Two new phenylbutenoids from the rhizomes of cassumunar ginger and their α-glucosidase inhibitory activity

An extract from the rhizomes of Cassumunar ginger (Zingiber purpureum Roscoe). was found to have significant α-glucosidase inhibitory activity with an IC50 value of 6.3 µg/mL. Two new phenylbutenoids, cassudimin A (1) and cassumunol N (2), and seven known compounds (3-9) were isolated. Their structures and relative configurations of two new compounds were elucidated based on spectra interpretation. Compounds 1-3, 6-9 showed more potent α-glucosidase inhibitory activity than a positive control, acarbose (IC50 = 168.0 µM). Dehydrozingerone (6) exhibited the most potent α-glucosidase inhibition with an IC50 value of 8.3 μM. Compounds 7 and 9 were found in Z. purpureum rhizomes for the first time.

In vitro biological evaluation and in silico studies of linear diarylheptanoids from Curcuma aromatica Salisb. as urease inhibitors

Plants of the Zingiberaceae family, specifically those belonging to the Curcuma species, are commonly under consideration as potential therapeutic agents for the management of gastrointestinal diseases. In this study, we carried out a phytochemical study on Curcuma aromatica Salisb. (or so-called "Nghe trang" in Vietnamese) grown in Vietnam, which yields three newly discovered 3,5-diacetoxy diarylheptanoids (1-3) and six known 3,5-dihydroxyl diarylheptanoids (4-9). The bioactivity assessment shows that all isolated compounds, except compounds 3, 7, and 8, could inhibit urease. Compounds 4 and 9 significantly inhibit urease, with an IC50 value of 9.6 and 21.4 μM, respectively, more substantial than the positive control, hydroxyurea (IC50 = 77.4 μM). The structure-activity relationship (SAR) of linear diarylheptanoids was also established, suggesting that the hydroxyl groups at any position of skeleton diarylheptanoids are essential for exerting anti-urease action. Through a comparative analysis of the binding sites of hydroxyurea and diarylheptanoid compounds via our constructed in silico model, the mechanism of action of diarylheptanoid compounds is predicted to bind to the dynamic region close to the dinickel active center, resulting in a loss of catalytic activity. Such insights certainly help design and/or find diarylheptanoid-based compounds for treating gastric ulcers through inhibiting urease.

Paratrimerin Z, an undescribed chromene derivative from the roots of Paramignya trimera

From an EtOAc-soluble fraction of the roots of Paramignya trimera, one undescribed chromene derivative, paratrimerin Z (1), was isolated. Its structure was elucidated on the basis of NMR spectroscopic interpretation. The absolute configuration of 1 was determined by the specific rotation analysis of its acid-catalyzed hydrolysis product. Paratrimerin Z (1), at a concentration of 100 μM, did not show cytotoxicity against Hep3B human liver cancer cell line.

A novel diphenylbutenoid-type compound from the rhizomes of Zingiber montanum (J.Koenig) Link ex A.Dietr. (Zingiberaceae)

From the EtOAc-soluble extract of the rhizomes of Zingiber montanum (J.Koenig) Link ex A.Dietr., a novel diphenylbutenoid, montadinin A (1) and a previously unreported phenylbutenoid compound, 1-(3,4-dimethoxyphenyl)but-3-en-2-ol (7), in natural source were isolated. Additionally, seven known phenylbutenoids were also identified. The structures of all compounds were elucidated through NMR spectroscopic interpretation. Compounds cis-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-ene (2), cis-4-[(E)-3,4-dimethoxystyryl]-3-(2,4,5-trimethoxyphenyl)cyclohex-1-ene (3), trans-3-(3,4,-dimethoxyphenyl)-4-[(E)-2,4,5-trimethoxystyryl]cyclohex-1-ene (5), and cis-3-(3,4-dimethoxyphenyl)-4-[(Z)-2,4,5-trimethoxylstyryl]cyclohex-1-ene (6) showed weak cytotoxicity against HepG2 cells with IC₅₀ values of 122.9, 127.3, 257.5, and 168.5 µM, respectively.

Taxotrophises A and B, two new polyphenols from the stems of Taxotrophis ilicifolius

From the EtOAc extract of the wood of the stems of Taxotrophis ilicifolius (Moraceae), two new secondary metabolites, named taxotrophises A (1) and B (2), were isolated, together with five known compounds (3-7). Their chemical structures have been elucidated by extensive NMR spectroscopic analysis. All isolated compounds have been evaluated for α-glucosidase inhibitory activity. In the present work, compounds 1 and 4 showed the strongest α-glucosidase inhibitory activity with IC50 values of 6.5 and 1.5 μM, respectively, and stronger than that of a positive control, acarbose (IC50; 214.5 μM).

