Structure-activity relationships of 1'S-1'-acetoxychavicol acetate for inhibitory effect on NO production in lipopolysaccharide-activated mouse peritoneal macrophages

1′-Acetoxyeugenol Acetate Isolated from Thai Ginger Induces Apoptosis in Human Ovarian Cancer Cells by ROS Production via NADPH Oxidase

The rhizomes of Alpinia galanga (Thai ginger) have been used extensively as a spice in Southeast Asian and Arabian cuisines and reported to possess a wide range of biological properties, such as antioxidant, antimicrobial, and antibacterial. However, the specific molecular and cellular mechanisms underlying the anti-tumor effects induced by Thai ginger and its corresponding active compounds have been poorly characterized. We found that upon EtOH extraction, Thai ginger extract exhibits cytotoxic activity (IC50 < 10 μg/mL) and triggers cell death via caspase-dependent apoptosis in human ovarian cancer cells. Among the three major compounds isolated from the extract, 1′-acetoxyeugenol acetate (AEA) exhibited potent cytotoxic activity in human ovarian cancer cells, SKOV3 and A2780. AEA induced apoptotic cell death through the activation of caspases-3 and -9. Notably, AEA enhanced the intracellular levels of reactive oxygen species (ROS), and the application of an antioxidant markedly reversed AEA-induced apoptosis of ovarian cancer cells. The knockdown of p47phox, a subunit of NADPH oxidase, suppressed both the pro-apoptotic and ROS-inducing effects of AEA. Additionally, the activation of the mitogen-activated protein kinase (MAPK) pathway by AEA through ROS regulation was found to be involved in AEA-induced apoptosis. Altogether, these results suggest that AEA exhibits potent apoptosis-inducing activity through the activation of the intrinsic pathway via ROS-mediated MAPK signaling in human ovarian cancer cells.

A New Monoterpene from the Rhizomes of Alpinia galanga and Its Anti-Vpr Activity

A new menthane-type monoterpene, alpigalanol (1), together with four known terpenes (2-5) were isolated from the ethyl acetate soluble fraction of the 70 % ethanol extract of the Alpinia galanga rhizomes. The structure of 1 was determined by spectroscopic analyses, including 1D- and 2D-NMR. The extract of the A. galanga rhizomes and all isolated compounds (1-5) possessed Vpr inhibitory activities against the TREx-HeLa-Vpr cells at a concentration of 1.25 μM without showing any cytotoxicity.

1'-Acetoxychavicol acetate inhibits NLRP3-dependent inflammasome activation via mitochondrial ROS suppression

The nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain containing (NLRP) 3 inflammasome is a multiprotein complex that triggers Caspase-1-mediated IL-1β production and pyroptosis, and its dysregulation is associated with the pathogenesis of inflammatory diseases. 1'-Acetoxychavicol acetate (ACA) is a natural compound in the rhizome of tropical ginger Alpinia species with anti-microbial, anti-allergic and anti-cancer properties. In this study, we found that ACA suppressed NLRP3 inflammasome activation in mouse bone marrow-derived macrophages and human THP-1 monocytes. ACA inhibited Caspase-1 activation and IL-1β production by NLRP3 agonists such as nigericin, monosodium urate (MSU) crystals, and ATP. Moreover, it suppressed oligomerization of the adapter molecule, apoptosis-associated speck-like protein containing a CARD (ASC), and Caspase-1-mediated cleavage of pyroptosis executor Gasdermin D. Mechanistically, ACA inhibited generation of mitochondrial reactive oxygen species (ROS) and prevented release of oxidized mitochondrial DNA, which trigger NLRP3 inflammasome activation. ACA also prevented NLRP3 inflammasome activation in vivo, as evidenced in the MSU crystal-induced peritonitis and dextran sodium sulfate-induced colitis mouse models accompanied by decreased Caspase-1 activation. Thus, ACA is a potent inhibitor of the NLRP3 inflammasome for prevention of NLRP3-associated inflammatory diseases.

