Cytotoxic cardiac glycosides and coumarins from Antiaris toxicaria.

Eight new cardiac glycosides/aglycones (antiaritoxiosides A-G, 1-7, and antiarotoxinin B, 8), two new coumarins (anticarins A-B, 41-42), and two new flavanones (antiarones L-K, 43-44) were isolated from trunk bark of Antiaris toxicaria together with 53 known compounds. The new structures were established by extensive analysis of spectroscopic data. Compound 1 (10-carboxy and 3α-hydroxy) and compounds 3-6 (10-hydroxy) contain unique substituents that are rarely found in cardiac glycosides. The cytotoxic effects of isolated compounds against ten human cancer cell lines, KB, KB-VIN, A549, MCF-7, U-87-MG, PC-3, 1A9, CAKI-1, HCT-9 and S-KMEL-2, were tested using the sulforhodamine B assay. Five compounds (12, 16, 20, 22, and 31) showed significant cytotoxicity against all ten cancer cell lines, with notable potency at the ng/mL level against some cell lines, which merits further development as clinical trial candidates.

A new periplogenin cardenolide from the seeds of Antiaris toxicaria.

A new periplogenin cardenolide, periplogulcoside (1), together with three known cardenolides, was isolated from the seeds of Antiaris toxicaria. The structure of the new compound was characterized as periplogenin-3-O-ß-D-glucopyranosyl-(1 → 4)-ß-D-glucopyranoside (1) by spectroscopic methods including 1D and 2D NMR, HR-TOF-MS, and CD spectrometry, and the known compounds were identified by comparison of their NMR and HR-TOF-MS data with those reported in the literature. Compound 1 showed significant cytotoxicity against Hela and HepG-2 cell lines.

Antiproliferative cardiac glycosides from the latex of Antiaris toxicaria.

Phytochemical investigation of the latex of Antiaris toxicaria resulted in the isolation of 15 new [antiarosides J-X (1-15)] and 17 known cardiac glycosides. The effects of the cardiac glycosides on apoptosis and the expression of orphan nuclear receptor Nur77 were examined in human NIH-H460 lung cancer cells. Several of the cardiac glycosides induced apoptosis in lung cancer cells, which was accompanied by induction of Nur77 protein expression. Treatment of cancer cells with the cardiac glycosides resulted in translocation of the Nur77 protein from the nucleus to the cytoplasm and subsequent targeting to mitochondria. The results show that the cardiac glycosides exert their apoptotic effect through the Nur77-dependent apoptotic pathway.

Synthesis and Biological Evaluation of Cardiac Glycosides for Cancer Therapy by Targeting the DNA Damage Response.

Cardiac glycosides (CGs) are bioactive compounds originally used to treat heart diseases, but recent studies have demonstrated their anticancer activity. We previously demonstrated that Antiaris toxicaria 2 (AT2) possesses anticancer activity in KRAS mutated lung cancers via impinging on the DNA damage response (DDR) pathway. Toward developing this class of molecules for cancer therapy, herein we report a multistep synthetic route utilizing k-strophanthidin as the initial building block for determination of structure-activity relationships (SARs). A systematic structural design approach was applied that included modifications of the sugar moiety, the glycoside linker, stereochemistry, and lactone ring substitutions to generate a library of O-glycosides and MeON-neoglycosides derivatives. These molecules were screened for their anticancer activities and their impact on DDR signaling in KRAS mutant lung cancer cells. These results demonstrate the ability to chemically synthesize CG derivatives and define the SARs to optimize AT2 as a cancer therapeutic.

Cytotoxic cardenolide glycosides from the seeds of Antiaris toxicaria.

Bioassay-guided fractionation of the ethanolic extract from the seeds of Antiaris toxicaria led to the isolation of three new cardiac glycosides named toxicarioside J, toxicarioside K, and toxicarioside L, together with a known glucostrophalloside. The structures of the new compounds were elucidated by spectroscopic methods including HRESIMS, UV, IR, and 1D, 2D NMR techniques. The cytotoxic activities of these cardiac glycosides against human gastric (SGC-7901) and human hepatoma (SMMC-7721) cell lines were evaluated, and all of them exhibited significant cytotoxicity.

A new drimane sesquiterpenoid glycoside from the seeds of Antiaris toxicaria.

A new drimane sesquiterpenoid glycoside, named 7-drimen-3ß,11-diol 3-O-ß-d-glucopyranoside, was isolated from the 95% EtOH extract of the seeds of Antiaris toxicaria (Pers.) Lesch. The chemical structure was completely elucidated using a combination of 1D and 2D NMR techniques (COSY, HMQC, HMBC, and ROESY) and HR-ESI-MS analysis. The compound showed inhibitory activities toward methicillin-resistant Staphylococcus aureus (MRSA), chronic myelogenous leukemia (K562), and human hepatoma (SMMC-7721) cell lines.

