Gamma-mangostin Protects S16Y Schwann Cells Against tert-Butyl Hydroperoxide-induced Apoptotic Cell Death

BACKGROUND

Peripheral neuropathy is a common complication that affects individuals with diabetes. Its development involves an excessive presence of oxidative stress, which leads to cellular damage in various tissues. Schwann cells, which are vital for peripheral nerve conduction, are particularly susceptible to oxidative damage, resulting in cell death.

MATERIALS AND METHODS

Gamma-mangostin (γ-mangostin), a xanthone derived from Garcinia mangostana, possesses cytoprotective properties in various pathological conditions. In this study, we employed S16Y cells as a representative Schwann cell model to investigate the protective effects of γ-mangostin against the toxicity induced by tert-Butyl hydroperoxide (tBHP). Different concentrations of γ-mangostin and tBHP were used to determine non-toxic doses of γ-mangostin and toxic doses of tBHP for subsequent experiments. MTT cell viability assays, cell flow cytometry, and western blot analysis were used for evaluating the protective effects of γ-mangostin.

RESULTS

The results indicated that tBHP (50 μM) significantly reduced S16Y cell viability and induced apoptotic cell death by upregulating cleaved caspase-3 and cleaved PARP protein levels and reducing the Bcl- XL/Bax ratio. Notably, pretreatment with γ-mangostin (2.5 μM) significantly mitigated the decrease in cell viability caused by tBHP treatment. Furthermore, γ-mangostin effectively reduced cellular apoptosis induced by tBHP. Lastly, γ-mangostin significantly reverted tBHP-mediated caspase-3 and PARP cleavage and increased the Bcl-XL/Bax ratio.

CONCLUSION

Collectively, these findings highlight the ability of γ-mangostin to protect Schwann cells from apoptotic cell death induced by oxidative stress.

HDAC inhibitor cowanin extracted from G. fusca induces apoptosis and autophagy via inhibition of the PI3K/Akt/mTOR pathways in Jurkat cells

Cowanin, a xanthone derivative extracted from the Garcinia fusca plant, has been recognized for various biological activities including, antimicrobial, anti-inflammatory, and anticancer activities. However, the mechanism to induce cancer cell death in cancer cells remains to be fully elucidated. Our previous report showed that other xanthones from these plants could act as histone deacetylase inhibitors (HDACi), so we deeply analyzed the role of cowanin, a major compound of G.fusca, and investigated through the mode of cell death both apoptosis and autophagy that have never been reported. As a result, it was demonstrated that cowanin indicated the role of HDACi as other xanthones. The molecular docking analysis showed that cowanin could interact within the catalytic pocket region of HDAC class I (HDAC2, 8) and II (HDAC4, 7) proteins and inhibit their activity. Also, the level of protein expression of HDAC2, 4, 7, and 8 was distinctly decreased, and the level of histone H3 and H4 acetylation increased in cowanin treated cells. For the mode of cell death, cowanin demonstrated both apoptosis and autophagy activation in Jurkat cells. Besides, cowanin significantly suppressed phosphorylation of PI3K, Akt, and mTOR signaling. Therefore, these findings revealed that cowanin represents a new promising candidate for development as an anticancer agent by inducing apoptosis and autophagy via PI3K/AKT/mTOR pathway and effectively inhibiting HDAC activity.

Stem Extract from Momordica cochinchinensis Induces Apoptosis in Chemoresistant Human Prostate Cancer Cells (PC-3)