Chemicals Constituents Isolated from Cultivate Alpinia conchigera Griff. and Antimicrobial Activity

Alpinia conchigera Griff. is a plant species from the family Zingiberaceae. Coloquially known as wild ginger, Alpinia conchigera Griff. is used as food condiment and for traditional treatment of skin diseases. Isolation studies to identify bioactive compounds of rhizomes of Alpinia conchigera yielded seven compounds; 1'S-1'-acetoxychavicol acetate (1), trans-p-coumaryl diacetate (2), p-hydroxycinnamyl acetate (3), 1'S-1'-hydroxychavicol acetate (4) p-hydroxybenzaldehyde (5), stigmasterol (6) and β-sitosterol (7). Compounds 1, 2 and 5 were evaluated for antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). Among the compounds tested, Compound 1 showed good antimicrobial activity against the strain of MRSA with minimum inhibition concentration (MIC) value of 0.5 mg/mL. Meanwhile, Compounds 2 and 5 exhibited moderate activity with MIC value between 1.0 and 2.0 mg/mL. These findings indicate antimicrobial potential of 1'S-1'-acetoxychavicol acetate (1), compound derived from rhizome of Alpinia conchigera Griff. against MRSA, which warrant further investigation.

Pharmacological Effects of 1'-Acetoxychavicol Acetate, a Major Constituent in the Rhizomes of Alpinia galanga and Alpinia conchigera

1'-Acetoxychavicol acetate (ACA) is found in the rhizomes or seeds of Alpinia galanga and Alpinia conchigera, which are used as traditional spices in cooking and traditional medicines in Southeast Asia. ACA possesses numerous medicinal properties. Those include anticancer, antiobesity, antiallergy, antimicrobial, antidiabetic, gastroprotective, and anti-inflammatory activities. ACA is also observed to exhibit antidementia activity. Recent studies have demonstrated that combining ACA with other substances results in synergistic anticancer effects. The structural factors that regulate the activity of ACA include (1) the acetyl group at position 1', (2) the acetyl group at position 4, and (3) the unsaturated double bond between positions 2' and 3'. ACA induces the activation of AMP-activated protein kinase (AMPK), which regulates the signal transduction pathways, and has an important role in the prevention of diseases, including cancer, obesity, hyperlipidemia, diabetes, and neurodegenerative disorders. Such findings suggest that AMPK has a central role in different pharmacological functions of ACA, and ACA is useful for the prevention of life-threatening diseases. However, more studies should be performed to evaluate the clinical effects of ACA and to better understand its potential.

Labdane-Type Diterpenes, Galangalditerpenes A-C, with Melanogenesis Inhibitory Activity from the Fruit of Alpinia galanga

In our continuing study of biologically active natural products from the fruit of Alpinia galanga (Zingiberaceae), we newly isolated three new labdane-type diterpenes, termed galangalditerpenes A–C (1–3), along with four known sesquiterpenes (4–7) and two diterpenes (8 and 9). The stereostructures of 1–3 were elucidated on the basis of their spectroscopic properties. The melanogenesis inhibitory activities in theophylline-stimulated murine B16 melanoma 4A5 cells of these isolates, including the new diterpenes (1–3, IC₅₀ = 4.4, 8.6, and 4.6 μM, respectively), were found to be more than 6–87-fold higher than that of arbutin (174 μM), a commercially available positive control.

Valorisation of softwood bark through extraction of utilizable chemicals. A review

Softwood bark is an important source for producing chemicals and materials as well as bioenergy. Extraction is regarded as a key technology for obtaining chemicals in general, and valorizing bark as a source of such chemicals in particular. In this paper, properties of 237 compounds identified in various studies dealing with extraction of softwood bark were described. Finally, some challenges and perspectives on the production of chemicals from bark are discussed.

Melanogenesis inhibitory activity of a 7-O-9'-linked neolignan from Alpinia galanga fruit

An aqueous acetone extract from the fruit of Alpinia galanga (Zingiberaceae) demonstrated inhibitory effects on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells (IC₅₀=7.3μg/mL). Through bioassay-guided separation of the extract, a new 7-O-9'-linked neolignan, named galanganol D diacetate (1), was isolated along with 16 known compounds including 14 phenylpropanoids (2-15). The structure of 1, including its absolute stereochemistry in the C-7 position, was elucidated by means of extensive NMR analysis and total synthesis. Among the isolates, 1 (IC₅₀=2.5μM), 1'S-1'-acetoxychavicol acetate (2, 5.0μM), and 1'S-1'-acetoxyeugenol acetate (3, 5.6μM) exhibited a relatively potent inhibitory effect without notable cytotoxicity at effective concentrations. The following structural requirements were suggested to enhance the inhibitory activity of phenylpropanoids on melanogenesis: (i) compounds with 4-acetoxy group exhibit higher activity than those with 4-hydroxy group; (ii) 3-methoxy group dose not affect the activity; (iii) acetylation of the 1'-hydroxy moiety enhances the activity; and (iv) phenylpropanoid dimers with the 7-O-9'-linked neolignan skeleton exhibited higher activity than those with the corresponding monomer. Their respective enantiomers [1' (IC₅₀=1.9μM) and 2' (4.5μM)] and racemic mixtures [(±)-1 (2.2μM) and (±)-2 (4.4μM)] were found to exhibit melanogenesis inhibitory activities equivalent to those of the naturally occurring optical active compounds (1 and 2). Furthermore, the active compounds 1-3 inhibited tyrosinase, tyrosine-related protein (TRP)-1, and TRP-2 mRNA expressions, which could be the mechanism of melanogenesis inhibitory activity.

