α-Solanine attenuates chondrocyte pyroptosis to improve osteoarthritis via suppressing NF-κB pathway.

α-Solanine has been shown to exhibit anti-inflammatory and anti-tumour properties; however, its efficacy in treating osteoarthritis (OA) remains ambiguous. The study aimed to evaluate the therapeutic effects of α-solanine on OA development in a mouse OA model. The OA mice were subjected to varying concentrations of α-solanine, and various assessments were implemented to assess OA progression. We found that α-solanine significantly reduced osteophyte formation, subchondral sclerosis and OARSI score. And it decreased proteoglycan loss and calcification in articular cartilage. Specifically, α-solanine inhibited extracellular matrix degradation by downregulating collagen 10, matrix metalloproteinase 3 and 13, and upregulating collagen 2. Importantly, α-solanine reversed chondrocyte pyroptosis phenotype in articular cartilage of OA mice by inhibiting the elevated expressions of Caspase-1, Gsdmd and IL-1ß, while also mitigating aberrant angiogenesis and sensory innervation in subchondral bone. Mechanistically, α-solanine notably hindered the early stages of OA progression by reducing I-κB phosphorylation and nuclear translocation of p65, thereby inactivating NF-κB signalling. Our findings demonstrate the capability of α-solanine to disrupt chondrocyte pyroptosis and sensory innervation, thereby improving osteoarthritic pathological progress by inhibiting NF-κB signalling. These results suggest that α-solanine could serve as a promising therapeutic agent for OA treatment.

Antioxidants Amelioration Is Insufficient to Prevent Acrylamide and Alpha-Solanine Synergistic Toxicity in BEAS-2B Cells.

Cells produce free radicals and antioxidants when exposed to toxic compounds during cellular metabolism. However, free radicals are deleterious to lipids, proteins, and nucleic acids. Antioxidants neutralize and eliminate free radicals from cells, preventing cell damage. Therefore, the study aims to determine whether the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) will ameliorate the maximum dose of acrylamide and alpha (α)-solanine synergistic toxic effects in exposed BEAS-2B cells. These toxic compounds are consumed worldwide by eating potato products. BEAS-2B cells were simultaneously treated with BHA 10 µM and BHT 20 µM and incubated in a 5% CO2 humidified incubator for 24 h, followed by individual or combined treatment with acrylamide (3.5 mM) and α-solanine (44 mM) for 48 h, including the controls. Cell morphology, DNA, RNA, and protein were analyzed. The antioxidants did not prevent acrylamide and α-solanine synergistic effects in exposed BEAS-2B cells. However, cell morphology was altered; polymerase chain reaction (PCR) showed reduced RNA constituents but not DNA. In addition, the toxic compounds synergistically inhibited AKT/PKB expression and its downstream genes. The study showed BHA and BHT are not protective against the synergetic toxic effects of acrylamide and α-solanine in exposed BEAS-2B cells.

Characterization of C-26 aminotransferase, indispensable for steroidal glycoalkaloid biosynthesis.

Steroidal glycoalkaloids (SGAs) are toxic specialized metabolites found in members of the Solanaceae, such as Solanum tuberosum (potato) and Solanum lycopersicum (tomato). The major potato SGAs are α-solanine and α-chaconine, which are biosynthesized from cholesterol. Previously, we have characterized two cytochrome P450 monooxygenases and a 2-oxoglutarate-dependent dioxygenase that function in hydroxylation at the C-22, C-26 and C-16α positions, but the aminotransferase responsible for the introduction of a nitrogen moiety into the steroidal skeleton remains uncharacterized. Here, we show that PGA4 encoding a putative γ-aminobutyrate aminotransferase is involved in SGA biosynthesis in potatoes. The PGA4 transcript was expressed at high levels in tuber sprouts, in which SGAs are abundant. Silencing the PGA4 gene decreased potato SGA levels and instead caused the accumulation of furostanol saponins. Analysis of the tomato PGA4 ortholog, GAME12, essentially provided the same results. Recombinant PGA4 protein exhibited catalysis of transamination at the C-26 position of 22-hydroxy-26-oxocholesterol using γ-aminobutyric acid as an amino donor. Solanum stipuloideum (PI 498120), a tuber-bearing wild potato species lacking SGA, was found to have a defective PGA4 gene expressing the truncated transcripts, and transformation of PI 498120 with functional PGA4 resulted in the complementation of SGA production. These findings indicate that PGA4 is a key enzyme for transamination in SGA biosynthesis. The disruption of PGA4 function by genome editing will be a viable approach for accumulating valuable steroidal saponins in SGA-free potatoes.

