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

Sesquilignans: Current research and potential prospective

Lignans are widely distributed in nature, primarily found in the xylem and resins of plants, with the constituent units C6-C3, and their dimers are the most common in plants. In recent years, the trimeric sesquilignans have also received increasing attention from scholars. More than 200 derivatives have been isolated and identified from nearly 50 families, most of which are different types (monoepoxy lignans, bisepoxy lignans, benzofuran lignans) connected with simple phenylpropanoids through ether bonds, C-C bonds, and oxygen-containing rings to constitute sesquilignans. Some of them also possess pharmacological properties, including antioxidants, hepatoprotectives, antitumors, anti-inflammatory properties, and other properties. In addition, the chemical structure of sesquilignans is closely related to the pharmacological activity, and chemical modification of methoxylation enhances the pharmacological activity. In contrast, phenolic hydroxyl and hydroxyl glycosides reduce the pharmacological activity. Therefore, the present review aims to summarize the chemical diversity, bioactivities, and constitutive relationships to provide a theoretical basis for the more profound development and utilization of sesquilignans.

Fingerprinting Chemical Markers in the Mediterranean Orange Blossom Honey: UHPLC-HRMS Metabolomics Study Integrating Melissopalynological Analysis, GC-MS and HPLC-PDA-ESI/MS

(1) Background: Citrus honey constitutes a unique monofloral honey characterized by a distinctive aroma and unique taste. The non-targeted chemical analysis can provide pivotal information on chemical markers that differentiate honey based on its geographical and botanical origin. (2) Methods: Within the PRIMA project "PLANT-B", a metabolomics workflow was established to unveil potential chemical markers of orange blossom honey produced in case study areas of Egypt, Italy, and Greece. In some of these areas, aromatic medicinal plants were cultivated to enhance biodiversity and attract pollinators. The non-targeted chemical analysis and metabolomics were conducted using ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). (3) Results: Forty compounds were disclosed as potential chemical markers, enabling the differentiation of the three orange blossom honeys according to geographical origin. Italian honey showed a preponderance of flavonoids, while in Greek honey, terpenoids and iridoids were more abundant than flavonoids, except for hesperidin. In Egyptian honey, suberic acid and a fatty acid ester derivative emerged as chemical markers. New, for honey, furan derivatives were identified using GC-MS in Greek samples. (4) Conclusions: The application of UHPLC-HRMS metabolomics combined with an elaborate melissopalynological analysis managed to unveil several potential markers of Mediterranean citrus honey potentially associated with citrus crop varieties and the local indigenous flora.

Stability Study of Alpinia galanga Constituents and Investigation of Their Membrane Permeability by ChemGPS-NP and the Parallel Artificial Membrane Permeability Assay

Alpinia galanga Willd., greater galangal, has been used for thousands of years as a spice as well as in traditional medicine. Its central nervous system (CNS) stimulant activity and neuroprotective effects have been proved both in animal models and human trials. However, the compounds responsible for these effects have not been identified yet. Therefore, the main constituents (p-OH-benzaldehyde (1), trans-p-coumaryl-alcohol (2), p-coumaryl-aldehyde (4), galanganol A (5), galanganol B (6), trans-p-acetoxycinnamyl alcohol (7), 1'S-1'-acetoxychavicol acetate (ACA, 9), and 1'S-1'-acetoxyeugenol acetate (AEA, 10)) were isolated to investigate their aqueous stability and passive diffusion across the gastro-intestinal tract (GIT) membrane and the blood-brain barrier (BBB) by the parallel artificial membrane permeability assay (PAMPA). Our positive results for compounds 1, 2, 4, 7, 9, and 10 suggest good permeability, thus potential contribution to the effects of greater galangal in the CNS. The results of the PAMPA-BBB were corroborated by in silico chemography-based ChemGPS-NP framework experiments. In addition, examination of the chemical space position of galangal compounds in relation to known psychostimulants revealed that all the molecules in proximity are NET/SERT inhibitors. As ACA and AEA did not show much proximity to either compound, the importance of further investigation of their degradation products becomes more pronounced.