Strebluses E-H, four new stilbene-like derivatives from the stems of Streblus ilicifolius

Following bioactivity-guided isolation, four new stilbene-like derivatives, named Strebluses E-H, were isolated from the EtOAc-soluble fraction of the stems of Streblus ilicifolius (Moraceae). Their chemical structures were elucidated based on NMR spectroscopic data interpretation and optical rotation calculation. Streblus E possesses potent tyrosinase inhibitory activity with an IC₅₀ value of 0.1 μM. Oxy-tyrosinase has two bound Cu²⁺ ions and a peroxide group in the binding site, which has a role in the catalytic oxidation. Thus, a docking study of Streblus E with oxy-tyrosinase was performed to analyze the ligand-protein interactions. With in silico modelling, the S value and the ligand-protein interactions suggested that Streblus E showed lower binding affinity for oxy-tyrosinase than that of Streblus C.

A New abeo-Icetexane-Type Diterpenoid from the Stem Barks of Taxus wallichiana

From a CH2 Cl2 -soluble fraction of the stem barks of Taxus wallichiana, one new abeo-icetexane-type diterpenoid, taxamairin I (1), was isolated. Its absolute configuration was elucidated based on spectroscopic interpretation and time-dependent density functional theory (TD-DFT) calculation of optical rotation. In addition, the plausible biosynthesis pathway for the formation of the new abeo-icetexane-type diterpenoid was proposed. Taxamairin I (1), at a concentration of 100 μM, did not show cytotoxicity against Hep3B human liver cancer cell lines.

Combinatorial CRISPR Interference Library for Enhancing 2,3-BDO Production and Elucidating Key Genes in Cyanobacteria

Cyanobacteria can convert CO₂ to chemicals such as 2,3-butanediol (2,3-BDO), rendering them promising for renewable production and carbon neutralization, but their applications are limited by low titers. To enhance cyanobacterial 2,3-BDO production, we developed a combinatorial CRISPR interference (CRISPRi) library strategy. We integrated the 2,3-BDO pathway genes and a CRISPRi library into the cyanobacterium PCC7942 using the orthogonal CRISPR system to overexpress pathway genes and attenuate genes that inhibit 2,3-BDO formation. The combinatorial CRISPRi library strategy allowed us to inhibit fbp, pdh, ppc, and sps (which catalyzes the synthesis of fructose-6-phosphate, acetyl-coenzyme A, oxaloacetate, and sucrose, respectively) at different levels, thereby allowing for rapid screening of a strain that enhances 2,3-BDO production by almost 2-fold to 1583.8 mg/L. Coupled with a statistical model, we elucidated that differentially inhibiting all the four genes enhances 2,3-BDO synthesis to varying degrees. fbp and pdh suppression exerted more profound effects on 2,3-BDO production than ppc and sps suppression, and these four genes can be repressed simultaneously without mutual interference. The CRISPRi library approach paves a new avenue to combinatorial metabolic engineering of cyanobacteria.

δ-Tocopherol derivatives from the leaves of Muntingia calabura L

From an ethyl acetate-soluble fraction of the leaves of Muntingia calabura, one new trimeric δ-tocopherol derivative named as tocomuntin A (1), together with three known δ-tocopherol derivatives (2-4) were isolated. Their structures were elucidated based on the interpretation of NMR and MS spectroscopic data. In this work, δ-tocopherol (3) was found to have α-glucosidase inhibitory activity for the first time (IC₅₀, 47.3 μM).

A new diphenylheptanoid from the rhizomes of Curcuma zedoaria

A phytochemical investigation of the rhizomes of Curcuma zedoaria was carried out, leading to the isolation of a new diphenylheptanoid, zedoaroxane A (1), together with four known compounds (2-5). Their structures were elucidated based on NMR spectroscopic data. All isolated compounds possessed α-glucosidase inhibitory activity, with the IC₅₀ values ranging from 35.2 to 89.0 µM, more potent than that of the positive control acarbose (IC₅₀, 214.5 µM).

A new 8,3'-neolignan from Solanum procumbens Lour

The phytochemical investigation of the EtOAc-soluble fraction of the aerial parts of Solanum procumbens Lour. has been carried out to obtain seven compounds, including a new 8,3'-neolignan named solacanin A (1). Their chemical structures were elucidated based on the spectroscopic data interpretation. All isolated compounds were tested for their α-glucosidase inhibitory activity. Compounds 1 and 3-6 showed inhibitory activity with IC₅₀ values of 221.5, 18.9, 6.0, 104.1, and 219.7 µM, respectively.

