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This study investigated the effect of lactic acid bacteria (LAB) fermentation on the chemical profile of autoclaved broccoli puree, using 7 broccoli-derived LAB isolates (named F1-F5, BF1 and BF2). The total concentrations of glucosinolates (glucoiberin, progoitrin and glucoraphanin) and 10 major phenolics significantly increased from trace level and 289 μg total phenolics/g dry weight (DW) respectively in autoclaved broccoli to 55 to ∼359 μg/g DW and 903 to ∼3105 μg/g DW respectively in LAB fermented broccoli puree. Differential impacts of LAB isolates on the chemical composition of autoclaved broccoli were observed, with the major differences being the significant increase in phloretic acid after fermentation by F1-F5 and an elevated glucoraphanin level in ferments by F1 and BF2. LAB fermentation is a promising way to increase the content of glucosinolates and polyphenolic compounds in broccoli, making the ferments attractive for use as functional ingredients or as a whole functional food.

Phloretic acid, phloretin and phlorizin (phloretin 2′-O-glucoside), plant-derived natural products, are well known for human health benefits and medical application. Here, we construct an artificial biosynthetic pathway of phlorizin by modular engineering strategy and realize the production of phloretic acid, phloretin and phlorizin in Escherichia coli. Extending from L-tyrosine biosynthetic pathway, we firstly established the phloretic acid module comprised of heterologous TAL and ER enzymes, and highest titer of phloretic acid was achieved from glucose. Then, through biochemical screening of functional microbial Aa4CL and structure-based mutagenesis of MdCHS3 in phloretin module, we successfully constructed the phloretin biosynthetic pathway. Finally, we tested several glycosyltransferases in phlorizin module, and phloretic acid was bioconverted to phlorizin. This is the first report on biosynthesis of phloretin and phlorizin in engineered E. coli, indicating the promising potential of microbial cell factories to produce natural and unnatural dihydrochalcones.

Graphical abstract, Highlights • Co-pigmentation pretreatment protected blackberry anthocyanins during drying. • Ethanol pretreatment with phenolic acids only enhanced water effective diffusivity. • Non-anthocyaninic soluble phenolics were better preserved under contact sonication. • Bound phenolics were less affected by pretreatments and ultrasound-assisted drying., In this work, the spraying of ethanol solution containing phenolic acid (ferulic acid or caffeic acid) was performed before subjecting to contact ultrasound-assisted air drying of blackberry. The mass transfer modeling results revealed that sonication intensified both internal water diffusion and external water exchange during drying, and ethanol pretreatment enhanced the effective diffusivity of water. Compared with air drying alone, the drying time for sequential ferulic acid pretreatment and drying with sonication was shortened by 89.2%. Owing to the co-pigmentation between phenolic acid and anthocyanins, the retention of anthocyanins was significantly enhanced after dehydration. At the end of drying, the total anthocyanin contents in the ultrasound-dried samples pretreated with ferulic acid and caffeic acid were 25.3% and 10.5% higher than the sonicated samples without pretreatments, respectively. Furthermore, drying simultaneously with sonication promoted the preservation of non-anthocyaninic soluble phenolics including catechin, phloretic acid, rutin in blackberry compared to air drying alone. Besides, bound phenolics in blackberry were less influences by the applied dehydration treatments. This study demonstrates that the combination of phenolic acid co-pigmentation pretreatment and ultrasound drying could be a promising method to protect anthocyanin pigments during dehydration of berry fruits.

Chemical investigation of a methanolic extract of leaves from Araucaria bidwillii (Araucariaceae) from Egypt afforded four new labdane diterpenoidal metabolites (1–4) together with one known diterpene, 7-oxocallitrisic acid (5), two triterpenoidal metabolites, 2-O-acetyl-11-keto-boswellic acid (6) and β-sitosterol-3-O-glucopyranoside (7), phloretic acid (8), and two methylated bisflavonoids, agathisflavone-4′,7,7″-trimethyl ether (9) and cupressuflavone-4′,7,7″-trimethyl ether (10). The new metabolites 1–4 were unambiguously identified by applying extensive 1D and 2D NMR spectroscopic studies as well as HRESIMS. The relative and absolute configurations of 1–4 were determined using ROESY and the modified Mosher's method, respectively. All isolated compounds were assessed for their antimicrobial, antitubercular and cytotoxic activities. Among the tested compounds, the new labdane diterpenes 1–4 revealed significant cytotoxic activity against mouse lymphoma L5178Y cell line with IC50 values ranging from 1.4 to 12.9 μM, respectively.