Involvement of miRNAs in response to oxidative stress induced by the steroidal glycoalkaloid α-solanine in hepatocellular carcinoma cells.

BACKGROUND: α-Solanine is a natural toxic glycoalkaloid produced in some species of the Solanaceae family with antiproliferative activity in various cancers. OBJECTIVE: This study aimed to investigate the effect of α-solanine on the oxidative stress status in human hepatocellular carcinoma HepG2 cells and to evaluate its influence on microRNAs (miRNAs) associated with oxidative stress and NF-κB regulation. METHODS: The prooxidant effect of α-solanine was tested by the decay rate of the fluorescent probe, ß-phycoerythrin, and by measuring malondialdehyde, reduced Glutathione, catalase, and superoxide dismutase following treatment of HepG2 cells with low doses of α-solanine. Immunocytochemical techniques were used to detect mitochondrial membrane potential (ΔΨm) and NF-κB protein. The gene expression of NF-κB and miRNAs was evaluated by real-time PCR. RESULTS: α-Solanine is a prooxidant that causes a rapid decay in the fluorescence intensity of ß-phycoerythrin. It induces oxidative stress-related alterations such as increased lipid peroxidation and reduced antioxidant markers. Oxidative stress induced by α-solanine was mediated by decreased ΔΨm, increased NF-κB expression, upregulation of miRNAs that control oxidative stress by regulating the NF-κB pathway, and downregulation of oncogenic miRNAs that inhibit the NF-κB pathway. CONCLUSION: α-Solanine-induced oxidative stress is mediated by alterations in the NF-κB pathway with a detected crosstalk between α-solanine treatment and the expression of oxidative stress-responsive miRNAs.

Solanaceae glycoalkaloids: α-solanine and α-chaconine modify the cardioinhibitory activity of verapamil.

CONTEXT: Solanaceae glycoalkaloids (SGAs) possess cardiomodulatory activity. OBJECTIVE: This study investigated the potential interaction between verapamil and glycoalkaloids. MATERIAL AND METHODS: The cardioactivity of verapamil and glycoalkaloids (α-solanine and α-chaconine) was tested in adult beetle (Tenebrio molitor) myocardium in vitro using microdensitometric methods. The myocardium was treated with pure substances and mixtures of verapamil and glycoalkaloids for 9 min with saline as a control. Two experimental variants were used: simultaneous application of verapamil and glycoalkaloids or preincubation of the myocardium with one of the compounds followed by perfusion with a verapamil solution. We used 9 × 10-6-5 × 10-5 M and 10-9-10-5 M concentration for verapamil and glycoalkaloids, respectively. RESULTS: Verapamil, α-solanine and α-chaconine showed cardioinhibitory activity with IC50 values equal to 1.69 × 10-5, 1.88 × 10-7 and 7.48 × 10-7 M, respectively. When the glycoalkaloids were applied simultaneously with verapamil, an antagonistic effect was observed with a decrease in the maximal inhibitory effect and prolongation of t50 and the recovery time characteristic of verapamil. We also confirmed the expression of two transcript forms of the gene that encodes the α1 subunit of L-type calcium channels in the myocardium and brain with equal transcription levels of both forms in the myocardium and significant domination of the shorter form in the brain of the insect species tested. DISCUSSION AND CONCLUSIONS: The results show that attention to the composition of the daily diet during therapy with various drugs is particularly important. In subsequent studies, the nature of interaction between verapamil and SGAs on the molecular level should be checked, and whether this interaction decreases the efficiency of cardiovascular therapy with verapamil in humans.

