Hydroxybenzoic Acid Derivatives Research Articles

Valle Agricola Chickpeas: Nutritional Profile and Metabolomics Traits of a Typical Landrace Legume from Southern Italy.

Chickpea (Cicer arietinum L.) from Valle Agricola is a legume cultivated in Southern Italy whose intake is strictly linked to rural traditions. In order to get new biochemical insight on this landrace and to promote its consumption and marketing, nutritional values (moisture content, total proteins, lipids, total and free amino acids) and metabolic traits are deeply investigated. Valle Agricola chickpea is nutritionally rich in proteins (19.70 g/100 g) and essential amino acids (7.12 g/100 g; ~40% of total). Carbohydrates, whose identity was unraveled by means of UHPLC-HR MS/MS analysis, were almost 60% of chemicals. In particular, a di-galactosylglycerol, a pinitol digalactoside, and a galactosylciceritol were found as constitutive, together with different raffinose-series oligosaccharides. Although lipids were the less constitutive compounds, glycerophospholipids were identified, while among free fatty acids linoleic acid (C18:2) was the most abundant, followed by oleic (C18:1) and palmitic (C16:0) acids. Isoflavones and hydroxybenzoic acid derivatives were also detected. Valle Agricola chickpeas showed very good levels of several mineral nutrients, especially magnesium (164 mg/100 g), potassium (748 mg/100 g), calcium (200 mg/100 g), zinc (4.20 mg/100 g) and manganese (0.45 mg/100 g). The boiling process favorably decreases anti-trypsin and anti-chymotrypsin activities, depleting this precious seed of its intrinsic antinutritional factors.

Bioconversion of polyphenols and organic acids by gut microbiota of predigested Hibiscus sabdariffa L. calyces and Agave (A. tequilana Weber) fructans assessed in a dynamic in vitro model (TIM-2) of the human colon

The present work aimed at understanding gut microbiota bioconversion of phenolic compounds (PC) and organic acids in predigested Hibiscus sabdariffa (Hb) calyces and the mixture of Hb and Agave (Agave tequilana Weber) fructans (AF). With this purpose, dried Hb and Hb/AF were predigested with enzymatic treatment, and then fermented in a dynamic in vitro model of the human colon (TIM-2). After HPLC-ESI-QToF-MS analysis of samples taken at 0, 24, 48 and 72 h of fermentation, it was observed that hydroxycinnamic acids, flavanols, flavonols, and anthocyanins were mainly transformed into derivatives of hydroxyphenylpropionic, hydroxyphenylacetic and hydroxybenzoic acids. Moreover, organic acids, such as hydroxycitric and hibiscus acids, were formed along with unidentified lactones and reduced compounds. Interestingly, no differences were observed between microbial-derived metabolites formed after the fermentation of Hb and Hb/AF. In conclusion, colonic fermentation of polyphenol-rich Hb yields a wide range of microbial phenolic metabolites with potential effects on health.

Phytochemical Profile, Antioxidant Activity, and Cytotoxicity Assessment of Tagetes erecta L. Flowers.

Tagetes erecta L. is a popular ornamental plant of the Asteraceae family, which is widely cultivated not only for its decorative use, but also for the extraction of lutein. Besides carotenoid representatives, which have been extensively studied, other important classes of secondary metabolites present in the plant, such as polyphenols, could exhibit important biological activities. The phytochemical analysis of a methanolic extract obtained from T. erecta inflorescences was achieved using liquid chromatography–mass spectrometry (LC-MS) techniques. The extract was further subjected to a multistep purification process, which allowed the separation of different fractions. The total extract and its fractions contain several polyphenolic compounds, such as hydroxybenzoic and hydroxycinnamic acid derivatives, flavonols (especially quercetagetin glycosides), and several aglycons (e.g., quercetin, patuletin). One of the fractions, containing mostly quercetagitrin, was subjected to two different antioxidant assays (metal chelating activity and lipoxygenase inhibition) and to in vitro cytotoxicity assessment. Generally, the biological assays showed promising results for the investigated fraction compared to the initial extract. Given the encouraging outcome of the in vitro assays, further purification and structural analysis of compounds from T. erecta extracts, as well as further in vivo investigations are justified.

