para-Menthane as a Stable Terpene Derived from Orange By-Products as a Novel Solvent for Green Extraction and Solubilization of Natural Substances.

This study aims at investigating p-menthane, a novel bio-based solvent resulting from the hydrogenation of d-limonene, as a green alternative to n-hexane or toluene for the extraction and solubilization of natural substances. First, conductor-like combination of quantum chemistry (COSMO) coupled with statistical thermodynamics (RS) calculations show a comparable solubilization profile of p-menthane and n-hexane for carotene, volatile monoterpenes such as carvone and limonene, and model triglycerides. Other data obtained experimentally in solid/liquid extraction conditions further indicate that p-menthane showed similar performances to n-hexane for extracting carotenes from carrots, aromas from caraway seeds, and oils from rapeseeds, as these products showed a comparable composition. p-Menthane was also tested using common analytical extraction procedures such as Soxhlet for determination of oil content via multiple extraction stages, and Dean-Stark for determination of water content via azeotropic distillation. For both systems, yields were comparable, but for Dean-Stark, the distillation curve slope was higher when using p-menthane, and the time needed to attain 100% water recovery was 55% shorter than for toluene. Taken together, these results reveal the potential of p-menthane as a green replacer for petroleum-based solvents such as n-hexane or toluene.

Carnosic acid.

Carnosic acid (salvin), which possesses antioxidative and antimicrobial properties, is increasingly exploited within the food, nutritional health and cosmetics industries. Since its first extraction from a Salvia species (∼70 years ago) and its identification (∼50 years ago), numerous articles and patents (∼400) have been published on specific food and medicinal applications of Rosmarinus and Salvia plant extracts abundant in carnosic acid. In contrast, relevant biochemical, physiological or molecular studies in planta have remained rare. In this overview, recent advances in understanding of carnosic acid distribution, biosynthesis, accumulation and role in planta, and its applications are summarised. We also discuss the deficiencies in our understanding of the relevant biochemical processes, and suggest the molecular targets of carnosic acid. Finally, future perspectives and studies related to its potential roles are highlighted.

Lipolytic activity of Svetol®, a decaffeinated green coffee bean extract.

The beneficial health effects of chlorogenic acids (CGAs), major components of coffee beans, are well known and have been attributed to multiple mechanisms of action. However, the lipolytic activity of CGAs does not appear to have been reported. We studied the effects of varying concentrations of Svetol®, a decaffeinated green coffee bean extract enriched in CGAs, on the liberation of free fatty acids from human adipocytes following short-term (2 h) and long-term (192 h) exposure. The results showed that although lipolytic activity observed following short-term incubation could be tentatively linked to residual caffeine traces in the sample, longer-term exposure clearly showed the effects of Svetol® on release of free fatty acids, and this effect was not due to caffeine. The results of this study provide a further mechanism by which to explain the long-term health benefits of CGAs and Svetol®.

Flavonoid glycosides from Microtea debilis and their cytotoxic and anti-inflammatory effects.

Two new 5-O-glucosylflavones, 5-O-ß-D-glucopyranosyl cirsimaritin (1) and 5, 4'-O-ß-D-diglucopyranosyl cirsimaritin (2), four known flavonoids, cirsimarin (3), cirsimaritin (4), salvigenin (5), 4', 5-dihydroxy-7-methoxyflavone (6), and a norisoprenoid, vomifoliol (7), have been isolated from the aerial parts of Microtea debilis. All isolates were tested for cytotoxicity in human cancer cell lines (Hep G2, COLO 205, and HL-60) and anti-inflammatory activities in LPS-treated RAW264.7 macrophages. Compound 6 was found to be a potent inhibitor to nitrite production in macrophages. Compounds 2, 4, 6, and 7 showed moderate anti-proliferative activity against COLO-205 cells with IC(50) values of 7.1, 13.1, 6.1, and 6.8 µM, respectively.

Fraxinus excelsior seed extract FraxiPure™ limits weight gains and hyperglycemia in high-fat diet-induced obese mice.

PURPOSE: The aim of this study was to determine whether a Fraxinus excelsior L. seed extract, FraxiPure™ (0.5% in the diet), limits weight gain and hyperglycemia in mice. In a previous report, we identified several secoiridoids in FraxiPure™, some of which activated peroxisome proliferator-activated receptor alpha (PPARα) in vitro and inhibited the differentiation of 3T3-L1 preadipocyte cells. In a separate study, FraxiPure™ reduced glycemia in healthy volunteers, following an oral glucose tolerance test. These findings suggest that FraxiPure™ has antiobesity and antihyperglycemia effects. MATERIALS AND METHODS: FraxiPure™ was tested in mice that were fed a high-fat diet over 16 weeks and compared with low-fat and high-fat diet controls. Weight gain, omental and retroperitoneal fat, fasting blood glucose, and fasting blood insulin were measured. RESULTS: FraxiPure™ reduced gains in body weight by 32.30% (p < 0.05), omental fat by 17.92%, and retroperitoneal fat by 17.78%. FraxiPure™ also lowered fasting blood glucose levels by 76.52% (p < 0.001) and plasma insulin levels by 53.43% (p < 0.05) after 16 weeks. Moreover, FraxiPure™ lowered liver weight gains by 63.62% (p < 0.05) and the incidence of fatty livers by 66.67%. CONCLUSIONS: Our novel results demonstrate the antiobesity effects of chronic administration of an F. excelsior seed extract and confirm its ability to regulate glycemia and insulinemia. In addition, this extract, which is rich in secoiridoid glucosides, protects against obesity-related liver steatosis.

