Common anticholinergic solanaceaous plants of temperate Europe - A review of intoxications from the literature (1966-2018).

Datura stramonium, Atropa belladonna, Hyoscyamus niger, and Scopolia carniolica are all temperate plants from the family Solanaceae, which as a result of their anticholinergic tropane alkaloids, hyoscyamine/atropine and scopolamine, have caused many cases of poisoning around the world. Despite the danger these nightshade plants represent, the literature often presents incomplete cases lacking in details and filled with ambiguity, and reviews on the topic tend to be limited in scope. Many also point to a gap in knowledge of these plants among physicians. To address this, the following review focuses on intoxications involving these plants as reported in the literature between 1966 and 2018, with brief mention to pertinent related plants to contextualise and provide a fuller picture of the situation surrounding the presently discussed temperate plants. Analysis of the literature displays that D. stramonium is largely associated with drug use among teens while A. belladonna is primarily ingested as a result of the berries being mistaken for edible fruits. H. niger was found to be largely ingested when mistaken for other plants, and S. carniolica was the cause of incredibly few intoxications.

The Steroidal Glycoalkaloids from Solanaceae: Toxic Effect, Antitumour Activity and Mechanism of Action.

Steroidal glycoalkaloids present in Solanaceae are toxic compounds biosynthesised for the protection of the plants. However, many health benefits of these compounds have been reported so far. One of their promising targets might be cancer, as demonstrated in a large number of studies. However, the main mechanism of action seems to be unclear. It could include the induction of apoptosis or trigger a necrosis with a subsequent inflammatory response. The relatively high systemic toxicity of steroidal compounds is another effect that must be taken into account in anticancer research. The main aim of this work was to summarise the recent progress in the investigation of the mechanisms of their antitumour action and to discuss their potential.

Biosynthesis of antinutritional alkaloids in solanaceous crops is mediated by clustered genes.

Steroidal glycoalkaloids (SGAs) such as α-solanine found in solanaceous food plants--as, for example, potato--are antinutritional factors for humans. Comparative coexpression analysis between tomato and potato coupled with chemical profiling revealed an array of 10 genes that partake in SGA biosynthesis. We discovered that six of them exist as a cluster on chromosome 7, whereas an additional two are adjacent in a duplicated genomic region on chromosome 12. Following systematic functional analysis, we suggest a revised SGA biosynthetic pathway starting from cholesterol up to the tetrasaccharide moiety linked to the tomato SGA aglycone. Silencing GLYCOALKALOID METABOLISM 4 prevented accumulation of SGAs in potato tubers and tomato fruit. This may provide a means for removal of unsafe, antinutritional substances present in these widely used food crops.

In vitro leishmanicidal and cytotoxic activities of the glycoalkaloids from Solanum lycocarpum (Solanaceae) fruits.

Leishmaniasis is an infection caused by a protozoan parasite of the genus Leishmania and is the second most prevalent parasitic protozoal disease after malaria in the world. We report the in vitro leishmanicidal activity on promastigote forms of Leishmania amazonensis and cytotoxicity, using LLCMK2 cells, of the glycoalkaloids from the fruits of Solanum lycocarpum, determined by colorimetric methods. The alkaloidic extract was obtained by acid-base extraction; solamargine and solasonine were isolated by silica-gel chromatography, followed by reversed-phase HPLC final purification. The alkaloidic extract, solamargine, solasonine, as well as the equimolar mixture of the glycoalkaloids solamargine and solasonine displayed leishmanicidal activity against promastigote forms of L. amazonensis, whereas the aglycone solasodine was inactive. After 24 and 72 h of incubation, most of the samples showed lower cytotoxicities (IC50 6.5 to 124 µM) as compared to leishmanicidal activity (IC50 1.1 to 23.6 µM). The equimolar mixture solamargine/solasonine was the most active with an IC50 value of 1.1 µM, after 72 h. Likewise, solamargine was the most active after 24 h with an IC50 value of 14.4 µM, both in comparison with the positive control amphotericin B.