Journey of Alpinia galanga from kitchen spice to nutraceutical to folk medicine to nanomedicine

ETHANOPHARMACOLOGICAL IMPORTANCE

Alpinia galanga (L.) Willd (AG), belonging to Zingiberaceae family is used as a spice and condiment in various culinary preparations of Indonesia, Thailand and Malaysia. It has been also used as a key ingredient in various traditional systems of medicine for the treatment of throat infection, asthma, urinary ailments, inflammation and rheumatism amongst other conditions. AG is widely used as a functional food and included in various preparations to obtain its nutraceutical and pharmacological benefits of its phytoconstituents such as phenyl propanoids, flavonoids and terpenoids. Over the past decades, several researchers have carried out systematic investigation on various parts of AG. Numerous studies on AG rhizomes have shown positive pharmacological effects such as anti-inflammatory, anticancer, antipsoriasis, antiallergic, neuroprotective and thermogenesis. Till date, no comprehensive review summarizing the exploitation of AG into nanomedicine has been published.

AIM OF THE REVIEW

This comprehensive review aims to briefly discuss cultivation methods, propagation techniques, extraction processes for AG. The ethnopharmacological uses and pharmacological activities of AG extracts and its isolates are discussed in detail which may contribute well in further development of novel drug delivery system (NDDS) i.e. future nanomedicine.

MATERIALS AND METHODS

Information about AG was collected using search engine tools such as Google, Google Scholar, PubMed, Google Patent, Web of Science and bibliographic databases of previously published peer-reviewed review articles and research works were explored. The obtained data sets were sequentially arranged for better understanding of AG's potential.

RESULTS

More advanced genetic engineering techniques have been utilized in cultivation and propagation of AG for obtaining better yield. Extraction, isolation and characterization techniques have reported numerous phytoconstituents which are chemically phenolic compounds (phenyl propanoids, flavonoids, chalcones, lignans) and terpenes. Ethnopharmacological uses and pharmacological activity of AG are explored in numerous ailments, their mechanism of action and its further potential to explore into novel drug delivery system are also highlighted.

CONCLUSIONS

The review highlights the importance of plant tissue culture in increasing the production of AG plantlets and rhizomes. It was understood from the review that AG and its phytoconstituents possess numerous pharmacological activities and have been explored for the treatment of cancer, microbial infection, gastrointestinal disorders, neuroprotective effects, obesity and skin disorders. However, the use of AG as alternative medicine is limited owing to poor solubility of its bioactive components and their instability. To overcome these challenges, novel drug delivery systems (NDDS) have been utilized and found good success in overcoming its aforementioned challenges. Furthermore, efforts are required towards development of scalable, non-toxic and stable NDDS of AG and/or its bioactives.

Antiviral and Antioxidant Components from the Fruits of Illicium verum Hook.f. (Chinese Star Anise)

Illicium verum Hook.f. (Chinese star anise), a known Chinese traditional spice, is commonly applied in Chinese cuisine and cooking in Southeast Asia. As a kind of medicinal and edible resource, the fruit of I. verum has attracted great attention for its chemical constituents and physiological activities. In this work, the phytochemical study of the fruits of I. verum led to the isolation and identification of 20 compounds, including 6 new lignans and phenylpropanoids (1-6) and 14 known ones (7-20). Their structures were characterized by extensive analysis of spectroscopic data (IR, UV, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), one-dimensional (1D) and two-dimensional (1D) NMR), electronic circular dichroism (ECD) calculation, and by comparison with literature data. Meanwhile, all compounds (1-20) were evaluated for their antiviral and antioxidant activities. Especially, compound 7 [(-)-bornyl p-coumarate] showed strong antiviral activities against influenza virus A/Puerto Rico/8/34 H1N1 (PR8) with an IC₅₀ value of 1.74 ± 0.47 μM, which is much better than those of Tamiflu (IC₅₀ = 10.01 ± 0.92 μM) and ribavirin (IC₅₀ = 10.76 ± 1.60 μM). The antiviral activity against PR8 of compound 7 was reported for the first time, which was sufficiently confirmed by cell counting kit 8 (CCK-8), cytopathic effect (CPE) reduction, and immunofluorescence assays. In this study, the discovery of antiviral and antioxidant components from the fruits of I. verum could benefit the further development and utilization of this plant.

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.

