Effects of escins Ia, Ib, IIa, and IIb from horse chestnuts on gastrointestinal transit and ileus in mice

New biofunctional effects of oleanane-type triterpene saponins

In the current review, we describe the novel biofunctional effects of oleanane-type triterpene saponins, including elatosides, momordins, senegasaponins, camelliasaponins, and escins, obtained from Aralia elata (bark, root cortex, young shoot), Kochia scoparia (fruit), Polygala senega var. latifolia (roots), Camellia japonica (seeds), and Aesculus hippocastanum (seeds), considering the following biofunctional activities: (1) inhibitory effects on elevated levels of blood alcohol and glucose in alcohol and glucose-loaded rats, respectively, (2) inhibitory effects on gastric emptying in rats and mice, (3) accelerative effects on gastrointestinal transit in mice, and (4) protective effects against gastric mucosal lesions in rats. In addition, we describe (5) suppressive effects of the extract and chakasaponins from Camellia sinensis (flower buds) on obesity based on inhibition of food intake in mice. The active saponins were classified into the following three types: (1) olean-12-en-28-oic acid 3-O-monodesmoside, (2) olean-12-ene 3,28-O-acylated bisdesmoside, and (3) acylated polyhydroxyolean-12-ene 3-O-monodesmoside. Furthermore, common modes of action, such as involvements of capsaicin-sensitive nerves, endogenous NO and PGs, and possibly sympathetic nerves, as well as common structural requirements, were observed. Based on our findings, a common mechanism of action might mediate the pharmacological effects of active saponins. It should be noted that the gastrointestinal tract is an important action site of saponins, and the role of the saponins in the gastrointestinal tract should be carefully considered.

Anti-Inflammatory and Gastroprotective Effects of Escin

Escin is a triterpenoid saponin extracted from the fruit of Aesculus wilsonii Rehd. and Aesculus hippocastanum (Hippocastanaceae). Clinically, it is widely used in the treatment of edema induced by either trauma or surgery, as well as treating chronic venous insufficiency. The anti-inflammatory and antiedema effects of escin have been extensively investigated. This article systematically reviews the effects of escin on inflammation and gastrointestinal diseases, including its role in inflammation, as an antioxidant, and in inhibiting gastric acid secretion and promoting gastrointestinal movement, especially, the molecular mechanism. The advantages and potential uses of escin have also been discussed.

Anti-proliferation and apoptosis-inducing effects of sodium aescinate on retinoblastoma Y79 cells

AIM

To investigate the anti-proliferation and apoptosis-inducing effects of sodium aescinate (SA) on retinoblastoma Y79 cells and its mechanism.

METHODS

Y79 cells were cultured at different drug concentrations for different periods of time (24, 48, and 72h). The inhibitory effect of SA on proliferation of Y79 cells was detected by the cell counting kit-8 (CCK-8) assay, and the morphology of Y79 cells in each group was observed under an inverted microscope. An IC50 of 48h was selected for subsequent experiments. After pretreatment with SA for 24 and 48h, cellular DNA distribution and apoptosis were detected by flow cytometry. Real-time qunatitative polymerase chain reaction (RT-qPCR) and Western blot were used to assess changes in related genes (CDK1, CyclinB1, Bax, Bcl-2, caspase-9, caspase-8, and caspase-3).

RESULTS

SA inhibited proliferation and induced apoptosis of Y79 cells in a time-dependent and concentration-dependent manner. Following its intervention in the cell cycle pathway, SA can inhibit the expression of CDK1 and CyclinB1 at the mRNA and protein levels, and block cells in the G2/M phase. In caspase-related apoptotic pathways, up-regulation of Bax and down-regulation of Bcl-2 caused caspase-9 to self-cleave and further activate caspase-3. What's more, the caspase-8-mediated extrinsic apoptosis pathway was activated, and the activated caspase-8 was released into the cytoplasm to activate caspase-3, which as a member of the downstream apoptotic effect group, initiates a caspase-cascade reaction that induces cell apoptosis.