Natural compounds have been recognized as valuable sources for anticancer drug development. In this work, different parts from Momordica cochinchinensis Spreng were selected to perform cytotoxic screening against human prostate cancer (PC-3) cells. Chromatographic separation and purification were performed for the main constituents of the most effective extract. The content of the fatty acids was determined by Gas Chromatography-Flame Ionization Detector (GC–FID). Chemical structural elucidation was performed by spectroscopic means. For the mechanism of the apoptotic induction of the most effective extract, the characteristics were evaluated by Hoechst 33342 staining, sub-G1 peak analysis, JC-1 staining, and Western blotting. As a result, extracts from different parts of M. cochinchinensis significantly inhibited cancer cell viability. The most effective stem extract induced apoptosis in PC-3 cells by causing nuclear fragmentation, increasing the sub-G1 peak, and changing the mitochondrial membrane potential. Additionally, the stem extract increased the pro-apoptotic (caspase-3 and Noxa) mediators while decreasing the anti-apoptotic (Bcl-xL and Mcl-1) mediators. The main constituents of the stem extract are α-spinasterol and ligballinol, as well as some fatty acids. Our results demonstrated that the stem extract of M. cochinchinensis has cytotoxic and apoptotic effects in PC-3 cells. These results provide basic knowledge for developing antiproliferative agents for prostate cancer in the future.

New bioactive cyclopeptide alkaloids with rare terminal unit from the root bark of Ziziphus cambodiana

Six new 14-membered ring cyclopeptide alkaloids, cambodines A–F (1–6), and two known compounds, frangufoline (7) and lotusanine B (8), were isolated from the root bark extract of Ziziphus cambodiana Pierre. Their structures and configurations were established based on 1D and 2D NMR, HRMS, ECD, and X-ray crystallographic data. Compounds 1 and 3 are rare 5(14)-type cyclopeptide alkaloids that possess an imidazolidin-4-one ring in the terminal unit. The cyclopeptides were tested for their in vitro antiplasmodial, antitubercular, and cytotoxic effects against three cancer cell lines. Compound 3 showed significant antiplasmodial activity against the malarial parasite Plasmodium falciparum, with an IC₅₀ value of 6.09 μM.

Six new 14-membered ring cyclopeptide alkaloids, cambodines A–F (1–6), and two known compounds, frangufoline (7) and lotusanine B (8), were isolated from the root bark extract of Ziziphus cambodiana Pierre.

Protective effects of γ-mangostin on 6-OHDA-induced toxicity in SH-SY5Y cells

γ-Mangostin is a xanthone with hydroxyl groups that confer the substance-free radical scavenging effects. As opposed to the other more extensively studied mangostins, scarce research has been conducted on neuroprotective effects of γ-mangostin on models of Parkinson's disease (PD). Therefore, this investigation aimed to elucidate its antioxidant and neuroprotective effects on 6-OHDA-induced toxicity in SH-SY5Y cells. 6-OHDA treatment, an inducer of PD pathology in vitro studies, decreased cell viability and increased the level of intracellular ROS production. Furthermore, the substance-induced the expression of phosphorylated p38 MAPK, negatively affected the Bax/Bcl-2 ratio and increased caspase-3 activity; all of which were factors that are associated with apoptosis. Pretreatment of cells with γ-mangostin at concentrations of 0.5, 1, and 2.5μM markedly increased cell survival and reduced the level of intracellular ROS formation as shown by DPPH radical scavenging activity of the compound. Furthermore, a significant suppression of p-p38, improved Bax/Bcl-2 ratio expression, and reduced caspase-3 activity was exhibited in the cells after γ-mangostin pretreatment. The reduction of apoptosis was further supported by the reduction of pyknotic nuclei indicated by Hoescht 33342 staining. These findings indicate that γ-mangostin could attenuate 6-OHDA-induced neuronal cell death and that the protective effect of γ-mangostin is associated with its antioxidative potential and through the modulation of the apoptotic signalling pathway. Therefore, γ-mangostin may be an effective xanthone among other mangostins for preventing neurodegeneration in PD caused by oxidative stress.

