Bitter Constituents Research Articles

Determination of the effect of different atmospheric conditions on bioactive components of various citrus juices

In this study, effects of various gas atmosphere (O2, CO2 and N2) and holding times (15, 30, 45 and 60 min) on changing of bioactive compounds (limonin, nomilin, hesperidin, neohesperidin, naringin, chlorogenic acid, ascorbic acid and total carotenoid, total phenolic content) were investigated in four different citrus varieties (Washington Navel, Valencia, Kozan Yerli and sour orange). When all gas atmospheres were evaluated, the effects of atmospheric gases on ascorbic acid, chlorogenic acid, naringin, neohesperidine, limonin contents were insignificant. Whereas the effects of different atmospheric conditions on total carotenoid, total phenolic, hesperidin, naringin contents were found significant. N2 gas had a protective effect on total carotenoid content of Washington Navel, Kozan Yerli, sour orange and total phenolic content of all citrus varieties. The highest content of ascorbic acid was detected for the samples kept under CO2. The bitter constituents (naringin, limonin, nomilin and neohesperidin) were found mostly in sour orange juice.

ANALYSIS OF THE SECONDARY METABOLITES OF VERNONIA AMYGDALINA AND THE ANTIMICROBIAL EFFECTS ON PATHOGENIC ORGANISMS

Medicinal plants have assumed the basis of traditional treatment and have proven effective in human health care worldwide. There is an increasing interest in complementary and alternative therapies to treat various illnesses. The continued consumption of antibiotics with little or no impact on bacteria has negatively affected health care delivery. Bitter leaf (Vernonia amygdalina) is a common shrub belonging to the family Asteraceae and a perennial shrub usually cultivated as a homestead vegetable and fodder tree in various parts of Nigeria. The current study examined the effect of bitter leafs phytochemical constituents and antimicrobial activity on Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. The result of the phytochemical analysis performed on the root and stem bark of V. amygdalina revealed the presence of alkaloids, steroids, tannin, flavonoids, saponins, and phenol. However, the investigation revealed that tannins and phenol were mainly deposited in the plants stem bark. Also, the antimicrobial analysis conducted showed that S. aureus was more vulnerable to the ethanol, acetone, and hot aqueous extracts of V. amygdalina. At the same time. Albicans and P. aeruginosa showed sensitivity on exposure to ethanol and acetone but did not react to the hot aqueous extracts. The study concludes that the observed biological reactions indicated in the aqueous extracts of V. amygdalina validate the traditional application of this plant as an alternative antibiotic.

A Simple Liquid-Liquid Fractionation (LLF) Method for Isolating Deoxyandrographolide dan Andrographolide from Herbs of Andrographis paniculata (Burm., F) Ness and Its Cytotoxic Activity on 3T3-L1 Preadipocyte Cells

The main bitter constituents of sambiloto (Androgaphis paniculata (Burm., F) Ness) are diterpene lactones, namely andrographolide and deoxyandrographolide which have been reported to have antidiabetic, cytotoxic, antiatherosclerosis, anti-inflammatory, and antimicrobial activity. There are many studies that performed the isolation of deoxyandrographolide and andrographolide from A. paniculata herbs, but most of them included several steps that make them not efficient. This research was conducted to do an isolation of deoxyandrographolide and andrographolide through liquid-liquid fractionation (LLF) due to its simplicity, low cost, and time efficient. The extraction of deoxyandrographolide and andrographolide from the herbs was carried out using chloroform as the solvent by using Soxhlet apparatus, and LLF was performed to isolate the compounds. The identities of the compounds were confirmed by TLC scanner compared to its standard references. Hence, these present methods were successfully isolated and determined deoxyandrographolide and andrographolide of A. paniculata. The compounds were also showed relatively moderate cytotoxicity on 3T3-L1 cell lines using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay, with LC50 of deoxyandrographolide and andrographolide; 29.3173 µg/mL and 37.7011 µg/mL, respectively.