CONCLUSION

SA inhibits the proliferation of Y79 cells by arresting the cell cycle at the G2/M phase, and induces apoptosis via the caspase-related apoptosis pathway, indicating that SA may have promising potential as a chemotherapeutic drug.

New biofunctional effects of the flower buds of Camellia sinensis and its bioactive acylated oleanane-type triterpene oligoglycosides

We review the biofunctional effects of the flower buds of Camellia sinensis and C. sinensis var. assamica, such as antihyperlipidemic, antihyperglycemic, antiobesity, and gastroprotective effects in vivo, and antiallergic, pancreatic lipase inhibitory, and amyloid β (Aβ) aggregation inhibitory activities in vitro. Although the biofunctional effects of tea leaves have been extensively studied, less attention has been given to those of the flowers and seeds of the tea plant. Our studies focused on the saponin constituents of the extracts of the flower buds of C. sinensis cultivated in Japan and China, and C. sinensis var. assamica cultivated in India, and we review their beneficial biofunctions for health promotion.

Oral Administration of Escin Inhibits Acute Inflammation and Reduces Intestinal Mucosal Injury in Animal Models

The present study aimed to investigate the effects of oral administration of escin on acute inflammation and intestinal mucosal injury in animal models. The effects of escin on carrageenan-induced paw edema in a rat model of acute inflammation, cecal ligation and puncture (CLP) induced intestinal mucosal injury in a mouse model, were observed. It was shown that oral administration of escin inhibits carrageenan-induced paw edema and decreases the production of prostaglandin E2 (PGE2) and cyclooxygenase- (COX-) 2. In CLP model, low dose of escin ameliorates endotoxin induced liver injury and intestinal mucosal injury and increases the expression of tight junction protein claudin-5 in mice. These findings suggest that escin effectively inhibits acute inflammation and reduces intestinal mucosal injury in animal models.

Escin Chemosensitizes Human Pancreatic Cancer Cells and Inhibits the Nuclear Factor-kappaB Signaling Pathway

Background. There is an urgent need to develop new treatment strategies and drugs for pancreatic cancer that is highly resistant to radio-chemotherapy. Aesculus hippocastanum (the horse chestnut) known in Chinese medicine as a plant with anti-inflammatory, antiedema, antianalgesic, and antipyretic activities. The main active compound of this plant is Escin (C54H84O23). Objective. To evaluate the effect of Escin alone and combined with chemotherapy on pancreatic cancer cell survival and to unravel mechanism(s) of Escin anticancer activity. Methods. Cell survival was measured by XTT colorimetric assay. Synergistic effect of combined therapy was determined by CalcuSyn software. Cell cycle and induction of apoptosis were evaluated by FACS analysis. Expression of NF- κ B-related proteins (p65, I κ Bα, and p-I κ Bα) and cyclin D was evaluated by western blot analysis. Results. Escin decreased the survival of pancreatic cancer cells with IC50 = 10-20 M. Escin combined with gemcitabine showed only additive effect, while its combination with cisplatin resulted in a significant synergistic cytotoxic effect in Panc-1 cells. High concentrations of Escin induced apoptosis and decreased NF- κ B-related proteins and cyclin D expression. Conclusions. Escin decreased pancreatic cancer cell survival, induced apoptosis, and downregulated NF- κ B signaling pathway. Moreover, Escin sensitized pancreatic cancer cells to chemotherapy. Further translational research is required.