Prenatal exposure to tobacco extract containing nicotinic alkaloids produces morphological and behavioral changes in newborn rats.

Tobacco exposure is not only a health concern for adults but has also been shown to exert deleterious effects on the health of the fetus, newborn, child, and adolescent. Decreased cognitive function, lower Intellectual Quotient (IQ) and deficits in learning and memory in children have been associated with maternal smoking during pregnancy. In this study, we have studied the effect of a tobacco plant extract on the growth and development in the rat. The extract contained relative proportions of alkaloids, including nicotine, purified by chemical separation. Pregnant rats received oral doses of either control (NaCl) or tobacco extract during the entire gestational period. Offspring length and body weight were measured. Each day, the offspring were observed for the following physical parameters: hair growth, incisor eruption and eye opening. The day of appearance of these developments was recorded. Before weaning, the offspring were examined to test their cliff avoidance response (6 postnatal day (PN)), surface righting reflex (05, 07, 13 postnatal day), swimming development (10, 12 postnatal day), negative geotaxis response (7,9,13 and 17 postnatal day) and jumping down choice cage (15, 17 postnatal day). Administration of tobacco extract to dams during the entire gestation period affects behavior and development in pups. The observed effects were a delay in opening eyes, incisor eruption and hair appearance, behavioral developments and an alteration in the rate of success behavior. However, in the jumping down choice cage test there was no difference compared to control animals. The results suggest that tobacco extract has a significant effect on the development of behavioral patterns, orientation and motor coordination and function. They also suggest significant growth retardation and teratogenic effects.

In vivo antimalarial activities of glycoalkaloids isolated from Solanaceae plants.

CONTEXT: Malaria is one of the most common and serious protozoan tropical diseases. Multi-drug resistance remains pervasive, necessitating the continuous development of new antimalarial agents. OBJECTIVE: Many glycosides, such as triterpenoid saponins, were shown to have antimalarial activity against Plasmodium falciparum in vitro. This study was to elucidate the ability of five glycoalkaloids against Plasmodium yoelii and develop new antimalarial lead compounds. MATERIALS AND METHODS: Glycoalkaloids were isolated from three kinds of Solanaceae plants: chaconine and solanine were isolated from Solanum tuberosum L. sprouts, solamargine and solasonine from Solanum nigrum L. fruit, tomatine from Lycopersicon esculentum Mill. fruit. The five isolated glycoalkaloids were evaluated against Plasmodium yoelii 17XL in mice with 4-day parasitemia suppression test in different concentrations. RESULTS: Chaconine showed a dose-dependent suppression of malaria infection, ED50, 4.49 mg/kg; therapeutic index (TI), approximately 9. At a dose of 7.50 mg/kg, the parasitemia suppressions of chaconine, tomatine, solamargine, solasonine and solanine were 71.38, 65.25, 64.89, 57.47 and 41.30%, respectively. At 3.75 mg/kg, the parasitemia suppression of chaconine was 42.66%, but the derivative, chaconine-6-O-sulfate, appeared to show no antimalarial activity. Simultaneous administration of chaconine and solanine in 1:1 did not show any synergistic effects. DISCUSSION AND CONCLUSION: The results showed that the glycoalkaloids with chacotriose (chaconine and solamargine) were more active than those with solatriose (solanine and solasonine). Chaconine was the most active among the five glycoalkaloids. We propose that the activity is dependent upon non-specific carbohydrate interactions. The 6-OH of chaconine is important for antimalarial activity.

Toxicological effects of alpha-solamargine in experimental animals.

Alpha-solamargine isolated from the fresh fruits of Solanum americanum Miller was studied for its toxicity. Lethality studies in rats showed a dose-mortality relationship with a LD(50) of 42 mg/kg body weight intraperitoneally. The chronic and subchronic toxicity investigations indicated that the size of the glycoalkaloid dose was more important than the total glycoalkaloid intake. No appreciable toxic effects were observed at doses below 35 mg/kg body weight as indicated by blood parameters, enzyme levels and histological sections of kidney, liver and cardiac muscle. Alpha-solamargine did not affect the weight of the testes and epididymis or the number of spermatozoa but produced a slight irritation and congestion in the epididymis and testis at doses up to 50 mg/kg body weight.

