Acetogenins in Annona muricata L. (annonaceae) leaves are potent molluscicides

Overcoming multi drug resistance mediated by ABC transporters by a novel acetogenin- annonacin from Annona muricata L

ETHNOPHARMACOLOGICAL RELEVANCE

Multi-Drug Resistance (MDR), mediated by P-glycoprotein (P-gp) is one of the barriers to successful chemotherapy in colon cancer patients. Annona muricata L. (A.muricata), commonly known as soursop/Graviola, is a medicinal plant that has been traditionally used in treating diverse diseases including cancer. Phytochemicals of A.muricata (Annonaceous Acetogenins-AGEs) have been well-reported for their anti-cancer effects on various cancers.

AIM OF THE STUDY

The study aimed to examine the effect of AGEs in reversing MDR in colorectal cancer cells.

METHODS

Based on molecular docking and molecular dynamic simulation, the stability of annonacin upon P-gp was investigated. Further in vitro studies were carried in oxaliplatin-resistant human colon cancer cells (SW480R) to study the biological effect of annonacin, in reversing drug resistance in these cells.

RESULTS

Molecular docking and simulation studies have indicated that annonacin stably interacted at the drug binding site of P-gp. In vitro analysis showed that annonacin was able to significantly reduce the expression of P-gp by 2.56 folds. It also induced apoptosis in the drug-resistant colon cancer cells. Moreover, the intracellular accumulation of P-gp substrate (calcein-AM) was observed to increase in resistant cells upon treatment with annonacin.

CONCLUSION

Our findings suggest that annonacin could inhibit the efflux of chemotherapeutic drugs mediated by P-gp and thereby help in reversing MDR in colon cancer cells. Further in vivo studies are required to decipher the underlying mechanism of annonacin in treating MDR cancers.

Effect of 4-Ethylbenzaldehyde from the Volatilome of Annona muricata on Meloidogyne incognita

The demand for new soil fumigants has increased as a result of more restrictive legislation regarding the use of pesticides. In the present study, the potent nematicidal activity of volatile organic compounds released by the Annona muricata leaf macerate was demonstrated. In addition, we searched in the A. muricata volatilome for a molecule with potential to be developed as a new fumigant nematicide. In the greenhouse, even the lowest concentration of soursop leaf macerate tested (1.0%) as a biofumigant caused a significant (P < 0.05) reduction in Meloidogyne incognita infectivity and reproduction when compared with the nontreated control (0%). Forty-one compounds were identified through gas chromatography-mass spectrometry analysis, of which three (sabinene, caryophyllene oxide, and 4-ethylbenzaldehyde) were selected for studies against the nematode. Among these compounds, in in vitro trails, only 4-ethylbenzaldehyde showed nematicidal activity at 250 µg ml-1. The effective doses of 4-ethylbenzaldehyde predicted to kill 50 and 95% of the M. incognita second-stage juvenile population after 48 h of exposure were 35 and 88 µg ml-1, respectively. In in vitro tests, 4-ethylbenzaldehyde at 150 µg ml-1 reduced M. incognita egg hatching to values similar (P > 0.05) to those of the commercial nematicide fluensulfone at a concentration of 200 µg ml-1. In plant experiments, as a soil fumigant, 4-ethylbenzaldehyde at a dose of 1 ml/liter of substrate had an effect similar (P > 0.05) to that of the commercial fumigant Dazomet (250 µg ml-1). Therefore, 4-ethylbenzaldehyde shows potential for development as a new nematicide.