Alpha Solanine: A Novel Natural Bioactive Molecule with Anticancer Effects in Multiple Human Malignancies.

Cancer is one of the leading causes of death worldwide. Despite improvement in existing treatment modalities and addition of new anticancer drugs in the cancer clinic, cancer associated mortalities are continuously increasing. It is therefore, necessary to explore alternative treatment options to reduce the burden of cancer. In recent years, there is growing concern toward the use of natural products for treating cancer because of their ability to target multiple signaling molecules. α-solanine is a glycolalkaloid mainly present in potato tuber and Nightshade family plants. It possesses anti-pyretic, anti-diabetic, anti-allergic, anti-inflammatory and antibiotic activities. In recent years, α-solanine has been explored for its anticancer activity and showed promising results. Among all sources, potato peel contains adequate concentration of α-solanine. Every year, a large volume of potato peel is produced as a waste or sold at low cost. So α-solanine can be proved as an effective and cheap source for cancer therapy. The aim of this review is to summarize the recent data on anticancer activity of α-solanine and discuss it as a potential lead for cancer therapy.

Wnt/PCP signalling cascade disruption by JNK inhibition as a potential mechanism underlying the teratogenic effects of potato glycoalkaloids.

It is hypothesised that the inhibition of the non-canonical Wnt/PCP intracellular signalling cascade by potato glycoalkaloids, [Formula: see text]-solanine and [Formula: see text]-chaconine, results in an increased risk of neural tube defects (NTDs). One very prominent intracellular signalling pathway with substantial implications in the development and closure of the neural tube is the Wnt/PCP pathway. Experimental inhibition of this results in NTDs. A vital element of this signalling cascade is JNK, which controls the transcription of DNA, which controls cell polarity and directional cell migration. JNK inhibition also results in NTDs experimentally. Through their use in cancer research, [Formula: see text]-solanine and [Formula: see text]-chaconine were found to inhibit metastasis by inhibiting JNK, among other intracellular signalling molecules. Thus, this shows that potato glycoalkaloids increase the likelihood of causing NTDs by inhibiting the proper functioning of JNK in the Wnt/PCP pathway, resulting in defective neural tube closure.

Emerging themes of regulation of oncogenic proteins by Solanum nigrum and its bioactive molecules in different cancers.

Research over the decades has sequentially and systematically provided a near-complete resolution of multifaceted and therapeutically challenging nature of cancer. Drug discovery from plants has enjoyed a renaissance in the past few years. Natural products have provided many of the lead structures, which are currently being used as templates for the design and synthesis of novel compounds with biologically enhanced properties. With the maturity and diversification of technologies, there is a growing need to design high-throughput functional assays for the evaluation of the myriad of compounds being catalogued. This review sheds light on the tumor suppressive properties of Solanum nigrum and its bioactive ingredients. Several worthy of mention include uttroside B, solanine, solamargine, and physalins, which have been tested for efficacy in cancer cell lines and xenografted mice. We have summarized the most recent findings related to S. nigrum-mediated regulation of intracellular protein network in different cancers. α-Solanine, an active component of S. nigrum, is involved in the regulation of microRNA-21 (miRNA-21) (oncogenic) and miRNA-138 (tumor suppressor) in prostate cancer. However, this is the only available evidence that gives us a clue related to the tumor suppressive effects exerted by components of S. nigrum at a posttranscriptional level. More interestingly, S. nigrum and its components exerted inhibitory effects on different pathways including PI3K/AKT, JAK-STAT, VEGF/VEGFR, and matrix metalloproteinases in different cancers. We also provide an overview of new tools, methodologies, and approaches, which will allow researchers to extract as much information as possible out of the tremendous data sets currently being generated. The use of computational tools will be helpful in processing structurally complex natural products and also in prediction of their macromolecular targets.

Maternal periconceptional consumption of sprouted potato and risks of neural tube defects and orofacial clefts.