Two new derivatives of 8-prenyl-5,7-dihydroxycoumarin from the stems of Streblus ilicifolius (S.Vidal) Corn

From the EtOAc-soluble extract of the stems of Streblus ilicifolius (Moraceae), two new secondary metabolites named strebluses A (1) and B (2) were isolated. Their chemical structures have been concluded based on the chemical derivatisation and the spectroscopic interpretation. All compounds have been tested for their tyrosinase inhibitory activity. They showed weaker inhibitory activity than that of kojic acid (IC₅₀, 44.6 µM).

Decumbic anhydride from the stem barks of Swintonia floribunda (Anacardiaceae)

From an EtOAc-soluble fraction of the stem barks of Swintonia floribunda (Anacardiaceae), decumbic anhydride (1) and four known compounds 2-5 were isolated. Their chemical structures were elucidated based on the spectroscopic data interpretation. The GIAO-DFT calculation of ¹³C NMR chemical shifts was carried out to clarify the structure of 1. The absolute configuration of 1 was assigned based on the Cotton effects in its ECD spectrum. Compound 1 showed potent tyrosinase inhibitory activity with an IC₅₀ value of 52.2 μM.

A new lignan from the stems of Buchanania lucida Blume (Anacardiaceae)

From the EtOAc-soluble extract of the stems of Buchanania lucida, one new lignan, (+)-(8S,8'S)-5'-methoxy-4,4'-di-O-methylsecoisolariciresinol (1), together with five known compounds (2-6) were isolated. Their structures were elucidated on the basis of NMR spectroscopic interpretation. The absolute configuration of 1 was determined based on the Cotton effects in the ECD spectrum. In the tyrosinase inhibitory activity test, p-hydroxybenzoic acid (6) showed the strong effect, with an IC₅₀ value of 9.35 µM.

Controllable synthesis of spherical carbon particles transition from dense to hollow structure derived from Kraft lignin

The tailored synthesis of carbon particles with controllable shapes and structures from biomass as a raw material would be highly beneficial to meet the demands of various applications of carbon materials from the viewpoint of sustainable development goals. In this work, the spherical carbon particles were successfully synthesized through a spray drying method followed by the carbonization process, using Kraft lignin as the carbon source and potassium hydroxide (KOH) as the activation agent. As the results, the proposed method successfully controlled the shape and structure of the carbon particles from dense to hollow by adjusting the KOH concentration. Especially, this study represents the first demonstration that KOH plays a crucial role in the formation of particles with good sphericity and dense structures. In addition, to obtain an in-depth understanding of the particle formation of carbon particles, a possible mechanism is also investigated in this article. The resulting spherical carbon particles exhibited dense structures with a specific surface area (1233 m²g^-1) and tap density (1.46 g cm^-3) superior to those of irregular shape carbon particles.

CRISPR-Cas13d for Gene Knockdown and Engineering of CHO Cells

Chinese hamster ovary (CHO) cells are the predominant cell chassis for biopharmaceutical production. Engineering cellular pathways related to cell death, metabolism, and glycosylation in CHO cells is desired but challenging. Here, we present a novel approach that exploits CRISPR-Cas13d for gene silencing and CHO cell engineering. CRISPR-Cas13d is a burgeoning system that exploits Cas13d nuclease and guide RNA (gRNA) for RNA cleavage and gene knockdown. We first showed that CRISPR-Cas13d effectively knocked down exogenous genes in CHO cell lines (K1, DG44, and DUXB11) commonly used for recombinant protein production. We next demonstrated that CRISPR-Cas13d robustly suppressed the expression of exogenous genes and various endogenous genes involved in gene amplification, apoptosis, metabolism, and glycosylation (e.g., GS, BAK, BAX, PDK1, and FUT8) in CHO cells with efficiencies ranging from 60% to 80%, simply by transient transfection. By integrating the entire CRISPR-Cas13d system with the Sleeping Beauty system and optimal gRNA design, we further improved the knockdown efficiency and rapidly generated stable cells with ≈80%-90% knockdown. With this approach, we knocked down FUT8 expression for >90% and significantly attenuated the IgG fucosylation. These data altogether implicated the potentials of CRISPR-Cas13d for gene regulation, glycoengineering, and cell engineering of CHO cells.