Evaluation of Genotoxicity and Toxicity of Annona muricata L. Seeds and In Silico Studies

Cancer is a multifactorial organic dysfunction for which great efforts are being devoted in searching for new treatments and therapeutic adjuvants. Annona muricata is a fruit that has promising activity against several types of cancer, as it contains acetogenins, the metabolite group associated with this action. Thus, the objective of this study was to evaluate, in experimental models, the toxic behavior of an extract and fraction rich in acetogenins from A. muricata seeds and study the acetogenin, Annonacin, in silico. Phytochemical characterization was made by thin layer chromatography, spectroscopy in the infrared region and nuclear magnetic resonance. Toxicity was evaluated by tests of Allium cepa and Artemia salina, and in silico studies using the SwissDock servers DockThor, PharmMapper, ADMETLab, PreADME, Osiris and ProTox. The extract and fraction showed genotoxic activity against meristematic cells of A. cepa, reducing the mitotic index; however, the extract produced great deleterious effects on the system, even causing cell necrosis. In A. Saline, the extract was more toxic than the fraction, but both samples were considered toxic. Annonacin was effectively linked to complex I, and presented different activities regarding toxicity. Thus, the results of this study are promising, highlighting the anticancer potential of acetogenins.

Non-targeted metabolomics characterization of Annona muricata leaf extracts with anti-angiogenic activity

The tropical plant Annona muricata has been widely used for traditional ethnobotanic and pharmacologic applications. Extracts from different parts of this plant have been shown to have a wide range of biological activities. In the present study, we carry out a metabolomic study of both aqueous and DMSO extracts from Annona muricata leaves that has allowed us to identify 33 bioactive compounds. Furthermore, we have shown that aqueous extracts are able to inhibit endothelial cell migration and both aqueous and DMSO extracts inhibit the formation of tubule-like structures by endothelial cells cultured on Matrigel. We conclude that extracts of Annona muricata leaves have great potential as anti-angiogenic natural combinations of bioactive compounds.

Study on reversal of ABCB1 mediated multidrug resistance in Colon cancer by acetogenins: An in-silico approach

Multi-Drug Resistance (MDR) exerted by tumor cells is majorly due to the overexpression of ATP Binding cassette transporters such as ABCB1/P-glycoprotein (P-gp). Annonaceous acetogenins (AGEs) exert anticancer activity by strongly inhibiting NADH oxidase of cancer cells. The present in silico study aims at screening a potent MDR inhibitor among acetogenins from the plant Annona muricata. Twenty-four AGEs were selected and screened for their pharmacokinetic properties. An inward facing conformation of P-gp is required for understanding the interaction of AGEs at the drug binding region and hence the human P-gp protein was modeled. The selected compounds were then docked with the ATP binding site and the drug binding site of modeled human P-gp. Annonacin A.1, Annohexocin.1 and Annomuricin E.1 docked better with high MM/GBSA dG binding in the drug binding region as compared with the conventional drugs. These compounds had a better docking score as compared with control inhibitor drugs at the ATP binding region. The complexes were subjected to MD simulation and Annonacin A was stable throughout the simulation period. Therefore, Annonacin A might act as a competitive inhibitor for the chemo drugs for binding at the drug binding region of P-gp. Hence it is capable of decreasing the efflux of chemo drugs out of the cells by P-Glycoprotein/ABCB1/MDR1. With this computational study, it is concluded that this compound might potentially reverse MDR, and hence can be taken forward for validation studies.Communicated by Ramaswamy H. Sarma.

Alkaloids from the root of Indonesian Annona muricata L

Annona muricata L. has been used traditionally in Indonesia to treat disease. Phytochemical studies on the alkaloid fractions from the root of Annona muricata L. from Malang-Indonesia resulted in the isolation of an unreported benzylisoquinoline alkaloid (+)-xylopine 5 as well as four known alkaloids (1-4). The crude methanol extract and alkaloid fractions were tested against Plasmodium falciparum K1 and against bacteria (Escherichia coli, Klebsiella pneumonia, Acinetobacter buamanii, Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus) with insignificant activities (MIC > 32 µg/mL). Individual alkaloids were tested against a human suspension cancer cell line (HL-60 leukemia cells) and two human fibroblastic cancer cell lines (A549 lung cancer cells and HepG2 liver cancer cells) in which compound 5 was the most toxic alkaloid with IC₅₀ values ranging from 20 to 80 µM.

