Impact of processing technologies on isoflavones, phenolic acids, and antioxidant capacities of soymilk prepared from 15 soybean varieties

In the present study, soymilk samples were prepared from 15 soybean varieties by employing dry method-raw slurry filtration (D-BAF), dry method-cooked slurry filtration (D-BBF), wet method-raw slurry filtration (W-BAF), and wet method-cooked slurry filtration (W-BBF). Different varieties of soybean and processing techniques were found to impose a significant impact on total phenolics, total flavonoids, phenolic acids, isoflavones and antioxidant capacity of soymilk samples. Overall, the soymilk prepared by W-BAF exhibited a higher level of total phenolic content and antioxidant activity. The soymilk samples prepared by W-BBF presented higher values for total flavonoid content and ferric-reducing antioxidant power assay. The soymilk prepared by W-BBF presented higher subtotal values of phenolic acids. In comparison, the soymilk prepared by D-BAF exhibited high amount of total isoflavones followed by the soymilk processed by W-BAF. Overall, the wet method was found to be responsible for improved phenolic contents and antioxidant activity of soymilk sample.

Anti-browning effect of Rosa roxburghii on apple juice and identification of polyphenol oxidase inhibitors

Enzymatic browning control of cloudy fruit juice with natural substances has received much attention for improving its nutritional and commercial value. This study explored the anti-browning potential of Rosa roxburghii in apple juice. The anti-browning effects and mechanisms were evaluated by serial measurements of appearance, browning index, polyphenol oxidase (PPO) activity, UPLC-QE-Orbitrap-MS identification, inhibition kinetics and molecular docking. The results showed that Rosa roxburghii juice (0.25%-1.25% w/w) could effectively inhibit browning and PPO activity of apple juice. Ascorbic acid (1.67 g/100 g) as a reducing agent was a main anti-browning factor. Furthermore, seven phenolic compounds in Rosa roxburghii were screened as PPO inhibitors. Representative phenolic inhibitors induced mixed or competitive inhibition of PPO, mainly driven by hydrophobic forces and hydrogen bonds. This work demonstrates that Rosa roxburghii is a promising natural anti-browning ingredient to control the browning of cloudy apple juice due to abundant ascorbic acid and PPO inhibitors.

Structure-affinity relationship of the binding of phenolic acids and their derivatives to bovine serum albumin

Phenolic acids perform biological effects which are largely influenced by their binding to serum albumin. Therefore, investigating structure-affinity relationship of binding between phenolic acids and serum albumin is important. In this study, 114 phenolic acids and their derivatives, sharing the benzoic acid core with different substituents groups, were selected to investigate structure-affinity relationships with bovine serum albumin. The binding constants were obtained through fluorescence quenching, and a comprehensive mathematical model with inner-filter effect correction was applied. The results showed that the hydroxy group at the 2-position led to stronger binding affinity, while it had a negative influence at the 4-position. Substituting hydroxy groups with methoxy groups at 4-position and with methyl groups at 3-position both strengthened the binding affinity, respectively. Hydrogen bonding was one of the key binding forces for this binding interaction. Our findings provide a fundamental insight on the binding mechanism of phenolic acids to bovine serum albumin.

Determination of free, esterified, glycosylated and insoluble-bound phenolics composition in the edible part of araticum fruit (Annona crassiflora Mart.) and its by-products by HPLC-ESI-MS/MS

Phenolics present in the free, esterified, glycosylated and insoluble-bound forms of araticum pulp, peel and seed were for the first time characterized and quantified using HPLC-ESI-MS/MS. Levels of total phenolics, flavonoids, condensed tannins and antioxidant activities from araticum fruit followed the order peel > pulp > seed. Overall, insoluble-bound and esterified phenolics were the dominant forms of phenolics from araticum fruit parts and the highest contributors to their antioxidant activities. Extracts were found to contain contrasting levels of phenolics that were specific to each fruit part. From 10 phenolics quantified in araticum fruit, catechin and epicatechin were the major ones from pulp and peel, whereas seed displayed caffeic acid, catechin and epicatechin as its main phenolics. Araticum fruit was found to provide a good source of phenolics, and the full exploitation of this fruit may find applications in the food, cosmetic and pharmaceutical industries.

Interaction of phenolic acids and their derivatives with human serum albumin: Structure-affinity relationships and effects on antioxidant activity

In this study, 111 phenolic acids and their derivatives were chosen to investigate their structure-affinity relationships when binding to human serum albumin (HSA), and effects on their antioxidant activity. A comprehensive mathematical model was employed to calculate the binding constants, using a fluorescence quenching method, and this was corrected for the inner-filter effect to improve accuracy. We found that a hydroxy group at the 2-position of the benzene ring exerted a positive effect on the affinities, while a 4-hydroxy substituent had a negative influence. Both methylation of the hydroxy groups and replacing the hydroxy groups with methyl groups at the 3- and 4-positions of the benzene ring enhanced the binding affinities. Hydrophobic force and hydrogen bonding were binding forces for the phenolic acids, and their methyl esters, respectively. The antioxidant activity of the HSA-phenolic acid interaction compounds was higher than that of the phenolic acids alone.