Induction of apoptosis and G2 /M cell cycle arrest by Scrophularia striata in a human leukaemia cell line

OBJECTIVES

Scrophularia striata Boiss (Scrophulariaceae) is a plant that grows in northeastern Iran; it has been used traditionally to treat various inflammatory disorders. This study was designed to investigate cytotoxic effects of S. striata extract, on the Jurkat human leukaemia cell line (T-cell leukaemia).

MATERIALS AND METHODS

Phytochemical assay by thin layer chromatography and 2, 2 diphenyl-1-picryl-hydrazyl were used to evaluate main compounds and antioxidant capacity of the plant extract, respectively. Its inhibitory effect on Jurkat cells was evaluated by MTT assay. In addition, cell cycle distribution and apoptotic cell death were evaluated by propidium iodide and annexin V-FITC/ propidium iodide staining.

RESULTS

These showed that the main components present in S. striata extract included flavonoids, phenolic compounds and phenyl propanoids. Treatment with extract was significantly cytotoxic to the tumour cell line. In addition, flow cytometry analysis indicated that S. striata extract induced cell cycle arrest in G2 /M phase and apoptosis of tumour cells.

CONCLUSIONS

Results of the study indicated that S. striata extract could inhibit leukaemia cell proliferation by inducing G2 /M phase arrest and apoptosis.

Protective effects of Scrophularia striata in Ovalbumin-induced mice asthma model

BACKGROUND

Scrophularia striata Boiss. (Scrophulariaceae) is a plant growing in the northeastern part of Iran and being used as a traditional herb for various inflammatory disorders.This study was designed to investigate the protective effects of the Scrophularia striata extract in Ovalbumin (OVA) induced-asthma mice model.

METHODS

OVA-sensitized mice were intrapritonealy treated with two doses (100 and 200 mg/kg) of the extract on days 8 to 14 separately. Broncoalveolar lavage fluids (BALF) was collected 48 h after the final OVA challenge and then the number of eosinophils and other inflammatory cells were assessed by direct microscopic counting. In addition, total immunoglubolin (Ig) E and OVA-specific IgE levels in serum, IL-4 and IL-5 cytokines in BALF were determined by Enzyme-Linked Immunosorbent Assay. Moreover, phytochemical assay by thin layer chromatography (TLC) and the 2, 2 diphenyl-1-picrylhydrazyl (DPPH) were used to evaluate the main compounds and the antioxidant capacity of the plant extract, respectively.

RESULTS

The results showed that the main components; including flavonoids, phenolic compounds and phenyl propanoids were presented in the S. striata extract. In addition, the treatment with extract significantly reduced the number of inflammatory cells and suppressed T-helper 2 (Th2) cytokines including IL-4 and IL-5 in BALF. Also, total IgE and OVA-specific IgE levels in the serum decreased.

CONCLUSION

Collectively, it is concluded that the extract has the potential to modulate the Th2 cytokines and could be used as immunomodulatory agent in the treatment of allergic asthma.

Invasion inhibitors of human fibrosarcoma HT 1080 cells from the rhizomes of Zingiber cassumunar: structures of phenylbutanoids, cassumunols

The methanolic extract and its EtOAc-soluble fraction from the rhizomes of Zingiber cassumunar inhibited invasion of human fibrosarcoma HT 1080 cells. From the EtOAc-soluble fraction, eight new phenylbutanoids, cassumunols A-H, were isolated together with 30 known constituents. The structures of new phenylbutanoids were elucidated on the basis of chemical and physicochemical evidence. Principal constituents were examined the inhibitory effects on the invasion of HT 1080 cells. Among them, phlain I and III, (E)-1-(3,4-dimethoxyphenyl)buta-1,3-diene, (E)-1-(2,4,5-trimethoxyphenyl)buta-1,3-diene, and (-)-β-sesquiphellandrene showed anti-invasion effects. Interestingly, (E)-1-(2,4,5-trimethoxyphenyl)buta-1,3-diene [inhibition (%) 46.8 ± 7.2 (p<0.05) at 30 µM] significantly inhibited the invasion, and only a weak cytotoxic effect was observed.

