Inhibitory effect of some oxygenated stigmastane-type sterols on 12-O-tetradecanoylphorbol-13-acetate-induced inflammation in mice

Phytosterols: Targeting Neuroinflammation in Neurodegeneration

Plant-derived sterols, phytosterols, are well known for their cholesterol-lowering activity in serum and their anti-inflammatory activities. Recently, phytosterols have received considerable attention due to their beneficial effects on various non-communicable diseases, and recommended use as daily dietary components. The signaling pathways mediated in the brain by phytosterols have been evaluated, but little is known about their effects on neuroinflammation, and no clinical studies have been undertaken on phytosterols of interest. In this review, we discuss the beneficial roles of phytosterols, including their attenuating effects on inflammation, blood cholesterol levels, and hallmarks of the disease, and their regulatory effects on neuroinflammatory disease pathways. Despite recent advancements made in phytosterol pharmacology, some critical questions remain unanswered. Therefore, we have tried to highlight the potential of phytosterols as viable therapeutics against neuroinflammation and to direct future research with respect to clinical applications.

Chemical Constituents from the Stems of Tinospora sinensis and Their Bioactivity

Fifty-seven compounds were purified from the stems of Tinospora sinensis, including three new compounds characterized as a lignan (1), a pyrrole alkaloid (11), and a benzenoid (17), respectively. Their structures were elucidated and established by various spectroscopic and spectrometric analytical methods. Among the isolates, fifteen compounds were examined for their anti-inflammatory potential in vitro. The results showed that several compounds displayed moderate inhibition of N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation and elastase release.

Plant sterol oxidation products--analogs to cholesterol oxidation products from plant origin?

Cholesterol and plant sterols are lipids which are abundantly present in a western type diet of animal and plant origin, respectively. The daily intake averages 300 mg/day each. Over the past decades, a steadily increasing consumption of plant sterol enriched dairy products (2-3 g/day) took place to lower circulating LDL cholesterol concentrations. Like all unsaturated components, plant sterols can be attacked by reactive oxygen species resulting in plant sterol oxidation products (POPs). The most widespread methods for POP determination are high-performance liquid chromatography and gas-liquid chromatography. Yet, based on the low plasma POP concentrations in normophytosterolemic subjects (POPs: ∼0.3-4.5 ng/mL), a reliable quantification yielding an appropriate limit of detection remains a challenge. While the more abundantly present cholesterol oxidation products (COPs) have elaborately been studied, research on the metabolism and biological effects of POPs is only emerging. In relation to atherogenity, biological effects including modulation of cholesterol homeostasis, membrane functioning, and inflammation are attributed to POPs. Although mostly supra-physiological concentrations are applied in in vitro assays, anti-tumor activity, cytotoxicity and estrogen-competition have been attributed to specific POPs. However, it is not obvious, if and how POPs may exert in vivo adverse or beneficial health effects similar to those attributed to COPs. In the field of nutritional science, standardized methods for the determination of POPs are required to perform relevant biological studies and to assess their presence in complex foods or biological tissues and fluids. The aim of this review is to provide an overview and evaluation of the published methods and an update on the biological effects attributed to POPs.

Absence of oxysterol-like side effects in human monocytic cells treated with phytosterols and oxyphytosterols

Oxysterols, found in some commonly consumed foods, can induce a wide range of cytotoxic effects, which have been extensively studied. On the other hand, the side effects of phytosterols and oxyphytosterols are less well-known. Over the past few years, different types of foods have been enriched with phytosterols on the basis of the properties of these compounds that reduce circulating cholesterol levels in certain experimental conditions. It is therefore important to gain better knowledge of the risks and benefits of this type of diet. In this study, conducted in human monocytic U937 cells, the ability of phytosterols (sitosterol, campesterol) and oxyphytosterols (7β-hydroxysitosterol, 7-ketositosterol) to induce cell death, polar lipid accumulation, and pro-inflammatory cytokine (MCP-1; IL-8) secretion was determined and compared to that of oxysterols (7-ketocholesterol, 7β-hydroxycholesterol). Phytosterols and oxyphytosterols had no significant effects on the parameters studied; only 7β-hydroxysitosterol slightly increased cell death, whereas at the concentration used (20 μg/mL), strong cytotoxic effects were observed with the oxysterols. With sitosterol, campesterol, and 7-ketositosterol, IL-8 secretion was decreased, and with campesterol the intracellular polar lipid level was reduced. The data show that phytosterols and oxyphytosterols have no oxysterol-like side effects, and they rather argue in favor of phytosterols' beneficial effects.