Recent trends in phytochemistry, ethnobotany and pharmacological significance of Alchornea cordifolia (Schumach. & Thonn.) Muell. Arg

ETHNOPHARMACOLOGICAL RELEVANCE

Alchornea cordifolia (Schumach. & Thonn.) Muell. Arg. (Euphorbiaceae) (A. cordifolia) is widely distributed throughout tropical Africa, where it is used extensively in traditional medicine. Conditions for which the plant has enjoyed wide use are: coughs, gonorrhoea, infertility, prostatitis, bacterial infections, diarrhoea, ulcers, pain, inflammation, fever and bronchial troubles. This review summarizes the achievements of the investigations in traditional uses, ethnobotany, phytochemistry, biological activities and toxicological profile of A. cordifolia; this review also describes the shortcomings of studies on this herbal drug and thus serves as the basis of further scientific research and development of this traditional herbal drug.

MATERIALS AND METHODS

A. cordifolia-related information was collected from various resources including published articles in peer-reviewed journals, unpublished materials, textbooks, government survey reports and scientific databases such as Scifinder®, Pubmed, Science Direct, Wiley, Springer, ACS, Scielo, Web of Science and other web search instruments (Google, Yahoo), published on the subject from 1950 to 2016. 'The Plant List' (www.theplantlist.org) and 'Kew Royal Botanic Gardens' (mpns.kew.org) were used to validate the scientific name of the plant.

RESULTS

The literature revealed several reports on traditional uses, biological activities, chemical constituents and toxicological evaluation of A. cordifolia. The phytochemical information indicates identification of 95 compounds including fatty acids, terpenoids, flavonoids, phenolic acids, alkaloids, which exhibited various pharmacological activities such as wound healing, anti-inflammation, anticancer, antioxidant, immunomodulation, antidiarrhoeal, antimicrobial, antidepressant, hepatoprotective, antiplasmodial and anxiolytic. However, there are still significant gaps in the completeness of our understanding of A. cordifolia bioactivity, therapeutic value, and roles played by each of the numerous phytoconstituents.

CONCLUSIONS

The present review indicated that A. cordifolia is a valuable medicinal plant with multiple pharmacological effects. However, further research on the pharmacological mechanism of action of this plant is recommended in order to unravel the pharmacokinetics, pharmacodynamics, clinical relevance and toxicity of its extracts as well as constituents.

From preclinical development to clinical application: Kit formulation for radiolabelling the minigastrin analogue CP04 with In-111 for a first-in-human clinical trial

Introduction

A variety of radiolabelled minigastrin analogues targeting the cholecystokinin 2 (CCK2) receptor were developed and compared in a concerted preclinical testing to select the most promising radiotracer for diagnosis and treatment of medullary thyroid carcinoma (MTC). DOTA–DGlu–DGlu–DGlu–DGlu–DGlu–DGlu– Ala–Tyr–Gly–Trp–Met–Asp–Phe–NH₂ (CP04) after labelling with ¹¹¹In displayed excellent characteristics, such as high stability, receptor affinity, specific and persistent tumour uptake and low kidney retention in animal models. Therefore, it was selected for further clinical evaluation within the ERA-NET project GRAN-T-MTC. Here we report on the development of a pharmaceutical freeze-dried formulation of the precursor CP04 for a first multi-centre clinical trial with ¹¹¹In-CP04 in MTC patients.

Materials and methods

The kit formulation was optimised by adjustment of buffer, additives and radiolabelling conditions. Three clinical grade batches of a final kit formulation with two different amounts of peptide (10 or 50 μg) were prepared and radiolabelled with ¹¹¹In. Quality control and stability assays of both the kits and the resulting radiolabelled compound were performed by HPLC analysis.

Results

Use of ascorbic acid buffer (pH 4.5) allowed freeze-drying of the kit formulation with satisfactory pellet-formation. Addition of methionine and gentisic acid as well as careful selection of radiolabelling temperature was required to avoid extensive oxidation of the Met¹¹-residue. Trace metal contamination, in particular Zn, was found to be a major challenge during the pharmaceutical filling process in particular for the 10 μg formulation. The final formulations contained 10 or 50 μg CP04, 25 mg ascorbic acid, 0.5 mg gentisic acid and 5 mg l-methionine. The radiolabelling performed by incubation of 200–250 MBq ¹¹¹InCl₃ at 90 °C for 15 min resulted in reproducible radiochemical purity (RCP) >94%. Kit-stability was proven for >6 months at +5 °C and at +25 °C. The radiolabelled product was stable for >4 h at +25 °C.

Conclusion

A kit formulation to prepare ¹¹¹In-CP04 for clinical application was developed, showing high stability of the kit as well as high RCP of the final product.

Flavonoids and phenolic acids from cranberry juice are bioavailable and bioactive in healthy older adults

Cranberries (Vaccinium macrocarpon) are a rich source of phenolic phytochemicals, which likely contribute to their putative health benefits. A single-dose pharmacokinetic trial was conducted in 10 healthy adults ⩾50y to evaluate the acute (24-h) absorption and excretion of flavonoids, phenolic acids and proanthocyanidins (PACs) from a low-calorie cranberry juice cocktail (54% juice). Inter-individual variability was observed in the Cmax and Tmax of many of these compounds in both plasma and urine. The sum total concentration of phenolics detected in plasma reached a peak of 34.2μg/ml between 8 and 10h, while in urine this peak was 269.8μg/mg creatinine, and appeared 2-4h earlier. The presence of PAC-A2 dimers in human urine has not previously been reported. After cranberry juice consumption, plasma total antioxidant capacity assessed using ORAC and TAP assays correlated with individual metabolites. Our results show phenolic compounds in cranberry juice are bioavailable and exert antioxidant actions in healthy older adults.