Identification and nitric oxide production inhibitory activity of phenolic derivatives from the trunks of Gnetum latifolium.

Phytochemical investigation of the trunks from Gnetum latifolium led to the isolation of a novel phenolic glucoside, 2E-2,4-di-(3,4-dihydroxyphenyl)but-2-en-1-yl-O-ß-D-glucopyranoside (1), along with five known stilbene derivatives (2-6). Their structures were determined mainly using high-resolution electrospray ionisation mass spectrometry and nuclear magnetic resonance spectroscopic analyses, followed by comparisons of observed spectral data with reported values. The novel compound 1 in G. latifolium was found to be useful as a chemotaxonomic marker. Biological evaluation revealed that compound 6 had remarkable inhibitory effects on nitric oxide production, with a half-maximal inhibitory concentration (IC50) value of 4.85 ± 0.20 µM, which was much higher than that of the positive control dexamethasone (IC50 = 14.20 ± 0.54 µM).

A new phenolic glycoside from the leaves of Flacourtia flavescens Willd.

Chemical study of the methanol extract from the leaves of Flacourtia flavescens led to the isolation of a new phenolic glucoside (1) along with fifteen known secondary metabolites namely shanzhiside methyl ester (2), aurantiamide acetate (3), caffeic acid methyl ester (4), caffeic acid (5), apigenin (6), luteolin (7), kaempferol (8), quercetin (9), gyrophoric acid (10), luteolin-7-O-ß-D-glucopyranoside (11), luteolin-4'-O-ß-D-glucopyranoside (12), kaempferol-7-O-α-L-rhamnopyranoside (13), kaempferol-3-O-ß-D-glucopyranosyl-(1→6)-O-α-L-rhamnopyranoside (14), kaempferol-3,7-O-α-L-dirhamnopyranoside (15) and (2S,3S,4R,8E)-2-((2'R)-2'-hydroxy-octadecanoylamino)-lignocerane-1,3,4-triol-8-ene (16). Their structures were elucidated by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active (MIC = 32 and 64 µg/mL) against E. coli and E. faecalis, respectively. Compounds 1, 2, 2b, 5, 8, 9, and 12 (MIC = 16-32 µg/mL) were moderately active against some tested bacteria.

Macroporous resin-assisted enrichment, characterizations, antioxidant and anticandidal potential of phytochemicals from Trachyspermum ammi.

Extract of de-oiled seeds of Trachyspermum ammi was purified using macroporous resins and the performance of three resins were evaluated to enrich major phytochemical component. A HPLC method has been developed to separate major phytochemical constituents in the crude (CTAE) and partially purified extracts (PTAE). Macroporous resin assisted enrichment and purification suggested XAD-16 as the most efficient (yield 29.8%) followed by XAD-7HP and Diaion HP-20. Concentrated PTAE was subjected to multiple preparative-TLC to afford three compounds, namely, rosmarinic acid-3-O-glucopyranoside (TA-1), kaempferol-(coumaroyl-glucosyl)-rhamnoside (TA-2) and quercetin-3-O-galactoside (TA-3). The structure of these compounds was elucidated from their corresponding spectroscopic characterizations in FT-IR, HR-MS, and partially by 1 H NMR. Total phenolic and flavonoid contents of the extracts were determined. Antioxidant activity by DPPH and ABTS radical scavenging, CUPRAC assays indicated the highest antioxidant potential of CTAE. Among the compounds, TA-1 exhibited the highest scavenging activity in ABTS (IC50 33.41 µg/ml) and DPPH (IC50 69.23 µg/ml), however, relatively lower than CTAE. In vitro anti-candidal activity against virulent strains of Candida spp. revealed C. albicans 4718 as the most susceptible (23.9 µg/ml) to PTAE. PRACTICAL APPLICATIONS: Seeds of Trachyspermum ammi has been extensively investigated for volatile aromatic components of the essential oil. However, the de-oiled seeds have rarely been exploited for potential bioactive phenolics. The present investigation envisaged possible utilization of the de-oiled Trachyspermum seeds for its phenolic constituents, which could be used as natural antioxidant with additional benefits of anticandidal properties. Indeed, macroporous resin assisted enrichment and purification of extracts of T. ammi seeds generate valuable reference compounds, rosmarinic acid-3-O-glucopyranoside, kaempferol-(coumaroyl glucosyl)-rhamnoside, and quercetin-3-O-galactoside.

Whitefly hijacks a plant detoxification gene that neutralizes plant toxins.

Plants protect themselves with a vast array of toxic secondary metabolites, yet most plants serve as food for insects. The evolutionary processes that allow herbivorous insects to resist plant defenses remain largely unknown. The whitefly Bemisia tabaci is a cosmopolitan, highly polyphagous agricultural pest that vectors several serious plant pathogenic viruses and is an excellent model to probe the molecular mechanisms involved in overcoming plant defenses. Here, we show that, through an exceptional horizontal gene transfer event, the whitefly has acquired the plant-derived phenolic glucoside malonyltransferase gene BtPMaT1. This gene enables whiteflies to neutralize phenolic glucosides. This was confirmed by genetically transforming tomato plants to produce small interfering RNAs that silence BtPMaT1, thus impairing the whiteflies' detoxification ability. These findings reveal an evolutionary scenario whereby herbivores harness the genetic toolkit of their host plants to develop resistance to plant defenses and how this can be exploited for crop protection.