Retention of regiochemistry and chirality in the ruthenium catalyzed allylic alkylation of disubstituted allylic esters

The regiospecific nucleophilic substitution during the ruthenium catalyzed allylic alkylation of 1,3-unsymmetrical disubstituted allylic esters was demonstrated. The nucleophile was selectively introduced at the position originally substituted with leaving group in the 2-DPPBA or ip-pybox ligated [RuCl(2)(p-cymene)](2) catalyzed allylic alkylation of 1,3-unsymmetrical disubstituted allylic esters. The chirality of the optically active allylic esters was also transferred to the alkylated products.

The apoptotic effect of 1's-1'-acetoxychavicol acetate from Alpinia conchigera on human cancer cells

1'-(S)-1'-Acetoxychavicol acetate (ACA) isolated from the Malaysian ethno-medicinal plant Alpinia conchigera Griff. was investigated for its potential as an anticancer drug. In this communication, we describe the cytotoxic and apoptotic properties of ACA on five human tumour cell lines. Data from MTT cell viability assays indicated that ACA induced both time- and dose-dependent cytotoxicity on all tumour cell lines tested and had no adverse cytotoxic effects on normal cells. Total mortality of the entire tumour cell population was achieved within 30 hrs when treated with ACA at 40.0 µM concentration. Flow cytometric analysis for annexin-V and PI dual staining demonstrated that cell death occurred via apoptosis, followed by secondary necrosis. The apoptotic effects of ACA were confirmed via the DNA fragmentation assay, in which consistent laddering of genomic DNA was observed for all tumour cell lines after a 24 hrs post-treatment period at the IC(50) concentration of ACA. A cell cycle analysis using PI staining also demonstrated that ACA induced cell cycle arrest at the G(0)/G(1) phase, corresponding to oral tumour cell lines. In conclusion, ACA exhibits enormous potential for future development as a chemotherapeutic drug against various malignancies.

1'S-1'-acetoxyeugenol acetate: a new chemotherapeutic natural compound against MCF-7 human breast cancer cells

Medicinal plants containing active natural compounds have been used as an alternative treatment for cancer patients in many parts of the world especially in Asia (Itharat et al. 2004). In this report, we describe the cytotoxic and apoptotic properties of 1'S-1'-acetoxyeugenol acetate (AEA), an analogue of 1'S-1'-acetoxychavicol acetate (ACA), isolated from the Malaysian ethno-medicinal plant Alpinia conchigera Griff (Zingiberaceae) on human breast cancer cells. Data from MTT cell viability assays indicated that AEA induced both time- and dose-dependent cytotoxicity with an IC(50) value of 14.0 μM within 36 h of treatment on MCF-7 cells, but not in HMEC normal control cells. Both annexin V-FITC/PI flow cytometric analysis and DNA fragmentation assays confirmed that AEA induced cell death via apoptosis. AEA was also found to induce cell cycle arrest in MCF-7 cells at the G(0)/G(1) phase with no adverse cell cycle arrest effects on HMEC normal control cells. It was concluded that AEA isolated from the Malaysian tropical ginger represents a potential chemotherapeutic agent against human breast cancer cells with higher cytotoxicity potency than its analogue, ACA.

Comparison of glutathione reductase activity and the intracellular glutathione reducing effects of 13 derivatives of 1'-acetoxychavicol acetate in Ehrlich ascites tumor cells

In a previous study, we showed that (1'S)-acetoxychavicol acetate ((S)-ACA) caused a rapid decrease in glutathione (GSH) levels less than 15 min after exposure. (S)-ACA-induced cell death was reversed by the addition of N-acetylcysteine. In the current study, we investigated the inhibitory activities of 13 derivatives of (S)-ACA on tumor cell viability, intracellular GSH level and GR activity. Correlations were found among a decrease in cell viability, intracellular GSH levels and the activity of GR in Ehrlich ascites tumor cells treated with the various ACA analogues. A test of the 13 derivatives revealed that the structural factors regulating activity were as follows: (1) the para or 1'-position of acetoxyl group (or other acyl group) was essential, (2) the presence of a C2'-C3' double or triple bond was essential, and (3) the S configuration of the 1'-acetoxyl group was preferable.