Participation of cholinergic pathways in α-hederin-induced contraction of rat isolated stomach strips

The dry extract of Hedra helix leaves and its main active compounds, predominantly α-hederin and hederacoside C, has been traditionally believed to act spasmolytic. However, it has been recently proved that both, the extract of ivy and triterpenoid saponins, exhibit strong contractile effect on rat isolated stomach smooth muscle strips. It turned out that the most potent contractile agent isolated from the extract of ivy leaves is α-hederin. Thus, it seems reasonable to estimate the mechanism of the contractile effect of this saponin. The presented study was aimed at verifying the participation of cholinergic pathways (muscarinic and nicotine receptors) in α-hederin-induced contraction. The experiments were carried out on rat isolated stomach corpus and fundus strips under isotonic conditions. The preparations were preincubated with either atropine or hexamethonium and then exposed to α-hederin. All results are expressed as the percentage of the response to acetylcholine - a reference contractile agent. The obtained results revealed that the pretreatment of isolated stomach strips (corpus and fundus) with atropine neither prevented nor remarkably reduced the reaction of the preparations to α-hederin. Similarly, if the application of saponin was preceded by the administration of hexamethonium, the strength of the contraction of stomach fundus strips induced by α-hederin was not modified. Concluding, it can be assumed that the cholinergic pathways do not participate in α-hederin-evoked contraction of rat isolated stomach preparations.

The effect of the whole extract of common ivy (Hedera helix) leaves and selected active substances on the motoric activity of rat isolated stomach strips

ETHNOPHARMACOLOGICAL RELEVANCE

The long tradition of using the dry extract of Hedera helix (common ivy) leaves in traditional and contemporary alternative medicine caused that many biological and pharmacological studies have been aimed at evaluating the effects of ivy. Some of the results suggest that Hedera helix extract possesses bronchodilatatory and antispasmodic activity. On the other hand, the symptoms of ivy intoxication in human and animals, as well as adverse-reactions observed during the therapy with ivy-based pharmaceuticals, indicate rather stimulant effect of the plant on smooth muscle. Thus, the aim of this study was to evaluate the effect of two main active substances extracted from the plant (α-hederin and hederacoside C) and the whole dry extract of Hedera helix on the gut motility.

MATERIALS AND METHODS

The experiments were carried out on isolated stomach corpus and fundus strips. The tissues were isolated from rats. The experiments were performed in isotonic conditions. The results are expressed as the percent of the reaction caused by a reference contractile substance, acetylcholine.

RESULTS AND CONCLUSIONS

The obtained results revealed that α-hederin applied in the concentration ranged from 25 to 320μM significantly changed the spontaneous motoric activity of rat stomach smooth muscle. The observed reaction had always the same character, a contraction, and its force was concentration dependent. The second tested saponin, hederacoside C, did not alter the motility of rat isolated stomach corpus and fundus strips when administered in the concentration up to 100 μM, however, if applied in the concentration of 350 μM it induced a remarkable concentration of smooth muscle. Eventually, the whole extract of Hedera helix in a dose containing 60 μM of hederacoside C produced a strong contraction which strength was comparable with the reaction generated by acetylcholine. According to the results, it is very likely that α-hederin, but not hederacoside C contributes to the contractile response of isolated stomach corpus and fundus strips to the application of Hedera helix leaves' extract.

Pilot postoperative ileus study of escin in cancer patients after colorectal surgery

BACKGROUND

Postoperative ileus, a common complication in patients after abdominal surgery, brings no benefit to the recovery of postoperative patients, and treatment targeted at restoring gastrointestinal motility may shorten the hospital stay. Studies have shown that escin accelerates gastrointestinal transit in mice and improves gastrointestinal motility in patients after abdominal surgery. A pilot study of escin's effect on the recovery of gastrointestinal motility was conducted in colorectal cancer patients in anticipation of a multiple-center randomized controlled trial.

METHODS

A total of 72 postoperative colorectal cancer patients were randomly assigned to four parallel groups on the basis of sealed envelopes-escin 5 mg group (E5 mg), escin 15 mg group (E15 mg), escin 25 mg group (E25 mg), and placebo group-with 18 patients in each group. Escin or placebo was diluted in 500 ml 5% dextrose injection, which was given once daily through the subclavian vein. The first injection took place 6 h after completion of the surgery. The treatment continued for 7 days or stopped at the time of the patient's first bowel movement. Time to recovery of passage of gas (TRPG), time to recovery of gastrointestinal sounds (TRGS), and time to recovery of bowel movements (TRBM) were recorded to evaluate the efficacy of escin.