A solution of N-vinyl imidazole (VIm), ethylene glycol dimethylacrylate (EGDMA), and phloretic acid (p-hydroxyphenylpropionic acid, HPPA) as functional monomer, crosslinker and template, respectively, were used to graft molecularly imprinted polymer (MIP) onto polyethylene/polypropylene (PE/PP) nonwoven fabric via gamma radiation at room temperature. Control grafted films were also synthesized using the same procedure in the absence of HPPA. Binding performance of the MIP grafts was investigated for different template molecule concentrations and contact time. An imprinting factor for the sample prepared at 5 kGy dose was determined as 2.41 for 50 ppm HPPA solution for 3-h incubation. MIP graft layers were investigated by positron annihilation lifetime spectroscopy (PALS) as well as SEM.

Phlorizin ( 1 ) was anaerobically incubated with human intestinal bacteria and five biotransformation products ( 2 – 6 ) were obtained. Their structures were elucidated as phloretin ( 2 ), phloroglucinol ( 3 ), phloretic acid ( 4 ), 2,3,4-trihydroxybenzenepropanoic acid ( 5 ), and phloretic acid methyl ester ( 6 ) on the basis of their spectroscopic data. Using high-performance liquid chromatography equipped with a diode array detector, chromatographic separation of 1 – 4 was performed on an analytical C 18 column. The time course of the biotransformation was studied to probe into the biotransformation mechanism of 1 by human intestinal flora. The abilities of isolated strains to transform 1 were also investigated in order to find an optimal transformation strain. In addition, the inhibitory activity of parent compound 1 and its three main biotransformation products 2 – 4 on mushroom tyrosinase was estimated. The result showed that 2 has better inhibitory effect on tyrosinase activity than 1 .

Because olives represent an important component of the Mediterranean diet, it is necessary to establish unequivocal identification and quantitation of the major potential antioxidant phenolic compounds they contain. The major phenolic antioxidants in two types of brined olives were isolated and purified by semi-preparative high performance liquid chromatography. Structural analysis was conducted using UV spectrophotometry, mass spectrometry and nuclear magnetic resonance spectroscopy. In particular, completely assigned 1H and 13C NMR data are presented and errors in literature data are corrected. The data show that tyrosol, hydroxytyrosol, 3-(3, 4-dihydroxyphenyl) propanoic acid (dihydrocaffeic acid), dihydro-p-coumaric acid (phloretic acid), the phenylpropanoid glucosides acteoside (verbascoside) and isoacteoside, along with the flavonoids luteolin and apigenin are major components of the phenolic fraction of brined black olives. Brined green olives contain only hydroxytyrosol and traces of other minor phenolics. Brined olives contain even higher concentrations of phenolic antioxidants than olive oil and may, therefore, be more important modulators of cancer chemopreventive activity.

The trimethylsilylester of β-(4-acetoxyphenyl) propionic acid (APPA), which is easier to isolate than the free acid, was used as monomer for all polycondensations. Copolycondensations with small amounts of 4-tert-butylbenzoic acid or 4-tert-butylphenol acetate yielded oligo- and polyesters with two different endgroups. All oligoesters show a reversible first order phase transition between 240 and 265°C yielding a solid mesophase upon heating. The formation of an isotropic melt occurs between 340 and 380°C depending on the degree of polymerization (DP). The glasstransition temperatures increased from 48–50°C to values around 63–65°C with increasing molecular weight. Copolycondensations with acetylated bisphenol-P yielded telechelic oligoesters with two identical endgroups. Four-armed star-shaped polyesters were prepared by copolycondensation of a tetraacetoxyspirobisindan. Since the bisphenol-P and the spirobisindane units are unfavourable for the crystallization, the crystallinity depends on the DP, and the solubility depends in turn on the crystallinity. Hyperbranched copolyesters were synthesized by copolycondensation of silylated APPA with silylated or free 3,5-bisacetoxybenzoic acid with variation of the molar ratio. The hyperbranched character of these copolyesters was demonstrated by their reluctance to crystallize and by 13C n.m.r. spectroscopic sequence analyses. The Tgs of these hyperbranched copolyesters follow almost exactly the Fox equation. G.p.c. measurements revealed number average molecular weights (Mn) up to 31 000 g mol−1 (for the 1 1 copolyester) and Mw/Mn ratios in the range of 3.5–6.5.