The effect of willow fodder feeding on immune cell populations in the blood and milk of late-lactating dairy goats.

In a previous study, we showed that access to willow fodder decreased somatic cell counts (SCC) in the milk of local Mamber goats grazing in brushland at the end of lactation. To test whether the consumption of willow affects the cells of the immune system, Alpine crossbred dairy goats grazing in the same environment were either offered free access to freshly cut willow fodder (W, n = 24) or not (C, n = 24) for 2 weeks. The willow fodder contained 7.5 g/kg DM of salicin. The other major secondary compounds were catechin, myricitrin, hyperin and chlorogenic acid (2.2, 2.6, 1.0 and 0.75 g/kg DM, respectively). Udder health status was determined before the experiment, and each of the two groups included five (W) or six (C) goats defined as infected, as established by microbial cfu in milk, and 19 (W) or 18 (C) non-infected goats. Goats ingested, on average, 600 g of DM from willow (25% of food intake), resulting in minor changes in dietary quality compared to the controls, as established by faecal near-IR spectrometry. Throughout the 2 weeks of experiment, differences between groups in dietary CP contents were minor and affected neither by infection nor by access to willow; the dietary percentage of neutral detergent fibre (NDF) decreased in C and increased in W; dietary acid detergent fibre (ADF) increased; and the dietary tannin contents decreased for both treatments. However, milking performance and milk quality attributes in both W and C goats were similar. Initial SCC and milk neutrophil (cluster of differentiation (CD)18+ and porcine granulocyte (PG)68) cell counts were higher in infected than in non-infected goats; counts decreased significantly in W but not in C uninfected goats. The percentage of CD8+ T-cells increased in all C goats, while in the W group, a significant increase was found only for infected goats. The consumption of willow mitigated an increase in CD8+ in blood and triggered an increase in CD8+ in milk, suggesting an immune-regulatory effect independent of udder status. To our knowledge, this is the first report of a direct nutraceutical effect of fodder ingestion on the immune status of goats.

A novel phenolic acid from the fruits of Rosa soulieana.

From the n-BuOH-soluble fraction of a MeOH extract of the fruits of Rosa soulieana, one new phenolic glucoside (1) was isolated along with five known compounds, comprising two lignin glycosides, two flavonoid glycosides and a phenolic glycoside. The chemical structure of the new compound was elucidated by extensive spectroscopic analyses, including ESI-MS, UV, IR, (1)H and (13)C NMR, DEPT and 2D NMR (HSQC and HMBC). All the isolated compounds were evaluated for their antioxidant activity by using ABTS (2,2'-azino-bis(3-ethylbenzoline-6-sulfonic acid)) assay. Among these compounds, 1, 3 and 6 exhibited strong scavenging activity in ABTS(·+)(SC50 = 102.10, 193.85, 65.38 µmol/L, respectively) compared with the positive control l-ascorbic acid (Vc) (SC50 = 117.16 µmol/L).

A novel phenolic glycoside from Cibotium barometz / 中草药

Objective: To study the chemical constituents from Cibotium barometz continuously. Methods: Column chromatography and HPLC were carried out to isolate and purify the chemical compounds in the ethanol extract from C. barometz, and their structures were elucidated on the basis of spectroscopy. Results: Six compounds isolated from C. barometz were identified as 6-O-protocatechuoyl-D-glucopyranose (1), 3-O-caffeoyl-D-glucopyranose (2), 1-O-caffeoyl-β-D-glucopyranose (3), caffeic acid (4), protocatechuic acid (5), and p-hydroxybenzoic acid (6). Conclusion: Compounds 1-3 and 6 are isolated from C. barometz for the first time, and compound 1 is a novel penolic glucoside named cibotiumbaroside D.

Phenolic glucosides from the leaves of Pieris japonica / 药学学报

The aim of the study is to investigate chemical constituents of the leaves of Pieris japonica. The isolation and purification of the constituents were performed by various chromatography and spectral analysis. Three new phenolic glucosides, erythro-syringoylglycerol 4-O-β-D-glucoside (1),1-(2-β-D-glucopyranoxyl-4-methoxyl-6-hydroxyphenyl)-3-hydroxyl-1-propanone (3),erythro-1-(4-hydroxyl-3-methoxyphenyl)-2-[4-(3-β-D-glucopyranoxypropyl)-2,6-dimethoxyphenoxy]-1,3-propanediol (4), along with five known phenolic glucosides, syringoylglycerol 8-O-β-D-glucoside (2), magnolenin C (5), syringaresinol mono-β-D-glucoside (6), 3-(4-hydroxyl-3-methyphenyl)-1-propanol-1-O-β-D-glucoside (7) and 3,5-dimethoxyl-4-hydroxybenzyl alcohol 4-O-β-D-glucoside (8) were isolated and identified from the plant leaves. Compounds 1 and 2 inhibited significantly (P<0.01) the proliferation of murine T and B cells at concentration of 1×10-6 mol·L-1, in vitro.