Malayoside, a cardenolide glycoside extracted from Antiaris toxicaria Lesch, induces apoptosis in human non-small lung cancer cells via MAPK-Nur77 signaling pathway.

Lung cancer is the leading cause of cancer deaths in the world. Non-small cell lung cancer (NSCLC), with poor prognosis and resistance to chemoradiotherapy, is the most common histological type of lung cancer. Therefore, it is necessary to develop new and more effective treatment strategy for NSCLC. Nur77, an orphan member of the nuclear receptor superfamily, induces apoptosis in cancer cells including NSCLC cells, by high expression and translocation to mitochondria. Small molecules trigger expression and mitochondrial localization of Nur77 may be an ideal anti-cancer drug candidate. Here, we report malayoside, a cardiac glycoside in the extract of Antiaris toxicaria Lesch., had different sensitivities to NSCLC cells. Malayoside induced apoptosis in NCI-H460 cells. Meanwhile, malayoside induced Nur77 expression and mitochondrial localization, and its induction of apoptosis was Nur77-dependent. To investigate the molecular mechanism of malayoside inducing Nur77 and apoptosis, we found that malayoside activated MAPK signaling pathway, including both ERK and p38 phosphorylation. The suppression of MAPK signaling activation inhibited the expression of Nur77 and apoptosis induced by malayoside. Our studies in nude mice showed that malayside potently inhibited the growth of tumor cells in vivo. Furthermore, the anti-cancer effect of malayosidwas in vivo was also related to the elevated expression of Nur77, p-ERK, and p-p38 proteins. Our results suggest that malayoside possesses an anti-NSCLC activity in vitro and in vivo mainly via activation of MAPK-Nur77 signaling pathway, indicating that malayoside is a promising chemotherapeutic candidate for NSCLC.

Cardiac glycosides from Antiaris toxicaria with potent cardiotonic activity.

An ethanolic extract of Antiaris toxicaria trunk bark showed potent in vitro cardiotonic effect on isolated guinea pig atria. Bioassay-guided fractionation of the extract led to identification of nine new cardiac glycosides (1-9, named antiarosides A-I), antiarotoxinin A (10), and 18 known compounds. Their structures were established using MS and NMR spectroscopic studies, including homonuclear and heteronuclear correlation experiments. The ability of these cardiotonic compounds to produce positive inotropic action and their safety indexes were examined in comparison with those of ouabain, a classical inhibitor of Na(+)/K(+)-ATPase. Malayoside (23) was nearly equipotent and had a similar safety index to ouabain in guinea pig atria. However, the maximal positive inotropic effect and safety index of 23 in papillary muscle were better than those of ouabain. An electrophysiological recording showed that 23 inhibited the sodium pump current in a concentration-dependent manner.

Antiarol cinnamate and africanoside, a cinnamoyl triterpene and a hydroperoxy-cardenolide from the stem bark of Antiaris africana.

From the methanol extract of the stem bark of the African tree Antiaris africana Engler, two new bioactive metabolites were isolated, namely, the α-amyrin derivative 1ß,11α-dihydroxy-3ß-cinnamoyl-α-amyrin (antiarol cinnamate, 1) and a cardiac glycoside, 3ß-O-(α-L-rhamnopyranosyl)-14ß-hydroperoxy-5ß-hydroxy-19-oxo-17ß-card-20(22)-enolide (africanoside, 2a), together with the known compounds ß-amyrin and its acetate, ß-sitosterol and its 3-O-ß-D-glucopyranoside, friedelin, ursolic and oleanolic acid, 19-norperiplogenin, strophanthidol, strophanthidinic acid, periplogenin (3a), 3-epiperiplogenin, strophanthidin (3b) and 3,3'-dimethoxy-4'-O-ß-D-xylopyronosyl-ellagic acid. Their structures were established on the basis of their spectroscopic data and by chemical methods, while 3a was additionally confirmed by X-ray crystal structure analysis. The aglycone moiety possessing a hydroperoxy group was found for the first time in cardenolides. Compounds 1 and 2a showed no activity against bacteria, fungi, and microalgae; however, the crude extract exhibited a high toxicity against Artemia salina and a selective antitumor activity against human tumor cell lines. Africanoside (2a) effected a concentration-dependent inhibition of tumor cell growth with a mean IC(50) value of 5.3 nM.

Two new cytotoxic cardenolides from the latex of Antiaris toxicaria.