Antioxidant and antiinflammation capacities of some pear cultivars

Five commercial pear cultivars were investigated for total phenolics and flavonoids contents, the main phenolic compounds, and their antioxidant and antiinflammation capacities. Four in vitro oxidant and 2 in vivo antiinflammation models were used to evaluate the pharmacological activities of the different pears. The main phenolic compounds were determined by high-performance liquid chromatography with diode-array detector, which result indicated that gallic acid ranged from 5.23 to 10.72 μg/g, catechin from 0.41 to 28.83 μg/g, chlorogenic acid from 485.11 to 837.03 μg/g, caffeic acid from 0 to 1.16 μg/g, epicatechin from 6.73 to 131.49 μg/g, and rutin from 0.92 to 104.64 μg/g. The total antioxidant capacity was in descending order: Shuijing > Fengshui > Xuehua > Ya > Xiang pear, which was consistent with the total phenol and flavonoid contents. Thus, the antioxidant capacity of pears may be attributed to their high contents of phenolics and flavonoids. However, the antiinflammation activity was in decreasing order: Xuehua > Xiang > Ya > Fengshui > Shuijing pear, which indicates that compounds other than antioxidants may be responsible for the antiinflammation effect.

PRACTICAL APPLICATION

The importance on antioxidant activities of phenolic compounds in foods and vegetables as natural antioxidants has reached a new high in recent years. In this study, the total phenol and flavonoid contents, and the antioxidant and antiinflammation activities of 5 different types of commercial pears in China were investigated, which may be the experimental basis for the further development and utilization of the pears.

Current and new insights on phytosterol oxides in plant sterol-enriched food

Over the past 15 years, plant sterol-enriched foods have faced a great increase in the market, due to the asserted cholesterol-lowering effect of plant sterols. However, owing to their chemical structures, plant sterols can oxidize and produce a wide variety of oxidation products with controversial biological effects. Although oxyphytosterols can derive from dietary sources and endogenous formation, their single contribution should be better defined. The following review provides an overall and critical picture on the current knowledge and future perspectives of plant sterols-enriched food, particularly focused on occurrence of plant sterol oxidation products and their biological effects. The final objective of this overview is to evince the different aspects of plant sterols-enriched food that require further research, for a better understanding of the influence of plant sterols and their oxides on consumers' health.

Oxysterols: A world to explore

Oxysterols (oxidized derivatives of cholesterol and phytosterols) can be generated in the human organism through different oxidation processes, some requiring enzymes. Furthermore, oxysterols are also present in food due to lipid oxidation reactions caused by heating treatments, contact with oxygen, exposure to sunlight, etc., and they could be absorbed from the diet, at different rates depending on their side chain length. In the organism, oxysterols can follow different routes: secreted into the intestinal lumen, esterified and distributed by lipoproteins to different tissues or degraded, mainly in the liver. Cholesterol oxidation products (COPs) have shown cytotoxicity, apoptotic and pro-inflammatory effects and they have also been linked with chronic diseases including atherosclerotic and neurodegenerative processess. In the case of phytosterol oxidation products (POPs), more research is needed on toxic effects. Nevertheless, current knowledge suggests they may also cause cytotoxic and pro-apoptotic effects, although at higher concentrations than COPs. Recently, new beneficial biological activities of oxysterols are being investigated. Whereas COPs are associated with cholesterol homeostasis mediated by different mechanisms, the implication of POPs is not clear yet. Available literature on sources of oxysterols in the organism, metabolism, toxicity and potential beneficial effects of these compounds are reviewed in this paper.

In vivo anti-inflammatory and in vitro antioxidant activities of Mediterranean dietary plants

Five hydroalcoholic extracts of edible plants from Calabria region (Italy) used in local traditional medicine for the treatment of inflammatory diseases were evaluated for their in vivo topical anti-inflammatory activity (inhibition of croton oil-induced ear oedema in mice) and in vitro antioxidant and antiradical properties (inhibition of linoleic acid oxidation and bovine brain liposomes peroxidation, DPPH radical scavenging). All the extracts showed an anti-inflammatory effect: 300 microg/cm(2) provoked oedema reductions ranging from 21 to 27%. All the extracts exerted also radical scavenging and/or antioxidant properties, the most active plant being Mentha aquatica L. (Lamiaceae) which contained the highest amount of phenolics (337 mg/g) and of flavonoids (15.75 mg/g). Moreover, the content and the composition of sterols were assessed by GC-MS in the examined plants Borago officinalis L. (Boraginaceae) contained the highest number of sterols.

Analgesic and antiinflammatory activities of vernonioside B2 fromVernonia condensata

Vernonioside B2 isolated from the methanol extract of the Brazilian herb Vernonia condensata Baker was evaluated in vivo for analgesic and antiinflammatory activities. The compound reduced writhings (93.28%) and Evans blue dye diffusion (91.80%) induced by acetic acid (0.1 N) in a dose-dependent manner.