BACKGROUND: The association between maternal consumption of sprouted potato during periconceptional period on the development of neural tube defects (NTDs) or orofacial clefts (OFCs) remains unclear. We aimed to examine the association between maternal consumption of sprouted potatoes during periconceptional period and risks of NTDs or OFCs. METHODS: Subjects included 622 NTD cases, 135 OFC cases and 858 nonmalformed controls, were recruited from a case-control study in Shanxi Province of northern China between 2002 and 2007. Information on demographics, maternal sprouted potato consumption, lifestyle behaviors and folic acid supplementation was collected. RESULTS: Consumption of sprouted potatoes was associated with elevated odds of total NTDs (OR = 2.20; 95% CI, 1.12-4.32) and anencephaly (OR = 2.48; 95% CI, 1.10-5.58); no association for spina bifida or encephalocele. Sprouted potato consumption increased the risk of total OFCs (OR = 3.49; 95% CI, 1.29-9.49) and cleft lip with or without cleft palate (CL ± P) (OR = 4.03; 95% CI, 1.44-11.28). CONCLUSION: Maternal consumption of sprouted potatoes during periconceptional period may increase the risks of NTDs and OFCs. Given that potato is commonly consumed around the world, improper preservation and use should be a matter of concern in respect of the potential teratogenicity.

The Impact of Steroidal Glycoalkaloids on the Physiology of Phytophthora infestans, the Causative Agent of Potato Late Blight.

Steroidal glycoalkaloids (SGAs) are plant secondary metabolites known to be toxic to animals and humans and that have putative roles in defense against pests. The proposed mechanisms of SGA toxicity are sterol-mediated disruption of membranes and inhibition of cholinesterase activity in neurons. It has been suggested that phytopathogenic microorganisms can overcome SGA toxicity by enzymatic deglycosylation of SGAs. Here, we have explored SGA-mediated toxicity toward the invasive oomycete Phytophthora infestans, the causative agent of the late blight disease in potato and tomato, as well as the potential for SGA deglycosylation by this species. Our growth studies indicate that solanidine, the nonglycosylated precursor of the potato SGAs α-chaconine and α-solanine, has a greater physiological impact than its glycosylated forms. All of these compounds were incorporated into the mycelium, but only solanidine could strongly inhibit the growth of P. infestans in liquid culture. Genes encoding several glycoside hydrolases with potential activity on SGAs were identified in the genome of P. infestans and were shown to be expressed. However, we found no indication that deglycosylation of SGAs takes place. We present additional evidence for apparent host-specific adaptation to potato SGAs and assess all results in terms of future pathogen management strategies.

Lanosterol synthase-like is involved with differential accumulation of steroidal glycoalkaloids in potato.

MAIN CONCLUSION: Phytosterol homeostasis may be maintained in leaves through diversion of intermediates into glycoalkaloid biosynthesis, whereas in tuber flesh, excess intermediates are catalyzed by tuber-specific StLAS - like , resulting in low tuber glycoalkaloids. Lanosterol synthase (LAS) and cycloartenol synthase (CAS) are phylogenetically related enzymes. Cycloartenol is the accepted precursor leading to cholesterol and phytosterols, and in potato, to steroidal glycoalkaloid (SGA) biosynthesis. LAS was also shown to synthesize some plant sterols, albeit at trace amounts, questioning its role in sterol homeostasis. Presently, a potato LAS-related gene (StLAS-like) was identified and its activity verified in a yeast complementation assay. A transgenic approach with targeted gene expression and metabolic profiling of sterols and SGAs was used. Analyses of StLAS-like transcript levels and StLAS-like-promoter::GUS reporter assays indicated specific expression in tuber flesh tissue. Overexpression of Arabidopsis AtLAS in leaves where the endogenic StLAS-like is not expressed, resulted with increased SGA level and reduced phytosterol level, while in the tuber flesh SGA level was reduced. StLAS-like expression only in tuber flesh may explain the differential accumulation of SGAs in commercial cultivars-low in tubers, high in leaves. In leaves, to maintain phytosterol homeostasis, an excess of intermediates may be diverted into SGA biosynthesis, whereas in tuber flesh these intermediates are catalyzed by tuber-specific StLAS-like instead, resulting in low levels of SGA.