Toxicological evaluations of long-term consumption of Solanum lycocarpum St. Hill fruits in male and female adult rats.

Solanum lycocarpum St. Hill is a common plant in the Brazilian savanna. This plant contains an alkaloid with stereospecific configuration to the synthesis of steroid hormones. Because the plant may be consumed long-term, the present study was undertaken to determine the possible toxic effects of S. lycocarpum fruit ingestion (3% added to the diet) on male (60 days of administration) and female (37 days) adult rats. Few significant differences in body weight and consumption of food and water, no significant differences in male and female weight gain or estrous cycle were detected. Female treated rats showed a significant reduction in uterus and liver weights; however, no significant differences were observed in other organ (adrenal, liver, seminal vesicle, testicle and ovary) weights in either sex. Additionally blood enzymes and proteins evaluated were not affected by treatment with 3% S. lycocarpum added to the diet. The present data, however, show sex-related differences in S. lycocarpum toxicity. Thus, other studies have to be conducted to better investigate female toxicity and other toxic effects of higher levels of exposure to this plant.

Assessment of the perinatal effects of maternal ingestion of Solanum malacoxylon in rats.

A perinatal study was performed to verify the toxic effects of Solanum malacoxylon, which contains a glycoside conjugated to Vitamin D(3). In the gestational study, female rats received S. malacoxylon leaves in the diet at 0, 0.1, 0.2, 0.5, and 1% from days 6 to 21 of pregnancy. At 21 days of gestation, blood samples were taken from the dams for evaluation of serum Ca and P. A laparotomy was performed and the rats were examined for standard parameters of reproductive performance. Fetuses were examined for skeletal changes and histopathologic evaluation. In the second trial, dams were fed diets containing 0 or 0.1% S. malacoxylon leaves during the gestation and lactation periods. After weaning, all animals were euthanized and biochemical and histopathologic evaluations were performed. The biochemical evaluation showed increase in Ca and P levels in females from all experimental groups; however, this effect did not occurred in a dose-related manner. Pups from dams exposed during gestation and lactationi also showed increased Ca and P levels. Fetal data suggested a delay of fetal development manifested by decreased body weight and skeletal alterations. There was also a reduction in live fetuses. Histopathologic study revealed alterations of the soft tissue in litters from dams given 1% dietary S. malacoxylon during pregnancy and 0.1% during pregnancy and lactation. These findings support our hypothesis that Vitamin D(3) glycoside crosses the placenta and suggests milk transfer of this substance.

Evaluation of the toxicity of Solanum lycocarpum in the reproductive system of male mice and rats.

Powdered Solanum lycocarpum fruit is commonly used to treat diabetes, but apparently no studies have been conducted to evaluate potential adverse side effects. In the present paper the toxic effect of S. lycocarpum was evaluated in adult male Wistar rats and Swiss mice. The administration of an aqueous extract prepared using a powder obtained from the S. lycocarpum fruit at two different dose levels (60 mg/15 ml and 120 mg/15 ml distilled water for rats and 30 mg/15 ml and 60 mg/15 ml distilled water for mice, twice daily for 5 days in each case) did not produce body weight variations in either species although a significant weight change was observed in some organs. Significant weight loss was observed only in the ventral prostate of mice receiving the high dose treatment. These results suggest a toxic effect of S. lycocarpum on the male reproductive system of the Swiss mouse, with possible antiandrogenic activity, but there was no apparent antifertility activity in rats at the doses given.

Evaluation in rabbits of the fetal effects of maternal ingestion of Solanum malacoxylon.