α-Conidendrin inhibits the expression of intercellular adhesion molecule-1 induced by tumor necrosis factor-α in human lung adenocarcinoma A549 cells

α-Conidendrin is a lignan isolated from Taxus wallichiana and other species. In the present study, we demonstrated that α-conidendrin inhibited the cell-surface expression of intercellular adhesion molecule-1 (ICAM-1) induced by tumor necrosis factor-α (TNF-α) at an IC₅₀ value of 40-60 μM in human lung adenocarcinoma A549 cells. α-Conidendrin decreased ICAM-1 protein and mRNA expression levels at concentrations of 40-100 μM in TNF-α-stimulated A549 cells. The TNF-α-induced mRNA expression of vascular cell adhesion molecule-1, E-selectin, and cyclooxygenase-2 was also reduced by α-conidendrin. In the TNF-α-induced nuclear factor κB (NF-κB) signaling pathway, α-conidendrin did not influence the translocation of the NF-κB subunit RelA from the cytoplasm to the nucleus at concentrations up to 100 μM. A chromatin immunoprecipitation assay revealed that α-conidendrin at 100 μM reduced the binding of RelA to the ICAM-1 promoter in response to a stimulation with TNF-α. Collectively, these results indicated that α-conidendrin interfered with the DNA binding of RelA to the ICAM-1 promoter, thereby reducing ICAM-1 transcription.

Engineering Stable Pseudomonas putida S12 by CRISPR for 2,5-Furandicarboxylic Acid (FDCA) Production

FDCA (2,5-furandicarboxylic acid) can be enzymatically converted from HMF (5-hydroxymethylfurfural). Pseudomonas putida S12 is promising for FDCA production, but generating stable P. putida S12 is difficult due to its polyploidy and lack of genome engineering tools. Here we showed that coupling CRISPR and λ-Red recombineering enabled one-step gene integration with high efficiency and frequency, and simultaneously replaced endogenous genes in all chromosomes. Using this approach, we generated two stable P. putida S12 strains expressing HMF/furfural oxidoreductase (HMFH) and HMF oxidase (HMFO), both being able to convert 50 mM HMF to ≈42-43 mM FDCA in 24 h. Cosupplementation of MnO₂ and CaCO₃ to the medium drastically improved the cell tolerance to HMF and enhanced FDCA production. Cointegrating HMFH and HMFT1 (HMF transporter) genes further improved FDCA production, enabling the cells to convert 250 mM HMF to 196 mM (30.6 g/L) FDCA in 24 h. This study implicates the potentials of CRISPR for generating stable P. putida S12 strains for FDCA production.

A new phenolic acid from the wood of Mangifera gedebe

From the methanol extract of the wood of Mangifera gedebe (Anacardiaceae), we had isolated a new secondary metabolite named gedebic acid (1) and six known compounds (2-7). Their chemical structures were determined by spectroscopic methods as well as comparing with data in the literature. All compounds were tested for α-glucosidase inhibitory activity. Compounds 4-7 showed more potent inhibitory activity, with IC₅₀ values ranging from 45.3 to 142.6 μM, than that of a positive control acarbose (IC₅₀, 214.5 μM).

A Laboratory-Scale Study of the Applicability of a Halophilic Sediment Bioelectrochemical System for in situ Reclamation of Water and Sediment in Brackish Aquaculture Ponds: Establishment, Bacterial Community and Performance Evaluation

In this study, we investigated the potential of using sediment bioelectrochemical systems (SBESs) for in situ treatment of the water and sediment in brackish aquaculture ponds polluted with uneaten feed. An SBES integrated into a laboratory-scale tank simulating a brackish aquaculture pond was established. This test tank and the control (not containing the SBES) were fed with shrimp feed in a scheme that mimics a situation where 50% of feed is uneaten. After the SBES was inoculated with microbial sources from actual shrimp pond sediments, electricity generation was well observed from the first experimental week, indicating successful enrichment of electrochemically active bacteria in the test tank sediment. The electricity generation became steady after 3 weeks of operation, with an average current density of 2.3 mA/m² anode surface and an average power density of 0.05 mW/m² anode surface. The SBES removed 20-30% more COD of the tank water, compared to the control. After 1 year, the SBES also reduced the amount of sediment in the tank by 40% and thus could remove approximately 40% more COD and approximately 52% more nitrogen from the sediment, compared to the control. Insignificant amounts of nitrite and nitrate were detected, suggesting complete removal of nitrogen by the system. PCR-DGGE-based analyses revealed the dominant presence of Methylophilus rhizosphaerae, Desulfatitalea tepidiphila and Thiothrix eikelboomii, which have not been found in bioelectrochemical systems before, in the bacterial community in the sediment of the SBES-containing tank. The results of this research demonstrate the potential application of SBESs in helping to reduce water pollution threats, fish and shrimp disease risks, and thus farmers' losses.

A New Compound from the Rhizomes of Boesenbergia pandurata

Phytochemical investigation of the methanol extract of the rhizomes of Vietnamese Boesenbergia pandurata resulted in the isolation of a new secondary metabolite named panduratin P (1). The structure of this compound was elucidated by NMR spectroscopic analysis. Compound 1 exhibited a mild activity against PANC-1 human pancreatic cancer cell lines in nutrient-deprived medium (NDM) with PC50 value of 55.9 μM.