Halogenated analogs of 1'-acetoxychavicol acetate, Rev-export inhibitor from Alpinia galanga, designed from mechanism of action

In the course of search for the robust analogs of 1'-acetoxychavicol acetate (ACA, 1), the Rev-export inhibitor from the medicinal plant Alpinia galanga, we clarified formation of the quinone methide intermediate ii to be essential for exerting the inhibitory activity of 1. Based on this mechanism of action, the rational design from the MO calculation of the conclusive activation energy to ii resulted in the four halogenated analogs with more potent activity than ACA (1). In particular, the difluoroanalog 20d exhibited approximately four-fold potent activity as compared with 1.

Structures of new phenylbutanoids and nitric oxide production inhibitors from the rhizomes of Zingiber cassumunar

The methanolic (MeOH) extract from the rhizomes of Zingiber cassumunar showed nitric oxide (NO) production inhibitory effects induced by lipopolysaccharide (LPS) in mouse peritoneal macrophages. From the MeOH extract, six new phenylbutanoids, phlains I-VI, were isolated together with 16 known constituents. The structures of new phenylbutanoids were determined on the basis of physicochemical and chemical evidence. In addition, the inhibitory effects of the principal constituents on the NO production were examined. Among them, phlain III (IC50=24 microM), (E)-1-(3,4-dimethoxyphenyl)buta-1,3-diene (69 microM), (E)-1-(2,4,5-trimethoxyphenyl)buta-1,3-diene (83 microM), and cassumunaquinone 1 (47 microM) were found to show the inhibitory effects.

Absolute stereostructures of olibanumols A, B, C, H, I, and J from olibanum, gum-resin of Boswellia carterii, and inhibitors of nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages

Three new monoterpenes, olibanumols A (1), B (2), and C (3), and three new triterpenes, olibanumols H (4), I (5), and J (6), were isolated from olibanum, the exuded gum-resin from Boswellia carterii BIRDW. Their structures including the absolute configuration were determined by chemical and physicochemical evidence. Among the constituents, olibanumols A (1), H (4), and I (5), and isofouquierol (12) exhibited nitric oxide production inhibitory activity in lipopolysaccharide-activated mouse peritoneal macrophages.

Acetoxybenzhydrols as highly active and stable analogues of 1'S-1'-acetoxychavicol, a potent antiallergic principal from Alpinia galanga

Through SAR studies on 1'S-1'-acetoxychavicol acetate (1) against Type I antiallergic activity by indexing release of beta-hexosaminidase, a marker of antigen-IgE-mediated degranulation in RBL-2H3 cells, more stable and potent analogue, 4-(methoxycarbonyloxyphenylmethyl)phenyl acetate (16), has been developed. The compound 16 also strongly inhibited the antigen-IgE-mediated TNF-alpha and IL-4 production.

Anti-inflammatory activity of p-coumaryl alcohol-gamma-O-methyl ether is mediated through modulation of interferon-gamma production in Th cells

BACKGROUND AND PURPOSE

p-Coumaryl alcohol-gamma-O-methyl ether (CAME) was isolated from Alpinia galanga and shown to contain a phenylpropanoid structure similar to p-coumaryl diacetate (CDA). CDA is known to have antioxidant and anti-inflammatory activity, but the biochemical activities of CAME are unknown. Inflammation is mediated by inflammatory cytokine production, in particular, by CD4+ T helper cells (Th cells), but it is unclear whether phenylpropanoids affect cytokine production in Th cells. In this study, we decided to investigate the functions of CAME and CDA in CD4+ Th cells.

EXPERIMENTAL APPROACH

Mouse CD4+ Th cells were isolated from C57BL6 mice and stimulated with an antibody against T cell receptors in the presence of phenylpropanoids. Cytokine production was measured by elisa and intracellular cytokine staining. Gene knockout mice and tetracycline-inducible transgenic mice were used to examine the molecular mechanisms of phenylpropanoids on modulation of cytokine production.