Identification of bitter constituents in milk-based infant formula with hydrolysed milk protein through a sensory-guided technique

Key bitter taste-active fractions were fractionated and identified from cows' milk-based infant formula (IF) containing hydrolysed (bovine) milk protein. A systematic and sensory-guided approach was applied to separate and identify taste-active bitter peptides. The degree of hydrolysis for the extensively hydrolysed (EH) and partially hydrolysed (PH) samples was >22% and <22%, respectively. The sample with EH milk protein had the highest sensory score for bitter taste, and more bitter peptides were identified from it. The proportions of micromolecular peptides (<500 Da) distributed in the EH sample and PH sample were approximately 100% and 80%, respectively. More importantly, a sequential difference in the peptides generated from milk-based IFs with PH and EH was observed, and total numbers of four and nine peptides were discovered in the PH and EH samples, respectively; Ser–Leu–Ala, Leu–Leu–Pro and Try–Try–Gln, were reported for the very first time.

Formulation and evaluation of Neem (Azadirachta indica A. Juss) seed oil suppositories

Background: Neem seed is very vital because of its rich lipid content and bitter constituents. Aims: This study was designed to provide a scientific rationale for the preparation and use of Neem seed oil as suppositories using dika fat (DF), and macrogol (MG), as bases. Materials and Methods: The suppositories which were prepared by fusion method using a pre-calibrated mould, were characterized using parameters like appearance, crushing strength, weight variation, melting point, pH, liquefaction time and in-vitro release according to standard procedures. Results: Results show that, the suppository strengths were in the order; bland, MG (25.00 ± 1.50N) > DF (12.90 ± 0.72 N), while those containing medicaments were NSM1 (20.00 ± 1.92) > NSD1 (12.90 ± 0.94) > NSM2 (12.70 ± 1.24 N) > NSD2 (10.00 ± 1.35 N). The pH of medicated formulations were NSM1 (6.50 ± 0.01), NSM2 (6.54 ± 0.03) > NSD1 (5.73 ± 0.04) and NSD2 (5.07 ± 0.03). Melting point values show that, macrogol base had mean values of 36.80 °C ± 0.62 and 36.40 °C ± 0.46 for NSM1 and NSM2 respectively, whereas, those with DF gave an average melting point values of 32.10 °C ± 0.87 and 30.90 °C ± 0.79 for NSD1 and NSD2 respectively. Conclusion: Results obtained showed that suppositories prepared with Macrogol (MG) base exhibited better physicochemical properties than Dika fat (DF) base suppositories, therefore water soluble bases may be bases of choice in the delivery of neem seed oil.

Why Humulinones are Key Bitter Constituents Only After Dry Hopping: Comparison With Other Belgian Styles

Although long renowned worldwide for its unique dry-hopped (DH) Trappist beer, Belgium did not develop this process for other brands until the last decade. Twenty-one commercial Belgian DH beers were investigated and compared with a few other typical Belgian beers whose production involves either late hopping or aged hop addition (Gueuze). Bitterness was determined by spectrophotometric measurements (isooctane extraction) and by reversed phase high performance liquid chromatographic with UV detector (RP-HPLC-UV) (simultaneous quantitation of humulones, cis-/trans-isohumulones, reduced isohumulones, humulinones, and hulupones). In dry-hopped Belgian beers, humulinones (found at concentrations up to 13.3 mg/L) were estimated to be responsible for up to 28% of their bitterness. As humulinones revealed to be gradually lost through boiling (22%), clarification (5%), and fermentation (14%), non-dry-hopped (NDH) beers often displayed levels below 1.7 mg/L. Even in Gueuze beers for which old, humulinone-containing hops are used, no humulinone was found. Contrary to humulones, which were detected up to 7.2 mg/L in DH beers, hulupones were found at less than 3 mg/L in all Belgian beer styles. Humulinones were not produced in the boiling wort from humulones (in contrast to hulupones, readily synthesized from lupulones) but were significantly solubilized from hop thanks to their hydrophilicity. Yet, while the co-form accounted for about 50% of the humulones, the n-form prevailed for humulinones. Some humulinone degradation products were evidenced by RP-HPLC-MS/MS, and as suggested by their retention time (RT), should be more polar than their precursors. Bottle refermentation emerged as an additional critical step of humulinone loss, explaining the low levels found even in some strongly DH beers.

Anti-Tobacco Mosaic Virus Quassinoids from Ailanthus altissima (Mill.) Swingle.