Willughbeia cochinchinensis prevents scopolamine-induced deficits in memory, spatial learning, and object recognition in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Willughbeia cochinchinensis (WC) has been used in Vietnamese traditional medicine for the treatment of dementia as well as diarrhea, heartburn, and cutaneous abscess and as a diuretic.

AIM

Alzheimer's disease (AD) is one of the most prevalent diseases in elderly individuals. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors have been widely used to treat patients with AD. In the present study, we investigated anti-AChE and anti-BChE activities of a natural product, WC, for its potential applications in therapies to prevent/treat dementia.

MATERIALS AND METHODS

First, compounds extracted from WC were tested for their AChE and BChE inhibitory activities in vitro. Second, in vivo behavioral experiments were performed to investigate the effects of WC at doses of 100, 150, and 200mg/kg on scopolamine (1.5mg/kg)-induced memory and cognitive deficits in mice. The behavior of mice treated with and without WC and/or scopolamine was tested using the Y-maze, Morris water maze, and novel object recognition task.

RESULTS

The results of the in vitro assay demonstrated anti-AChE and anti-BChE activities of the compounds extracted from WC. The results of behavioral experiments showed that the administration of WC prevented 1) scopolamine-induced decrease in spontaneous alternation (%) behavior in the Y-maze, 2) scopolamine-induced deficits in spatial learning and memory in the Morris water maze, and 3) scopolamine-induced deficits in novel object recognition. These results indicate that WC prevents cognitive and memory deficits induced by scopolamine injection.

CONCLUSIONS

Our findings suggest that WC may represent a novel candidate for the treatment of memory and cognitive deficits in humans with dementia.

A New Alkenylphenol from the Propolis of Stingless Bee Trigona minor

A new alkenylphenol, 2-hydroxyl-6-(14' Z -nonadecenyl)benzoic acid (1), was isolated from the ethanolic extract of Vietnamese stingless bee propolis Trigona minor (Meliponini, Apidae), together with two known compounds (2 and 3). Their chemical structures were determined by extensive NMR spectroscopic analysis. All compounds were tested for preferential cytotoxicity against the PANC-1 human pancreatic cell line under nutrition-deprived conditions (NDM). Compound 1 exhibited the strongest preferential cytotoxicity, with a PC50 value of 2.4 μM.

Moracin VN, A New Tyrosinase and Xanthine Oxidase Inhibitor from the Woods of Artocarpus heterophyllus

Bioactivity-guided fractionation of the woods extract of Artocarpus heterophyllus collected in Vietnam revealed that a new 2-arylbenzofuran, moracin VN (1) together with two known compounds were isolated. Compound 1 possessed the inhibitory activity on tyrosinase with IC50 value of 0.82 μM, more potent than the positive control kojic acid (IC50, 44.6 μM). Compound 1 also showed moderate inhibitory activity on xanthine oxidase with IC50 value of 22.8 μM. The kinetic study of tyrosinase was performed on moracin VN (1) showed non-competitive inhibition with Ki value of 2.40 μM.

α-Glucosidase Inhibitory and Cytotoxic Taxane Diterpenoids from the Stem Bark of Taxus wallichiana

From a CH₂Cl₂ extract of the bark of Taxus wallichiana, six new taxoids, wallitaxanes A-F (1-6), were isolated, together with 29 known compounds. The structures of the new compounds were elucidated on the basis of spectroscopic data interpretation. Wallitaxane D (4) was identified as an opened oxetane-type taxoid having the first naturally occurring C(H)-20 acetal group, while wallitaxanes E (5) and F (6) are representative of the rare abeo-taxoid class. The isolated compounds were evaluated for their α-glucosidase inhibitory activity and for cytotoxicity against the HeLa human cervical cancer cell line. In the present work, taxanes were found to exhibit α-glucosidase inhibitory activity for the first time, and wallitaxane A (1) showed the most potent effect, with an IC₅₀ value of 3.6 μM. In turn, 7-epi-taxol (16) and 7-epi-10-deacetyltaxol (17) showed IC₅₀ values of 0.05 and 0.085 nM, respectively, against HeLa cells.

Constituents of the Rhizomes of Boesenbergia pandurata and Their Antiausterity Activities against the PANC-1 Human Pancreatic Cancer Line

Human pancreatic cancer cell lines have a remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions represents a novel antiausterity strategy in anticancer drug discovery. In this investigation, a methanol extract of the rhizomes of Boesenbergia pandurata showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions, with a PC₅₀ value of 6.6 μg/mL. Phytochemical investigation of this extract led to the isolation of 15 compounds, including eight new cyclohexene chalcones (1-8). The structures of the new compounds were elucidated by NMR spectroscopic data analysis. Among the isolated compounds obtained, isopanduratin A1 (14) and nicolaioidesin C (15) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 1.0 and 0.84 μM, respectively.

