the Expression of Sugar-Sensitive Proteins in Pancreatic Cancer Cells, Which Are Altered in Data from the Rat Model and Patients

Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy with no effective treatment, particularly in the advanced stage. This study explored the antiproliferative activity of khasianine against pancreatic cancer cell lines of human (Suit2-007) and rat (ASML) origin. Khasianine was purified from Solanum incanum fruits by silica gel column chromatography and analyzed by LC-MS and NMR spectroscopy. Its effect in pancreatic cancer cells was evaluated by cell proliferation assay, chip array and mass spectrometry. Proteins showing sensitivity to sugars, i.e. sugar-sensitive lactosyl-Sepharose binding proteins (LSBPs), were isolated from Suit2-007 cells by competitive affinity chromatography. The eluted fractions included galactose-, glucose-, rhamnose- and lactose-sensitive LSBPs. The resulting data were analyzed by Chipster, Ingenuity Pathway Analysis (IPA) and GraphPad Prism. Khasianine inhibited proliferation of Suit2-007 and ASML cells with IC50 values of 50 and 54 μg/mL, respectively. By comparative analysis, khasianine downregulated lactose-sensitive LSBPs the most (126%) and glucose-sensitive LSBPs the least (85%). Rhamnose-sensitive LSBPs overlapped significantly with lactose-sensitive LSBPs and were the most upregulated in data from patients (23%) and a pancreatic cancer rat model (11.5%). From IPA, the Ras homolog family member A (RhoA) emerged as one of the most activated signaling pathways involving rhamnose-sensitive LSBPs. Khasianine altered the mRNA expression of sugar-sensitive LSBPs, some of which were modulated in data from patients and the rat model. The antiproliferative effect of khasianine in pancreatic cancer cells and the downregulation of rhamnose-sensitive proteins underscore the potential of khasianine in treating pancreatic cancer.

A review of emerging and non-US FDA-approved topical agents for the treatment of basal cell carcinoma

Although surgical therapy continues to be the gold standard for the treatment of basal cell carcinoma given high cure rates and the ability to histologically confirm tumor clearance, there are a number of nonsurgical treatment options that may be considered based on individual tumor characteristics, functional and cosmetic considerations, patient comorbidities and patient preference. Topical 5-fluorouracil 5% cream and imiquimod 5% cream have been US FDA-approved for the treatment of superficial basal cell carcinoma. Additionally, a number of new and emerging topical agents and techniques have been described for the treatment of basal cell carcinoma and will be reviewed herein.

Cytotoxic and chemosensitizing effects of glycoalkaloidic extract on 2D and 3D models using RT4 and patient derived xenografts bladder cancer cells

Glycoalkaloids have been widely demonstrated as potential anticancer agents. However, the chemosensitizing effect of these compounds with traditional chemotherapeutic agents has not been explored yet. In a quest for novel effective therapies to treat bladder cancer (BC), we evaluated the chemosensitizing potential of glycoalkaloidic extract (GE) with cisplatin (cDDP) in RT4 and PDX cells using 2D and 3D cell culture models. Additionally, we also investigated the underlying molecular mechanism behind this effect in RT4 cells. Herein, we observed that PDX cells were highly resistant to cisplatin when compared to RT4 cells. IC50 values showed at least 2.16-folds and 1.4-folds higher in 3D cultures when compared to 2D monolayers in RT4 cells and PDX cells, respectively. GE + cDDP inhibited colony formation (40%) and migration (28.38%) and induced apoptosis (57%) in RT4 cells. Combination therapy induced apoptosis by down-regulating the expression of Bcl-2 (p < 0.001), Bcl-xL (p < 0.001) and survivin (p < 0.01), and activating the caspase cascade in RT4 cells. Moreover, decreased expression of MMP-2 and 9 (p < 0.01) were observed with combination therapy, implying its effect on cell invasion/migration. Furthermore, we used 3D bioprinting to grow RT4 spheroids using sodium alginate-gelatin as a bioink and evaluated the effect of GE + cDDP on this system. Cell viability assay showed the chemosensitizing effect of GE with cDDP on bio-printed spheroids. In summary, we showed the cytotoxicity effect of GE on BC cells and also demonstrated that GE could sensitize BC cells to chemotherapy.