Distribution of polyphenolic and sugar compounds in different buckwheat plant parts.

The aim of this study was to provide information on the phenolic and sugar profiles of different parts of the buckwheat plant, which can define that buckwheat is a functional food, with a high nutritional value and very useful for human health. Therefore, the extracts of buckwheat leaf, stem, and flower, as well as buckwheat grain were analysed for the content of polyphenol and antioxidant tests. The identification of a notable number of phenolic compounds and quantification of sugars in different parts of buckwheat indicates that buckwheat is a highly valuable plant. A total of 60 phenolic compounds were identified (18 cinnamic acid derivatives, 14 flavonols, 13 flavan-3-ols (including proanthocyanidins), 10 hydroxybenzoic acid derivatives, and 5 flavones) using ultra-high-performance liquid chromatography (UHPLC), coupled with a hybrid mass spectrometer which combines the Linear Trap Quadrupole (LTQ) and OrbiTrap mass analyzer. The highest number of phenolic compounds was found in the analysed buckwheat flower sample, and then in the leaf, followed by the grain and the stem. In addition, the sugar profile of buckwheat leaf, stem, flower and grain, as well as the buckwheat pollen and the nectar was analysed. Hence, 16 sugars and 5 sugar alcohols were detected by the high-performance anion exchange chromatography (HPAEC) with a pulsed amperometric detector (PAD). Sucrose was found in a significant amount with the highest content in buckwheat leaf. Trisaccharides had similar accumulation in the sample extracts, while disaccharides dominated in buckwheat leaf, followed by nectar and pollen. The sugar alcohols showed the highest content in buckwheat grain, where erythritol was predominant. The obtained results show that buckwheat is very rich in phenolic compounds and sugars. In addition to grain, the other parts of the buckwheat plant can be used as a very good source of different classes of phenolic compounds. This study provides useful information on the distribution of phytochemicals in different parts of the buckwheat plant, which contribute to the maintaining of the status of buckwheat as a functional food.

Bioconversion by gut microbiota of predigested mango (Mangifera indica L) ‘Ataulfo’ peel polyphenols assessed in a dynamic (TIM-2) in vitro model of the human colon

Gut microbiota bioconversion of polyphenols in predigested mango ‘Ataulfo’ peel was studied using a validated, dynamic in vitro human colon model (TIM-2) with faecal microbial inoculum. Dried peels were predigested with enzymatic treatment, followed by TIM-2 fermentation (72 h). Samples were taken at 0, 24, 48 and 72 h and analyzed by HPLC-QToF. Derivatives of hydroxyphenylpropionic, hydroxyphenylacetic and hydroxybenzoic acids, as well as, pyrogallol were the main polyphenols identified. These metabolites might derivate from flavonoid (flavanols and flavonols), gallate and gallotannin biotransformation. Despite the high content of ellagic acid in mango peel, low amounts were detected in TIM-2 samples due to transformation into urolythins A and C, mainly. Xanthone and benzophenone derivatives, specific to mango, remained after the colonic biotransformation, contrary to flavonoids, which completely disappeared. In conclusion, microbial-derived metabolites, such as xanthone and benzophenone derivatives, among others, are partially stable after colonic fermentation, and thus have the potential to contribute to mango peel bioactivity.

Synthesis of 4-Hydroxybenzoic Acid Derivatives in Escherichia coli.