Acetogenins and alkaloids during the initial development of Annona muricata L. (Annonaceae)

In plants, the presence and distribution of specialized metabolites during the early stages of development are not documented enough, even though their biosynthesis is one of the most important strategies for survival. In this study, five alkaloids and four acetogenins were detected in Annona muricata L. during early development seedling, including three phases of root emergence and three of seedling formation. Hexane and alkaloid extracts were obtained from each organ, which were analyzed in a gas-mass chromatograph and in a high-performance liquid chromatograph coupled with a photodiode array UV detector (HPLC-DAD). This research shows the presence of the acetogenins cis-uvarimicin IV, mosinone, muricina B, and cis-annonacin-10-one, as well as of the alkaloids reticuline, coreximine, anonaine, asimilobine, and nornuciferine, both groups with a variable organ-specific distribution, related with the formation of organs and tissues.

Assessment of the antioxidant, cytotoxic, and genotoxic potential of the Annona muricata leaves and their influence on genomic stability

The popular use of Annona muricata L. is based upon a range of medicinal purposes, and the plant exhibits biological activities including antihyperglycemic, antiparasitic, and antitumor activities. The objectives of this study were to examine the antioxidant, cytotoxic, and genotoxic potential of the hydroalcoholic extract of A. muricata leaves (AMEs), as well as its effects on genotoxicity induced by methyl methanesulfonate (MMS) and hydrogen peroxide (H₂O₂). The results using 2,2-diphenyl-1-picrylhydrazyl assay showed that AME was able to scavenge 44.71% of free radicals. The extract significantly reduced the viability of V79 cells in the clonogenic assay at concentrations ≥8 µg/ml. No significant differences in micronucleus (MN) frequency were observed between V79 cell cultures treated with different concentrations of the extract (0.125, 0.25, 0.5, and 1 µg/ml) and negative control. When AME concentrations were combined with MMS, data revealed no marked differences from mutagen alone. In contrast, significant reductions in the frequencies of MN were noted in cultures treated with AME combined with H₂O₂ compared to H₂O₂ alone. In vivo studies found no significant differences in the frequencies of micronucleated polychromatic erythrocytes (MNPCEs) between animals treated with different AME doses compared to control. Animals treated with AME doses of 125 and 250 mg/kg and MMS exhibited significantly higher frequencies of MNPCE compared to mutagen alone. In conclusion, under current experimental conditions, AME was not genotoxic and exerted a modulatory effect on DNA damage depending upon the experimental conditions. The extract did not influence markedly MMS-induced genotoxicity in in vitro test system. However, the extract increased DNA damage induced by mutagen in mice. In V79 cells, AME reduced the genotoxicity produced by H₂O₂, and this protective effect was attributed in part to the antioxidant activity of AME.

Antiulcerogenic activity of the hydroalcoholic extract of leaves of Annona muricata Linnaeus in mice

Annona muricata Linnaeus, popularly known as “graviola” and also called soursop, is a species typical of countries with a tropical climate, and it is used in folk medicine as an anticancer, analgesic and antispasmodic agent. The aim of the present study was to validate the gastroprotective activity of the hydroalcoholic extract of the leaves of A. muricata (HEAM) and to investigate the underlying mechanisms of action for this effect. Gastric lesions were induced in mice by absolute ethanol, acidified ethanol or indomethacin. Before, the animals were pretreated with saline, omeprazole or HEAM orally at doses of 50–400 mg/kg. To determine the mechanism of action of the extract, we investigated, using specific inhibitors, the involvement of nitric oxide (NO), prostaglandins (PGEs), ATP-dependent K⁺ channels and α2-noradrenergic receptors. HEAM showed significant antiulcer activity against lesions induced by absolute ethanol, acidified ethanol or indomethacin, which was mediated by endogenous gastric prostaglandins.