Two-step Synthesis of Solasodine Pivalate from Diosgenin Pivalate

A two-step synthesis of solasodine pivalate from diosgenin pivalate is described. The key transformation involves the reaction of diosgenin pivalate with benzyl carbamate (CbzNH₂) promoted by TMSOTf. During the reaction the F-ring of the spiroketal moiety opens up with a simultaneous introduction of a Cbz-protected amino group in position 26. A one-pot deprotection of 26-amine with AcBr/BuOH followed by the N-cyclization affords solasodine pivalate in 45% overall yield.

Revision of the Structure of N, O-Diacetylsolasodine. Unusual Epimerization at the Spiro Carbon Atom during Acetylation of Solasodine

The steroidal alkaloid solasodine (1) undergoes inversion of configuration at the C-22 spiro atom when treated with acetic anhydride-pyridine at ambient temperature. The basic solvolysis of the N, O-diacetyl derivative (2) reverses the reaction, yielding the starting solasodine (1). The mechanisms of both processes (acetylation and deacetylation) were studied in terms of possible reaction pathways.

Steroidal glycoalkaloids from Solanum nigrum target cytoskeletal proteins: an in silico analysis

Background

Solanum nigrum (black nightshade; S. nigrum), a member of family Solanaceae, has been endowed with a heterogeneous array of secondary metabolites of which the steroidal glycoalkaloids (SGAs) and steroidal saponins (SS) have vast potential to serve as anticancer agents. Since there has been much controversy regarding safety of use of glycoalkaloids as anticancer agents, this area has remained more or less unexplored. Cytoskeletal proteins like actin play an important role in maintaining cell shape, synchronizing cell division, cell motility, etc. and along with their accessory proteins may also serve as important therapeutic targets for potential anticancer candidates. In the present study, glycoalkaloids and saponins from S. nigrum were screened for their interaction and binding affinity to cytoskeletal proteins, using molecular docking.

Methods

Bioactivity score and Prediction of Activity Spectra for Substances (PASS) analysis were performed using softwares Molinspiration and Osiris Data Explorer respectively, to assess the feasibility of selected phytoconstituents as potential drug candidates. The results were compared with two standard reference drugs doxorubicin hydrochloride (anticancer) and tetracycline (antibiotic). Multivariate data obtained were analyzed using principal component analysis (PCA).

Results

Docking analysis revealed that the binding affinities of the phytoconstituents towards the target cytoskeletal proteins decreased in the order coronin>villin>ezrin>vimentin>gelsolin>thymosin>cofilin. Glycoalkaloid solasonine displayed the greatest binding affinity towards the target proteins followed by alpha-solanine whereas amongst the saponins, nigrumnin-I showed maximum binding affinity. PASS Analysis of the selected phytoconstituents revealed 1 to 3 violations of Lipinski’s parameters indicating the need for modification of their structure-activity relationship (SAR) for improvement of their bioactivity and bioavailability. Glycoalkaloids and saponins all had bioactivity scores between −5.0 and 0.0 with respect to various receptor proteins and target enzymes. Solanidine, solasodine and solamargine had positive values of druglikeness which indicated that these compounds have the potential for development into future anticancer drugs. Toxicity potential evaluation revealed that glycoalkaloids and saponins had no toxicity, tumorigenicity or irritant effect(s). SAR analysis revealed that the number, type and location of sugar or the substitution of hydroxyl group on alkaloid backbone had an effect on the activity and that the presence of α-L-rhamnopyranose sugar at C-2 was critical for a compound to exhibit anticancer activity.

Conclusion

The present study revealed some cytoskeletal target(s) for S. nigrum phytoconstituents by docking analysis that have not been previously reported and thus warrant further investigations both in vitro and in vivo.

The synthesis of solasodine F-homo-analogues

An efficient synthesis of F-homosolasodine analogues containing the 5/7 spirohemiaminal moiety was elaborated. The method benefited from an easy opening of diosgenin F-ring and the introduction of a cyano group in position 26.