RESULTS

The TRPGs of the three escin treatment groups were 76.78 + 28.81 h (E5 mg), 72.06 + 14.65 h (E15 mg), and 65.50 + 26.70 h (E25 mg), respectively, with differences of 6.03 +/- 7.64 h (p = 0.436; E5 mg), 10.75 +/- 4.92 h (p = 0.036; E15 mg), and 17.31 +/- 7.20 h (p = 0.022; E25 mg) compared with the placebo group. The TRGSs of the three escin treatment groups were 45.28 +/- 26.15 h (E5 mg), 41.22 +/- 16.98 h (E15 mg), and 40.33 +/- 14.09 h (E25 mg), respectively, with differences of 4.33 +/- 7.12 h (p = 0.547; E5 mg), 8.39 +/- 5.36 h (p = 0.127; E15 mg), and 9.28 +/- 4.87 h (p = 0.065; E25 mg) compared with the placebo group. The TRBMs of the three escin treatment groups were 89.25 +/- 23.77 h (E5 mg), 84.83 +/- 27.91 h (E15 mg), and 84.44 +/- 19.74 h (E25 mg), respectively, with differences of 19.03 +/- 10.13 h (p = 0.069; E5 mg), 23.44 +/- 10.70 h (p = 0.035; E15 mg), and 23.83 +/- 9.63 h (p = 0.019; E25 mg) compared with the placebo group.

CONCLUSION

The results of this pilot Postoperative Ileus Study of Escin (PISE) showed that escin can shorten the time to recovery of gastrointestinal motility in cancer patients after colorectal surgery.

Saponins, classification and occurrence in the plant kingdom

Saponins are a structurally diverse class of compounds occurring in many plant species, which are characterized by a skeleton derived of the 30-carbon precursor oxidosqualene to which glycosyl residues are attached. Traditionally, they are subdivided into triterpenoid and steroid glycosides, or into triterpenoid, spirostanol, and furostanol saponins. In this study, the structures of saponins are reviewed and classified based on their carbon skeletons, the formation of which follows the main pathways for the biosynthesis of triterpenes and steroids. In this way, 11 main classes of saponins were distinguished: dammaranes, tirucallanes, lupanes, hopanes, oleananes, taraxasteranes, ursanes, cycloartanes, lanostanes, cucurbitanes, and steroids. The dammaranes, lupanes, hopanes, oleananes, ursanes, and steroids are further divided into 16 subclasses, because their carbon skeletons are subjected to fragmentation, homologation, and degradation reactions. With this systematic classification, the relationship between the type of skeleton and the plant origin was investigated. Up to five main classes of skeletons could exist within one plant order, but the distribution of skeletons in the plant kingdom did not seem to be order- or subclass-specific. The oleanane skeleton was the most common skeleton and is present in most orders of the plant kingdom. For oleanane type saponins, the kind of substituents (e.g. -OH, =O, monosaccharide residues, etc.) and their position of attachment to the skeleton were reviewed. Carbohydrate chains of 18 monosaccharide residues can be attached to the oleanane skeleton, most commonly at the C3 and/or C17 atom. The kind and positions of the substituents did not seem to be plant order-specific.