Quassinoids are bitter constituents characteristic of the family Simaroubaceae. A total of 18 C20 quassinoids, including nine new quassinoid glycosides, named chuglycosides A-I (1-6 and 8-10), were identified from the samara of Ailanthus altissima (Mill.) Swingle. All of the quassinoids showed potent anti-tobacco mosaic virus (TMV) activity. A preliminary structure-anti-TMV activity relationship of quassinoids was discussed. The effects of three quassinoids, including chaparrinone (12), glaucarubinone (15), and ailanthone (16), on the accumulation of TMV coat protein (CP) were studied by western blot analysis. Ailanthone (16) was further investigated for its influence on TMV spread in the Nicotiana benthamiana plant.

Determination of Bitterness of Extra Virgin Olive Oils by Amperometric Detection

AbstractA flow injection system with amperometric detection at potentials poised at +0.4 and +0.9 V was used to evaluate intensity of the bitter taste in monovarietal Extra Virgin Olive Oils (EVOO). Results from the proposed method were based on the extraction of the bitter constituents of the virgin olive oil samples in methanol‐water, followed by the direct amperometric measurement. These potentials were selected according to the hydrodynamic voltammogram of oleuropein, one of the most prominent and bitter phenolic compound found in EVOO. The amperometric detection was applied on 32 monovariatal EVOO samples. Results were correlated with the phenolic profile measured by high performance liquid chromatography (HPLC). The amperometric signal at +0.9 V mainly correlated with the total phenols of the samples (R2=0.81), whereas the signal at +0.4 V mainly correlated with oleuropein aglycone (3,4 DHPEA‐EDA, R2=0.79). Bitterness intensity of the samples was evaluated by a trained sensory panel of experts and the results compared to those obtained by the amperometric flow system. The best correlation with the bitter taste was achieved by the sensor at +0.4 V (R2=0.72). A calibration model based on partial least squares was built with three variables, namely the sensors set at +0.4 and +0.9 V and the total phenol content of the EVOO extracts. The model showed a moderate capacity to predict the bitterness of the EVOO samples using leave one out method, (R2=0.75) and in prediction of a test set of samples (R2=0.7). Such approach is very promising for future studies.

Molecular Regulation of the Metabolic Pathways of the Medicinal Plants: &amp;lt;i&amp;gt;Phyla dulcis&amp;lt;/i&amp;gt;

Phyla (Lippia) dulcis contains hernundulcin sesquiterpene zero-caloric sweetener that is about a thousand times sweeter than sucrose, and also bitter constituents including camphor and limonene. There is yet no simple method to remove the undesirable constituents. The yield of sweetener hernundulcin is very low, and there is no simple method to maximize its composition. The aim of the project was to characterize the mRNA targets that regulate the primary and terpenoid metabolic enzymes of P. dulcis. Restriction fragment differential display polymerase chain reaction of P. dulcis glutamate dehydrogenase-synthesized RNA showed that many mRNAs encoding β-caryophyllene, (+)-epi-α-bisabolol, bicyclogermacrene, bifunctional sesquiterpene, and geraniol synthases shared sequence homologies with ribulose-1,5-bisphophatase carboxylase, granule-bound starch synthase, pyruvate kinase, glucose-6-phosphate dehydrogenase, and phosphoenol pyruvate carboxylase. Sequence similarities between mRNAs encoding primary metabolic enzymes and terpene synthases suggested that photosynthesis could regulate terpenoid metabolism in order to increase the yield of sweetener hernundulcin.

An Overview on Chemical Aspects and Potential Health Benefits of Limonoids and Their Derivatives

Limonoids are heavily oxygenated, modified triterpenes dominant in Meliaceae and Rutaceae plant families. The term ‘limonoid’ is derived from limonin, which was first identified as the bitter constituent of Citrus seeds in 1841. This group of secondary metabolites exhibits a wide range of biological properties, including anticancer, antibacterial, antifungal, antimalarial, and antiviral activities. Significant progress on the role of limonoids as promising candidates for cancer chemoprevention and/or therapy has been achieved in particular in recent years. The aim of this review article is to discuss the recent developments on limonoids chemical aspects and biological activities with the relationship between structure and activity, supporting the new possibilities for the medicinal and/or nutraceutical use of these compounds.