Dihydro-p-coumaric (phloretic) and dihydroferulic acids have been identified in Pteridium aquilinum. Whereas the latter has been located in cyanogenic and acyanogenic plants, the first has only been detected in cyanogenic forms.

Summary A number of factors that affect the in vitro rooting of M.9 both during the shoot proliferation and the root-inducing phase of the micropropagation process have been examined. Work with the phenolic compound phloroglucinol (1, 3, 5 trihydroxybenzene) has shown that it can precondition shoots to root whilst shoots are multiplying on a cytokinin-based medium. Excision of single shoots and exposure to auxin and phloroglucinol (PG) also stimulated rooting compared to auxin-alone controls, although the size of the effect was not as great as that recorded during shoot multiplication. The easier-to-root M.26 was not affected by PG at either stage of the micropropagation process. Ageing of shoot cultures increased the capacity for auxin-induced rooting but shoot etiolation was without effect. A number of phenolic compounds at 10 -3 M, were assessed as IAA synergists during the root- initiation phase. Of the simple phenols only PG and hydroquinone had any effect on root number. Salicylic acid completely inhibited the root-inducing effect of IAA. The phenylpropanoids ferulic acid and umbelliferone significantly reduced rooting whilst chlorogenic acid increased root number. Phloridzin and its degradation products phloretin, phloretic acid and PG all increased root number compared to IAA controls.

Phloretin, a 7,8-dihydrochalcone of plant origin, and the high molecular weight (less than 15,000) polyphloretinphosphate (PPP) polymers are potent inhibitors of iodothyronine monodeiodinase activity from rat liver microsomal preparations, whereas phlorizin, the 2'-O-glucoside of phloretin, is inactive. The polymers, differing in degree of phosphorylation-dependent polymerization, exhibited a concentration-dependent, and ultimately complete, inhibition of deiodinase activity with an IC50 between 0.2 and 0.5 micrograms PPP/ml. Phloretin inhibition, on the other hand, was cofactor (DTE) competitive, with a Ki = 0.75 microM. 2',4',6',3,4- Pentahydroxychalcone, which has a substitution pattern in the A-ring identical to that of phloretin, was the only active inhibitor (IC50 = 8 microM) among several derivatives tested. The phloretin biodegradation products, phloretic acid and phloroglucinol, and its biosynthetic precursors, monomeric cinnamic acid and cinnamic acid derivatives, were inactive in concentrations up to 100 microM. The X-ray crystal structure analysis of phlorizin dihydrate showed that the molecule is planar and fully extended, similar to the conformation observed in chalcone structures that are characterized by an alpha, beta-unsaturated bond between phenol rings. Comparison of the planar phlorizin crystal structure with a skewed or antiskewed thyroid hormone conformation revealed that the beta-D-glucose moiety does not share any of the thyroid hormone's conformational space, and that the best structural homology is found with the antiskewed conformation of 3',5',3-triiodothyronine, the natural deiodinase substrate that also inhibits further deiodination.

A variety of fungi were shown to degrade phloridzin to phloretin, phloroglucinol and phloretic acid. Phloretic acid in turn was metabolized to p -hydroxybenzoic acid. Aspergillus niger yielded cell-free preparations which catalyzed the hydrolysis of phloretin to phloroglucinol and phloretic acid.

Eleven compounds isolated from the growth inhibiting active fraction of male flowers of Cucurbita pepo , were identified as p -hydroxybenzaldehyde, anisyl alcohol, p -hydroxybenzyl methyl ether, p -hydroxybenzyl alcohol, veratryl alcohol, isovanillyl alcohol, p -coumaric acid, phloretic acid, benzyl-β- d -glucoside, 4-methoxybenzyl-β- d -glucoside and 3, 4-dimethoxybenzyl-β- d -glucoside. Each compound was assayed for growth inhibiting activity using lettuce seedlings; three showed strong activity, whereas the glucosides were inactive.