Bioactive Compounds Found in Brazilian Cerrado Fruits

Functional foods include any natural product that presents health-promoting effects, thereby reducing the risk of chronic diseases. Cerrado fruits are considered a source of bioactive substances, mainly phenolic compounds, making them important functional foods. Despite this, the losses of natural vegetation in the Cerrado are progressive. Hence, the knowledge propagation about the importance of the species found in Cerrado could contribute to the preservation of this biome. This review provides information about Cerrado fruits and highlights the structures and pharmacologic potential of functional compounds found in these fruits. Compounds detected in Caryocar brasiliense Camb. (pequi), Dipteryx alata Vog. (baru), Eugenia dysenterica DC. (cagaita), Eugenia uniflora L. (pitanga), Genipa americana L. (jenipapo), Hancornia speciosa Gomes (mangaba), Mauritia flexuosa L.f. (buriti), Myrciaria cauliflora (DC) Berg (jabuticaba), Psidiumguajava L. (goiaba), Psidium spp. (araçá), Solanum lycocarpum St. Hill (lobeira), Spondias mombin L. (cajá), Annona crassiflora Mart. (araticum), among others are reported here.

Chemistry and anticarcinogenic mechanisms of glycoalkaloids produced by eggplants, potatoes, and tomatoes

Inhibition of cancer can occur via apoptosis, a genetically directed process of cell self-destruction that involves numerous biomarkers and signaling pathways. Glycoalkaloids are nitrogen-containing secondary plant metabolites found in numerous Solanaceous plants including eggplants, potatoes, and tomatoes. Exposure of cancer cells to glycoalkaloids produced by eggplants (α-solamargine and α-solasonine), potatoes (α-chaconine and α-solanine), and tomatoes (α-tomatine) or their hydrolysis products (mono-, di-, and trisaccharide derivatives and the aglycones solasodine, solanidine, and tomatidine) inhibits the growth of the cells in culture (in vitro) as well as tumor growth in vivo. This overview comprehensively surveys and consolidates worldwide efforts to define the following aspects of these natural compounds: (a) their prevalence in the three foods; (b) their chemistry and structure-activity relationships; (c) the reported factors (biomarkers, signaling pathways) associated with apoptosis of bone, breast, cervical, colon, gastric, glioblastoma, leukemia, liver, lung, lymphoma, melanoma, pancreas, prostate, and squamous cell carcinoma cell lines in vitro and the in vivo inhibition of tumor formation and growth in fish and mice and in human skin cancers; and (d) future research needs. The described results may make it possible to better relate the structures of the active compounds to their health-promoting function, individually, in combination, and in food, and allow the consumer to select glycoalkaloid-containing food with the optimal content of nontoxic beneficial compounds. The described findings are expected to be a valuable record and resource for further investigation of the health benefits of food-related natural compounds.

Application of hypoiodite-mediated aminyl radical cyclization to synthesis of solasodine acetate

Solasodine acetate, an anticancer steroidal alkaloid, was synthesized from diosgenin in 8 steps with an overall yield of 23%. A key synthetic step involves the formation of 5/6-oxazaspiroketal moiety via hypoiodite-mediated aminyl radical cyclization of a steroidal primary amine.

Effects of auxins on the production of steroidal alkaloids in rapidly proliferating tissue and cell cultures of Solanum lyratum

INTRODUCTION

Solanum lyratum, a rare species, is used to treat cancer, tumours and warts. Plant cell and tissue culture of S. lyratum, producing steroidal alkaloids, could be useful supplements to natural sources.

OBJECTIVE

To study the production of solanine, solanidine and solasodine by adding auxin-type phytohormones including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) to cell and callus cultures of S. lyratum.

METHODOLOGY

Methanolic extracts were made from callus and cell cultures of S. lyratumand and analysed using RP C₁₈ HPLC with UV detection.

RESULTS

2,4-D-induced calli from roots led to a significant enhancement in solanine production with a value of 4.13 mg/g dry weight (DW). The maximal solanidine and solasodine levels of 6.26 and 7.69 mg/g DW were respectively obtained with IBA- and IAA-treated S. lyratum cells at concentrations of 1 and 5 mg/L.