Six New Phenylpropanoid Derivatives from Chemically Converted Extract of Alpinia galanga (L.) and Their Antiparasitic Activities

Chemical conversion of the extract of natural resources is a very attractive way to expand the chemical space to discover bioactive compounds. In order to search for new medicines to treat parasitic diseases that cause high morbidity and mortality in affected countries in the world, the ethyl acetate extract from the rhizome of Alpinia galanga (L.) has been chemically converted by epoxidation using dioxirane generated in situ. The biological activity of chemically converted extract (CCE) of A. galanga (L.) significantly increased the activity against Leishmania major up to 82.6 ± 6.2 % at 25 μg/mL (whereas 2.7 ± 0.8% for the original extract). By bioassay-guided fractionation, new phenylpropanoids (1-6) and four known compounds, hydroquinone (7), 4-hydroxy(4-hydroxyphenyl)methoxy)benzaldehyde (8), isocoumarin cis 4-hydroxymelein (9), and (2S,3S,6R,7R,9S,10S)-humulene triepoxide (10) were isolated from CCE. The structures of isolated compounds were determined by spectroscopic analyses of 1D and 2D NMR, IR, and MS spectra. The most active compound was hydroquinone (7) with IC50 = 0.37 ± 1.37 μg/mL as a substantial active principle of CCE. In addition, the new phenylpropanoid 2 (IC50 = 27.8 ± 0.34 μg/mL) also showed significant activity against L. major compared to the positive control miltefosine (IC50 = 7.47 ± 0.3 μg/mL). The activities of the isolated compounds were also evaluated against Plasmodium falciparum, Trypanosoma brucei gambisense and Trypanosoma brucei rhodeisense. Interestingly, compound 2 was selectively active against trypanosomes with potent activity. To the best of our knowledge, this is the first report on the bioactive "unnatural" natural products from the crude extract of A. galanga (L.) by chemical conversion and on its activities against causal pathogens of leishmaniasis, trypanosomiasis, and malaria.

Chemical Constituents and Bioactivities of Several Indonesian Plants Typically Used in Jamu

This article reviews the chemical constituents and bioactivities of several Indonesian plants typically used in Jamu prescriptions in Indonesia. Jamu is Indonesia traditional medicine: it consists of either a single ingredient or a mixture of several medicinal plants. One plant family always used in Jamu is Zingiberaceae (ginger), such as Curcuma domestica/C. longa, C. xanthorrhizae, C. heyneana, C. zedoaria, C. aeruginosa, Zingiber aromaticum, Alpinia galanga. We also report other commonly used plant families such as Justicia gendarussa and Cassia siamea, whose activities have been extensively explored by our department.

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.

An overview of chemical constituents from Alpinia species in the last six decades

Alpinia species is one of the most important genera of the Zingiberaceae family. Up to 2015, 544 compounds with various bioactivities were isolated, the major components are diarylheptanoids (143) and sesquiterpenoids (132).

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.

(±)-Torreyunlignans A-D, rare 8-9' linked neolignan enantiomers as phosphodiesterase-9A inhibitors from Torreya yunnanensis

(±)-Torreyunlignans A-D (1a/1b-4a/4b), four pairs of new 8-9' linked neolignan enantiomers featuring a rare (E)-2-styryl-1,3-dioxane moiety, were isolated from the trunk of Torreya yunnanensis. The structures were determined by combined spectroscopic and chemical methods, and the absolute configurations were elucidated by ECD calculations. The compounds were screened by using tritium-labeled adenosine 3',5'-cyclic monophosphate ([(3)H]-cGMP) as a substrate for inhibitory affinities against phosphodiesterase-9A (PDE9A), which is a potential target for the treatment of diabetes and Alzheimer's disease. All of the enantiomers exhibited inhibition against PDE9A with IC50 values ranging from 5.6 to 15.0 μM. This is the first report of PDE9A inhibitors from nature.

Determination of the absolute configuration of two pairs of C-8 - C-9' linked neolignan enantiomers

Two pairs of new neolignan enantiomers, (±)-torreyayunan A (1a/1b) and (±)-torreyayunan B (2a/2b), featuring a rare C-8 - C-9' linked skeleton, were isolated from leaves and twigs of Torreya yunnanensis. Their absolute configuration involving two chiral centers was determined by combined spectral and Density Functional Theory (DFT) calculation. This is the first report of the absolute configuration of this group of neolignans.

Antimelanoma and antityrosinase from Alpinia galangal constituents

Two compounds, 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (BHPHTO) and bisdemethoxycurcumin (BDMC) they have been isolated from the rhizomes of Alpinia galangal, and the structures of both pure constituents were determined using spectroscopic analyses. The study examined the bioeffectivenesses of the two compounds on the human melanoma A2058 and showed that significantly inhibited the proliferation of melanoma cells in the cell viability assay. This research was also taken on the tests to B16-F10 cell line and showed minor inhibitory consequences of cellular tyrosinase activities and melanin contents. Our results revealed the anticancer effects of A. galangal compounds, and therefore, the target compounds could be potentially applied in the therapeutic application and the food industry.

