Chemical constituents from the leaves of Sindora siamensis var. maritima and their antimicrobial and α-glucosidase inhibitory activities.

Two new glycosides, sindosides A-B (1-2), along with 11 previously identified metabolites (3-13), were isolated from an ethanolic extract of the leaves of Sindora siamensis var. maritima. The structures of the purified phytochemicals were elucidated by interpreting their spectroscopic data (IR, NMR, and HRMS). The absolute configuration of compound 1 was established by experimental and calculated ECD spectra. The antimicrobial results revealed that compound 8 selectively inhibited C. albicans fungal with a MIC value of 64 µg/mL, whereas 11 presented a weak inhibition toward E. faecalis, S. aureus, and B. cereus bacterial strains with the same MIC value of 128 µg/mL. Interestingly, compounds 1, 2, 8, 9, and 11 showed α-glucosidase inhibitory activity with IC50 values ranging from 14.42 ± 0.21 to 30.62 ± 0.18 µM, which were more active than the positive control (acarbose, with an IC50 value of 46.78 ± 1.37 µM). Enzyme kinetic analysis revealed that compounds 1, 2, and 11 behaved as uncompetitive inhibitors with Ki values of 8.60 ± 1.04, 5.16 ± 0.73, and 7.17 ± 0.98 µM, respectively.

Glycoside constituents from Miliusa sinensis leaves and their anti-inflammatory and acetylcholine protective effects.

Repeated column chromatography resulted in the isolation of two new glycosides, miliusides A-B (1 and 7), along with six known metabolites (2-6, and 8) from the leaves of Miliusa sinensis Finet and Gagnep. The structures of the purified phytochemicals were elucidated by interpreting their spectroscopic data (NMR, HRMS), as well as comparison with the previous literature. The biological evaluation of acetylcholinesterase (AChE) inhibitory effects and anti-inflammatory activity by measuring nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 mouse macrophage cells, were also conducted. Among them, compounds 5 and 7 exhibited significant AChE inhibitory activities (IC50 = 53.36 ± 4.20 and 88.50 ± 8.79 µM, respectively), compared with the positive control (Galanthamine, IC50 = 1.65 ± 0.15 µM). Only the MeOH extract showed suppression effects on NO production in LPS-induced RAW264.7 cells (IC50 = 38.18 ± 3.25 µg/mL) comparable to that of the positive control, l-NMMA (IC50 = 2.21 ± 0.56 µg/mL).

Polycyclic aromatic hydrocarbons (PAHs) in dry tea leaves and tea infusions in Vietnam: contamination levels and dietary risk assessment.

The total mean ∑[Formula: see text] in samples were from 75.3 to 387.0 ng/g dry weight (d.w) and showed high value in black dry tea, followed by herbal, oolong, and green tea. The mean ∑[Formula: see text] (a combination of benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) values were 54.3 ng/g, 16.4 ng/g, 14.2 ng/g, and 6.6 ng/g for black, herbal, green, and oolong teas, respectively. Concentration for benzo[a]pyrene (BaP) was from 0.4 to 35.8 ng/g, and the BaP equivalent concentration values ranged from 0.3 to 48.1 ng/g. There was only 1 black tea sample that BaP concentration exceeded the maximum level according to European Union (EU) standards. Tea samples marketed in Vietnam showed insignificant difference with the samples from other origins by same analytical method. Black teas showed high PAHs contents in dry tea samples but the released percentage of sum of PAHs from tea-to-tea infusion was lower than that in other tea type samples. The released percentages of PAH4 from tea-to-tea infusion were 40.7, 15.4, and 1.9 for green, herbal, and black tea. High temperature in black tea manufacturing processes might reduce essential oil content in tea that might effect on the PAHs partially release into the infusion. Indeed, based on EU regulations, we may conclude that tea consumers are safe in risk of exposure to PAHs obtained from teas.

Acylated flavonoid glycosides from Barringtonia racemosa.