Hydroxybenzoic acids (HBAs) such as 4-hydroxybenzoic acid (4-HBA) and 3,4-dihydroxybenzoic acid (DHB; protocatechuic acid) and its ester with methanol (methylparaben [MP]) are known to have various functional biological properties, including antibacterial, anticancer, antidiabetic, antiaging, antiviral, and anti-inflammatory activities. Since these compounds are widely used in cosmetic, food, and pharmaceutical industries, the use of renewable feedstocks for the production of HBAs is an area of growing interest. In this study, we used Escherichia coli to synthesize these three hydroxybenzoic acid derivatives (4-HBA, DHB, and MP). We overexpressed ubiC in E. coli to synthesize 4-HBA from chorismate, a substrate that is produced by the shikimate pathway in E. coli. For the synthesis of DHB, an additional gene (pobA) was introduced, while hbad and EHT1 were co-expressed to synthesize MP. To supply more chorismate, we introduced the shikimate gene module construct and selected the best construct for increased yields. Using this approach, 723.5 mg/L 4-HBA, 942.0 mg/L DHB, and 347.7 mg/L MP were synthesized. Our study showed that the shikimate gene module constructs can be applicable to increase the yields of HBA derivatives in HBA-tolerant microorganisms.

Antiradical and Antimicrobial Activity of Thiosemicarbaside and 1,2,4-Triazole Derivatives of Hydroxybenzoic Acid

The antimicrobial and antioxidant activity of synthesized biologically active compounds have been evaluated in comparison with the standard antioxidant, ascorbic acid. The antioxidant activity of the compounds has been studied by their ability to interact with the 2,2-diphenyl-1-picrylhydrazyl radical ( $${\text{DPP}}{{{\text{H}}}^{\centerdot }}$$ ). The proposed test system has revealed the pronounced antiradical activity of 2-(2-hydroxybenzoyl)-N-phenylhydrazinecarbothioamide (1) (IC50(DPPH) = 15.5 μM) and 2-(4-hydroxybenzoyl)N-phenylhydrazinecarbothiamide (2) (IC50(DPPH) = 31.7 μM). A weak antibacterial activity of these compounds has been shown against gram-positive and gram-negative test strains.

Study on the improvement of storage of strawberry using chlorine dioxide

딸기(Fragaria ananassa Duch.)는 장미과(Rosaceae)에 속하는 다년초로서 향기와 색상이 우수하며, 신맛과 단맛이 조화가 잘 되어 있고, 독특한 향기를 가진 과채류이다. 딸기에는 anthocyanins, monomere flavan-3-oles, hydroxybenzoic acid 유도체, hydroxycinnamic acid 유도체, tannins, flavonols, procyanidins 등과 같은 다양한 phytochemical들을 함유하고 있으며, 이러한 물질들에 의해 항산화, 암 발현 억제, 세포증식 억제 등의 생물 활성을 가진다고 알려져 있다. 딸기의 품질 유지 기간은 최적 저장조건인 0℃, 90~95%의 상대습도에서 3~7일 정도이고, 상온에서는 1~2일로 매우 짧은 편으로, 수확 후 선별, 저장 및 유통 중 부패 미생물 발생과 물리적 손상 및 조직의 연화 등을 초래한다. 또한, 활발한 호흡작용 및 지나친 증산작용으로 표피 건조, 무게 감소, 그리고 과숙으로 인한 변색 등이 일어나, 상품성 손실에 영향을 주는 등 외관의 품질 저하를 가져온다. 딸기 신선도 유지를 위한 전처리 방법으로는 예냉처리, MAP 포장, 산소흡착제 및 항균성 포장 등 여러 가지 방법에 따라 딸기의 저장성 증진에 관한 연구를 수행하여 왔다. 그러나 아직까지는 딸기 저장성 향상을 위한 이들 방법의 활용은 잘 이루어지고 있지는 않은 편에 있으므로 적용이 용이하고 비용면에서도 효과적인 새로운 저장 방법을 제시하고 이에 대한 실험 결과에 대하여 고찰하고 분석할 필요가 있다.Strawberry (Fragaria ananassa Duch.) is a perennial plant belonging to the family Rosaceae. It is a fruit and vegetable that has excellent aroma and color, good sourness and sweetness, and a unique fragrance. Strawberries contain various phytochemicals such as anthocyanins, monomere flavan-3-oles, hydroxybenzoic acid derivatives, hydroxycinnamic acid derivatives, tannins, flavonols, and procyanidins. It is known to have activity. The duration of quality maintenance of strawberries is 3~7 days at 0℃, 90~95% relative humidity, which is the optimal storage condition, and is very short, 1~2 days at room temperature, causing spoilage microorganisms during harvesting, storage, and distribution And physical damage and tissue softening. In addition, due to active breathing and excessive evaporation, epidermis drying, weight loss, and discoloration due to overfruiting occur, resulting in deterioration of appearance, such as affecting product loss. As a pre-treatment method for maintaining strawberry freshness, studies have been conducted on the improvement of shelf life of strawberries by various methods such as pre-cooling treatment, MAP packaging, oxygen absorbing agent and antibacterial packaging. However, the utilization of these methods for improving the shelf life of strawberries is not yet well performed, so it is necessary to present a new storage method that is easy to apply and cost-effective and to consider and analyze the experimental results.