Escin: inhibiting inflammation and promoting gastrointestinal transit to attenuate formation of postoperative adhesions

Postoperative peritoneal adhesions are common, serious complications of general abdominal and gynecologic surgery that can lead to chronic abdominal pain, intestinal obstruction, and infertility. As yet, there are no ideal drugs that may be prescribed for patients to prevent adhesion formation effectively. In this study the effects of escin, a natural drug, on the various steps of adhesion formation were investigated. The effects of escin on increased vascular permeability induced by acetic acid in a mouse model of acute inflammation, granuloma formation in a subchronic inflammatory rat model, gastrointestinal transit in rats with intestinal paralysis, intestinal motility in postoperative patients, and postoperative adhesion formation in a rat model were observed. It was shown that escin could inhibit acute inflammation and granuloma formation, cause acceleration of gastrointestinal transit, help recover intestinal motility, and attenuate the formation of postoperative adhesions. The findings suggest that escin attenuates the formation of postoperative adhesions by inhibiting inflammation and promoting gastrointestinal transit. Thus it may be concluded that both inhibition of inflammation and increased gastrointestinal motility during the early postoperative period have a positive effect on decreasing the formation of adhesions.

Medicinal foodstuffs. XXII. Structures of oleanane-type triterpene oligoglycosides, pisumsaponins I and II, and kaurane-type diterpene oligoglycosides, pisumosides A and B, from green peas, the immature seeds of Pisum sativum L

Two new oleanane-type triterpene oligoglycosides, pisumsaponins I and II, and two new kaurane-type diterpene oligoglycosides, pisumosides A and B, were isolated from the immature seeds (green peas) of Pisum sativum L. together with soyasaponin I, bersimoside I, dehydrosoyasaponin I, and their 6'-methyl esters. The structures of pisumsaponins and pisumosides were determined on the basis of chemical and physicochemical evidence as 22-O-malonylsoyasapogenol B 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucopyranosiduronic acid (22-O-malonylsoyasaponin I), sandosapogenol 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucopyranosiduronic acid, 17-O-beta-D-glucopyranosyl-6beta,7beta,13gamma,17-tetrahydroxy-19-kauranoic acid 19-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranoside, and 6beta,7beta,13beta,17-tetrahydroxy-19-kauranoic acid 19-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranoside, respectively.

Medicinal foodstuffs. XXI. Structures of new cucurbitane-type triterpene glycosides, goyaglycosides-a, -b, -c, -d, -e, -f, -g, and -h, and new oleanane-type triterpene saponins, goyasaponins I, II, and III, from the fresh fruit of Japanese Momordica charantia L

Eight cucurbitane-type triterpene glycosides called goyaglycosides-a, -b, -c, -d, -e, -f, -g, and -h and three oleanane-type triterpene saponins termed goyasaponins I, II, and III were isolated from the fresh fruit of Japanese Momordica charantia L. (Cucurbitaceae) together with five known cucurbitane-type triterpene glycosides momordicosides A, C, F1, I, and K. The structures of goyaglycosides and goyasaponins were elucidated on the basis of chemical and physicochemical evidence.

Possible involvement of 5-HT and 5-HT2 receptors in acceleration of gastrointestinal transit by escin Ib in mice

We have reported previously that escin Ib accelerated gastrointestinal transit (GIT) in mice, and that its effect may be mediated by the release of endogenous prostaglandins (PGs) and nitric oxide (NO). In this study, the possible involvement of 5-HT and 5-HT receptors in the GIT acceleration of escin Ib was investigated in mice. The acceleration of GIT by escin Ib (25 or 50 mg/kg, p.o.) was attenuated by pretreatment with ritanserin (0.5-5 mg/kg, s.c., a 5-HT(2A/2C/2B) receptor antagonist), but not with MDL 72222 (1 and 5 mg/kg, s.c.) and metoclopramide (10 mg/kg, s.c.) (5-HT3 receptor antagonists) or tropisetron (1 and 10 mg/kg, s.c., a 5-HT(3/4) receptor antagonist). Furthermore, pretreatment with ketanserin (0.05-5 mg/kg, s.c.), haloperidol (1-5 mg/kg, s.c.) and spiperone (0.5-5 mg/kg, s.c.) (5-HT2A receptor antagonists), as well as a bolus of dl-p-chlorophenylalanine methyl ester (PCPA, 1000 mg/kg, p.o., 1, 6 or 24 h before administration of the sample) (an inhibitor of 5-HT synthesizing enzyme tryptophan hydroxylase) and reserpine (5 mg/kg, p.o.) (a 5-HT depletor), but not 6-hydroxydopamine (80 mg/kg, i.p., a dopamine depletor) or repeated PCPA (300 mg/kg x2, p.o., 72 and 48 h before administration of the sample), also attenuated the effects of escin Ib. It is postulated that escin Ib accelerates GIT, at least in part, by stimulating the synthesis of 5-HT to act through 5-HT2, possibly 5-HT2A receptors, which in turn causes the release of NO and PGs.