A study was performed to determine the possible toxic effects on the young of does that had been fed during the gestational period on a ration containing Solanum malacoxylon (Sm), a calcinogenic plant that contains a vitamin D3-glycoside conjugate. Experimental animals received a ration containing 0.03% or 0.04% of Sm leaves on days 6 to 30 of gestation. The levels of calcium, phosphorus and alkaline phosphatase in their sera, as well as their feed intake and body weight, were evaluated weekly. The does were euthanized 3 days after parturition and paraffin sections stained with haematoxylin and eosin were prepared from their heart, lungs, kidneys and aorta for histopathological examination. The young from does in the Sm 0.03% group were euthanized 3 days after birth and biochemical and histopathological determinations were performed, as described for the does. The does in both experimental groups showed decreased feed consumption and those in the Sm 0.04% group showed lower body weights throughout their gestation. Animals treated with Sm 0.04% presented a high incidence of abortion and stillbirth. There were biochemical and histopathological alterations in both experimental groups, which were more prominent in the does in the Sm 0.04% group. Litters from does treated with Sm 0.03% showed mineralization of soft tissue and an increase in phosphorus and calcium levels. These findings indicate that the vitamin D3-glycoside passes through the placental barrier to the fetus.

Developmental toxicology of solamargine and solasonine glycoalkaloids in frog embryos.

As part of an effort to improve the safety of plant foods, a need exists to define the relative toxicities of structurally different glycoalkaloids and metabolites which may be present in Solanum plant species such as potatoes, tomatoes and eggplants. The objectives of this study were to determine the relative toxicities and the modes of action of the eggplant (Solanum melongena) glycoalkaloids solamargine and solasonine in Xenopus laevis frog embryos, using membrane potential and embryo growth and teratogenicity assays. In the cell membrane assays, adverse effects on embryos were evaluated by measuring membrane potentials using an electrochromic dye, di-4-ANEPPS, as a fluorescence probe for the integrity of the membranes. In the embryo growth and teratogenesis assays, the survival of the embryos and organ malformations was used as an index of embryo toxicity. The relative potencies of glycoalkaloids are similar for frog embryo effects (survival and teratogenicities) and for membrane effects (membrane potential). Experiments with solasonine at pH 6 and 8 suggest that the unprotonated form of the glycoalkaloids appears to be involved in the membrane effects. The nature of the carbohydrate side-chains of the steroidal glycosides governs relative potencies. The possible significance of the findings to food safety and plant physiology and possible application of the membrane assays to bacterial toxins are discussed.

Induction of terata in hamsters by solanidane alkaloids derived from Solanum tuberosum.

The potential induction of terata by solanidanes has been of public health concern since a report in 1972 hypothesized that certain birth defects in humans could be attributed to ingestion of blighted potatoes. The potential teratogenicity of solanidane alkaloids from potatoes and tomatoes in domestic livestock had been considered even earlier. In the present report, oral administration of the steroidal alkaloid glycosides alpha-solanine and alpha-chaconine and their aglycone solanidine is shown to induce craniofacial malformations (exencephaly, encephalocele, and anophthalmia) in Syrian hamsters. All three alkaloids, that were either isolated or obtained by hydrolysis from Solanum tuberosum (var. Kennebec) sprouts, possessed the 22-(R),25(S)-configuration in the indolizidine moiety with no other isomers present. Toxicity constraints precluded administration of dosages high enough to induce statistically significant levels of terata in litters dosed with alpha-chaconine and permitted the attainment of only marginal statistical significance for alpha-solanine. However, malformation induction at p < 0.005 was observed in litters upon dosing both the nontoxic aglycone solanidine and the derivative solanidine N-oxide at higher levels. The relatively high teratogenicity of nontoxic solanidine, compared to the glycosides, demonstrates that terata induction by solanidanes is not due to maternal toxicity nor is the oligosaccharide portion of steroidal alkaloid glycosides required to facilitate passage of the teratogen to the fetus. The teratogenicity of solanidine N-oxide, a putative metabolite, suggests that N-oxidation is not an effective mammalian detoxification pathway. Relative teratogenic potencies (RTP) were assigned to solanidanes by conversion of literature data to equimolar doses compared to the powerful Veratrum teratogen jervine and the nonteratogenic spirosolane tomatidine. RTP values are as follows: jervine (100), 22(S),-25(R)-solanidanes (50), alpha-chaconine (43), alpha-solanine (32), 22(R),25(S)-solanidine (32), solanidine N-oxide (32), 5 alpha,6-dihydrosolanidine (9), and tomatidine (0).