Three unusual sesquineolignans from Alpinia conchigera

Three unusual sesquineolignans conchignans A, B, and C, together with two known compounds vanillin and phloroglucinol, were isolated from the whole plants of Alpinia conchigera. Their structures were established by spectroscopic analysis, including 2D NMR spectroscopic techniques.

Phenylpropanoids of Alpinia galanga as efflux pump inhibitors in Mycobacterium smegmatis mc² 155

The first and second line drugs used for the treatment of tuberculosis are now becoming ineffective due to emergence of resistant strains. Efflux pump provokes resistance in mycobacterium and hence could be explored as a new target for the discovery of anti-TB agents. In search of efflux pump inhibitors, MIC and modulation factor of phenylpropanoids isolated from A. galanga rhizome were determined prior to the accumulation and efflux assay. Phenylpropanoid compounds viz. 1'-S-1'-acetoxychavicol acetate, trans-p-coumaryl diacetate and 1'-S-1'-acetoxyeugenol acetate were found to be potent modulators and decreased the MIC of ethidium bromide by 64 fold at the concentration of 2.5, 6.25 and 5.0 mg/L respectively. 1'-S-1'-acetoxyeugenol acetate enhanced the accumulation and inhibited the efflux of EtBr in Mycobacterium smegmatis mc² 155 cells.

Alkenenitrile Transmissive Olefination: Synthesis of the Putative Lignan "Morinol I"

Grignard reagents trigger an addition-elimination with α'-hydroxy acrylonitriles to selectively generate Z-alkenenitriles. The modular assembly of Z-alkenenitriles from a Grignard reagent, acrylonitrile, and an aldehyde is ideal for stereoselectively synthesizing alkenes as illustrated in the synthesis of the putative lignan "morinol I."

Transmissive olefination route to putative "morinol I" lignans

A series of morinol-type lignans were rapidly assembled using a Grignard-based transmissive olefination. In combination with palladium-catalyzed arylations, the strategy provides stereoselective access to (7Z,7'E), (7E,7'E), and (7E,7'Z) morinol diastereomers and the (7Z,8'E) and (7E,8'E) conjugated analogues. Critical for the E/Z stereoselectivity is a new, general method for converting alkenenitriles to alkenemethanols that circumvents the enal E/Z isomerization commonly encountered during conventional i-Bu(2)AlH reduction.

Modeling natural anti-inflammatory compounds by molecular topology

One of the main pharmacological problems today in the treatment of chronic inflammation diseases consists of the fact that anti-inflammatory drugs usually exhibit side effects. The natural products offer a great hope in the identification of bioactive lead compounds and their development into drugs for treating inflammatory diseases. Computer-aided drug design has proved to be a very useful tool for discovering new drugs and, specifically, Molecular Topology has become a good technique for such a goal. A topological-mathematical model, obtained by linear discriminant analysis, has been developed for the search of new anti-inflammatory natural compounds. An external validation obtained with the remaining compounds (those not used in building up the model), has been carried out. Finally, a virtual screening on natural products was performed and 74 compounds showed actual anti-inflammatory activity. From them, 54 had been previously described as anti-inflammatory in the literature. This can be seen as a plus in the model validation and as a reinforcement of the role of Molecular Topology as an efficient tool for the discovery of new anti-inflammatory natural compounds.

Neuroprotective effect of Alpinia galanga (L.) fractions on Aβ(25-35) induced amnesia in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizomes of Alpinia galanga (L.) Willd (Zingiberaceae), a ginger substitute for flavouring food was traditionally used as nervine tonic and stimulant.

AIM OF THE STUDY

This investigation is designed to screen cognitive improvement of Alpinia galanga (AG) fractions in Alzheimer's type of amnesia in mice induced by Aβ((25-35)).