CONCLUSION

Auxins were found to be useful phytohormones for the production of steroidal alkaloids. The callus and cell culture system developed is simple and can hence be a method of production of steroidal alkaloids in S. lyratum and other Solanaceae species.

Bioactivities of glycoalkaloids and their aglycones from Solanum species

Potatoes, tomatoes, and aubergines are all species of the Solanum genus and contain a vast array of secondary metabolites including calystegine alkaloids, phenolic compounds, lectins, and glycoalkaloids. Glycoalkaloids have been the subject of many literature papers, occur widely in the human diet, and are known to induce toxicity. Therefore, from a food safety perspective further information is required regarding their analysis, toxicity, and bioavailability. This is especially important in crop cultivars derived from wild species to prevent glycoalkaloid-induced toxicity. A comprehensive review of the bioactivity of glycoalkaloids and their aglycones of the Solanum species, particularly focused on comparison of their bioactivities including their anticancer, anticholesterol, antimicrobial, anti-inflammatory, antinociceptive, and antipyretic effects, toxicity, and synergism of action of the principal Solanum glycoalkaloids, correlated to differences of their individual molecular structures is presented.

Characterization of health-related compounds in eggplant (Solanum melongena L.) lines derived from introgression of allied species

The purpose of the present study was to investigate the levels of either the nutraceutical and health-promoting compounds or the antioxidant properties of innovative eggplant (Solanum melongena L.) genotypes tolerant and/or resistant to fungi, derived from conventional and non-conventional breeding methodologies (i.e., sexual interspecific hybridization, interspecific protoplast electrofusion, androgenesis, and backcross cycles) in comparison with their allied and cultivated parents. Chemical measures of soluble refractometric residue (SRR), glycoalkaloids (solamargine and solasonine), chlorogenic acid (CA), delphinidin 3-rutinoside (D3R), total phenols (TP), polyphenoloxidase (PPO) activity, antiradical activity on superoxide anion and hydroxyl radical were carried out in raw fruit and peel of 57 eggplant advanced introgression lines (ILs), of three eggplant recurrent genotypes and of three allied species during 2005 and 2006. The majority of the ILs, obtained after several backcross cycles, showed positive characteristics with respect to the allied parents such as good levels of SRR, CA, D3R, TP, PPO activity, the scavenging activity against superoxide anion and hydroxyl radical and, in particular, significantly (p <or= 0.05) reduced concentrations of the toxic steroidal glycoalkaloids, solasonine and solamargine. These results showed the possibility to obtain new eggplant genotypes bearing useful traits derived from the allied parents (i.e., resistance/tolerance to plant pathogen fungi) together with nutraceutical and antioxidant properties typical of the cultivated species.

Effect of Solanum trilobatum on hepatic drug metabolising enzymes during diethylnitrosamine-induced hepatocarcinogenesis promoted by Phenobarbital in rat

The present study was aimed to investigate the chemopreventive effects of Solanum trilobatum (ST) extract against diethylnitrosamine (DEN)-induced hepatocarcinogenesis promoted by Phenobarbital (PB) in Wistar rats. Hepatocarcinogenesis was initiated by a single intraperitoneal injection of DEN (200 mg/kg b.w.) and promoted with PB (0.05%) in basal diet. The experimental study extended for periods of 13 and 26 weeks. Alcoholic extract of ST was orally administered for the entire experimental period after initiation along with commencement of promotion. The chemopreventive effect of ST was assessed from the incidence of nodules, drug metabolizing phase I components such as contents of cytochrome P450, cytochrome b(5), activities of NADPH cytochrome c reductase, NADH - cytochrome b(5) reductase and phase II components such as levels of glutathione, activities of UDP-glucuronyl transferase, glutathione S-transferase and gamma-glutamyl transpeptidase in the liver. Lipid peroxidation at basal and prooxidants-induced (NADPH + ADP + Fe and Ascorbate + Fe) states was assessed in the microsomes. Animals administered with ST extract evidenced significant inhibition of tumor nodular incidence in DEN + PB + ST animals compared to DEN + PB animals, with favorable alterations in the hepatic drug-metabolizing phase I and phase II components. Administration of ST inhibited basal and pro-oxidant-induced lipid peroxidation. The present result suggests the probable mediation of chemoprevention by ST against DEN-induced carcinogenesis by the modulation of drug metabolizing components in the liver of treated animals.

