Purification of phenylethanoids from Brandisia hancei and the antiproliferative effects on aortic smooth muscle

The hydroxytyrosol-typed phenylpropanoidglycosides: A phenylpropanoid glycoside family with significant biological activity

Hydroxytyrosol-typed phenylpropanoid glycosides (HPGs), composed of phenylethanol and various complex oligosaccharides, are widespread and abundant in different plant, and have a diverse range of biological activities. All HPGs reported previously have been isolated from natural sources, and most of them showed significant bioactivities, such as anti-inflamatory, anti-cancer, cytoprotection, neuro-protective effects, enzyme-inhibitory, anti-microbial effects, and cardiovascular activity. The goal of this review is to summarize the structures of HPGs reported over the past few decades, as well as to introduce their pharmacological effects. We also introduce the possible relationship between the structures of HPGs and their source plants, as well as the structure-activity relationships of some important activities. This review will serve as a resource for future research into this class of compounds, and demonstrate their potential value.

Phytochemical analysis on the aerial parts of Teucrium capitatum L. with aspects of chemosystematics and ethnobotany

The phytochemical analysis on the aerial parts of Teucrium capitatum L. collected from a new population in Central Italy, led to the identification of eight compounds, i.e. pheophytin a (1), poliumoside (2), apigenin (3), luteolin (4), cirsimaritin (5), cirsiliol (6), 8-O-acetyl-harpagide (7) and teucardoside (8) belonging to four different classes of secondary metabolites. Pheophytin a (1) represents a newly identified compound in the genus whereas compounds (7-8) are newly identified compound in the species. The chemotaxonomic and ethnobotanical aspects relative to the presence of these compounds were widely discussed suggesting important conclusions for both.

Antioxidant and Anti-Proliferative Active Constituents of Tecoma Stans against Tumor Cell Lines

A new phenylethanoid, 2-(3,4-dihydroxyphenyl)ethyl-,2-O-(6-deoxy-α-L-mannopyranosyl-,4-(3,4-dihydroxyphenyl)-2-propenoate)-β-D-glucopyranoside (3) and a novel monoterpene alkaloid, 5-hydroxy-skytanthine hydrochloride (8), along with eleven known compounds have been isolated from Tecoma stans Juss. fruits and flowers. 4-O-E-Caffeoyl-α-L-rhamnopyranosyl-(1′→3)-α/β-D-glucopyranose (1), E/Z-acetoside (2), isoacetoside (4), rutin (5), luteolin 7-O-β-D-neohespridoside (6), luteolin 7-O-β-D-glucopyranoside (7) and sucrose (9) were isolated from the fruits, while luteolin 7-O-β-D-glucuronopyranoside (10), diosmetin 7-O-β-D-glucuronopyranoside (11), diosmetin 7-O-β-D-glucopyranoside (12), diosmetin 7-O-β-D-glucuronopyranoside methyl ester (13), and 2 from the flowers. Their structures were determined on the basis of chemical and spectroscopic evidence. It was found that the extract of T. stans fruits and compounds 1, 2 and 4 possess strong scavenging activity to DPPH, peroxyl and hydroxyl radicals. Unlike 4, which potentially induced NO generation in bacterial lipopolysaccharide-stimulated Raw murine macrophages (RAW 264.7), the extract, and compounds 1, 2, and 8 significantly inhibited NO generation. The extract, and compounds 2 and 4 exhibited a cytotoxic effect on human hepatocarcinoma cells (Hep-G2), while the extract, 2 and 8 were potent growth inhibitors of human breast carcinoma (MCF-7). Also, 1 and 2 were remarkable growth inducers of human lymphoblastic leukemia cells (1301), whereas the extract, 2, and 8 stimulated the macrophage proliferation rate.

Lignans from the stems and leaves of Brandisia hancei and their effects on VEGF-induced vascular permeability and migration of HRECs and DLAV formation in zebrafish

In our continuing search for novel antiangiogenic agents, a new lignan glycoside, (7R,8R)-1-(4-O-β-d-glucopyranosyl-3-methoxyphenyl)-2-{2-methoxy-4-[1-(E)-propene-3-ol]-phenoxyl}-propane-1,3-diol (1), along with three known lignans (2–4), were isolated from the 80% EtOH extract of Brandisia hancei stems and leaves. These isolates (1–4) were subjected to an in vitro bioassay to evaluate their effects on vascular endothelial growth factor (VEGF)-induced vascular permeability and migration of human retinal endothelial cells (HRECs). Of the compounds tested, compound 1 resulted in the greatest reduction in VEGF-induced vascular permeability by about 31.5% at 10 μM compared to the VEGF-treated control. In the migration assay, compounds 1 and 2 significantly decreased VEGF-induced HREC migration. Furthermore, zebrafish embryos treated with compounds 1 and 2 showed mild reductions of dorsal longitudinal anastomotic vessel (DLAV) formation.