MATERIALS AND METHODS

Alzheimer's disease induced mice treated with fractions (n-hexane, chloroform and ethyl acetate) of AG in 200 and 400mg/kg. Neurotoxicity was induced by intracerebroventricular injection of Aβ((25-35)) on the 14th day of 21 days drug treatment. Open field and water maze were carried to determine habituation memory and hippocampal memory. Na(+)/K(+)-ATPase, acetylcholinesterase (AChE) and antioxidant enzymes (SOD, GPx, catalase and vitamin C) were determined in brain tissue homogenate to estimate the brain biochemical changes and its anti-amnesic potential with intensity of oxidative stress signaling. Further bioactive (chloroform) fraction was eluted through column chromatography to identify the lead molecules.

RESULTS

Increased habituation memory and decreased escape latency in behavioral parameter are the indicative of the cognitive enhancement after treatment with Alpinia galanga fractions. Increment in Na(+)/K(+)-ATPase and antioxidant activity depicts brain membrane integrity improvement and free radical scavenging property. AChE level was decreased to improve the cognition by enhancing cholinergic transmission.

CONCLUSION

Anti-amnesic effect was exerted by various fractions of Alpinia galanga. Among all fractions, preeminent neuroprotection was exerted by chloroform fraction, which has compound, 1'δ-1'-acetoxyeugenol acetate and it may be a potential therapeutic agent for Alzheimer's type of amnesia. These results further motivate us to explore the activity of lead compound's anti-amnesic effect on transgenic mice model of AD.

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.

Antioxidant activity of lignin phenolic compounds extracted from kraft and sulphite black liquors

The antioxidant activity of the phenolic compounds present in industrial black liquors obtained from the two cooking processes (kraft and sulphite) used in Portugal to produce Eucalyptus globulus pulp was evaluated. The black liquors treated at several pH values were extracted with ethyl acetate. Phenolic fractions were further separated by liquid chromatography of the crude extracts of kraft liquor at pH = 6 and sulphite liquor at the original pH. Total phenolic content was determined in terms of gallic acid equivalents (Folin-Ciocalteu colorimetric method), and the antioxidant activity in the crude extracts at several pH values and in the separated fractions was measured using the DPPH test for radical scavenging capacity. The total phenolic content of crude extracts and separated fractions ranged from 92.7 to 181.6 and from 91.6 to 1,099.6 mg GAE/g, respectively, while the antioxidant activity index (AAI) ranged from 2.20 to 3.41 and from 2.21 to 11.47 respectively, showing very strong antioxidant activity in all studied cases. The fractions separated by column chromatography were submitted to mass spectrometry analysis and the results were compared to others in the literature of natural products, mainly from Eucalyptus, and the characteristic bands of functional groups were identified by ¹H-NMR and FTIR. These methods allowed the identification of 17 phenolic compounds.

Antibacterial activity of Thai herbal extracts on acne involved microorganism

Ethyl acetate and methanol extracts of 18 Thai medicinal plants were investigated for their antibacterial activity against Propionibacterium acnes, Stapylococcus aureus, and S. epidermidis. Thirteen plant extracts were capable of inhibiting the growth of P. acnes and S. epidermidis, while 14 plant extracts exhibited an inhibitory effect on S. aureus. Based on the broth dilution method, the ethyl acetate extract of Alpinia galanga (L.) Wild. (Zingiberaceae) rhizome showed the strongest antibacterial effect against P. acnes, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 156.0 and 312.0 microg/mL, respectively. On the basis of bioassay-guided purification, the ethyl acetate extract was isolated to afford the antibacterial active compound, which was identified as 1'-acetoxychavicol acetate (1'-ACA). 1'-ACA had a strong inhibitory effect on P. acnes with MIC and MBC values of 62.0 and 250.0 microg/mL, respectively. Thus, 1'-ACA was used as an indicative marker for standardization of A. galanga extract using high performance liquid chromatography. These results suggest that A. galanga extract could be an interesting agent for further studies on an alternative treatment of acne.

Median lethal dose, antimalarial activity, phytochemical screening and radical scavenging of methanolic Languas galanga rhizome extract

The methanolic extract of Languas galanga rhizomes was investigated for antimalarial activity against Plasmodium berghei (NK65) infections in mice. The median lethal dose was determined to ascertain the safety of the extract in ICR mice of both sexes. The antimalarial activities during early and established infections, as well as the prophylactic activity were evaluated. Phytochemical screening and radical scavenging activity of the extract were also investigated to elucidate the possible mechanism of the antimalarial properties. The acute oral toxicity (LD₅₀) of Languas galanga extract in mice was established to be 4.998 mg/kg. The extract of Languas galanga rhizomes demonstrated significant antiplasmodial activity in all the three models of the antimalarial evaluations. Phytochemical screening revealed the presence of some vital antiplasmodial constituents such as terpenoids and flavonoids. The extract also exhibited a moderate capacity to scavenge the free radicals. The rhizome extract of Languas galanga thus possesses antimalarial activity, which explains the rational usage of this plant in traditional Malaysian medicine.