Efficient Synthesis of Solasodine,O-Acetylsolasodine, and Soladulcidine as Anticancer Steroidal Alkaloids

An efficient synthesis of the steroidal alkaloids solasodine (1), O-acetylsolasodine (2), and soladulcidine (3) starting from easily available diosgenin and tigogenin in five or six steps (overall yield 25, 24, and 28%, resp.) is described. Moreover, our synthetic route provides a selective modification at C(3) of 1 and related compounds in order to carry out lead optimization on these natural antitumor steroidal alkaloids.

Potato glycoalkaloids and metabolites: roles in the plant and in the diet

Potatoes, members of the Solanaceae plant family, serve as major, inexpensive low-fat food sources providing energy (starch), high-quality protein, fiber, and vitamins. Potatoes also produce biologically active secondary metabolites, which may have both adverse and beneficial effects in the diet. These include glycoalkaloids, calystegine alkaloids, protease inhibitors, lectins, phenolic compounds, and chlorophyll. Because glycoalkaloids are reported to be involved in host-plant resistance and to have a variety of adverse as well as beneficial effects in cells, animals, and humans, a need exists to develop a clearer understanding of their roles both in the plant and in the diet. To contribute to this effort, this integrated review presents data on the (a) history of glycoalkaloids; (b) glycoalkaloid content in different parts of the potato plant, in processed potato products, and in wild, transgenic, and organic potatoes; (c) biosynthesis, inheritance, plant molecular biology, and glycoalkaloid-plant phytopathogen relationships; (d) dietary significance with special focus on the chemistry, analysis, and nutritional quality of low-glycoalkaloid potato protein; (e) pharmacology and toxicology of the potato glycoalkaloids comprising alpha-chaconine and alpha-solanine and their hydrolysis products (metabolites); (f) anticarcinogenic and other beneficial effects; and (g) possible dietary consequences of concurrent consumption of glycoalkaloids and other biologically active compounds present in fresh and processed potatoes. An enhanced understanding of the multiple and overlapping aspects of glycoalkaloids in the plant and in the diet will benefit producers and consumers of potatoes.

Antitumor efficacy of the novel chemotherapeutic agent coramsine is potentiated by cotreatment with CpG-containing oligodeoxynucleotides

Coramsine is a novel chemotherapeutic agent isolated from Solanum linnaeanum (devil's apple). Topical treatment provides clinical benefit for skin tumors. To evaluate the potential broader applicability of the drug, its in vivo anticancer efficacy in a murine model of malignant mesothelioma and its mode of action were investigated. Systemic administration of coramsine slowed tumor growth and prolonged survival time. Importantly, the antitumor efficacy of coramsine was enhanced when treatment was combined with stimulation of innate immunity using unmethylated CpG-containing oligodeoxynucleotides (ODNs). Combination treatment further slowed tumor growth and provided a survival benefit. Coramsine seems to kill tumor cells by direct cell lysis. Using 2 different assays to detect apoptosis (caspase activation and DNA fragmentation), we found no evidence that coramsine induces any form of programmed cell death. The fact that the efficacy of coramsine is potentiated by CpG ODNs suggests that coramsine-induced cell death is an immunologic null event.

Effect of Solanum trilobatum on the antioxidant status during diethyl nitrosamine induced and phenobarbital promoted hepatocarcinogenesis in rat

AIM

The methanolic extract of Solanum trilobatum (ST) is cytotoxic and exerts an inhibitory effect on tumor growth and in the present study, its role on the antioxidant status of N-diethylnitrosamine (DEN) induced and phenobarbital (PB) promoted hepatocarcinogenesis was assessed.

METHODS

The protective role of ST on DEN induced and PB promoted hepatocarcinogenesis in Wistar rats was assessed from total nodular incidence, nodule multiplicity and volume of persistent nodules after an experimental period of 3 and 6 months following co-administration. The levels of thiobarbituric reactive substances (TBARS), glutathione (GSH) and activities of antioxidant enzymes were assessed in the haemolysate and liver of experimental animals to evaluate the antioxidant status.