2-Arylbenzofurans from Artocarpus lakoocha and methyl ether analogs with potent cholinesterase inhibitory activity

In vitro screening for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of the Artocarpus lakoocha root-bark extracts revealed interesting results. Bioassay-guided fractionation resulted in the isolation of two new (1 and 2) and six known 2-arylbenzofurans 3-8, along with one stilbenoid 9 and one flavonoid 10. The structures of the isolated compounds were elucidated by UV, IR, 1D- and 2D-NMR and MS spectroscopic data analysis. Compounds 4, 6 and 7 exhibited more potent AChE inhibitory activity (IC₅₀ = 0.87-1.10 μM) than the reference drug, galantamine. Compounds 4, 8 and 9 displayed greater BChE inhibition than the standard drug. The preferential inhibition of BChE over AChE indicated that 4 also showed a promising dual AChE and BChE inhibitor. The synthetic mono-methylated analogs 4a-c and 6a-b were found to be good BChE inhibitors with IC₅₀ values ranging between 0.31 and 1.11 μM. Based on the docking studies, compounds 4 and 6 are well-fitted in the catalytic triad of AChE. Compounds 4 and 6 showed different binding orientations on BChE, and the most potent BChE inhibitor 4 occupied dual binding to both CAS and PAS more efficiently.

Effects of Long-Term Alpha-mangostin Supplementation on Hyperglycemia and Insulin Resistance in Type 2 Diabetic Rats Induced by High Fat Diet and Low Dose Streptozotocin

OBJECTIVE

The present study investigated the effects of long-term supplementation of alpha-mangostin (MG; a xanthone isolated from mangosteen fruit) on hyperglycemia, and insulin resistance in type 2 diabetic rats.

MATERIAL AND METHOD

Type 2 diabetes (DM2) was induced in male Sprague-Dawley rats by feeding high fat diet for three weeks followed by an IP injection of low dose streptozotocin. The rats were divided into four groups: control and diabetes without or with alpha-MG supplementation (CON, DM2, CON-MG and DM2-MG group, respectively). Alpha-MG was administered by gavage feeding in the amount of 200 mg/kg BW/day for 8 or 40 weeks. Fasting blood glucose, plasma HbA1c, cholesterol, and triglyceride were determined in all groups of rats. Serum insulin, calculated HOMA-IR and Oral glucose tolerance test were also carried out.

RESULTS

The results showed that both 8 and 40 weeks DM2 groups had a significant increase in fasting blood glucose, HbA1c, plasma cholesterol and triglyceride compared with their aged-match control groups. Furthermore, the serum insulin and HOMA-IR were significantly elevated in 8 weeks DM2 whereas these two parameters were significantly decreased in 40 weeks DM2 group compared with their aged-match CON groups (p < 0.001). The OGTT showed impaired glucose tolerance in DM2 groups. Interestingly, alpha-MG supplemented DM2-MG group had significantly decreased levels of fasting blood glucose, HbA1c, plasma cholesterol, triglyceride when compared with the untreated DM2 groups. Supplementation of alpha-MG for 40 weeks in DM2-MG group showed significantly increase serum insulin levels compared with that of DM2 group (p < 0.001). Moreover alpha-MG supplemented DM-MG group demonstrated a better glucose tolerance pattern which was different from that of DM2 group at both 8 weeks and 40 weeks experimental periods.

CONCLUSION

Long-term alpha-mangostin supplementation has anti-hyperglycemic, anti-hyperlipidemic effects and increase insulin sensitivity by improving beta-cell functions in type 2 diabetes mellitus.

Combating Helicobacter pylori infections with mucoadhesive nanoparticles loaded with Garcinia mangostana extract

Aim: To combat the resistance of Helicobacter pylori to antibiotics through the use of Garcinia mangostana extract (GME) in the form that can be localized at stomach mucosa. Materials & methods: GME and its major active component, α-mangostin, are encapsulated into the moderately acid stable mucoadhesive nanocarriers, and tested for anti-H. pylori and antiadhesion activities in vitro and their ability to eradicate H. pylori in infected mice. Results: The two in vitro activities are observed and are enhanced when the materials are encapsulated into nanocarriers. Preliminary in vivo tests revealed the ability to combat H. pylori in mice following oral administration of the encapsulated GME, but not the unencapsulated GME. Conclusion: Nanoencapsulated GME is a potential anti-H. pylori agent.