Annona muricata (Annonaceae): A Review of Its Traditional Uses, Isolated Acetogenins and Biological Activities

Annona muricata is a member of the Annonaceae family and is a fruit tree with a long history of traditional use. A. muricata, also known as soursop, graviola and guanabana, is an evergreen plant that is mostly distributed in tropical and subtropical regions of the world. The fruits of A. muricata are extensively used to prepare syrups, candies, beverages, ice creams and shakes. A wide array of ethnomedicinal activities is contributed to different parts of A. muricata, and indigenous communities in Africa and South America extensively use this plant in their folk medicine. Numerous investigations have substantiated these activities, including anticancer, anticonvulsant, anti-arthritic, antiparasitic, antimalarial, hepatoprotective and antidiabetic activities. Phytochemical studies reveal that annonaceous acetogenins are the major constituents of A. muricata. More than 100 annonaceous acetogenins have been isolated from leaves, barks, seeds, roots and fruits of A. muricata. In view of the immense studies on A. muricata, this review strives to unite available information regarding its phytochemistry, traditional uses and biological activities.

Synergistic interactions among flavonoids and acetogenins in Graviola (Annona muricata) leaves confer protection against prostate cancer

Phytochemical complexity of plant extracts may offer health-promoting benefits including chemotherapeutic and chemopreventive effects. Isolation of 'most-active fraction' or single constituents from whole extracts may not only compromise the therapeutic efficacy but also render toxicity, thus emphasizing the importance of preserving the natural composition of whole extracts. The leaves of Annona muricata, commonly known as Graviola, are known to be rich in flavonoids, isoquinoline alkaloids and annonaceous acetogenins. Here, we demonstrate phytochemical synergy among the constituents of Graviola leaf extract (GLE) compared to its flavonoid-enriched (FEF) and acetogenin-enriched (AEF) fractions. Comparative quantitation of flavonoids revealed enrichment of rutin (~7-fold) and quercetin-3-glucoside (Q-3-G, ~3-fold) in FEF compared to GLE. In vivo pharmacokinetics and in vitro absorption kinetics of flavonoids revealed enhanced bioavailability of rutin in FEF compared to GLE. However, GLE was more effective in inhibiting in vitro prostate cancer proliferation, viability and clonogenic capacity compared to FEF. Oral administration of 100mg/kg bw GLE showed ~1.2-fold higher tumor growth-inhibitory efficacy than FEF in human prostate tumor xenografts although the concentration of rutin and Q-3-G was more in FEF. Contrarily, AEF, despite its superior in vitro and in vivo efficacy, resulted in death of the mice due to toxicity. Our data indicate that despite lower absorption and bioavailability of rutin, maximum efficacy was achieved in the case of GLE, which also comprises of other phytochemical groups including acetogenins that make up its natural complex environment. Hence, our study emphasizes on evaluating the nature of interactions among Graviola leaf phytochemcials for developing favorable dose regimen for prostate cancer management to achieve optimal therapeutic benefits.

Antiproliferative activity and induction of apoptosis by Annona muricata (Annonaceae) extract on human cancer cells

Background

Annona muricata (A. muricata) is widely distributed in Asia, Africa and South America. Different parts of this plant are used to treat several diseases in Cameroon. The aim of this study is to determine the in vitro anti-proliferative effects and apoptotic events of A. muricata extracts on HL-60 cells as well as to quantify its phenols content.

Methods

The cell viability was measured by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay while the changes in morphology of HL-60 cells, membrane mitochondrial potential (MMP) and the cell cycle were used for assessment apoptosis induction.

Results

The results show that the concentration of phenols, flavonoids and flavonols in the extracts varied depending on the part of the plant. All the extracts tested inhibited the proliferation of HL-60 cells in a concentration dependent manner with IC₅₀ varied from 6–49 μg/mL. The growth inhibition of the cells by extracts was associated with the disruption of MMP, reactive oxygen species (ROS) generation and the G0/G1 cell arrest.