RESULTS

In DEN+PB+ST animals, the nodular incidence, multiplicity and volume reduced significantly compared to DEN+PB treated animals. In DEN+PB animals, the levels of TBARS increased significantly, whereas the levels of GSH and the activities of antioxidant enzymes-superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and glucose 6 phosphate dehydrogenase showed significant alterations compared to control both in the haemolysate and liver. However, in DEN+PB+ST animals, the levels of TBARS decreased significantly and the levels of GSH increased with favorable alterations in the activities of antioxidant enzymes in both the haemolysate and liver.

CONCLUSION

The present results suggest that ST exerts its chemopreventive effects by modulating the antioxidant status during DEN induced hepatocarcinogenesis.

Glycoalkaloids and metabolites inhibit the growth of human colon (HT29) and liver (HepG2) cancer cells

As part of an effort to improve plant-derived foods such as potatoes, eggplants, and tomatoes, the antiproliferative activities against human colon (HT29) and liver (HepG2) cancer cells of a series of structurally related individual compounds were examined using a microculture tetrazolium (MTT) assay. The objective was to assess the roles of the carbohydrate side chain and aglycon part of Solanum glycosides in influencing inhibitory activities of these compounds. Evaluations were carried out with four concentrations each (0.1, 1, 10, and 100 microg/mL) of the the potato trisaccharide glycoalkaloids alpha-chaconine and alpha-solanine; the disaccharides beta(1)-chaconine, beta(2)-chaconine, and beta(2)-solanine; the monosaccharide gamma-chaconine and their common aglycon solanidine; the tetrasaccharide potato glycoalkaloid dehydrocommersonine; the potato aglycon demissidine; the tetrasaccharide tomato glycoalkaloid alpha-tomatine, the trisaccharide beta(1)-tomatine, the disaccharide gamma-tomatine, the monosaccharide delta-tomatine, and their common aglycon tomatidine; the eggplant glycoalkaloids solamargine and solasonine and their common aglycon solasodine; and the nonsteroidal alkaloid jervine. All compounds were active in the assay, with the glycoalkaloids being the most active and the hydrolysis products less so. The effectiveness against the liver cells was greater than against the colon cells. Potencies of alpha-tomatine and alpha-chaconine at a concentration of 1 microg/mL against the liver carcinoma cells were higher than those observed with the anticancer drugs doxorubicin and camptothecin. Because alpha-chaconine, alpha-solanine, and alpha-tomatine also inhibited normal human liver HeLa (Chang) cells, safety considerations should guide the use of these compounds as preventative or therapeutic treatments against carcinomas.

Membrane disruption and enzyme inhibition by naturally-occurring and modified chacotriose-containing Solanum steroidal glycoalkaloids

Naturally-occurring 3beta-O-chacotriosides of solasodine (solamargine), of its 22S, 25S isomer tomatidenol (beta-solamarine), and of solanidine (chaconine), as well as ring E- and F-modified derivatives of solamargine were prepared and assayed in order to assess the relevance of aglycone structural features to membrane-disruption and enzyme-inhibitory activities of the related glycoalkaloids. A ring E-opened dihydro-derivative of solasodine (the chacotrioside of dihydrosolasodine A) did not bind to cholesterol, stigmasterol or ergosterol in vitro, disrupt PC/cholesterol liposomes or mammalian erythrocytes. or inhibit acetylcholinesterase in vitro. It did not synergise with the solatrioside of dihydrosolasodine A or solasonine (nor did solamargine with dihydrosolasodine A solatrioside) in haemolysis tests. The ring F modified derivative, N-nitrososolamargine, did not inhibit acetylcholinesterase in vitro, but lysed liposomes at > or = 150 microM and pH 7. Increasing the pH to 8 (but not 9) further enhanced disruption. The combination of N-nitrososolamargine and solasonine did not cause any disruption of liposomes. Beta-solamarine showed no anti-acetylcholinesterase activity in vitro at up to 100 microM, but disrupted liposomes at 75 and 150 microM, although not to the extent caused by solamargine or chaconine. In combination with both the (inactive) solatriosides, solasonine and solanine, 75 microM beta-solamarine produced synergistic effects, with liposome disruption greater than 150 microM beta-solamarine alone. Beta-solamarine, solamargine and chaconine showed similar haemolytic activity. Beta-solamarine synergised with the solatriosides solasonine and solanine in disrupting erythrocytes. Preliminary structure-activity relationships were evaluated for the active chacotriosides in an attempt to define the scope and limitations of this model study.