A preliminary assessment of the toxic and mutagenic potential of steroidal alkaloids in transgenic mice.

Impregnated CD2 transgenic mice, which contain multiple copies of a lambda gt10lacZ construct integrated into the genome of each cell, were given a predetermined estimated maximum tolerated dose of several steroidal alkaloids: Solanum glycoalkaloids from potato, alpha-chaconine and alpha-solanine; aglycones, solanidine and solasodine, and a Veratrum alkaloid, jervine. Observations were made of dams and foetuses for indications of toxicity and/or terata; some dam livers and foetuses were assayed for mutagenicity using the lacZ gene. Other dams were gavaged with a single dose of 75 mg all-trans-retinol/kg to serve as a reference teratogen. Unexpectedly, this level of retinol was not clearly teratogenic. The results of both positive and non-positive selection systems showed that the mutation frequencies in the livers of the dams dosed with alpha-chaconine, alpha-solanine and solanidine were three to four times higher than historically normal in the livers of this transgenic mouse strain.

Absence of genotoxicity of potato alkaloids alpha-chaconine, alpha-solanine and solanidine in the Ames Salmonella and adult and foetal erythrocyte micronucleus assays.

To assess whether reported toxicities of potato-derived glycoalkaloids could be the result of interactions with cellular DNA, the genotoxic effects of alpha-solanine, alpha-chaconine and solanidine were studied, using the Ames test (Salmonella strains TA98 and TA100), the mouse peripheral blood micronucleus test and the mouse transplacental micronucleus test. The Ames test for mutagenicity with alpha-solanine was weakly positive in TA100 with S-9 activation (29 revertants per millimole per plate). However, pooled data from duplicate tests gave a negative effect. Pooled data from two experiments with alpha-chaconine gave a weak positive response in TA98 without microsomes (17 revertants per millimole per plate). The micronucleus tests for clastogenicity using male mouse and foetal blood were negative. The absence of mutagenicity and clastogenicity suggests lack of damage to intracellular DNA for potato alkaloid toxicity.

Developmental toxicology of potato alkaloids in the frog embryo teratogenesis assay--Xenopus (FETAX).

Potatoes frequently contain growth inhibitors and toxic compounds including digestive enzyme inhibitors, lectins and glycoalkaloids. The literature suggests that Solanum alkaloids have the ability to induce neurological damage such as spina bifida and other malformations. As part of a programme of improvement in the safety of potatoes using molecular plant genetics and parallel food safety evaluation, we evaluated the effect of several potato glycoalkaloids and aglycones in the frog embryo teratogenesis assay--Xenopus (FETAX) with and without metabolic activation by Aroclor 1254-induced rat liver microsomes. The data suggest that the glycoalkaloid alpha-chaconine is teratogenic and more embryotoxic than alpha-solanine, in terms of the median lethal concentration (LC50) after 96 hr of exposure, the concentration inducing gross terata in 50% of the surviving frog embryos (96-hr EC50, malformation), and the minimum concentration needed to inhibit the growth of the embryos. Since these two compounds differ only in the nature of the carbohydrate side chain attached to the 3-OH group of solanidine, the side chain appears to be an important factor in governing teratogenicity. The aglycones demissidine, solanidine and solasodine were less toxic than the glycosides alpha-chaconine and alpha-solanine. The in vitro teratogenesis assay should be useful for: (a) predicting the teratogenic potential of solanaceae alkaloids, glycoalkaloids and related natural products; and (b) facilitating experimental approaches to suppress plant genes and enzymes that control the biosynthesis of the most toxic compounds.