Quantification of main bioactive metabolites from saffron (Crocus sativus) stigmas by a micellar electrokinetic chromatographic (MEKC) method

Saffron is an expensive spice, cultivated in many regions of the world. Its chief metabolites include crocins, which are responsible for the coloring ability, safranal, which is the main essential oil constituent, and picrocrocin which is the main bitter constituent of the spice. A simple micellar capillary electrochromatographic (MEKC) method capable of quantifying all three types of main constituents was established. The pH, sodium dodecyl sulphate (SDS) content and electrolyte concentration of the background electrolyte was optimized. A simple extraction protocol was developed which can extract all metabolites of different polarity from the saffron stigmas. Optimal background electrolyte composed of 20 mM disodium phosphate, 5mM sodium tetraborate, 100 mM SDS, pH was set 9.5. Optimal extracting solvent was the background electrolyte, incubated with the sample for 60 min. The proposed method allows quantification of picrocrocin, safranal, crocetin- Di-(β-D-gentiobiosyl) ester and crocetin (β-D-glycosyl)-(β-D-gentiobiosyl) ester within 17.5 min, with limit of detection values ranging from 0.006 to 0.04 mg/ml, from a single stigma.

Purification of Azadirachta indica Seed Cake and Its Impact on Nutritional and Antinutritional Factors

Azadirachta indica Juss. (family Meliaceae) is a vital plant with multiple agricultural and medicinal utilities. The seed cake after oil extraction can be a good source of nutrition in animal feed. The limitation to its use is the presence of azadirachtin, salannin, and other bitter constituents. To make it palatable for use as a source of animal nutrition it was detoxified using 50 and 80% methanol and was analyzed for contents of azadirachtin, salannin, and nutritional contents such as total carbohydrates, protein, crude fiber, in vitro protein digestibility, and trypsin inhibitor activity (TIA), prior to and after purification. The contents of azadirachtin and salannin were quantified using HPTLC and HPLC. Various validation parameters were also investigated. A highly significant decrease of antinutritional factor (TIA) was recorded after purification of samples, retaining the contents of protein, carbohydrates, crude fiber, and in vitro protein digestibility. The purified seed cake was found to be free of azadirachtin and salannin contents.

Identification of Bitter Constituents from Angelica keiskei KOIDZUMI

Laserpitin (LAS), isolaserpitin (ILA) and (8S,9R)-8-angeloxy-8,9-dihyrooroselol (DHO) were identified as bitter constituents from Angelica (A.) keiskei KOIDZUMI, which is becoming popular as vegetables and dietary supplements in Japan. A yellow juice from the aerial parts of 140 samples of A. keiskei could be grouped into 4 types (Type A∼D) according to the HPLC profiles with the peaks of bitter constituents. Type A was from the Hachijyo island strain, which detected LAS and ISO, and Type B was from the Oshima island strain, which only detected DHO. The LAS, ILA and DHO contents were 0.066∼0.092%, 0.040∼0.068% and 0.064∼0.279%, respectively.

Sweet and bitter constituents of Wilbrandia species

Two novel cucurbitane glycosides, wilbrandisides A and B were isolated as sweet-taste substances from the root of Wilbrandia species ( Cucurbitaceae) along with seven known cucurbitane glycosides. Their structures were determined by spectroscopic means, including two-dimensional NMR experiments. Their sweet-taste properties were evaluated by a human sensory panel test. Consequently, wilbrandiside A was shown to be 28 times sweeter than sucrose and was the compound having the most potent sweet taste of all the cucurbitane glycosides isolated from this plant.

Influence of drying mode on iridoid bitter constituent levels in gentian root

AbstractRoot samples of wild gentian (Gentiana lutea L) were harvested from six localities (altitude 970 m to 1350 m) from May to November 2000. Each batch of roots was split into three: fresh roots, naturally dried roots (ambient air) and artificially dried roots (40 °C). In all the samples, levels of iridoid bitter constituents and of xanthone coloured compounds were determined by HPLC. The mean total iridoid content in the fresh roots was 102.4 g kg−1 in dry matter (DM). The mean level of the principal bitter compound gentiopicroside was particularly high at 81 g kg−1 DM. Loganic acid, not previously reported in G lutea, was the second most abundant bitter compound at a mean level of 14.3 g kg−1 DM. Swertiamarin was present at 5.4 g kg−1, with another minor unidentified iridoid. Levels of iridoid compounds were strongly dependent of the drying mode. These amounts were 88.5 g kg−1 DM in artificially dried roots and 62.5 g kg−1 DM in naturally dried roots, mostly owing to a marked decrease in gentiopicroside. The temperature of 40 °C preserved the bitter compounds and the bitterness of fresh gentian roots. The amount of coloured xanthones was relatively low at 3.3 g kg−1 and did not change with the drying mode. Copyright © 2004 Society of Chemical Industry