Importance of extract standardization and in vitro/ex vivo assay selection for the evaluation of antioxidant activity of botanicals: a case study on three Rosmarinus officinalis L. extracts.

The overproduction of free radicals and oxygen reactive species is suspected to be implicated in a wide range of metabolic reactions that can have pernicious consequences in the development of a variety of human diseases. Botanical extracts are sources of antioxidants that counteract both free radicals and oxygen reactive species. The processing conditions used in the botanical extraction may influence the antioxidant composition; therefore, different extracts from the same plant may have different antioxidant properties. To illustrate this fact, we conducted a study using three commercial rosemary (Rosmarinus officinalis L.) leaf extracts. The three extracts were standardized to contain, respectively, 20% carnosic acid, 40% ursolic acid, or 20% rosmarinic acid. They were evaluated for their total (hydrophilic + lipophilic) antioxidant effects on oxygen radical absorbance capacity (ORAC), their ferric reducing/antioxidant power (FRAP), and their capacity to inhibit Cu(2+)-induced low-density lipoprotein (LDL) oxidation ex vivo. The ursolic acid extract showed the lowest antioxidant capacity on all models. The rosmarinic acid extract had an antioxidant capacity 1.5 times higher on ORAC and four times higher on FRAP than the carnosic acid extract. However, the carnosic acid extract was better than the rosmarinic acid extract in inhibiting the oxidation of LDL ex vivo. These results encourage conducting further studies to evaluate the carnosic acid and rosmarinic acid extracts in vivo. Our study offers an example of the importance of the extraction procedures, on which depends the nature of the antioxidant composition, and highlights interest to proceed with in vitro/ex vivo assay selection for the evaluation of the antioxidant properties of botanical extracts.

Iridoids from Fraxinus excelsior with adipocyte differentiation-inhibitory and PPARalpha activation activity.

Two new secoiridoid glucosides, excelsides A (1) and B (2), were isolated from the seeds of Fraxinus excelsior. Their structures were elucidated as (2S,4S,3E)-methyl 3-ethylidene-4-(2-methoxy-2-oxoethyl)-2-[(6-O-beta-D-glucopyranosyl-beta-d-glucopyranosyl)oxy]-3,4-dihydro-2H-pyran-5-carboxylate and (2S,4S,3E)-methyl 3-ethylidene-4-{2-[2-(4-hydroxyphenyl)ethyl]oxy-2-oxoethyl}-2-[(6-O-beta-d-glucopyranosyl-beta-d-glucopyranosyl)oxy]-3,4-dihydro-2H-pyran-5-carboxylate, respectively, on the basis of NMR and MS data. Eight known compounds were identified as nuzhenide (3), GI3 (4), GI5 (5), ligstroside (6), oleoside 11-methyl ester (7), oleoside dimethyl ester (8), 1'''-O-beta-D-glucosylformoside (9), and salidroside (10). Compounds 1-9 inhibited adipocyte differentiation in 3T3-L1 cells. Dilutions of the aqueous extract of F. excelsior (1:10,000) as well as compounds 2, 3, 4, 5, and 8 activated the peroxisome proliferator-mediated receptor-alpha (PPARalpha) reporter cell system in the range of 10(-4) M, compared to 10(-7)-10(-8) M for the synthetic PPARalpha activator, WY14,643. Both biological activity profiles support the hypothesis that inhibition of adipocyte differentiation and PPARalpha-mediated mechanisms might be relevant pathways for the antidiabetic activity of F. excelsior extract.

Acute effects of Fraxinus excelsior L. seed extract on postprandial glycemia and insulin secretion on healthy volunteers.

AIM OF THE STUDY: Fraxinus excelsior L. (Family: Oleaceae) seeds are consumed as a food, condiment, and folk medicine. The seeds are traditionally used as a potent hypoglycemic agent, but no clinical evidence exists in as to this regard. We assessed the clinical efficacy and safety of the seed extract (FraxiPure, Naturex), containing 6.8% of nuzhenide and 5.8% of GI3 (w/w), on plasma glucose and insulin levels against glucose (50 g) induced postprandial glycemia. MATERIALS AND METHODS: Preselected dose (1.0 g) was used in a double blind, randomized, crossover, placebo (wheat bran) controlled study on 16 healthy volunteers. Each treatment was given immediately after a fasting blood glucose sample (0 min). Postprandial plasma glucose levels were estimated at 0, 15, 30, 45, 60, 90 and 120 min; and postprandial plasma insulin at 0, 30, 60, 90 and 120 min. RESULTS: The extract lowered the incremental postprandial plasma glucose concentration as compared to placebo at 45 min (P = 0.06) and 120 min (P = 0.07). It statistically (P = 0.02) reduced the glycemic area under the blood glucose curve. The seed, also, induced a significant (P = 0.002) secretion of insulin at 90 min after glucose administration. However, the insulinemic area under the blood insulin curve was not different than the placebo. No adverse events were reported. CONCLUSIONS: Our findings confirm the hypoglycemic action of Fraxinus excelsior L. seed extract. These promising results, thus, encourage conducting long-term clinical studies to further evaluate the efficacy and safety of Fraxinus excelsior L. seed extract in healthy and diabetic volunteers and also to explore the possible mechanism(s) of action.