Original submitted 10 August 2012; Revised submitted 9 December 2012; Published online 3 June 2013

Dietary α-mangostin, a xanthone from mangosteen fruit, exacerbates experimental colitis and promotes dysbiosis in mice

SCOPE

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon. α-Mangostin (α-MG), the most abundant xanthone in mangosteen fruit, exerts anti-inflammatory and antibacterial activities in vitro. We evaluated the impact of dietary α-MG on murine experimental colitis and on the gut microbiota of healthy mice.

METHODS AND RESULTS

Colitis was induced in C57BL/6J mice by administration of dextran sulfate sodium (DSS). Mice were fed control diet or diet with α-MG (0.1%). α-MG exacerbated the pathology of DSS-induced colitis. Mice fed diet with α-MG had greater colonic inflammation and injury, as well as greater infiltration of CD3(+) and F4/80(+) cells, and colonic myeloperoxidase, than controls. Serum levels of granulocyte colony-stimulating factor, IL-6, and serum amyloid A were also greater in α-MG-fed animals than in controls. The colonic and cecal microbiota of healthy mice fed α-MG but no DSS shifted to an increased abundance of Proteobacteria and decreased abundance of Firmicutes and Bacteroidetes, a profile similar to that found in human UC.

CONCLUSION

α-MG exacerbated colonic pathology during DSS-induced colitis. These effects may be associated with an induction of intestinal dysbiosis by α-MG. Our results suggest that the use of α-MG-containing supplements by patients with UC may have unintentional risk.

α-Mangostin: anti-inflammatory activity and metabolism by human cells

Information about the anti-inflammatory activity and metabolism of α-mangostin (α-MG), the most abundant xanthone in mangosteen fruit, in human cells is limited. On the basis of available literature, we hypothesized that α-MG will inhibit the secretion of pro-inflammatory mediators by control and activated macrophage-like THP-1, hepatic HepG2, enterocyte-like Caco-2, and colon HT-29 human cell lines, as well as primary human monocyte-derived macrophages (MDM), and that such activity would be influenced by the extent of metabolism of the xanthone. α-MG attenuated TNF-α and IL-8 secretion by the various cell lines but increased TNF-α output by both quiescent and LPS-treated MDM. The relative amounts of free and phase II metabolites of α-MG and other xanthones present in media 24 h after addition of α-MG was shown to vary by cell type and inflammatory insult. Increased transport of xanthones and their metabolites across Caco-2 cell monolayers suggests enhanced absorption during an inflammatory episode. The anti-inflammatory activities of xanthones and their metabolites in different tissues merit consideration.

Synthesis, Structural Characterisation, and Preliminary Evaluation of Non-Indolin-2-one-based Angiogenesis Inhibitors Related to Sunitinib (Sutent®)

The indolin-2-one fused-ring system and the 2,4-dimethylpyrrole unit represent key structural motifs in the anticancer drug sunitinib (Sutent®) and predecessor angiogenesis inhibitors that have undergone anticancer clinical trials (e.g. semaxanib, SU5416). In pursuit of novel anti-angiogenic scaffolds, we were interested in identifying whether the indolin-2-one group in these structures could be modified without losing activity. This paper describes novel condensation chemistry used to prepare a test series of (E)- and (Z)-alkenes related to SU5416 that retain the 2,4-dimethylpyrrole unit while incorporating ring-opened indolin-2-ones. Unique structural characteristics were identified in the compounds, such as intramolecular hydrogen bonds in the (Z)-alkenes, and several examples were shown to possess significant anti-angiogenic activity in a rat aorta in vitro model of angiogenesis. The work demonstrates that the indolin-2-one moiety is not an absolute requirement for angiogenesis inhibition in the sunitinib/SU5416 class.

Mechanisms of vasorelaxation to gamma-mangostin in the rat aorta

OBJECTIVE

To investigate the effects of gamma-mangostin on vascular tone and its mechanisms in the isolated rat aorta.