Two new cardenolides, toxicarioside F (1) and toxicarioside G (2), were isolated from the latex of Antiaris toxicaria (Pers.) Lesch (Moraceae). Their structures were elucidated on the basis of spectral data and chemical evidence. Compounds 1 and 2 showed significant cytotoxicity against K562, SGC-7901, SMMC-7721, and HeLa cell lines in vitro by the MTT method.

A new cytotoxic 19-nor-cardenolide from the latex of Antiaris toxicaria.

A new nor-cardenolide, named toxicarioside H (1), was isolated from the latex of Antiaris toxicaria (Pers.) Lesch (Moraceae). Its structure was elucidated on the basis of HRFAB-MS and spectroscopic techniques (IR, UV, 1D and 2D NMR). Compound 1 showed significant cytotoxicity against K562, SGC-7901, SMMC-7721, and HeLa cell lines in vitro by MTT method.

Modulation of key enzymes linked to Parkinsonism and neurologic disorders by Antiaris africana in rotenone-toxified rats.

Background The physiopathologies of many neurologic diseases are characterized by related biochemical dysfunctions that could be explored as drug targets. This study evaluated the effect of a methanol leaf extract of Antiaris africana (MEA) on critical bioindices of Parkinsonism and related neurologic dysfunctions in rats with rotenone-induced neurotoxicity. Methods Animals were administered 50 or 100 mg/kg MEA for 14 consecutive days. Rotenone (1.5 mg/kg) was administered three times per day on days 13 and 14. Coenzyme Q10 (5 mg/kg) was the reference drug. Complex I activity, dopamine level, activities of acetylcholinesterase, myeloperoxidase, Na+/K+ ATPase and glutamine synthetase, as well as oxidative stress indices were evaluated at the end of the period of treatment. Results Rotenone-intoxicated group showed disruption of complex 1 activity, dopamine level, and glutamine synthetase activity with negative alterations to activities of acetylcholinesterase, myeloperoxidase, and Na+/K+ ATPase as well as heightened cerebral oxidative stress. MEA restored brain mitochondria functionality, mitigated altered neurochemical integrity, and ameliorated cerebral oxidative stress occasioned by rotenone neurotoxicity. The activity of A. Africana was comparable with that of 5 mg/kg coenzyme Q10. Conclusions These results indicated that A. africana displayed therapeutic potential against Parkinsonism and related neurologic dysfunctions and support its ethnobotanical use for the treatment of neurologic disorders.

Anticonvulsant effects of antiaris toxicaria aqueous extract: investigation using animal models of temporal lobe epilepsy.

BACKGROUND: Antiaris toxicaria has previously shown anticonvulsant activity in acute animal models of epilepsy. The aqueous extract (AAE) was further investigated for activity in kindling with pentylenetetrazole and administration of pilocarpine and kainic acid which mimic temporal lobe epilepsy in various animal species. RESULTS: ICR mice and Sprague-Dawley rats were pre-treated with AAE (200-800 mg kg-1) and convulsive episodes induced using pentylenetetrazole, pilocarpine and kainic acid. The potential of AAE to prevent or delay onset and alter duration of seizures were measured. In addition, damage to hippocampal cells was assessed in kainic acid-induced status epilepticus test. 800 mg kg-1 of the extract suppressed the kindled seizure significantly (P < 0.05) as did diazepam. AAE also produced significant effect (P < 0.01) on latency to first myoclonic jerks and on total duration of seizures. The latency to onset of wet dog shakes was increased significantly (P < 0.05) by AAE on kainic acid administration. Carbamazepine and Nifedipine (30 mg kg-1) also delayed the onset. Histopathological examination of brain sections showed no protective effect on hippocampal cells by AAE and nifedipine. Carbamazepine offered better preservation of hippocampal cells in the CA1, CA2 and CA3 regions. CONCLUSION: Antiaris toxicaria may be effective in controlling temporal lobe seizures in rodents.

MODULATION OF KEY BIOCHEMICAL MARKERS RELEVANT TO STROKE BY ANTIARIS AFRICANA LEAF EXTRACT FOLLOWING CEREBRAL ISCHEMIA/REPERFUSION INJURY.