Design and synthesis of chalcone derivatives as potential non-purine xanthine oxidase inhibitors

Background

Based on some previous research, the chalcone derivatives exhibited potent xanthine oxidase inhibitory activity, e.g. sappanchalcone (7), with IC₅₀ value of 3.9 μM, was isolated from Caesalpinia sappan. Therefore, objectives of this research are design and synthesis of 7 and other chalcone derivatives by Claisen–Schmidt condensation and then evaluate their XO inhibitory activity.

Results

Fifteen chalcone derivatives were synthesized by Claisen–Schmidt condensation, and were evaluated for XO inhibitory activity. Nine out of 15 synthetic chalcones showed inhibitory activity (3; 5–8; 10–13). Sappanchalcone derivatives (11) (IC₅₀, 2.5 μM) and a novel chalcone (13) (IC₅₀, 2.4 μM) displayed strong xanthine oxidase inhibitory activity that is comparable to allopurinol (IC₅₀, 2.5 μM). The structure–activity relationship of these chalcone derivatives was also presented.

Conclusions

It is the first research on synthesis sappanchalcone (7) by Claisen–Schmidt condensation. The overall yield of this procedure was 6.6 %, higher than that of reported procedure (4 %). Design, synthesis, and evaluation of chalcone derivatives were carried out. This result suggests that the chalcone derivative can be used as potential non-purine XO inhibitors.Graphical abstract

Chemical Constituents of Mangifera indica and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cell lines such as PANC-1 have an altered metabolism, enabiling them to tolerate and survive under extreme conditions of nutrient starvation. The search for candidates that inhibit their viability during nutrition starvation represents a novel antiausterity strategy in anticancer drug discovery. A methanol extract of the bark of Mangifera indica was found to inhibit the survival of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions with a PC50 value of 15.5 μg/mL, without apparent toxicity, in normal nutrient-rich conditions. Chemical investigation on this bioactive extract led to the isolation of 19 compounds (1-19), including two new cycloartane-type triterpenes, mangiferolate A (1) and mangiferolate B (2). The structures of 1 and 2 were determined by NMR spectroscopic analysis. Among the isolated compounds, mangiferolate B (2) and isoambolic acid (12) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under the nutrition-deprived condition with PC50 values of 11.0 and 4.8 μM, respectively.

Anti-cholinesterases and memory improving effects of Vietnamese Xylia xylocarpa

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia among the elderly and is characterized by loss of memory and other cognitive functions. An increase in AChE (a key enzyme in the cholinergic nervous system) levels around β-amyloid plaques and neurofibrillary tangles is a common feature of AD neuropathology. Amnesic effects of scopolamine (acetylcholine receptor antagonist) can be investigated in various behavioral tests such as Morris water maze, object recognition, Y-maze, and passive avoidance. In the scope of this paper, we report the anti-AChE, anti-BChE properties of the isolated compound and the in vivo effects of the methanolic extract of Xylia xylocarpa (MEXX) on scopolamine-induced memory deficit.

RESULTS

In further phytochemistry study, a new hopan-type triterpenoid, (3β)-hopan-3-ol-28,22-olide (1), together with twenty known compounds were isolated (2-21). Compound 1, 2, 4, 5, 7-9, and 11-13 exhibited potent acetylcholinesterase (AChE) inhibitory activity in a concentration-dependent manner with IC50 values ranging from 54.4 to 94.6 μM. Compound 13 was also shown anti-butyrylcholinesterase (BChE) activity with an IC50 value of 42.7 μM. The Morris water Y-maze, Y-maze, and object recognition test were also carried out.

CONCLUSIONS

It is noteworthy that MEXX is effective when administered orally to mice, experimental results are consistent with the traditional use of this medicinal plant species.

α-Glucosidase inhibitors from the bark of Mangifera mekongensis

Background

Mangifera mekongensis (Anacardiaceae) is cultivated for its edible fruit and has been used in traditional Vietnamese medicine for its anti-aging properties and for treating diabetes, vermifuge, and dysentery. As part of a search for biologically active compounds with reduction of the rate of glucose absorption, a screening has been initiated to evaluate natural product extracts for the inhibition of enzyme α-glucosidase. A n-hexane extract of the bark of M. mekongensis showed strong α-glucosidase inhibitory activity with IC₅₀ value of 1.71 µg/mL. Thus, the constituents of this plant were examined.