MATERIAL AND METHOD

Aortic rings from male Wistar rats were precontracted with methoxamine. Changes in tension were measured using an isometric force transducer and recorded on the MacLab recording system. Vasorelaxant effects of gamma-mangostin were studied in the presence of 300 microM N(G)-nitro L-arginine methyl ester (L-NAME), 10 microM 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (ODQ), 10 microM indomethacin, 60 mM KCl, 5 mM tetraethylammonium (TEA), 10 microM glibenclamide, 1 mM4-aminopyridine (4-AP) or 30 microM barium chloride (BaCl2). Moreover the effects of gamma-mangostin on contraction to CaCl2 were evaluated.

RESULTS

Gamma-mangostin (1-100 microM) induced a concentration-dependent vasorelaxation in rat aortic rings precontracted with methoxamine. This effect was significantly reduced after removal of the endothelium and after pretreatment of the rings with L-NAME, ODQ, high KCl solution, or TEA. However, vasorelaxant responses to gamma-mangostin were not altered by indomethacin, 4-AP, BaCl2 or glibenclamide. Moreover, contractions to CaCl2 (10 mM-30 mM) were reduced by pre-treatment with gamma-mangostin (10 and 100 microM).

CONCLUSION

Gamma-mangostin causes vasorelaxation which is mediated via the NO-cGMP pathway. Moreover activation of K+ channels and inhibition of extracellular Ca2+ influx from the extracellular space are largely involved in the relaxant effects of gamma-mangostin. These data suggest that gamma-mangostin may acts as an antihypertensive agent.

Antiproliferative effect of α-mangostin on canine osteosarcoma cells

Osteosarcoma is the most frequently diagnosed primary bone tumor in dog. Since chemotherapeutics are quite limited due to high cost and severe toxicity, therefore, the ultimate goal is to discover cost-effective therapeutics with less toxicity. We have studied the effect of α-mangostin, a xanthone derivative isolated from pericarp of mangosteen (Garcinia mangostana Linn.) in canine osteosarcoma, D-17 cells. The results showed that α-mangostin induced antiproliferation with IC(50) at 15 μg/ml. Hoechst 33342 nuclear staining and nucleosomal DNA-gel electrophoresis revealed that α-mangostin could induce nuclear condensation and fragmentation, typically seen in apoptosis. Cell cycle analysis demonstrated that α-mangostin induced sub-G1 peak. In addition, α-mangostin also induced membrane flipping of the phosphatidylserine and the loss of mitochondrial membrane potential in D-17 cells. In conclusion, α-mangostin, induced apoptotic cell death against canine osteosarcoma D-17 cells, could be a potential candidate for preventive and therapeutic application for bone cancer treatment in dogs.

Microbial metabolism of α-mangostin isolated from Garcinia mangostana L

α-Mangostin (1), a prenylated xanthone isolated from the fruit hull of Garcinia mangostana L., was individually metabolized by two fungi, Colletotrichum gloeosporioides (EYL131) and Neosartorya spathulata (EYR042), repectively. Incubation of 1 with C. gloeosporioides (EYL131) gave four metabolites which were identified as mangostin 3-sulfate (2), mangostanin 6-sulfate (3), 17,18-dihydroxymangostanin 6-sulfate (4)and isomangostanin 3-sulfate (5). Compound 2 was also formed by incubation with N. spathulata (EYR042). The structures of the isolated compounds were elucidated by spectroscopic data analysis. Of the isolated metabolites, 2 exhibited significant anti-mycobacterial activity against Mycobacterium tuberculosis.