BACKGROUND: Oxidative stress plays a significant role in stroke pathogenesis. Hence, plants rich in antioxidant phytochemicals have been suggested as effective remedies for prevention and treatment of stroke and other neurological diseases. Antiaris africana Engl. (Moraceae) is traditionally used for the management of brain-related problems but there is paucity of data on its anti-stroke potential. MATERIALS AND METHODS: Ischemia/reperfusion injury was induced by a 30 min bilateral common carotid artery occlusion/ 2 h reperfusion (BCCAO/R) in the brain of male Wistar rats. A sham-operated group which was not subjected to BCCAO/R and a group subjected to BCCAO/R without treatment with MEA served as controls. The ameliorative effect of 14 days of pretreatment with 50 mg/kg or 100 mg/kg A. africana methanol leaf extract (MEA) on BCCAO/R-mediated alterations to key markers of oxidative stress (malondialdehyde, reduced glutathione, xanthine oxidase, superoxide dismutase, catalase and glutathione peroxidase) and neurochemical disturbances and excitotoxicity (myeloperoxidase, glutamine synthetase, Na+/K+ ATPase, acetylcholinesterase and tyrosine hydroxylase), was evaluated and compared with the effect produced by treatment with 20 mg/kg quercetin as a reference standard. RESULTS: Results show that pretreatment with MEA significantly mitigated or reversed BCCAO/R-induced changes in the level or activity of the evaluated biochemical markers of oxidative stress, neurochemical dysfunction and excitotoxicity compared with the BCCAO/R untreated control group (p < 0.05). The effect produced by 100 mg/kg MEA was similar to that of the reference standard, quercetin. CONCLUSION: These results revealed the neuroprotective potential of A. africana in stroke and other ischemia-related pathologies.

Cardiac glycosides from the bark of Antiaris toxicaria.

Five new cardiac glycosides (1-5, namely antiaroside Y-ZC) together with 19 known compounds were obtained from the bark of Antiaris toxicaria. Their chemical structures were determined by IR, HR-ESI-MS, 1D and 2D NMR (HSQC, (1)H-(1)H COSY, HMBC, ROESY). The absolute configuration of sugar unit was defined by acid hydrolysis and appropriate derivatization. Compound 1 was rare 5ß-H-10ß-H-19-nor-cardenolide, which might derive from decarboxylative derivative of 19-COOH cardenolide. The inhibitory effects of cardiac glycosides 1-11 on the viability of NIH-H460 lung cancer cells and their induction of Nur77 expression were evaluated and preliminary structure-activity relationship (SAR) was also discussed.

Convallatoxin, a dual inducer of autophagy and apoptosis, inhibits angiogenesis in vitro and in vivo.

Autophagy and apoptosis are important processes that control cellular homeostasis and have been highlighted as promising targets for novel cancer therapies. Here, we identified convallatoxin (CNT), isolated from Antiaris toxicaria, as a dual inducer of autophagy and apoptosis. CNT exerts cytotoxic effects on a number of cancer and normal cell lines and induces apoptosis by increasing caspase-3 and poly ADP ribose polymerase (PARP) cleavage. Moreover, dose- and time-dependent autophagic activity was detected in CNT-treated cells, and mammalian target of rapamycin (mTOR)/p70S6K signal pathway inhibition was observed. Notably, CNT inhibits human umbilical vein endothelial cell (HUVEC) growth and exerts anti-angiogenic activity in vitro and in vivo. Collectively, these results demonstrate that the naturally occurring compound, CNT, is a novel anti-angiogenic compound via dual inducing of autophagy and apoptosis.

Toxicarioside M, a new cytotoxic 10ß-hydroxy-19-nor-cardenolide from Antiaris toxicaria.

A new 10ß-hydroxy-19-nor-cardenolide, named toxicarioside M (1), was isolated from the trunk bark of Antiaris toxicaria (Pers.) Lesch (Moraceae), along with six known cardenolides (convallatoxin (2), convallatoxol (3), convalloside (4), 3-O-ß-D-xylopyranosylstrophanthidin (5), glucostrophanthidin (6) and strophanthidin (7)). Their structures were elucidated on the basis of HR-MS(n) analysis, spectroscopic methods (IR, UV, 1D and 2D NMR) and by comparison with data reported in the literature. The cardenolides were evaluated for their cytotoxic activity against KB, HCT-116, SF-268, MCF-7, HL-60, PC-3 and MRC-5 cell lines.

Phenylpropanoid and lignan derivatives from Antiaris toxicaria and their effects on proliferation and differentiation of an osteoblast-like cell line.

Antiarisin A and B (1 and 2), together with seventeen known compounds (3-19), were isolated from the EtOAc extract of the stem of Antiaris toxicaria Lesch. Their structures were determined on the basis of spectroscopic analyses and chemical methods. Most of the compounds were reported for the first time from the Antiaris genus and firstly studied for their proliferative and differentiative activity on osteoblast-like cells. Screening results indicated that, at the concentration of 10(-8) M, benzofuran lignans 5, 6, 11 and 13 could significantly stimulate the proliferation of UMR106 cells, while 8, 9, 11, 14, 15 and 17 could enhance ALP (alkaline phosphatase) activity.