Anti-angiogenic effects of the fruit of Alpinia oxyphylla

AIM OF STUDY

The fruit of Alpinia oxyphylla, an herb commonly used in East Asian medicine, is variously used for the treatment of cancer and inflammatory conditions, which may possibly be mediated through anti-angiogenesis. This study aims to check for anti-angiogenic functions in the herb.

MATERIALS AND METHODS

The 95% ethanol extract and four subsequent fractions (n-hexane, ethyl acetate, n-butanol and aqueous fractions) of the fruit of A. oxyphylla were tested on zebrafish model by quantitative endogenous alkaline phosphatase assay; then the active fractions were further tested on wild type and Tg(fli1a:EGFP)y1 zebrafish embryos and human umbilical vein endothelial cells and tumor cell lines for the anti-angiogenic effects.

RESULTS

The n-hexane and ethyl acetate fractions showed anti-angiogenic potentials in both in vivo and in vitro models.

CONCLUSIONS

The use of A. oxyphylla for cancer and inflammation diseases may be partly due to its effects against vessel formation.

A new amide, piperchabamide F, and two new phenylpropanoid glycosides, piperchabaosides A and B, from the fruit of Piper chaba

A new amide, piperchabamide F (1), and two new phenylpropanoid glycosides, piperchabaosides A (2) and B (3), were isolated from 80% aqueous acetone extract from fruit of Piper chaba. Their stereostructures were elucidated on the basis of chemical and physicochemical evidence.

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.

The effects of p-hydroxycinnamaldehyde from Alpinia galanga extracts on human chondrocytes

Osteoarthritis (OA) is the most common form of arthritis and affects millions of people worldwide. Patients have traditionally been treated with non-steroidal anti-inflammatory drugs (NSAIDs), but these are associated with significant side effects. Purification of the acetone extract of Alpinia galanga afforded p-hydroxycinnamaldehyde, as identified by nuclear magnetic resonance and mass spectrometry analyses. By exploiting the cartilage explant culture, p-hydroxycinnamaldehyde suppressed loss of uronic acid, resulting in release of hyaluronan (HA), sulfated glycosaminoglycans (s-GAGs) and matrix metalloproteinases (MMPs). p-Hydroxycinnamaldehyde and interleukin-1beta (IL-1beta), when incubated in primary human chondrocytes, also reduced release of HA, s-GAG and MMP-2. The results demonstrated: (a) that expression levels of the catabolic genes MMP-3 and MMP-13 were suppressed and (b) mRNA expression levels of anabolic genes of collagen II, SOX9 and aggrecan were increased. This study shows that p-hydroxycinnaldehyde from A. galanga Linn. is a potential therapeutic agent for treatment of OA.

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.

Effect of Alpinia galanga extract on cartilage degradation and on gene expression in human chondrocyte and synovial fibroblast metabolism

We investigated the effects of A. galanga extract on metabolism and gene expression involved in the interleukin-1β (IL-1β) response of human chondrocyte and synovial fibroblast. A. galanga extract inhibited IL-1β enhanced matrix breakdown of the cartilage explants in a dose-dependent manner. It suppressed uronic acid loss from the tissue and decreased the release of sulfated GAG and hyaluronan into the medium. MMP-2 and MMP-9 activity in the culture medium of chondrosarcomas and synovial fibroblasts were significantly reduced in the presence of A. galanga extract, which also suppressed the production of MMP-1,-3 and-13. The A. galanga extract also significantly increased type II collagen, SOX9 and aggrecan gene expression, suggesting an ability to enhance anabolic activity. At a high dose of A. galanga extract there was a down-regulation of aggrecan gene expression. Comparison with Diacerein® showed its general anti-inflammatory potential to be similar. The A. galanga extract was shown to inhibit IL-1β-stimulated cartilage matrix degradation in both systems. Additionally, the extract showed the potential to up-regulate certain chondrocyte anabolic genes. It may, therefore, offer some cartilage protective and anti-inflammatory properties as a therapeutic agent in arthritis.

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.