Enhancement by escins Ib and IIb of Mg(2+) absorption from digestive tract in mice: role of nitric oxide

The effects of escins Ib and IIb isolated from horse chestnuts on Mg(2+) absorption from the digestive tract and the role of endogenous nitric oxide (NO) were investigated in mice. Test samples were given orally to fasted mice 30, 120, 180, 240 and 300 min before administration of 0.5 M MgSO(4) (10 ml/kg, p.o.). The serum Mg(2+) levels were determined 30, 60, 120 and 180 min after administration of MgSO(4). Escins Ib and IIb (12.5 and 25 mg/kg) significantly increased the serum Mg(2+) by 10.0-27.3%, 30, 120 and 180 min after administration of the samples, and 30, 60, 120 and 180 min after administration of MgSO(4). Escins Ib and IIb (12.5 mg/kg) significantly decreased the Mg(2+) content in the small intestinal fluid in MgSO(4)-loaded mice, but did not increase the serum Mg(2+) levels in normal mice. The effects of escins Ib and IIb (12.5 mg/kg) on serum Mg(2+) levels were attenuated in a dose-related manner by the pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME, 3-20 mg/kg, i.p., an inhibitor of constitutive and inducible NO synthase), but not with D-NAME (10 mg/kg, i.p., the inactive enantiomer of L-NAME) or dexamethasone (0.05 and 0.5 mg/kg, s.c., an inhibitor of inducible NO synthase). The effect of L-NAME was reversed by L-arginine (600 mg/kg, i.p., a substrate of NO synthase), but not by D-arginine (900 mg/kg, i.p., the enantiomer of L-arginine). These results suggest that escins Ib and IIb enhance Mg(2+) absorption from the digestive tract in mice, in which the constitutive, but not the inducible, NO synthase plays an important role.

Structure-related enhancing activity of escins Ia, Ib, IIa and IIb on magnesium absorption in mice

We examined the effects of the saponin fraction and its principal saponins, escins Ia (1), Ib (2), IIa (3) and IIb (4), obtained from European horse chestnut, and their hydrolyzed products, desacylescins I (5) and II (6) on magnesium absorption from the gastrointestinal tract in mice. Test samples were given orally to fasted mice before loading of 0.5 or 1.67 M MgSO4 (10 mL/kg, p.o.). The saponin fraction (12.5-100 mg/kg) significantly enhanced the Mg2+ absorption 30, 60, 120 and 240 min after administration, with maximum enhancement by 48.3% at 50 mg/kg. Escins Ib (2) and IIb (4) (12.5 and 25 mg/kg) also enhanced the absorption, whereas escins Ia (1) and IIa (3) (12.5 and 25 mg/kg) and desacylescins I(5) and II (6) (25 mg/kg) showed no activity. These results suggested that the 21-O-tigloyl and/or 22-O-acetyl group(s) is essential for such activity. The saponin fraction, 2 and 4 (50 mg/kg) also affected the activity, but their effects were attenuated in streptozotocin-induced diabetic mice. Furthermore, pretreatment with insulin or indomethacin did not reduce the effect of 2 and 4. These results also implied that neither the sympathetic nervous system nor endogenous prostaglandins were involved. The involvement of parathyroid hormone, and/or the metabolism of vitamin D should be considered.