Physical Characteristics of Cilostazol–Hydroxybenzoic Acid Cocrystals Prepared Using a Spray Drying Method

The cocrystal formation of pharmaceuticals can improve the various physical properties of drugs, such as solubility, without the need for chemical modification of the drug substances. In the present study, we prepared cocrystals of cilostazol and additive coformers (derivatives of hydroxybenzoic acid) using a spray drying method. Based on the preparation of the cocrystals of cilostazol and the coformers as reported previously, the characteristics of the cilostazol cocrystals prepared using solvent evaporation, slurry, and spray drying methods were compared. The physical characterization revealed that the spray drying method successfully produced cilostazol–4-hydroxybenzoic acid and cilostazol–2,4-dihydroxybenzoic acid cocrystals, whereas samples of cocrystals of cilostazol and 2,5-dihydroxybenzoic acid produced via the spray drying process appeared to contain coformer polymorphs. The dissolution of cilostazol was improved using the spray-dried cocrystal samples composed of coformers compared to samples prepared using cilostazol alone or a physical mixture. The present results provide useful information regarding the manufacture of cilostazol cocrystals and pharmaceutical cocrystals via spray drying in large-batch production.

Characterization of Secondary Metabolites in Flowers of Sanguisorba officinalis L. by HPLC-DAD-MSn and GC/MS.

The investigations reported here focus on an in-depth characterization of the secondary metabolite profile of Sanguisorba officinalis flowers. For this purpose, fresh flowers were extracted with MeOH/H2 O and EtOH/H2 O and the resulting crude extracts fractionated using CH2 Cl2 , AcOEt, and BuOH. Individual compounds were characterized by high performance liquid chromatography and gas chromatography coupled with mass spectrometric detection (HPLC-DAD-MSn and GC/MS). MeOH/H2 O extraction and LC/MSn investigations revealed the occurrence of flavonoid glycosides (quercetin, kaempferol), ellagitannin glycosides and four anthocyanins. Among the latter, two components, i. e., cyanidin-malonyl-glucose and cyanidin-galloyl-hexose, have not been reported for S. officinalis so far. Furthermore, phenylethylamine was characterized for the first time in Sanguisorba by pH value dependent extraction with CH2 Cl2 . In addition, AcOEt and BuOH extracts were analyzed by GC/MS both prior to and after acid hydrolysis of secondary metabolites. For this purpose, the extracts were treated with 1 n HCl solution (105 °C, 1 h) and derivatized with BSTFA. Analyses revealed the occurrence of several classes of phenolic compounds, such as gallic acid, hydroxybenzoic acid, hydroxycinnamic acid and ellagic acid derivatives. Additionally, the most prominent ursane-type triterpenoid (ziyu-glycoside I) from Sanguisorba and its corresponding aglycone isomers were detected and assigned based on their characteristic fragmentation patterns.