Use of Vernonia amygdalina by wild chimpanzee: Possible roles of its bitter and related constituents

Bitter principles and related constituents have been isolated from Veronia amygdalina (Compositae), a plant ingested by wild chimpanzees sometimes suffering from parasiterelated diseases in the Mahale Mountains National Park, Tanzania. These isolated constituents were the known sesquiterpene lactones (vernodalin, vernolide, hydroxyvernolide), and new stigmastane-type steroid glucosides (vernonioside A 1–A 4: for bitter tasting constituents and vernonioside B 1–B 3: for nonbitter related constituents). Antiparasitic activity tests of these constituents together with quantitative analyses of the major active constituents, vernodalin and vernonioside B 1, supported the hypothesis that Mahale chimpanzees control parasite-related diseases by ingesting the pith of this plant, found to contain several steroid-related constituents. While the major active steroid-related constituents (vernonioside B 1 and its primary aglycone, vernoniol B 1) do not taste bitter themselves, it was hypothesized that the highly bitter constituents including vernodalin may play an important role as signals to the ingester guiding their choice of the appropriate plant, plant part, and possibly also as signals which help to control the amount of intake.

Studies on the Constituents of the Root of Cayaponia tayuya (VELL.) COGN. I. Structures of Cayaponosides, New 29-Nor-1,2,3,4,5,10-hexadehydrocucurbitacin Glucosides.

The bitter constituents in the root of Cayaponia tayuya (VELL.) COGN. were investigated, and 24 29-norcucurbitacin glucosides, named cayaponosides were isolated. Among them, the structures of cayaponosides A, A3, A4, A6, B, B2, B3, B4, C, C2, C5a, D and D1 were determined based mainly on spectral analyses. They are all glucosides of 29-nor-1, 2, 3, 4, 5, 10-hexadehydrocucurbitacins, different only in side chain structure.

Studies on the Constituents of the Root of Cayaponia tayuya (VELL.) COGN. II. Structures of Cayaponosides, New 29-Nor-2,11-dioxocucurbita-3,5-diene Glucosides.

The bitter constituents in the root of Cayaponia tayuya (VELL.) COGN. were investigated, and 24 29-norcucurbitacin glucosides, named cayaponosides, were isolated. Among the 24 29-norcucurbitacin glucosides, named cayaponosides, isolated from the root of Cayaponia tayuya (VELL.) COGN., structures of cayaponosides A1, B6a, B6b, C3 D3a and C3b were determined based mainly on spectral analyses. They are all 3-O-glucosides of 29-nor-2, 11-dioxocucurbita-3, 5-diene, only different in side chain structure.

Utilisation of waste hop foliage by solvent extraction

A process for solvent extraction of bitter constituents from waste hop foliage is presented. It consists of (a) drying of fresh hop foliage, (b) disintegration of the dry foliage material, (c) extraction of soluble substances with an organic solvent, (d) separation of organic solvent from the extracted meal, and (e) regeneration of the solvent from the miscella by evaporation. Ten different organic solvents were used in the experimental work. The extraction efficiency was found to be a function of the type of the extraction process, the solid/liquid phase ratio, the initial humidity of the meal and other parameters. The bitterness of the waste hop foliage can be completely removed, producing a material very rich in proteins (about 23%). The solvent-free extract contains hop resins, waxes, essential oils and dyes, which can, after separation, be used for various purposes.

Evaluation of the bitter taste in virgin olive oil

An analytical method has been developed to evaluate the intensity of the bitter taste in virgin olive oil. Results from the proposed method, based on extraction of the bitter constituents of virgin olive oil with methanol/water and measurement of the absorbance at 225 nm, show a significant correlation with the intensity of bitterness that had been evaluated in a sensorial manner by a panel. The developed method, therefore, offers a real alternative to the panel test for the evaluation of this attribute.