KEY RESULTS

CAME potently reduced intracellular reactive oxygen species in Th cells, as does CDA. However, although CDA was cytotoxic, CAME selectively and potently suppresses interferon-gamma (IFNgamma) production in CD4+ Th cells, without toxicity. This effect was caused by attenuated expression of the transcription factor, T-box protein expressed in T cells (T-bet), and T-bet was essential for CAME to inhibit IFNgamma production in CD4+ Th cells.

CONCLUSIONS AND IMPLICATIONS

CAME selectively and substantially suppresses IFNgamma production in CD4+ Th cells by decreasing T-bet expression. As increased IFNgamma production by CD4+ Th cells can mediate inflammatory immune responses, a selective IFNgamma suppressor, such as CAME may be an effective, naturally occurring, compound for modulating inflammatory immune disorders.

Effect of naturally occurring hydroxychavicol acetate on the cytokine production in T helper cells

Naturally occurring phenolic compounds, such as chavicol analogues, have been shown to have potent antioxidant and anti-inflammatory activities. We have previously isolated two chavicol acetate analogues, acetoxychavicol acetate (ACA) and hydroxychavicol acetate (HCA) from the rhizomes of Alpinia galanga. Although the function of ACA has been studied in many systems, the function of HCA has yet to be systemically examined. In this study, we have comparably examined the functions of ACA and HCA on the cytokine production in Th cells. ACA exhibited potent antioxidant activity and increased cell apoptosis; therefore, cytokine production by Th cells was diminished. Although HCA had neither antioxidant activity nor pro-apoptotic function, it was shown to increase IL-2 production and attenuate IFNgamma expression in Th cells. In addition, we demonstrated that HCA suppressed T-bet expression, which is responsible for IL-2 suppression and IFNgamma induction in Th cells and inhibited T-bet-mediated Th1 cell differentiation. Therefore, we suggest that HCA may be beneficial as therapeutics for treating inflammatory immune disorders caused by extravagant activation of Th1-mediated immune responses.

Structures of new monoterpenes from Thai herbal medicine Curcuma comosa

Three new monoterpenes, comosoxide A (1), comosoxide B (2), and comososide (3), were isolated from the methanolic extract of the rhizomes of Curcuma comosa cultivated in Thailand. Their structures were elucidated on the basis of chemical and physicochemical evidence.

(1'S)-Acetoxychavicol acetate and its enantiomer inhibit tumor cells proliferation via different mechanisms

Elucidation of the mechanisms underlying potential anticancer drugs continues and unraveling these mechanisms would not only provide a conceptual framework for drug design but also promote use of natural products for chemotherapy. The biological effects of (1'S)-acetoxychavicol acetate ((S)-ACA) have been widely investigated. However, in most cases, a natural product or synthetic racemic compound was used in the study. In this study, we prepared (S)-ACA and its enantiomer (R)-ACA by a lipase-catalyzed esterification method and sought to determine the mechanisms of action of (S)-ACA and (R)-ACA in the growth inhibitory effect in Ehrlich ascites tumor cells (EATC). (S)-ACA caused an accumulation of tumor cells in the G1 phase of the cell cycle, which was accompanied by a decrease in phosphorylated retinoblastoma protein (Rb), an increase in Rb and a decrease in the phosphorylation of p27kip1. However, (R)-ACA caused an accumulation of tumor cells in the G2 phase of the cell cycle, an increase in hyperphosphorylated Rb and an increase in the phosphorylation of p27kip1. The results obtained in the present study demonstrate for the first time, to the best of our knowledge, that both (S)-ACA and (R)-ACA caused the inhibition of tumor cells growth but the inhibition was caused via different mechanisms.

Medicinal Flowers. XII.1) New Spirostane-Type Steroid Saponins with Antidiabetogenic Activity from Borassus flabellifer

The methanolic extract from the male flowers of Borassus flabellifer was found to inhibit the increase of serum glucose levels in sucrose-loaded rats at a dose of 250 mg/kg, p.o. From the methanolic extract, six new spirostane-type steroid saponins, borassosides A-F (1-6), were isolated together with 23 known constituents. The structures of borassosides (1-6) were elucidated on the basis of chemical and physicochemical evidences. In addition, the principal steroid saponin, dioscin (13), inhibited the increase of serum glucose levels in sucrose-loaded rats at a dose of 50 mg/kg, p.o.