Phenolic acids in selected scab-resistant and mildew-tolerant apple cultivars

Phenolic compounds play important roles in plant defences against both biotic and abiotic stressors, and many in crop plants are highly beneficial for human health, but their quantities and profiles are influenced by numerous factors. Thus, the purpose of this study was to quantify free and glycosylated phenolic acids in apples (important sources of beneficial phenolics) in the course of fruit development, at harvest and during 5 months of storage. We selected three scab-resistant and powdery mildew-tolerant varicoloured cultivars for testing, and found they had qualitatively similar spectra of phenolic acids. The major free phenolic acid in both peel and flesh of the apples was chlorogenic acid, followed by (at much lower concentrations) three hydroxybenzoic acid derivatives (protocatechuic, vanillic and gallic acids) and three hydroxycinnamic acid derivatives (p-coumaric, ferulic and caffeic acids). Spectra of phenolic glycosides were broader, and included glycosylated forms of protocatechuic acid (most abundantly) and four other hydroxybenzoic acids (gallic, p-hydroxybenzoic, gentisic and syringic acids). Dynamic changes in phenolic acid contents during apple development and storage were also observed. Contents of free chlorogenic and glycosylated protocatechuic acids were highest at the beginning of apple fruit growth and markedly declined during ripening. Levels of chlorogenic acid in both peel and flesh continually increased during storage, accompanied by marked increases in contents of glycosylated protocatechuic acid in all studied cultivars. Both of these acids have strong radical scavenging activity and contribute considerably to apples’ antioxidant capacities.

Polyphenolic Characterization, Antioxidant, and Cytotoxic Activities of Mangifera indica Cultivars from Costa Rica.

The phenolic profile of skin and flesh from Manifera indica main commercial cultivars (Keitt and Tommy Atkins) in Costa Rica was studied using ultra performance liquid chromatography coupled with high resolution mass spectrometry (UPLC-ESI-MS) on enriched phenolic extracts. A total of 71 different compounds were identified, including 32 gallates and gallotannins (of different polymerization degree, from galloyl hexose monomer up to decagalloyl hexoses and undecagalloyl hexoses); seven hydroxybenzophenone (maclurin and iriflophenone) derivatives, six xanthonoids (including isomangiferin and mangiferin derivatives); 11 phenolic acids (hydroxybenzoic and hydroxycinnamic acid derivatives); and eight flavonoids (rhamnetin and quercetin derivatives). The findings for T. Atkins skin constitute the first report of such a high number and diversity of compounds. Also, it is the first time that the presence of gallotannin decamers and undecamers are reported in the skin and flesh of Keitt cultivar and in T. Atkins skins. In addition, total phenolic content (TPC) was measured with high values especially for fruits’ skins, with a TPC of 698.65 and 644.17 mg gallic acid equivalents/g extract, respectively, for Keitt and T. Atkins cultivars. Antioxidant potential using 2,2-diphenyl-1-picrylhidrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) methods were evaluated, with T. Atkins skin showing the best values for both DPPH (IC50 = 9.97 µg/mL) and ORAC (11.02 mmol TE/g extract). A significant negative correlation was found for samples between TPC and DPPH antioxidant values (r = −0.960, p < 0.05), as well as a significant positive correlation between TPC and ORAC (r = 0.910, p < 0.05) and between DPPH and ORAC antioxidant methods (r = 0.989, p < 0.05). Also, cytotoxicity was evaluated in gastric adenocarcinoma (AGS), hepatocarcinoma (HepG2), and colon adenocarcinoma (SW620), with T. Atkins skin showing the best results (IC50 = 138–175 µg/mL). Finally, for AGS and SW 620 cell lines particularly, a high significant negative correlation was found between cytotoxic activity and gallotannins (r = −0.977 and r = −0.940, respectively) while for the HepG2 cell line, the highest significant negative correlation was found with xanthonoids compounds (r = −0.921).