Antiplasmodial and antimycobacterial cyclopeptide alkaloids from the root of Ziziphus mauritiana

Investigation of the MeOH extract obtained from the root of the Ziziphus mauritiana grown in Thailand resulted in the isolation of two 14- and 13-membered cyclic alkaloids, mauritine L (1) and mauritine M (2), and three known cyclopeptide alkaloids, nummularines H (3), B (4) and hemsine A (5). Their structures were elucidated on the basis of extensive NMR spectroscopic analysis. The first single crystal X-ray diffraction study of the 13-membered ring cyclopeptide, nummularine B methiodide (4'), revealed all S configurations on the amino acid residues. The isolated alkaloids exhibited potent antiplasmodial activity against the parasite Plasmodium falciparum with the inhibitory concentration (IC50) ranging from 3.7 to 10.3 μM. Compounds 2 and 3 also demonstrated antimycobacterial activity against Mycobacterium tuberculosis with the MIC of 72.8 and 4.5 μM, respectively.

α-Mangostin induces apoptosis in human chondrosarcoma cells through downregulation of ERK/JNK and Akt signaling pathway

Chondrosarcoma is a malignant primary bone tumor that is resistant to chemotherapy and radiation therapy. α-Mangostin, a component of Garcinia mangostana Linn, is a xanthone derivative shown to have antioxidant and antitumor properties. This study is the first to investigate anticancer effects of α-mangostin in the human chondrosarcoma cell line SW1353. We showed that α-mangostin inhibited cell proliferation of SW1353 cells in a time- and dose-dependent manner by using the trypan blue exclusion method. Hoechst 33342 nuclear staining and nucleosomal DNA-gel electrophoresis revealed that α-mangostin could induce nuclear condensation and fragmentation, typically seen in apoptosis. Flow cytometry using Annexin V/PI double staining assessed apoptosis, necrosis and viability. α-Mangostin activated caspase-3, -8, -9 expression, decreased Bcl-2 and increased Bax. This promotes mitochondrial dysfunction, leading to the release of cytochrome c from the mitochondria to the cytoplasm. In addition, total and phosphorylated ERK and JNK were downregulated in α-mangostin-treated SW1353 cells but no changes in p38. α-Mangostin also decreased phosphorylated Akt without altering total Akt. These results suggest that α-mangostin inhinbited cell proliferation and induced apoptosis through downregulation of ERK, JNK and Akt signaling pathway in human chondrosarcoma SW1353 cells.

Effects of α-mangostin on apoptosis induction of human colon cancer

AIM: To investigate the effect of α-mangostin on the growth and apoptosis induction of human colon cancer cells.

METHODS: The three colorectal adenocarcinoma cell lines tested (COLO 205, MIP-101 and SW 620) were treated with α-mangostin to determine the effect on cell proliferation by MTT assay, cell morphology, chromatin condensation, cell cycle analysis, DNA fragmentation, phosphatidylserine exposure and changing of mitochondrial membrane potential. The molecular mechanisms of α-mangostin mediated apoptosis were further investigated by Western blotting analysis including activation of caspase cascade, cytochrome c release, Bax, Bid, p53 and Bcl-2 modifying factor.

RESULTS: The highest inhibitory effect of α-mangostin on cell proliferation of COLO 205, MIP-101 and SW 620 were 9.74 ± 0.85 μg/mL, 11.35 ± 1.12 μg/mL and 19.6 ± 1.53 μg/mL, respectively. Further study showed that α-mangostin induced apoptotic cell death in COLO 205 cells as indicated by membrane blebbing, chromatin condensation, DNA fragmentation, cell cycle analysis, sub-G1 peak (P < 0.05) and phosphatidylserine exposure. The executioner caspase, caspase-3, the initiator caspase, caspase-8, and caspase-9 were expressed upon treatment with α-mangostin. Further studies of apoptotic proteins were determined by Western blotting analysis showing increased mitochondrial cytochrome c release, Bax, p53 and Bmf as well as reduced mitochondrial membrane potential (P < 0.05). In addition, up-regulation of tBid and Fas were evident upon treatment with α-mangostin (P < 0.01).

CONCLUSION: α-Mangostin may be effective as an anti-cancer agent that induced apoptotic cell death in COLO 205 via a link between extrinsic and intrinsic pathways.