Conclusion

These findings suggest that the extracts from A. muricata have strong antiproliferation potential and can induce apoptosis through loss of MMP and G0/G1 phase cell arrest.

Influence of Annona muricata (soursop) on biodistribution of radiopharmaceuticals in rats

PURPOSE

To evaluate the effect of hydroalcoholic extract of A. muricata on biodistribution of two radiopharmaceuticals: sodium phytate and dimercaptosuccinic acid (DMSA), both labeled with 99mtechnetium.

METHODS

Twenty four Wistar rats were divided into two treated groups and two controls groups. The controls received water and the treated received 25mg/kg/day of A. muricata by gavage for ten days. One hour after the last dose, the first treated group received 99mTc-DMSA and the second sodium 99mTc-phytate (0.66MBq each group), both via orbital plexus. Controls followed the same protocol. Forty min later, all groups were sacrificed and the blood, kidney and bladder were isolated from the first treated group and the blood, spleen and liver isolated from the second treated group. The percentage of radioactivity per gram of tissue (%ATI/g) was calculated using a gamma counter.

RESULTS

The statistical analysis showed that there was a statistically significant decrease (p<0.05) in the uptake of %ATI/g in bladder (0.11±0.01and1.60±0.08), kidney (3.52±0.51and11.84±1.57) and blood (0.15±0.01and 0.54±0.05) between the treated group and control group, respectively.

CONCLUSION

The A. muricata hydroalcoholic extract negatively influenced the uptake of 99mTc-DMSA in bladder, kidney and blood of rats.

Chemopreventive potential of Annona muricata L leaves on chemically-induced skin papillomagenesis in mice

Annona muricata L (Annonaceae), commonly known as soursop has a long, rich history in herbal medicine with a lengthy recorded indigenous use. It had also been found to be a promising new anti-tumor agent in numerous in vitro studies. The present investigation concerns chemopreventive effects in a two-stage model of skin papillomagenesis. Chemopreventive effects of an ethanolic extract of A. muricata leaves (AMLE) was evaluated in 6-7 week old ICR mice given a single topical application of 7,12-dimethylbenza(α)anthracene (DMBA 100 μg/100 μl acetone) and promotion by repeated application of croton oil (1% in acetone/ twice a week) for 10 weeks. Morphological tumor incidence, burden and volume were measured, with histological evaluation of skin tissue. Topical application of AMLE at 30, 100 and 300 mg/kg significantly reduced DMBA/croton oil induced mice skin papillomagenesis in (i) peri-initiation protocol (AMLE from 7 days prior to 7 days after DMBA), (ii) promotion protocol (AMLE 30 minutes after croton oil), or (iii) both peri-initiation and promotion protocol (AMLE 7 days prior to 7 day after DMBA and AMLE 30 minutes after croton oil throughout the experimental period), in a dose dependent manner (p<0.05) as compared to carcinogen-treated control. Furthermore, the average latent period was significantly increased in the AMLE-treated group. Interestingly, At 100 and 300 mg/ kg, AMLE completely inhibited the tumor development in all stages. Histopathological study revealed that tumor growth from the AMLE-treated groups showed only slight hyperplasia and absence of keratin pearls and rete ridges. The results, thus suggest that the A.muricata leaves extract was able to suppress tumor initiation as well as tumor promotion even at lower dosage.

Possible mechanisms of action of the hypotensive effect of Annona muricata (soursop) in normotensive Sprague-Dawley rats

CONTEXT

Annona muricata Linn (Annonaceae) (soursop) is a food plant reported to have antihypertensive properties.

OBJECTIVE

We investigated the blood pressure reducing effect of its aqueous leaf extract and the possible mechanisms that may be responsible.