Qualitative composition and quantitative determination of the fatty and organic acids of Rhododendron purdomii R. leaves using gas chromatography – mass spectrometry method

For today the range of herbal medicines constitute about 30-40 % and tend to increase. Herbal remedies usually have a soft complex effect on the human body with the least amount of side effects. In this regard, plants, including various groups of biologically active substances, deserve attention. Representatives of the Heath family (Ericaceae), a genus of rhododendron (Rhododendron L.) are such plants, which are widely cultivated and have an adequate resource base. Plants of this genus are used in folk medicine for the treatment of cardiovascular diseases, vegetative neuroses, rheumatism and epilepsy. The chemical composition and pharmacological activity of most species of the genus, wild growing and cultivated in Ukraine, has not been studied enough. Aim. To determine the qualitative composition and quantitative content of fatty and organic acids in rhododendron purdom leaves (Rhododendron purdomii R.) by gas chromatography – mass spectrometry method is the aim of our study. Results. According to the results of experimental studies by gas chromatography–mass spectrometry method in the leaves of Rhododendron purdomii R. 37 substances were determined. The presence of 17 fatty acids has been established. Among the saturated fatty acids the palmitic acid amount presented (1537.79 mg/kg), among the monounsaturated acids the oleic acid amount presented (716.23 mg/kg), among the polyunsaturated acids the linolenic acid amount presented (652.81 mg/kg), were found in significant. During the study we revealed the presence of 20 organic acids, among which the oxalic (5260.08 mg/kg), citric (2913.04 mg/kg) and malic (1401.48 mg/kg) dominate. Among the derivatives of hydroxybenzoic acid the gentisic acid (764.88 mg/kg) dominates. Among derivatives of hydroxybenzoic acid the ferulic acid (189.63 mg/kg) dominates. Conclusions. For the first time, the qualitative composition and quantitative content of fatty and organic acids in the leaves of Rhododendron purdomii R. were determined by gas chromatography – mass spectrometry method. It is established that fatty acids, namely palmitic, oleic and linolenic; from organic acids – oxalic, citric and malic; from hydroxybenzoic acid derivatives – gentisinic; from hydroxycinnamic acid derivatives – ferulic acid are found in significant amounts in the leaves. The results determine the prospects for further study of the leaves of Rhododendron purdomii R. and the development of raw material extract.

Characterization of the phenolic profile of commercial Montenegrin red and white wines

The phenolic characterization was conducted on 43 commercial red (Vranac, Kratosija, and Cabernet Sauvignon) and white (Krstac and Chardonnay) Montenegrin wines during the vintages of 2015 and 2016. Several phenolic groups were determined: total anthocyanins, low- and high-molecular-weight proanthocyanidins. Non-flavonoids, such as phenolic acids (seven hydroxycinnamic acid derivatives—tartaric esters and free forms, and hydroxybenzoic acid derivatives—gallic acid), and stilbenes (resveratrols trans/cis isomers and their 3-glucosides) were analyzed by HPLC–UV and HPLC–DAD, respectively. Red wines reported higher concentrations of phenolic compounds and antioxidant properties, these parameters being strongly correlated. Among red wines, Cabernet Sauvignon in 2015 reported the highest content of total phenols (2197 mg L−1), low and high content of proanthocyanidins and antioxidant activity (20.0 mM L−1), respectively, and the lowest content of stilbenes (1.15 mg L−1). Vranac wines showed the highest content of anthocyanins (799–810 mg L−1). Kratosija wines reported the highest content of hydroxycinnamic acids (92.0–97.7 mg L−1) in both vintages. Among white wines, in the 2016 vintage, Krstac reported higher contents of total phenols and stilbenes (300 and 0.41 mg L−1, respectively) when compared with Chardonnay wines (226 and 0.12 mg L−1, respectively). The results showed that the variety influences the content and composition of hydroxycinnamic acid derivatives and stilbenes. The same was verified in vintages, where edaphoclimatic conditions probably influenced the results obtained. The wines studied were differentiated and discriminated. The factor variety was always present and sometimes it was difficult to classify wines according to the vintage, showing that the varietal factor prevails.

Regulation of Geldanamycin Biosynthesis by Cluster-Situated Transcription Factors and the Master Regulator PhoP.