Potential of xanthones from tropical fruit mangosteen as anti-cancer agents: caspase-dependent apoptosis induction in vitro and in mice

The pericarp of mangosteen (Garcinia mangostana L.) is rich in various xanthones that are known to possess unique biological activities. In this work, we characterized the anti-proliferative and cytotoxic activities of mangosteen xanthones both in vitro and in mice. In vitro analysis with a human colorectal adenocarcinoma cell line, COLO 205, showed that mangosteen xanthones not only inhibit the proliferation of target cells but also induce their death by apoptosis that involves the activation of the caspase cascade. In vivo analysis using a mouse subcutaneous tumor model with COLO 205 cells showed that, at relatively low doses, the growth of tumors was repressed upon intratumoral administration of mangosteen xanthones. When a higher dose of mangosteen xanthones was administered, the size of tumors was reduced gradually, and, in some mice, the disappearance of tumors was seen. Histopathological evaluation and biochemical analysis of tumors that received mangosteen xanthones indicate the induction of apoptosis in tumors, which resulted in the repression of their growth and the reduction of their sizes. These results demonstrate the potential of mangosteen xanthones to serve as anti-cancer agents for the chemotherapy of cancer.

Cytotoxic Prenylated Xanthones from the Young Fruit of Garcinia mangostana

Three new prenylated xanthones, mangostenones C (1), D (2), and E (3), together with 16 known xanthones 4-19, were isolated from the young fruit (7-week maturity stage) of Garcinia mangostana. The structural elucidation of the new compounds was mainly established on the basis of 1D and 2D NMR and HR-MS spectroscopic analysis. Compound 1 showed cytotoxic properties against three human cancer cell lines, epidermoid carcinoma of the mouth (KB), breast cancer (BC-1), and small cell lung cancer (NCI-H187), with IC50 values of 2.8, 3.53, and 3.72 microg/ml, respectively. Among the isolates, alpha-mangostin (12), the major metabolite, exhibited the most potent effects against the BC-1 cells with an IC50 value of 0.92 microg/ml, an activity greater than that of the standard drug ellipticine (IC50 = 1.46 microg/ml). Compound 12 also showed the highest activity against KB cells, while gartanin (10) displayed the strongest activity against the NCI-H187 cells at the respective IC50 values of 2.08 microg/ml and 1.08 microg/ml.

Ceanothane- and Lupane-Type Triterpenes with Antiplasmodial and Antimycobacterial Activities from Ziziphus cambodiana

One new and eight known ceanothane- and lupane-type triterpenes were isolated from the root bark of Ziziphus cambodiana PIERRE (Rhamnaceae). Based on spectral analyses, the structure of the new compound was elucidated as 3-O-(4-hydroxy-3-methoxybenzoyl)ceanothic acid (3-O-vanillylceanothic acid) (1), while the known compounds were identified as lupeol (2), betulinaldehyde (3), betulinic acid (4), 2-O-E-p-coumaroyl alphitolic acid (5), alphitolic acid (6), zizyberanalic acid (7), zizyberenalic acid (8) and ceanothic acid (9). Compounds 1, 5 and 8 exhibited significant in vitro antiplasmodial activity against the parasite Plasmodium falciparum, with inhibitory concentration (IC50) values of 3.7, 0.9 and 3.0 microg/ml, respectively. Compounds 1 and 3-8 showed antimycobacterial activity against Mycobacterium tuberculosis with respective MIC values of 25, 25, 25, 12.5, 50, 50 and 100 microg/ml.