Results

Two new steroids named mekongsterol A (1) and mekongsterol B (2), were isolated from the n-hexane extract of the bark of M. mekongensis (Anacardiaceae), together with seven known compounds (3–9). Their chemical structures were elucidated on the basis of spectroscopic data. All compounds possessed significant α-glucosidase inhibitory activity in a concentration-dependent manner, except for 3 and 4. Compounds 1, 2, 5–9 showed more potent inhibitory activity, with IC₅₀ values ranging from 1.2 to 112.0 µM, than that of a positive control acarbose (IC₅₀, 214.5 µM).

Conclusions

These results suggested that the traditional use of the bark of M. mekongensis for the treatment of diabetes diseases in Vietnam may be attributable to the α-glucosidase inhibitory activity of its steroid and cycloartane constituents.

Electronic supplementary material

The online version of this article (doi:10.1186/s13065-016-0193-9) contains supplementary material, which is available to authorized users.

A New Cassane-type Diterpene from the Seed of Caesalpinia sappan

Phytochemical investigation of the CH2Cl2 extract of the Vietnamese medicinal plant Caesalpinia sappan Linn resulted in the isolation of a new cassane-type diterpene named tomocin I (1). Its chemical structure was determined by NMR spectroscopic and mass spectrometric analysis.

A New Cassane-type Diterpene from the Seed of Caesalpinia Sappan

Phytochemical investigation of the CH2C12 extract of the Vietnamese medicinal plant Caesalpinia sappan Linn resulted in the isolation of a new cassane-type diterpene named tomocin I (1). Its chemical structure was determined by NMR spectroscopic and mass spectrometric analysis.

Cassane diterpenes from the seed kernels of Caesalpinia sappan

Eight structurally diverse cassane diterpenes named tomocins A-H were isolated from the seed kernels of Vietnamese Caesalpinia sappan Linn. Their structures were determined by extensive NMR and CD spectroscopic analysis. Among the isolated compounds, tomocin A, phanginin A, F, and H exhibited mild preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived condition without causing toxicity in normal nutrient-rich conditions.

Tyrosinase inhibitory activity of flavonoids from Artocarpus heterophyllous

Background

Tyrosinase is an oxidoreductase that is very important in medicine and cosmetics because the excessive production of melanin causes hyperpigmentation. The development of novel, effective tyrosinase inhibitors has long been pursued. In preliminary tests, we found that an extract of the wood of Artocarpus heterophyllous (AH) potently inhibited tyrosinase activity.

Results

Two new flavonoids, artocaepin E (1) and artocaepin F (2), were isolated from the wood of AH, together with norartocarpetin (3), artocarpanone (4), liquiritigenin (5), steppogenin (6), and dihydromorin (7). Their structures were elucidated using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry. The absolute configuration of 2 was determined from the circular dichroism (CD) spectrum. Artocarpanone (4) had the most potent tyrosinase inhibitory effect, with an IC₅₀ of 2.0 ± 0.1 μM, followed by artocaepin E (1) and steppogenin (6), with IC₅₀ values of 6.7 ± 0.8 and 7.5 ± 0.5 μM, respectively. A kinetic investigation indicated that 1 showed competitive inhibition, with an inhibition constant (K_i) of 6.23 μM.

Conclusions

These results demonstrate that extracts of the wood of AH and its phytochemical constituents are potential sources for skin-whitening agents.Graphical abstract

Artocarmin E (1) and artocarmin F (2) were isolated from the wood of Artocarpus heterophyllous. Their structures were elucidated using nuclear magnetic resonance analysis and mass spectrometric methods

Electronic supplementary material

The online version of this article (doi:10.1186/s13065-016-0150-7) contains supplementary material, which is available to authorized users.

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Geranyl dihydrochalcones from Artocarpus altilis and their antiausteric activity

Human pancreatic cancer cell lines have remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions is a novel antiausterity strategy in anticancer drug discovery. In this study, the methanolic extract of the leaves of Artocarpus altilis showed 100 % preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions at a concentration of 50 µg/mL. Further investigation of this extract led to the isolation of eight new geranylated dihydrochalcones named sakenins A-H (1-8) together with four known compounds (9-12). Among them, sakenins F (6) and H (8) were identified as potent preferentially cytotoxic candidates with PC50 values of 8.0 µM and 11.1 µM, respectively.

Tyrosinase inhibitors from the wood of Artocarpus heterophyllus

From the methanolic-soluble extract of the wood of Artocarpus heterophyllus, four new flavones, artocarmins A-D (1-4), and three new chalcones, artocarmitins A-C (5-7), have been isolated together with 13 known compounds. Their structures were determined on the basis of the spectroscopic data. Compounds 1-4, 6, 7, 9-16, and 20 displayed significant tyrosinase inhibitory activity. The most active compound, morachalcone A (12) (IC50, 0.013 μM), was 3000 times more active as a tyrosinase inhibitor than a positive control, kojic acid (IC50, 44.6 μM).