METHODS

Intravenous administration of an aqueous leaf extract (9.17-48.5 mg/kg) of A. muricata on the mean arterial pressure and heart rate were recorded invasively on anaesthetized, normotensive Sprague-Dawley rats. Contractile responses of rat aortic rings to the extract (0.5-4.0 mg/mL) were studied using standard organ bath techniques.

RESULTS

A. muricata (9.17-48.5 mg/kg) caused significant (p < 0.05) dose-dependent reduction in blood pressure without affecting the heart rates. The hypotensive effects were unaffected by atropine (2 mg/kg), mepyramine (5 mg/kg), propranolol (1 mg/kg) and L-NAME (5 mg/kg). A. muricata leaf aqueous extract significantly (p < 0.05) relaxed phenylephrine (10(-9)-10(-4) M) and 80 mM KCl induced contractions in endothelium intact and denuded aortic rings; and caused a significant (p < 0.05) rightward shift of the Ca(2+) dose response curves in Ca(2+)-free Kreb's solution containing 0.1 mM EGTA.

CONCLUSIONS

The hypotensive effects of A. muricata are not mediated through muscarinic, histaminergic, adrenergic and nitric oxide pathways, but through peripheral mechanisms involving antagonism of Ca(2+).

Antinociceptive and anti-inflammatory activities of the ethanol extract of Annona muricata L. leaves in animal models

Antinociceptive and anti-inflammatory activities of the ethanol extract from Annona muricata L. leaves were investigated in animal models. The extract delivered per oral route (p.o.) reduced the number of abdominal contortions by 14.42% (at a dose of 200 mg/kg) and 41.41% (400 mg/kg). Doses of 200 and 400 mg/kg (p.o) inhibited both phases of the time paw licking: first phase (23.67% and 45.02%) and the second phase (30.09% and 50.02%), respectively. The extract (p.o.) increased the reaction time on a hot plate at doses of 200 (30.77% and 37.04%) and 400 mg/kg (82.61% and 96.30%) after 60 and 90 minutes of treatment, respectively. The paw edema was reduced by the ethanol extract (p.o.) at doses of 200 (23.16% and 29.33%) and 400 mg/kg (29.50% and 37.33%) after 3 to 4 h of application of carrageenan, respectively. Doses of 200 and 400 mg/kg (p.o.), administered 4 h before the carrageenan injection, reduced the exudate volume (29.25 and 45.74%) and leukocyte migration (18.19 and 27.95%) significantly. These results suggest that A. muricata can be an active source of substances with antinociceptive and anti-inflammatory activities.

Antiprotozoal and cytotoxic activities in vitro of Colombian Annonaceae

Ethnobotanical and chemotaxonomical studies for antiparasitic activity of Colombian Annonaceae were carried out. In vitro antiprotozoal activity of 36 extracts obtained from six different species was determined against promastigotes of three Leishmania species, epimastigotes of Trypanosoma cruzi and both chloroquine sensitive (F32) and resistant (W2) Plasmodium falciparum. Cytotoxic activity was evaluated in U-937 cells. Active extracts were selected according their selectivity index (SI). Extracts from Annona muricata, Rollinia exsucca, Rollinia pittieri and Xylopia aromatica were active against Leishmania spp. and Trypanosoma cruzi showing IC50 values lower than 25 microg/ml. Hexane extract from Rollinia pittieri leaves was the most selective against Trypanosoma cruzi and Leishmania spp. (IS=10 and 16, respectively). The extracts from Desmopsis panamensis, Pseudomalmea boyacana, Rollinia exsucca and Rollinia pittieri showed good antiplasmodial activity (IC50 < 10 microg/ml). No correlation between antiplasmodial activity and inhibition of beta-hematin production was found. The present study gives specific and useful information about antiprotozoal and cytotoxic activities of some Annonaceae extracts. Results presented here also demonstrate which plants and/or plant parts could be useful in the treatment of leishmaniasis, Chagas' disease and malaria.