Geldanamycin and the closely related herbimycins A, B, and C are benzoquinone-type ansamycins with antitumoral activity. They are produced by Streptomyces hygroscopicus var. geldanus, Streptomyces lydicus and Streptomyces autolyticus among other Streptomyces strains. Geldanamycins interact with the Hsp-90 chaperone, a protein that has a key role in tumorigenesis of human cells. Geldanamycin is a polyketide antibiotic and the polyketide synthase contain seven modules organized in three geldanamycin synthases genes named gdmAI, gdmAII, and gdmAIII. The loading domain of GdmI activates AHBA, and also related hydroxybenzoic acid derivatives, forming geldanamycin analogues. Three regulatory genes, gdmRI, gdmRII, and gdmRIII were found associated with the geldanamycin gene cluster in S. hygroscopicus strains. GdmRI and GdmRII are LAL-type (large ATP binding regulators of the LuxR family) transcriptional regulators, while GdmRIII belongs to the TetR-family. All three are positive regulators of geldanamycin biosynthesis and are strictly required for expression of the geldanamycin polyketide synthases. In S. autolyticus the gdmRIII regulates geldanamycin biosynthesis and also expression of genes in the elaiophylin gene cluster, an unrelated macrodiolide antibiotic. The biosynthesis of geldanamycin is very sensitive to the inorganic phosphate concentration in the medium. This regulation is exerted through the two components system PhoR-PhoP. The phoRP genes of S. hygroscopicus are linked to phoU encoding a transcriptional modulator. The phoP gene was deleted in S. hygroscopicus var geldanus and the mutant was unable to grow in SPG medium unless supplemented with 5 mM phosphate. Also, the S. hygroscopicus pstS gene involved in the high affinity phosphate transport was cloned, and PhoP binding sequences (PHO boxes), were found upstream of phoU, phoRP, and pstS; the phoRP-phoU sequences were confirmed by EMSA and nuclease footprinting protection assays. The PhoP binding sequence consists of 11 nucleotide direct repeat units that are similar to those found in S. coelicolor Streptomyces avermitilis and other Streptomyces species. The available genetic information provides interesting tools for modification of the biosynthetic and regulatory mechanisms in order to increase geldanamycin production and to obtain new geldanamycin analogues with better antitumor properties.

Effect of zinc on the production of phenolic acids and hypoxoside in micropropagated Hypoxis hemerocallidea

The present study was conducted to investigate the effect of zinc (Zn) on the synthesis of secondary metabolites in micropropagated Hypoxis hemerocallidea. In vitro raised plantlets of H. hemerocallidea were exposed to various exogenous concentrations of Zn (100, 200, 400 and 800 µM) for 6 weeks. The concentrations of phenolic acids and the accumulation of hypoxoside were determined using ultra-high performance liquid chromatography-tandem mass spectrometry. Application of Zn significantly increased the concentrations of hydroxybenzoic acid derivatives, namely gallic acid, p-hydroxybenzoic acid, protocatechuic acid, salicylic acid, syringic acid and vanillic acid. Variable concentrations of hydroxycinnamic acid derivatives were recorded with the highest concentration of caffeic acid and p-coumaric acid detected in plants grown on standard Murashige and Skoog (MS) medium containing the normal 30 µM-Zn concentration. Media supplemented with exogenous Zn (200 µM) stimulated the highest concentrations of chlorogenic acid and sinapic acid whereas Zn (100 µM) significantly increased the concentration of ferulic acid. Significantly high concentration of hypoxoside was recorded in the control and Zn (800 µM) treated cultures. The results revealed that exposure to Zn enhanced plant biomass and the accumulation of most phenolic acids, but significantly reduced the accumulation of hypoxoside, and antioxidant activity.

Grape Seed Polyphenols and Fatty Acids of Autochthonous Prokupac Vine Variety from Serbia