Phenolic Constituents from the Heartwood of Artocapus Altilis and their Tyrosinase Inhibitory Activity

From the MeOH extract of the heartwood of Artocapus altilis, thirteen phenolic compounds have been isolated, namely curcumin (1), desmethoxycurcumin (2), retrodihydrochalcone (3), apigenin (4), tangeretin (5), nobiletin (6), O-methyldehydrodieugenol (7), dehydrodieugenol (8), β-hydroxypropiovanillone (9), p-coumaric acid (10), p-hydroxybenzaldehyde (11), vanillin (12), and vanillic acid (13). This is the first report on the presence of these compounds in the heartwood of A. altilis. Compounds 1, 2, and 10 showed more potent tyrosinase inhibitory activities, with IC50 values ranging from 2.3 to 42.0 μM, than the positive control kojic acid (IC50, 44.6 μM). The most active compound, p-coumaric acid (10) (IC50, 2.3 μM), was 22 times more active in tyrosinase inhibitory activity than kojic acid.

Phenolic constituents from the heartwood of Artocapus altilis and their tyrosinase inhibitory activity

From the MeOH extract of the heartwood of Artocapus altilis, thirteen phenolic compounds have been isolated, namely curcumin (1), desmethoxycurcumin (2), retrodihydrochalcone (3), apigenin (4), tangeretin (5), nobiletin (6), O-methyldehydrodieugenol (7), dehydrodieugenol (8), beta-hydroxypropiovanillone (9), p-coumaric acid (10), p-hydroxybenzaldehyde (11), vanillin (12), and vanillic acid (13). This is the first report on the presence of these compounds in the heartwood of A. altilis. Compounds 1, 2, and 10 showed more potent tyrosinase inhibitory activities, with IC50 values ranging from 2.3 to 42.0 microM, than the positive control kojic acid (IC50, 44.6 microM). The most active compound, p-coumaric acid (10) (IC50, 2.3 microM), was 22 times more active in tyrosinase inhibitory activity than kojic acid.

A new lupane triterpene from Tetracera scandens L., xanthine oxidase inhibitor

From the MeOH extract of the stem of Tetracera scandens L., a new nor-lupane triterpene, 28-O-β-D-glucopyranosyl ester of platanic acid (1), has been isolated together with six known compounds. Their structures were elucidated on the basis of spectroscopic data. Compounds 1-6 displayed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and compound 4 showed more potent inhibitory activity with an IC(50) value of 1.9 µM than that of a positive control allopurinol (IC(50) 2.5 µM).

Xanthine oxidase inhibitors from Vietnamese Blumea balsamifera L

From the MeOH extract of the aerial part of Blumea balsamifera L., a new dihydroflavonol, (2R,3S)-(-)-4'-O-methyldihydroquercetin (1), together with seven known compounds has been isolated. Their structures were elucidated on the basis of spectroscopic data. Compounds 1-4 and 6-8 displayed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and compounds 1, 6 and 8 showed more potent inhibitory activity, with IC₅₀ values ranging from 0.23 to 1.91 µM, than that of a positive control allopurinol (IC₅₀ 2.50 µM).

Xanthine oxidase inhibitory activity of Vietnamese medicinal plants

Among 288 extracts, prepared from 96 medicinal plants used in Vietnamese traditional medicine to treat gout and related symptoms, 188 demonstrated xanthine oxidase (XO) inhibitory activity at 100 microg/ml, with 46 having greater than 50% inhibition. At 50 microg/ml, 168 of the extracts were active, with 21 possessing more than 50% inhibition. At 25 microg/ml, 146 extracts exhibited inhibitory activity, with 8 showing over 50% inhibition, while 126 extracts presented activity at 10 microg/ml, with 2 having greater than 50% inhibition. The MeOH extracts of Artemisia vulgaris, Caesalpinia sappan (collected at the Seven-Mountain area), Blumea balsamifera (collected in Lam Dong province), Chrysanthemum sinense and MeOH-H(2)O extract of Tetracera scandens (Khanh Hoa province) exhibited strong XO inhibitory activity with IC(50) values less than 20 microg/ml. The most active extract was the MeOH extract of the flower of C. sinense with an IC(50) value of 5.1 microg/ml. Activity-guided fractionation of the MeOH extract led to the isolation of caffeic acid (1), luteolin (2), eriodictyol (3), and 1,5-di-O-caffeoylquinic acid (4). All these compounds showed significant XO inhibitory activity in a concentration-dependent manner, and the activity of 2 was more potent (IC(50) 1.3 microM) than the clinically used drug, allopurinol (IC(50) 2.5 microM).