Two Cytochrome P450 Monooxygenases Catalyze Early Hydroxylation Steps in the Potato Steroid Glycoalkaloid Biosynthetic Pathway.

α-Solanine and α-chaconine, steroidal glycoalkaloids (SGAs) found in potato (Solanum tuberosum), are among the best-known secondary metabolites in food crops. At low concentrations in potato tubers, SGAs are distasteful; however, at high concentrations, SGAs are harmful to humans and animals. Here, we show that POTATO GLYCOALKALOID BIOSYNTHESIS1 (PGA1) and PGA2, two genes that encode cytochrome P450 monooxygenases (CYP72A208 and CYP72A188), are involved in the SGA biosynthetic pathway, respectively. The knockdown plants of either PGA1 or PGA2 contained very little SGA, yet vegetative growth and tuber production were not affected. Analyzing metabolites that accumulated in the plants and produced by in vitro enzyme assays revealed that PGA1 and PGA2 catalyzed the 26- and 22-hydroxylation steps, respectively, in the SGA biosynthetic pathway. The PGA-knockdown plants had two unique phenotypic characteristics: The plants were sterile and tubers of these knockdown plants did not sprout during storage. Functional analyses of PGA1 and PGA2 have provided clues for controlling both potato glycoalkaloid biosynthesis and tuber sprouting, two traits that can significantly impact potato breeding and the industry.

α-Solanine Isolated From Solanum Tuberosum L. cv Jayoung Abrogates LPS-Induced Inflammatory Responses Via NF-κB Inactivation in RAW 264.7 Macrophages and Endotoxin-Induced Shock Model in Mice.

α-Solanine, a trisaccharide glycoalkaloid, has been reported to possess anti-cancer effects. In this study, we investigated the anti-inflammatory effects of α-solanine isolated from "Jayoung" a dark purple-fleshed potato by examining its in vitro inhibitory effects on inducible nitric-oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines in LPS-induced RAW 264.7 macrophages and its in vivo effects on LPS-induced septic shock in a mouse model. α-Solanine suppressed the expression of iNOS and COX-2 both at protein and mRNA levels and consequently inhibited nitric oxide (NO) and prostaglandin E2 (PGE2 ) production in LPS-induced RAW 264.7 macrophages. α-Solanine also reduced the production and mRNA expression of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) induced by LPS. Furthermore, molecular mechanism studies indicated that α-solanine inhibited LPS-induced activation of nuclear factor-κB (NF-κB) by reducing nuclear translocation of p65, degradation of inhibitory κBα (IκBα), and phosphorylation of IκB kinaseα/ß (IKKα/ß). In an in vivo experiment of LPS-induced endotoxemia, treatment with α-solanine suppressed mRNA expressions of iNOS, COX-2, IL-6, TNF-α, and IL-1ß, and the activation of NF-κB in liver. Importantly, α-solanine increased the survival rate of mice in LPS-induced endotoxemia and polymicrobial sepsis models. Taken together, our data suggest that the α-solanine may be a promising therapeutic against inflammatory diseases by inhibiting the NF-κB signaling pathway. J. Cell. Biochem. 117: 2327-2339, 2016. © 2016 Wiley Periodicals, Inc.

α-Solanine Modulates the Radiosensitivity of Esophageal Cancer Cells by Inducing MicroRNA 138 Expression.