Bioactive Constituents of the Root Bark of Artocarpus rigidus subsp. rigidus

Investigation of the chemical constituents of the root bark of Artocarpus rigidus BLUME subsp. rigidus has led to the isolation of six, structurally diverse phenolic compounds. These included two new compounds with modified skeletons, the flavonoid 7-demethylartonol E (1) and the chromone artorigidusin (2), together with four known phenolic compounds, the xanthone artonol B (3), the flavonoid artonin F (4), the flavonoid cycloartobiloxanthone (5), and the xanthone artoindonesianin C (6). Compounds 1, 4, and 5 exhibited antiplasmodial activity against Plasmodium falciparum. All compounds showed antimycobacterial activity against Mycobacterium tuberculosis, with 4 being the most active compound (MIC 6.25 microg/ml). Compounds 5 and 6 were active against KB cells, whereas 2, 5, and 6 showed varying toxicity to BC cells. Compounds 1-3, 5, and 6 were active in the NCI-H187 cytotoxicity assay, with 3 being the most active compound (IC(50) 1.26 microg/ml).

Antimycobacterial and antioxidant flavones from Limnophila geoffrayi

The chloroform extract of the aerial part of Limnophila geoffrayi showed antimycobacterial and antioxidant activities. Bioassay-guided fractionation has led to the isolation of the flavones nevadensin (5,7-dihydroxy-6,8,4'-trimethoxyflavone, 1) and isothymusin (6,7-dimethoxy-5,8,4'-trihydroxyflavone, 2). Both compounds 1 and 2 exhibited inhibition activity against Mycobacterium tuberculosis, with equal MIC value of 200 microg/mL. Only compound 2 exhibited antioxidant activity against the radical scavenging ability of DPPH, with the IC50 value of 7.7 microg/mL. The crude hexane, chloroform and methanol extracts as well as the pure compounds 1 and 2 did not exhibit mutagenic activity in the Bacillus subtilis recassay.

Iridoid glucosides from the flowers of Barleria lupulina

A new iridoid diglucoside, lupulinoside, and eight known iridoid glucosides, acetylbarlerin, ipolamiidoside ( 3), 6-O-acetylshanzhiside methyl ester, barlerin, shanzhiside methyl ester, mussaenosidic acid, 8-O-acetylshanzhiside, and shanzhiside have been isolated from the flowers of Barleria lupulina. The structure of the new compound was established as 8-O-acetyl-2'- O-(beta-glucopyranosyl)mussaenoside by spectroscopic, especially 2D NMR, techniques. When tested for anti-herpes simplex type 1 activity, only compound 3 exhibited antiviral properties. None of the compounds showed cytotoxic effects to the vero cells and none of them inhibited cyclooxygenase-2 enzyme.

Antimycobacterial activity of prenylated xanthones from the fruits of Garcinia mangostana

Prenylated xanthones, isolated from the fruit hulls and the edible arils and seeds of Garcinia mangostana, were tested for their antituberculosis potential. Alpha- and beta-mangostins and garcinone B exhibited strong inhibitory effect against Mycobacterium tuberculosis with the minimum inhibitory concentration (MIC) value of 6.25 microg/ml. Tri- and tetra-oxygenated xanthones with di-C5 units or with a C5 and a modified C5 groups are essential for high activities. Substitution in the A and C rings has been shown to modify the bioactivity of the compounds.

Xanthones from the green fruit hulls of Garcinia mangostana

Three new xanthones, mangostenol (1), mangostenone A (2), and mangostenone B (3), were isolated from the green fruit hulls of Garcinia mangostana, along with the known xanthones, trapezifolixanthone, tovophyllin B (4), alpha- and beta-mangostins, garcinone B, mangostinone, mangostanol, and the flavonoid epicatechin. The structures of the new xanthones were elucidated by analysis of their spectroscopic data.

Iridoids with anti-inflammatory activity from Vitex peduncularis

A new iridoid, pedunculariside, together with the known iridoid agnuside were isolated from the butanol extract of Vitex peduncularis stem bark. Both pedunculariside and agnuside showed preferential inhibition of COX-2, with IC50 values of 0.15 +/- 0.21 mg/ml and 0.026 +/- 0.015 mg/ml respectively, while having only small inhibitory effects on COX-1. Both compounds did not exhibit cytotoxicity against vero cells.