The rhamnose moiety of solamargine plays a crucial role in triggering cell death by apoptosis

Solamargine, solasodine and khasianine steroidal alkaloids are utilized to determine the role of carbohydrate moiety in the mechanism of apoptosis. The C3 side chain of solamargine, khasianine and solasodine contains 4'Rha-Glc-Rha2', 4'Rha-Glc and H, respectively. Solamargine possessed potent cytotoxicity to human hepatoma cells, while the cytotoxicity of khasianine was greatly diminished. Nevertheless, only solamargine could induced "sub-G1" of apoptotic feature in flowcytometry. Thus, the 2'Rha moiety of solamargine may play a crucial role in triggering cell death by apoptosis. In addition, the molecular modeling of solamargine indicated that the 2'Rha moiety was adjacent to the rigid steroid structure, and drastically changed the dihedral angle of the glycosidic bond. The regulations of TNFR I and II expression by different carbohydrate moieties were also distinct. It implied that the carbohydrate moieties of steroidal alkaloids might alter the binding specificity to steroid receptors and consequently regulate the gene expression in different manners.

Inhibition of binding of bacteria to amniochorionic membranes by amniotic fluid

The immunological composition of amniotic fluids is shown to be of such a lower order of activity that its role in fetal protection may be limited. Also, amniotic fluids were found not to have classical antibiotic activity. Amniotic fluids (25/31), however, were found to inhibit, by 27.5% to 88.2%, three target bacteria from binding to discs of amniochorionic membranes. This inhibition is also demonstrable with the monosaccharides alpha-D(+)-fucose, D(+)-galactose, alpha-D-glucose, alpha-D-lactose and bovine serum albumin-lactose conjugate, whereas other glycoconjugates enhanced bacterial binding. This demonstrates that the test bacteria bind to the amniochorionic membranes using bacterial lectins. In intraamniotic infection bacterial lectins may be complexed by amniotic fluid glycoconjugates which prevent the bacteria from binding to the amniochorionic membranes. This would explain asymptomatic infection and in the absence or reduced levels of the glycoconjugates the bacteria would bind to the amniochorionic membranes giving rise to symptomatic infection.

Topical treatment of malignant and premalignant skin lesions by very low concentrations of a standard mixture (BEC) of solasodine glycosides

A cream formulation containing high concentrations (10%) of a standard mixture of solasodine glycosides (BEC) has been shown to be effective in the treatment of malignant and benign human skin tumours. We now report that a preparation (Curaderm) which contains very low concentrations of BEC (0.005%) is effective in the treatment of keratoses, basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin of humans. In an open study, clinical and histological observations indicated that all lesions (56 keratoses, 39 BCCs and 29 SCCs) treated with Curaderm had regressed. A placebo formulation had no effect on a smaller number of treated lesions. Curaderm had no adverse effect on the liver, kidneys or haematopoietic system.

Solasodine glycosides. Selective cytotoxicity for cancer cells and inhibition of cytotoxicity by rhamnose in mice with sarcoma 180

BEC, a standard mixture of solasodine glycosides is effective in vivo against murine sarcoma 180 (S180), whereas the aglycone solasodine at equimolar concentrations is ineffective. The efficacy of BEC against S180 in vivo can be inhibited by rhamnose. Mice which are in their terminal stage with S180 can tolerate and become symptom-free of cancer by single dose administration of BEC at concentrations of BEC three times the LD100 for normal mice. These observations suggest that the binding of solasodine glycosides on tumour cells may be mediated through the monosaccharide rhamnose, which forms part of solasonine, solamargine and di-glycosides of solasodine in BEC. Furthermore, these results provide evidence that BEC selectively destroys tumour cells relative to normal cells in vivo.