BACKGROUND: Esophageal cancer (EC) is one of the most common malignant tumors in the world. Due to difficulties with performing the operation, most patients choose to have palliative treatment instead. Radiotherapy is one of the main palliative treatments of EC. However, the clinical efficacy of radiotherapy is not satisfactory α-Solanine is a bioactive component of steroidal glycoalkaloids which has been demonstrated to exhibit anti-metastasis activity in different cancers. In the present study, we determined the effect of α-solanine on the radiosensitivity of EC cells and priliminarily explored the underlying molecular mechanisms. METHODS: Cell Counting Kit-8 (CCK-8) assay was conducted to found the cytotoxic effect of α-solanine on EC cells. CCK-8 assay and colony-forming survival assays were performed to explore the effect of α-solanine on cell viability and proliferation of EC cells after irradiation. Immunofluorescence and comet assays were used to detect the effect of α-solanine on DNA repair capacity of EC cells after irradiation. The flow cytometry (FCM) and Hoechst/PI staining were conductd to study the effect of α-solanine on apoptosis of EC cells after irradiation. RESULTS: The cytotoxic effect of α-solanine to EC cells was dose-dependent. The results of CCK-8, colony-forming survival assay, immunofluorescence, comet assay, FCM and Hoechst/PI staining showed that α-solanine could enhance the radiosensitivity of EC cells. α-Solanine could downregulate Survivin expression level by upregulating miR-138 expression in EC cells. Upregulation of miR-138 and knock down Survivin both enhanced the radiosensitivity of EC cells. Moreover, Survivin could restore the effect of α-solanine and miR-138 on radiosensitivity of EC cells. CONCLUSIONS: α-solanine could enhance the radiosensitivity of esophageal cancer cells by inducing microRNA-138 expression, and probably be an effective radiosensitizer in treating EC.

Anticancer function of α-solanine in lung adenocarcinoma cells by inducing microRNA-138 expression.

Currently, lung cancer is still a main cause of malignancy-associated death worldwide. Even though various methods for prevention and treatment of lung cancer have been improved in recent decades, the 5-year survival rate has remained very low. Insights into the anticancer function of small-molecule anticancer compounds have opened our visual field about cancer therapy. α-Solanine has been well studied for its antitumor properties, but its effect in lung cancer and associated molecular mechanisms have not yet been evaluated. To explore the anticancer function of α-solanine, we performed an MTT assay, Transwell arrays, colony-forming survival assay, quantitative reverse transcription PCR (qRT-PCR), Western blotting, and dual luciferase reporter assays in A549 and H1299 cells. We found that α-solanine not only inhibited cell migration and invasion ability but also enhanced the chemosensitivity and radiosensitivity of A549 and H1299 cells. Moreover, we discovered that α-solanine could affect the expression of miR-138 and focal adhesion kinase (FAK), both of which were also found to affect the chemosensitivity and radiosensitivity of A549 and H1299 cells. In conclusion, α-solanine could affect miR-138 and FAK expression to restrict cell migration and invasion and enhance the chemosensitivity and radiosensitivity of A549 and H1299 cells. The α-solanine/miR-138/FAK cascade can probably be a potential therapy target against lung adenocarcinoma.

Antifungal activity of secondary plant metabolites from potatoes (Solanum tuberosum L.): Glycoalkaloids and phenolic acids show synergistic effects.

AIMS: To study the antifungal effects of the potato secondary metabolites α-solanine, α-chaconine, solanidine and caffeic acid, alone or combined. METHODS AND RESULTS: Resistance to glycoalkaloids varied among the fungal species tested, as derived from minimum inhibitory concentrations assays. Synergistic antifungal activity between glycoalkaloids and phenolic compounds was found. Changes in the fluidity of fungal membranes caused by potato secondary plant metabolites were determined by calculation of the generalized polarization values. The results partially explained the synergistic effect between caffeic acid and α-chaconine and supported findings on membrane disruption mechanisms from previous studies on artificial membranes. LC/MS analysis was used to determine variability and relative amounts of sterols in the different fungal species. Results suggested that the sterol pattern of fungi is related to their resistance to potato glycoalkaloids and to their taxonomy. CONCLUSION: Fungal resistance to α-chaconine and possibly other glycoalkaloids is species dependent. α-Chaconine and caffeic acid show synergistic antifungal activity. The taxonomic classification and the sterol pattern play a role in fungal resistance to glycoalkaloids. SIGNIFICANCE AND IMPACT OF THE STUDY: Results improve the understanding of the antifungal mode of action of potato secondary metabolites, which is essential for their potential utilization as antifungal agents in nonfood systems.

