Cinnamate derivatives of fructo-oligosaccharides from Lindelofia stylosa

Phytochemistry and biological activity of Erigeron annuus (L.) Pers

Erigeron annuus L. is a flowering herb of North America, Europe, Asia and Russia. This plant is used as folk medicine in China for the cure of indigestion, enteritis, epidemic hepatitis, haematuria and diabetes. Phytochemical studies showed the presence of 170 bioactive compounds like coumarins, flavonoids, terpenoids, polyacetylenic compounds; γ-pyrone derivatives, sterols and various caffeoylquinic acids derived from the essential oil and organic extracts from its various parts such as aerial parts, roots, leaves, stems and flowers. The pharmacological studies demonstrated various extracts and the compounds of E. annuus to exhibit anti-fungal, anti-atherosclerosis, anti-inflammatory, antidiabetic, phytotoxic, cytoprotective, antiobesity and antioxidant activities. This article covers a critical compendious on geographical distribution, botanical description, phytochemistry, ethnomedicinal uses and pharmacological activities of E. annuus. However, further in-depth studies are needed to determine the medical uses of E. annuus and its chemical constituents, pharmacological activities and clinical applications.

Cell extraction method coupled with LC-QTOF MS/MS analysis for predicting neuroprotective compounds from Polygonum tinctorium

The cell extraction method coupled with LC-QTOF-MS/MS is a biological screening technique in which cells are incubated with extracts of natural products, which results in potential bioactive compounds selectively combining with various extracellular and intracellular targets. Although the neuroprotective effects of the plant Polygonum tinctorium are unknown, the ethyl acetate (EtOAc) fraction exhibits significant neuroprotective effects against ʟ-glutamate-induced cytotoxicity in HT22 cells. In this study, we attempted to identify the neuroprotective compounds in the EtOAc fraction of P. tinctorium using the cell extraction method coupled with LC-QTOF MS/MS. Potential neuroprotective components derived from P. tinctorium were combined selectively with HT22 cells, and cell-derived metabolites were identified. A new flavonoid compound, 3,5,3',4'-tetrahydroxy-6,7-methylendioxyflavone-3-O-β-ᴅ-glucopyranoside (1), and 14 known compounds (2-15), with compounds 2, 3, 8, 13, and 15 detected by the cell extraction method, were isolated from the EtOAc fraction of P. tinctorium. Compounds 2, 8, 12, and 14 showed strong neuroprotective effects, with compounds 2 and 14 identified in this plant for the first time in this study. Our results indicate that the cell extraction method coupled with LC-QTOF MS/MS is a useful tool for screening and identifying neuroprotective compounds in natural products.

Phenolic sucrose esters: evolution, regulation, biosynthesis, and biological functions

Phenolic sucrose esters (PSEs) are a diverse group of specialized metabolites that are present in several angiosperm lineages. Phylogenetic reconstruction and structural variation suggest that these metabolites may have evolved independently in monocots and dicots. Constitutive variation in PSE abundance across plant organs and developmental stages is correlated with transcriptional regulation of the upstream phenylpropanoid pathway, whereas pathogen induction is regulated by stress-related phytohormones such as ethylene. Shared structural features of PSEs indicate that their biosynthesis may involve one or more hydroxycinnamoyl transferases and BAHD acetyltransferases, which could be identified by correlative analyses of multi-omics datasets. Elucidation of the core biosynthetic pathway of PSEs will be essential for more detailed studies of the biological function of these compounds and their potential medicinal and agricultural applications.

Orthogonal Approach for the Precise Synthesis of Phenylpropanoid Sucrose Esters

Phenylpropanoid sucrose esters (PSEs) are plant-derived metabolites that exist widely in medicinal plants and possess important bioactivities. Their precise synthesis is challenging due to the distinct and diverse substitution patterns...

Purification of Phenylpropanoids from the Scaly Bulbs of Lilium Longiflorum by CPC and Determination of Their DPP-IV Inhibitory Potentials