Grape pomace (grape skin, seeds, and stems) represents a valuable source of bioactive compounds, thus the interest in making use of these wine waste products is increasing. Prokupac is an autochthonous Serbian variety of black grape with a long tradition in production of red wine. Identification of the superficial polyphenolic compounds by LC/MS revealed presence of 19 compounds including hydroxybenzoic acid derivatives, ellagic acid derivatives, flavan-3-ol monomers, proanthocyanidins, and flavonols. Catechin and epicatechin together with proanthocyanidins were the most abundant compounds and the highest content of phenolic compounds was determined in Prokupac clones 43/1, 40/1, and 40/2. Grape seed oil consisted of dominantly UFA (87-95 %) where methyl linoleate was the most abundant in all samples (69-81 %). Palmitic (3-8 %) and stearic acid (2-4 %) methyl esters were dominant SFA. Prokupac clone 43/3 was the most abundant in UFA (95 %) with the lowest percentage of SFA (5 %), while clones 41/1 and 43/5 had the lowest percentage of UFA (87 %) and the highest content of SFA (13 %). Favorable chemical profile of Prokupac clone seeds implicates its potential to be used as a raw material in further processing and possibility to be included as one of the quality parameters in further selection of the most interesting Prokupac clone.

Alterations in physicochemical and functional properties of buckwheat straw insoluble dietary fiber by alkaline hydrogen peroxide treatment

To enhance the physicochemical and functional properties of insoluble dietary fiber (IDF) from buckwheat straw, we investigated the effects of alkaline hydrogen peroxide (AHP) treatment. Electron microscopy showed that the IDF had regular and compact tubes that turned into wrinkled lamellar products. After AHP treatment, X-ray diffraction indicated that the crystalline structure of the IDF was perturbed. And an undesirable decrease was observed in the content of hydroxybenzoic acid derivatives, hydroxycinnamic acid derivatives, flavonoids and the antioxidant capacity of IDF modified by AHP; however, the hydration properties (such as water holding capacity), α-amylase inhibition activity and glucose adsorption capacity of IDF were significantly enhanced by AHP. Furthermore, AHP led to a redistribution of monosaccharides in soluble dietary fiber and IDF, an interesting finding hinting at the mechanism and potential applications of AHP modification of IDF. In this study, AHP enhanced the physiological and functional properties of buckwheat straw IDF.

HPLC-DAD profiling and antioxidant activity of the n-butanol extract from aerial parts of Algerian Crithmum maritimum L.

Abstract In this study, phenolic compounds from Crithmum maritimum L. n-butanol soluble fraction were quantified and identified spectrophotometrically and by using HPLC-DAD technics. They equally investigated for their antioxidant potential utilizing six in vitro assays: DPPH•, ABTS•+, O2 •−, Bleaching of β-carotene in linoleic acid, CUPRAC and Ferric reducing power. High amounts of total phenolics and flavonoids were recorded: 161.57± 0.479 μg GAeq.mg−1 and 31.56± 0.291 μg Qeq.mg−1 respectively. Nine compounds among them hydroxicinnamic acid and hydroxybenzoic acid derivatives, coumarins and flavonoids were identified. Chlorogenic acid known for their various pharmacological properties was detected as major compound of the extract. Rutin, vanillin, trans-2-hydroxycinnamic acid, ellagic acid, ferrulic acid, 6,7 dihydroxy coumarin, methyl 1,4 benzoquinone and trans-cinnamic acid were also detected. The extract was found to exhibit strong antioxidant capacities in all systems. Based on these results, it is right to conclude the n-butanol extract is promising source of natural antioxidants.

Phytochemical characterization of bioactive compounds composition of Rosmarinus eriocalyx by RP–HPLC–ESI–QTOF–MS

Rosmarinus eriocalyx (rosemary or Elyazir) is an endemic species growing in arid steppe and rocky mountain in the South-West Algeria. This plant is well known in Algeria and Morocco due to its medicinal properties. However, little is known about its phytochemical composition. For this purpose, natural antioxidant compounds from R. eriocalyx were recovered by solid-liquid extraction and characterized by reversed-phase high-performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry using negative and positive ionization modes. This analytical methodology enabled the characterization of 101 compounds, which were distributed in five major categories namely hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, flavonoids, phenolic diterpenes and phenolic triterpenes. Moreover, the studied extract generally showed free radical-scavenging and reductive abilities in the range of butylated hydroxyanisole, butylated hydroxytoluene, α-tocopherol, and ascorbic acid. Therefore, the result suggests that the aqueous-methanolic extract of R. eriocalyx could serve as a potential source of antioxidants.