Effect of Drying Methods on the Steroidal Alkaloid Content of Potato Peels, Shoots and Berries.

The present study has found that dried potato samples yielded significantly higher levels of steroidal alkaloids such as α-solanine and α-chaconine than the corresponding fresh samples, as determined by the UPLC-MS/MS technique. Among the drying techniques used, air drying had the highest effect on steroidal alkaloid contents, followed by freeze drying and vacuum oven drying. There was no significant difference between the freeze dried and vacuum oven dried samples in their α-chaconine contents. However, freeze dried potato shoots and berries had significantly higher α-solanine contents (825 µg/g dry weight (DW) in shoots and 2453 µg/g DW in berries) than the vacuum oven dried ones (325 µg/g dry weight (DW) in shoots and 2080 µg/g DW in berries). The kinetics of steroidal alkaloid contents of potato shoots during air drying were monitored over a period of 21 days. Both α-solanine and α-chaconine content increased to their maximum values, 875 µg/g DW and 3385 µg/g DW, respectively, after 7 days of drying. The steroidal alkaloid contents of the shoots decreased significantly at day 9, and then remained unchanged until day 21. In line with the potato shoots, air dried potato tuber peels also had higher steroidal alkaloid content than the freeze dried and vacuum oven dried samples. However, a significant decrease of steroidal alkaloid content was observed in air dried potato berries, possibly due to degradation during slicing of the whole berries prior to air drying. Remarkable variation in steroidal alkaloid contents among different tissue types of potato plants was observed with the potato flowers having the highest content.

Structural effects of the Solanum steroids solasodine, diosgenin and solanine on human erythrocytes and molecular models of eukaryotic membranes.

This report presents evidence that the following Solanum steroids: solasodine, diosgenin and solanine interact with human erythrocytes and molecular models of their membranes as follows: a) X-ray diffraction studies showed that the compounds at low molar ratios (0.1-10.0mol%) induced increasing structural perturbation to dimyristoylphosphatidylcholine bilayers and to a considerable lower extent to those of dimyristoylphosphatidylethanolamine; b) differential scanning calorimetry data showed that the compounds were able to alter the cooperativity of dimyristoylphosphatidylcholine, dimyristoylphosphatidylethanolamine and dimyristoylphosphatidylserine phase transitions in a concentration-dependent manner; c) in the presence of steroids, the fluorescence of Merocyanine 540 incorporated to the membranes decreased suggesting a fluidization of the lipid system; d) scanning electron microscopy observations showed that all steroids altered the normal shape of human erythrocytes inducing mainly echinocytosis, characterized by the formation of blebs in their surfaces, an indication that their molecules are located into the outer monolayer of the erythrocyte membrane.

Self-organizing behaviour of glycosteroidal bolaphiles: insights into lipidic microsegregation.

In this article we describe work on the synthesis of bolaphile biomimics composed of glucose head groups and steroidal units linked together by a methylene chain of varying length. The condensed phases formed by self-organization of the products as a function of temperature were characterized by differential scanning calorimetry and thermal polarized light microscopy. The results of these studies show that the thermal stabilities of the lamellar mesophases formed vary linearly as a function of increasing aliphatic composition, which reflects a linear hydrophobic-hydrophilic balance with respect to transition temperatures.

Recovery of steroidal alkaloids from potato peels using pressurized liquid extraction.

A higher yield of glycoalkaloids was recovered from potato peels using pressurized liquid extraction (1.92 mg/g dried potato peels) compared to conventional solid-liquid extraction (0.981 mg/g dried potato peels). Response surface methodology deduced the optimal temperature and extracting solvent (methanol) for the pressurized liquid extraction (PLE) of glycoalkaloids as 80 °C in 89% methanol. Using these two optimum PLE conditions, levels of individual steroidal alkaloids obtained were of 597, 873, 374 and 75 µg/g dried potato peel for α-solanine, α-chaconine, solanidine and demissidine respectively. Corresponding values for solid liquid extraction were 59%, 46%, 40% and 52% lower for α-solanine, α-chaconine, solanidine and demissidine respectively.