Using various chromatographic separations, three new acylated flavonoid glycosides, namely barringosides G-I (1-3), were isolated from the water-soluble extract of Barringtonia racemosa branches and leaves. The structure elucidation was performed by extensive analysis of the 1D and 2D NMR and HR-QTOF-MS data. Of the isolated compounds, barringoside I (3) showed moderate inhibitory effects on LPS-induced NO production in RAW264.7 cells with an IC50 of 52.48 ± 1.04 µM.

Transcriptome sequencing and identification of cytochrome P450 monooxygenases involved in the biosynthesis of maslinic acid and corosolic acid in Avicennia marina.

Grey mangrove (Avicennia marina) is a traditional medicine used for the treatment of various diseases, including rheumatism and ulcers; however, the compounds responsible for its curative effects remain largely unknown. Triterpenoids are a diverse group of plant-specialized metabolites derived from a common precursor, 2,3-oxidosqualene. Triterpenoids are potentially responsible for the beneficial effects of A. marina; however, the chemical profiles of triterpenoids in A. marina and their biosynthetic genes have not been identified. Cytochrome P450 monooxygenases (P450s) have key roles in the structural diversification of plant triterpenoids by catalyzing site-specific oxidation of triterpene scaffolds. Recent studies have revealed that the CYP716 family represents the most common clade of P450s involved in triterpenoid biosynthesis. In this study, we performed triterpenoid profiling and RNA sequencing of A. marina leaves. Mining of CYP716 family genes and enzymatic activity assays of encoded proteins revealed that CYP716A259 catalyzed oxidation at the C-28 position of the pentacyclic triterpene skeletons of ß-amyrin, α-amyrin, and lupeol to produce oleanolic acid, ursolic acid, and betulinic acid, respectively. The other functionally defined P450, CYP716C53, catalyzed the C-2α hydroxylation of oleanolic acid and ursolic acid to produce maslinic acid and corosolic acid, respectively. The possible involvement of CYP716A259 and CYP716C53 in the biosynthesis of these health-benefiting compounds in A. marina leaves, and the possible contribution of the resulting compounds to the reported bioactivities of A. marina leaf extract, are discussed.

Two new guaiane sesquiterpene lactones from the aerial parts of Artemisia vulgaris.

Two new guaiane sesquiterpene lactones, vulgarolides A and B (1 and 2), were isolated from Artemisia vulgaris aerial parts using various chromatographic separations. The structure elucidation was performed by combination of spectroscopic experiments including 1D and 2D NMR, HR ESI MS, and CD. Their in vitro cytotoxic activities against five human cancer cell lines were also evaluated using SRB method.

Two new simple iridoids from the ant-plant Myrmecodia tuberosa and their antimicrobial effects.

Six iridoid derivatives (1-6), including two new compounds myrmecodoides A and B (1 and 2), were isolated from the ant-plant Myrmecodia tuberosa. Their structures were determined on the basis of spectroscopic data ((1)H and (13)C NMR, HSQC, HMBC, (1)H-(1)H COSY, NOESY and HR-ESI-MS) and by comparison with the literature values. Among isolates, 3 and 4 exhibit weak antibacterial effect against Staphylococcus aureus subsp. aureus with MIC value of 100.0 µg/mL.

In vitro anti-inflammatory components isolated from the carnivorous plant Nepenthes mirabilis (Lour.) Rafarin.