The scaly bulbs of Lilium longiflorum (Liliaceae) are used as a food ingredient and a traditional medicine in East Asia. A preliminary study revealed that treatment with 100 μg/mL of the ethyl acetate fraction of this plant material inhibited dipeptidyl peptidase IV (DPP-IV) to 58.99%. Phytochemical studies were conducted to identify the active ingredient, and five compounds, namely, 1 (2.9 mg, 75.8% purity at 320 nm), 2 (12.2 mg, 97.9% purity at 320 nm), 3 (3.1 mg, 66.5% purity at 320 nm), 4 (6.8 mg, 96.9% purity at 320 nm), and 5 (6.2 mg, 90.2% purity at 320 nm) were purified from 200 mg of the ethyl acetate fraction of L. longiflorum via centrifugal partition chromatography (CPC) with a two-phase solvent system composed of chloroform/methanol/isopropanol/water (5:2:2:4, v/v/v/v) in an ascending mode. Their structures were identified as 1-O-p-coumaroyl-2-O-β-glucopyranosylglycerol (regaloside D, 1), 3,6'-O-diferuloylsucrose (2), 1-O-p-coumaroyl-2-O-β-glucopyranosyl-3-O-acetylglycerol (regaloside B, 3), 1-O-p-coumaroylglycerol (4), and 4-O-acetyl-3,6'-O-diferuloylsucrose (5), respectively, by ¹H and ¹³C NMR and MS analysis. Compounds 2 and 5 exhibited DPP-IV inhibitory activities with IC₅₀ values of 46.19 and 63.26 μM, respectively. Compounds 1, 3, and 4 did not show activities, indicating that biphenylpropanoids linked via the sugar moiety are more effective than phenylpropanoids with glycerol or glyceryl glucoside. This is the first report of simultaneous separation of five phenylpropanoids from L. longiflorum by CPC and evaluation of their DPP-IV inhibitory activities.

Towards understanding vacuolar antioxidant mechanisms: a role for fructans?

Recent in vitro, in vivo, and theoretical experiments strongly suggest that sugar-(like) molecules counteract oxidative stress by acting as genuine reactive oxygen species (ROS) scavengers. A concept was proposed to include the vacuole as a part of the cellular antioxidant network. According to this view, sugars and sugar-like vacuolar compounds work in concert with vacuolar phenolic compounds and the 'classic' cytosolic antioxidant mechanisms. Among the biologically relevant ROS (H(2)O(2), O(2)·(-), and ·OH), hydroxyl radicals are the most reactive and dangerous species since there are no enzymatic systems known to neutralize them in any living beings. Therefore, it is important to study in more detail the radical reactions between ·OH and different biomolecules, including sugars. Here, Fenton reactions were used to compare the ·OH-scavenging capacities of a range of natural vacuolar compounds to establish relationships between antioxidant capacity and chemical structure and to unravel the mechanisms of ·OH-carbohydrate reactions. The in vitro work on the ·OH-scavenging capacity of sugars and phenolic compounds revealed a correlation between structure and ·OH-scavenging capacity. The number and position of the C=C type of linkages in phenolic compounds greatly influence antioxidant properties. Importantly, the splitting of disaccharides and oligosaccharides emerged as a predominant outcome of the ·OH-carbohydrate interaction. Moreover, non-enzymatic synthesis of new fructan oligosaccharides was found starting from 1-kestotriose. Based on these and previous findings, a working model is proposed describing the putative radical reactions involving fructans and secondary metabolites at the inner side of the tonoplast and in the vacuolar lumen.

Separation of phenylpropanoids and evaluation of their antioxidant activity

Phenylpropanoids are a group of natural products with a wide range of biological and pharmacological importance. They have been isolated from a large number of plants by utilizing a diverse range of chromatographic techniques. We describe here the utilization of normal, reverse phase, and high pressure liquid column chromatographic techniques for the purification of phenylpropanoids from the crude plant extracts. Most important of them is the recycling reverse phase HPLC effectively utilized to purify the highly oxygenated phenylpropanoids glycosides from the butanolic and water extracts. The antioxidant activity of the different phenylpropanoids is also reported on the basis of DPPH, superoxide anion scavenging and Fe(2+)-chelating assays, along with electron spin resonance (ESR) method.

Constituents of the flowers of Erigeron annuus with inhibitory activity on the formation of advanced glycation end products (AGEs) and aldose reductase

Seven phenolic compounds, caffeic acid (1), 4-hydroxybenzoic acid (2), 4-methoxybenzoic acid (3), protocatechuic acid (4), eugenol O-beta-D: -glucopyranoside (5), 3,6-di-O-feruloylsucrose (6), and 3,5-di-O-caffeoylquinic acid methyl ester (7), were isolated from an EtOAc-soluble partition of the flowers of Erigeron annuus. The structures of 1-7 were determined by spectroscopic data interpretation, particularly 1D and 2D NMR studies, and by comparison of their data with those published in the literature. All the isolates were subjected to in vitro bioassays to evaluate their inhibitory activities against the formation of advanced glycation end products (AGEs) and rat lens aldose reductase (RLAR). Of the compounds, 1, 6, and 7 exhibited potent inhibitory activities against the formation of AGEs. In the RLAR assay, compound 7 showed the most potent inhibitory activity.