Inhibitory activities of acteoside, isoacteoside, and its structural constituents against protein glycation in vitro

BACKGROUND

Advanced glycation end products (AGE) are substances that can induce insulin resistance in adipocyte, hepatocyte and muscle cells. This resistance correlates highly with cardiovascular disease and diabetic complications. Acteoside (A), a phenylethanoid glycoside, is an active compound in several plants and traditional herbal medicines. Acteoside, its structural isomer, isoacteoside (I), and their constituents, caffeic acid (C) and 3,4-dihydroxyphenylethanol (D), were used in the study to investigate the inhibitory activity against AGE formations in vitro.

RESULTS

AGE formations were detected by anti-(N^ϵ-(carboxymethyl)lysine (anti-CML), using bovine serum albumin (BSA)/glucose (glc) and BSA/galactose (gal) as models, or by anti-argpyrimidine (anti-AP), using BSA/methylglyoxal (MGO) as models. It was found that A, I, C, or D, each at 5 mM, could attenuate the CML formations detected by ELISA in the BSA/gal model of a 3-day or 5-day reaction, and showed significant differences (P < 0.01 or P < 0.001) compared to the control. However, these compounds showed a minor effect after a 7-day incubation. It was also found that C or D could lower the CML formations in the BSA/glc model and showed significant differences (P < 0.05 or P < 0.01) compared to the control after a 3-day, 5-day and 7-day reaction. It was found that A, I, C, or D, each at 0.5 mM or 5 mM, could attenuate the AP formations in the BSA/MGO model of a 3-day reaction and showed significant differences (P < 0.001) compared to the control.

CONCLUSIONS

The results suggest the potential anti-glycation activities of A and I in vitro may apply to cell models at higher glucose concentrations or to diabetic animal models, and need further investigation.

New triterpene saponins from Duranta repens Linn. and their cytotoxic activity

From the leaves of Duranta repens (Verbenaceae) two new triterpene saponins, named durantanin IV (1) and V (2) were isolated. In addition, ten known compounds were isolated, namely a bidesmosidic saponin, oleanolic acid, three phenylethanoids and five flavonoids. All metabolites were isolated for the first time from this genus except for 3 (oleanolic acid) and 7 (E/Z acteoside). The structures were determined mainly by spectroscopic methods (UV, IR, HRESI-MS, ¹H-, ¹³C-NMR, ¹H-¹H COSY, HSQC and HMBC). Cytotoxic screening of the chloroform, ethyl acetate and methanol extracts was carried out on brine shrimps. In addition, the investigated methanol extract and compounds 1, 2 and 7 showed significant cytotoxic activity against a HepG2 cell line.

Attenuated endothelium-mediated relaxation by acteoside in rat aorta: Role of endothelial [Ca2+]i and nitric oxide/cyclic GMP pathway

Acteoside and other phenylethanoid glycoside are contained in many plants that are widely used in traditional Chinese herbal medicine. Acteoside possesses multiple biological actions. Its effect on the vascular system is, however, incompletely understood. This study was aimed to investigate the role of endothelial [Ca2+]i, nitric oxide (NO), and cyclic GMP in acteoside-induced inhibition of endothelial NO-mediated relaxation in rat aorta. Acteoside reduced endothelial NO-dependent relaxation induced by acetylcholine (Ach) or A23187. Acteoside inhibited Ach-stimulated increase in tissue content of cyclic GMP in endothelium-intact rings. L-NNA abolished the stimulatory effect of Ach. Treatment with acteoside significantly suppressed bradykinin-induced increase in [Ca2+]i of cultured rat aortic endothelial cells. Acute exposure to acteoside (30 microM) did not affect the expression of eNOS mRNA in endothelium-intact rings. In summary, acteoside impairs endothelial NO-mediated aortic relaxation partially through inhibition of agonist-induced endothelial Ca2+ mobilization and Ca2+-dependent NO production and subsequent suppression of cyclic GMP formation. This novel pharmacological action if occurring in small vessels in vivo, may contribute to the reported anti-inflammatory effect of acteoside against NO-mediated vascular permeability-related acute edema.

A new iridoid glycoside with nerve growth factor-potentiating activity, gelsemiol 6'-trans-caffeoyl-1-glucoside, from Verbena littoralis

A new iridoid glycoside, gelsemiol 6'-trans-caffeoyl-1-glucoside (1), was isolated from Verbena littoralis, together with four known phenylethanoid glycosides, acteoside (2), 2'-acetylacteoside (3), jionoside (4), and isoverbascoside (5). Their structures were elucidated by spectral data. Compound 1 showed weak enhancement of nerve growth factor (NGF)-mediated neurite outgrowth from PC12D cells.