Hepatic ornithine decarboxylase induction by potato glycoalkaloids in rats.

The induction of hepatic ornithine decarboxylase (ODC) activity in rat livers by the potato glycoalkaloids alpha-solanine, alpha-chaconine, and their aglycone solanidine, has been studied. Ip administration of alpha-solanine at 7.5, 15 and 30 mg/kg body weight produced markedly elevated enzyme activity at 4 hr after treatment, with a linear dose response. The increase was four-fold at the lowest dose administered to 12-fold at the highest. ODC activity was measured at 1, 2, 3, 4, 5, 6, 8, and 24hr after alpha-solanine was given. A statistically significant increase in enzyme activity was evident at 3 hr after treatment; maximal activity occurred at 5 hr and was approximately 12 times greater than the dimethylsulphoxide (DMSO) control level. Elevated activities persisted for several hours, decreasing to about one-third of the maximal level at 8 hr. The relative effects of alpha-solanine, alpha-chaconine and solanidine on ODC activities were studied at 4 hr using an equimolar dose of 17 mM/kg body weight. ODC activity induced by alpha-chaconine was higher than that induced by alpha-solanine; the latter activity was two-thirds that of the former. The aglycone solanidine did not induce any increase in activity compared with the DMSO control. ODC activity with dexamethasone, a glucocorticoid, at 4 mg/kg body weight, followed a pattern similar to that of alpha-solanine. However, maximal activity occurred slightly earlier at 4 hr after treatment. The results show that the extent of induced ODC activity depends on the structure of the potato alkaloid.

Spirosolane-containing Solanum species and induction of congenital craniofacial malformations.

Comparison by GC analysis of purified alkaloid extracts of Solanum species revealed no measurable free solasodine, other spirosolanes, or any non-spirosolane steroidal alkaloid aglycones in unhydrolyzed total alkaloid fractions of fruit of Solanum elaeagnifolium Cav. (silverleaf nightshade), Solanum sarrachoides (S. villosum Lam.--hairy nightshade), Solanum dulcamara L. (European bittersweet nightshade) or Solanum melongena L. (eggplant). All alkaloidal material was apparently present as glycoside. Conversely, sprouts of Solanum tuberosum L. (potato) contained 67% of its alkaloids as glycosides, which was freed only upon hydrolysis with the remaining 33% present as free solanidine. GC/MS analysis of hydrolysates of purified extracts of the test Solanum species revealed that solasodine was a principal or sole aglycone of the alkaloid glycosides in each of the test species except Solanum tuberosum. In the latter, solanidine was the sole aglycone. Among the test species, exclusive of S. tuberosum, only S. dulcamara contained aglycones other than solasodine. In addition to solasodine, S. dulcamara contained appreciable amounts of an unknown spirosolane, an aglycone provisionally identified as soladulcidine. The induction of congenital craniofacial malformations in hamsters by high oral doses of the four Solanum species that contained mainly solasodine glycosides--S. elaeagnifolium, S. dulcamara, S. sarrachoides and S. melongena was compared to inductions of malformations by Solanum tuberosum, that contained mainly solanidane glycosides. Compared to controls, Solanum elaeagnifolium and Solanum dulcamara fruit both induced a high percentage incidence of deformed litters (20.4 and 16.3, respectively) that was statistically significant (P less than 0.001 level) while percentage incidence of deformed litters induced by Solanum sarrachoides and Solanum melongena fruit (9.5 and 7.6 respectively) were both higher than controls (3.4%), in neither case was the incidence statistically significant (P less than .05). Deformed litter incidence induced by sprouts of Solanum tuberosum was 24.0%, (P less than 0.001).

Effect of alkaloids of Solanum melongena on the central nervous system.

Crude alkaloidal fraction isolated from the leaves of Solanum melongena was screened for its effects on the central nervous system. It exhibited significant analgesic effect and some CNS depression but no anticonvulsant action. The analgesic effects were of non-narcotic type. LD50 was estimated to be higher than 1 g/kg i.p. in mice.