Lipase-catalyzed preparation of optically active 1′-acetoxychavicol acetates and their structure–activity relationships in apoptotic activity against human leukemia HL-60 cells

Structure-activity relationships of 1'-acetoxychavicol acetate (ACA) for apoptotic activity against human leukemia HL-60 cells were investigated using optically active ACA and various racemic ACA analogues. Natural-type (or with different acyl group) ACA showed a high apoptotic activity, but the ortho or meta isomers, 4-deacetoxy analogue, and the 2'-3' dehydrogenated derivative had no effect, or a weak activity. Optically active (R)- and (S)-ACA were prepared by a lipase-catalyzed esterification. Using a mixture of vinyl acetate-tetrahydrofuran (1:1 v/v) as a solvent at refluxing temperature, optically pure (R)- and (S)-ACA were obtained (99.7% ee and 99.1% ee, respectively). The apoptosis-inducing effects of both enantiomers were compared by means of an MTT assay and the detection of typical apoptotic phenomena (DNA fragmentation, caspase-3 activation, and PARP cleavage) and these two activities were almost equal. These results indicate that the essential moieties of ACA for apoptotic activity against HL-60 cells are both the presence of a 4-acetoxyl group and an unsaturated double bond between C-2' and C-3', and that the configuration at the 1'-position is unrelated to activity.

Structures of New Flavonoids, Erycibenins D, E, and F, and NO Production Inhibitors from Erycibe expansa Originating in Thailand

A new flavanol, erycibenin D, and two new flavans, erycibenins E and F, were isolated from the stems of Erycibe expansa originating in Thailand. The structures of new flavonoids were elucidated on the basis of chemical and physicochemical evidence. In addition, the inhibitory activities of the isolated constituents from E. expansa on lipopolysaccharide-activated nitric oxide production in mouse peritoneal macrophages were examined. Among the principal constituents, two isoflavones, clycosin (IC50 = 13 microM) and erythrinin B (18 microM), and two rotenoids, deguelin (26 microM) and rotenone (27 microM), were found to show potent inhibitory activity.

1'S-1'-Acetoxychavicol acetate as a new type inhibitor of interferon-beta production in lipopolysaccharide-activated mouse peritoneal macrophages

1'S-1'-Acetoxychavicol acetate from the rhizomes of Alpinia galanga was known to show potent inhibitory effect on the production of nitric oxide (NO) in lipopolysaccharide-activated mouse peritoneal macrophages. To clarify its mechanism of action, the effects of 1'S-1'-acetoxychavicol acetate on the expression of interferon-beta (IFN-beta) mRNA and activation of nuclear factor-kappaB (NF-kappaB), both of which participate in the induction of inducible NO synthase, were examined in lipopolysaccharide-activated macrophages. The results were compared with those of two inhibitors of the NF-kappaB activation, costunolide and caffeic acid phenethyl ester. 1'S-1'-Acetoxychavicol acetate inhibited IFN-beta mRNA expression as well as NF-kappaB activation, and two related compounds, (+/-)-1-acetoxy-1-(2-acetoxyphenyl)-2-propene and (+/-)-1-acetoxy-1-(4-acetoxyphenol)-3-butene, also inhibited IFN-beta mRNA expression. In addition, 1'S-1'-acetoxychavicol acetate inhibited the production of NO stimulated by poly(I:C) via Toll-like receptor 3.

Inhibitors of Nitric Oxide Production from the Rhizomes of Alpinia galanga: Structures of New 8-9' Linked Neolignans and Sesquineolignan

The 80% aqueous acetone extract from the rhizomes of Alpinia galanga showed nitric oxide (NO) production inhibitory activities in mouse peritoneal macrophages. From the aqueous acetone extract, three new 8-9' linked neolignans, galanganal, galanganols A and B, and a sesquineolignan, galanganol C, were isolated together with nine known phenylpropanoids and p-hydroxybenzaldehyde. The structures of new neolignans were determined on the basis of physicochemical and chemical evidence. In addition, the inhibitory effects of the constituents from the rhizomes of A. galanga on NO production induced by lipopolysaccharide in mouse peritoneal macrophages were examined. Among them, galanganal (IC50=68 microM), galanganols B (88 microM) and C (33 microM), 1'S-1'-acetoxychavicol acetate (2.3 microM), 1'S-1'-acetoxyeugenol acetate (11 microM), trans-p-hydroxycinnamaldehyde (ca. 20 microM), trans-p-coumaryl alcohol (72 microM), and trans-p-coumaryl diacetate (19 microM) were found to show inhibitory activity.