CONTEXT: Nepenthes mirabilis (Lour.) Rafarin (Nepenthaceae) is a carnivorous plant used as a folk medicine in the treatment of jaundice, hepatitis, gastric ulcers, ureteral stones, diarrhea, diabetes, and high blood pressure. Neither the phytochemical content nor biological activities of N. mirabilis have been reported. OBJECTIVE: The anti-inflammatory activity from the N. mirabilis methanolic extract led to the isolation of compounds (1-26). MATERIALS AND METHODS: Chromatographic methods were used to isolate compounds from the methanol extract of N. mirabilis branches and leaves. The anti-inflammatory activity of these isolated compounds was investigated in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) using ELISA. Primary BMDCs were used to examine the production of pro-inflammatory cytokines (IL-12 p40, IL-6, and TNF-α, at concentrations of 0.1, 0.2, and 1.0 µM) as compared with a positive control, SB203580 (1.0 µM). MTT assays showed that isolated compounds (1-26) did not exhibit significant cytotoxicity at concentrations up to 20.0 µM. RESULTS: Compound 9 showed potent inhibition of IL-12 p40, IL-6, and TNF-α production (IC50 = 0.17 ± 0.02, 0.46 ± 0.01, and 8.28 ± 0.21 µM, respectively). Compound 4 showed potent inhibition of IL-12 p40 and IL-6 production (IC50 = 1.17 ± 0.01 and 2.15 ± 0.04 µM). In addition, IL-12 p40 inhibition by naphthalene derivatives (1-7, 9, and 10), phenolic compounds (11-15), lupeone (18), and flavonoids (22, 25, and 26) was more potent than with the positive control. The isolated compounds exhibited little and/or no inhibitory effects on TNF-α production in LPS-stimulated BMDCs. DISCUSSION AND CONCLUSION: Taken together, these data suggest that the isolated components have significant inhibitory effects on pro-inflammatory cytokine production and warrant further study concerning their potential medicinal use.

Two new naphthalene glucosides and other bioactive compounds from the carnivorous plant Nepenthes mirabilis.

Two new naphthalene diglucosides named nepenthosides A (1) and B (2), together with eleven known compounds (3-13), were isolated from the carnivorous plant Nepenthes mirabilis. The structures of these compounds were elucidated based on extensive spectroscopic analysis, including 1D- and 2D-NMR, and MS. The antioxidant activities of compounds 1-13 were evaluated in terms of their peroxyl radical-scavenging (trolox equivalent, TE) and reducing capacities. All isolates showed peroxyl radical-scavenging and reducing activities at concentrations of 1.0 and 10.0 µM. Anti-osteoporotic activities were investigated using murine osteoclastic RAW 264.7 cells. Compounds 1-7 and 9-12 significantly suppressed tartrate-resistant acid phosphatase activity down to 91.13 ± 1.18 to 42.39 ± 1.11%, relative to the control (100%) in nuclear factor-κB ligand (RANκL)-induced osteoclastic RAW 264.7 macrophage cells.

Chemical constituents from Kandelia candel with their inhibitory effects on pro-inflammatory cytokines production in LPS-stimulated bone marrow-derived dendritic cells (BMDCs).

Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), including one new sesquiterpene glycoside, kandelside (1), three megastigman glycoside compounds (7-9), 16 known phenolic compounds (2-6 and 10-19). Structures of the isolated compounds were elucidated based on spectral data comparison with reported values. Isolated compounds were also evaluated for their inhibitory effects on the production of pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumor necrosis factor α (TNF-α) in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. Among these compounds, compound 9 exhibited strong inhibitory activity against IL-6 production (IC50=0.07 ± 0.05 µM) and moderate inhibitory activity against TNF-α production (IC50=49.86 ± 1.02 µM), but exhibited no activity on IL-12 p40 production. Compounds 5 and 6 significantly inhibited IL-12 p40, IL-6, and TNF-α production with IC50 values of 11.68 ± 0.38, 44.52 ± 1.08, and 28.73 ± 0.96 µM, respectively.

A new cycloartane glucoside from Rhizophora stylosa.

Nine secondary metabolites, including a new cycloartane glucoside, rhizostyloside (1), were isolated from a methanol extract of Rhizophora stylosa leaves through several chromatographic experiments. The structures of the compounds were determined on the basis of NMR spectroscopic (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY) and HR-ESI-MS data and by comparison with literature values. Compound 1 exhibited significant cytotoxicity against three human cancer cell lines: KB (epidermoid carcinoma), LU-1 (lung adenocarcinoma), and SK-Mel-2 (melanoma). In addition, 1 strongly activated caspase-3/7 in LU-1 cells.