Comparisons of the active components in four unripe raspberry extracts and their activites

An Integrated Extraction-Purification Process for Raspberry Leaf Polyphenols and Their In Vitro Activities

To improve the utilization value of raspberry leaves, the extraction and purification conditions of phenolic compounds from raspberry leaves were optimized, and the contents of phenolic compounds and the biological activities of extracts were studied. After steam explosion pretreatment at 115 °C for 15 min, raspberry leaf extract with a total phenolic content (TPC) of 136.30~140.51 mg GAE/g was obtained via homogenization and ultrasound-assisted extraction. In addition, the adsorption relationship between raspberry leaf polyphenols and middle polar XDA-6 macroporous resin was best described by the Langmuir model, and tended to be monolayer adsorption. Its adsorption kinetics best resembled the pseudo second-order kinetic model, and it was speculated that this was influenced by multiple factors. According to the optimal integrated extraction-purification process, the TPC of the extracts increased to 738.98 mg GAE/g after one application of purification and 905.27 mg GAE/g after two applications of purification. Moreover, the latter case showed the highest antioxidant activity and α-glucosidase inhibition activity, and the content of the most typical compound, quercetin-3-glucuronide, reached 199.69 mg/g. SE has a double-edged effect, and is more conducive to the release of active substances as a pre-treatment method. This study provides a theoretical basis for the efficient use of raspberry leaves, further improving their medicinal and economic value.

Modulation of the bacterial virulence and resistance by well-known European medicinal herbs

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia officinalis L., Sambucus nigra L., Matricaria chamomilla L., Agrimonia eupatoria L., Fragaria vesca L. and Malva sylvestris L. are plants that have a long tradition in European folk medicine. To this day, they are part of medicinal teas or creams that help with the healing of skin wounds and the treatment of respiratory or intestinal infections. However, so far these plants have not been investigated more deeply than in their direct antibacterial effect.

AIM OF THE STUDY

Our research is focused on adjuvants that inhibit the mechanism of antibiotic resistance or modulate bacterial virulence. Based on a preliminary screening of 52 European herbs, which commonly appear as part of tea blends or poultice. Six of them were selected for their ability to revert the resistant phenotype of nosocomial bacterial strains.

METHODS

Herbs selected for this study were obtained from commercially available sources. For the extraction of active compounds ethanol was used. Modulation of virulence was observed as an ability to inhibit bacterial cell-to-cell communication using two mutant sensor strains of Vibrio campbellii. Biofilm formation, and planktonic cell adhesion was measured using a static antibiofilm test. Ethidium bromide assay was used to checked the potential of inhibition bacterial efflux pumps. The antibacterial activities of the herbs were evaluated against resistant bacterial strains using macro dilution methods.

RESULTS

Alcohol extracts had antibacterial properties mainly against Gram-positive bacteria. Of all of them, the highest antimicrobial activity demonstrated Malva sylvestris, killing both antibiotic resistant bacteria; Staphylococcus aureus with MIC of 0.8 g/L and Pseudomonas aeruginosa 0.7 g/L, respectively. Fragaria vesca extract (0.08 g/L) demonstrated strong synergism with colistin (4 mg/L) in modulating the resistant phenotype to colistin of Pseudomonas aeruginosa. Similarly, the extract of S. officinalis (0.21 g/L) reverted resistance to gentamicin (1 mg/L) in S. aureus. However, Sambucus nigra and Matricaria chamomilla seem to be a very promising source of bacterial efflux pump inhibitors.

CONCLUSION

The extract of F. vesca was the most active. It was able to reduce biofilm formation probably due to the ability to decrease bacterial quorum sensing. On the other hand, the activity of S. nigra or M. chamomilla in reducing bacterial virulence may be explained by the ability to inhibit bacterial efflux systems. All these plants have potential as an adjuvant for the antibiotic treatment.

Metabolomic analysis and ecofriendly enrichment of sunflower meal extract

BACKGROUND

The presence of phenolic compounds in sunflower is well reported in the literature; however, knowledge is scarce when it comes to the composition of other secondary metabolites in this species and their by-products. This work evaluated, for the first time, the phytochemical composition of sunflower meal produced in Brazil. A combination of mixture design and central composite rotatable design 2³ models was then applied to maximize the recovery of bioactive compounds using ecologically friendly solvents and concentrating by applying activated carbon, a sustainable adsorbent. The product of this extraction-concentration was also evaluated by an untargeted metabolomic approach using ultra-performance liquid chromatography coupled to mass spectrometry.

RESULTS

A diverse and abundant profile of phenolic compounds was obtained from Brazilian sunflower meal: in total, 51 natural products were tentatively identified, 35 of which for the first time in sunflower. The sorption capacity of the activated charcoal, in the optimized process conditions, was effective in the separation and concentration of minority secondary metabolites. The ecofriendly extract proved to be enriched in plumberoside, p-coumaric acid, and alkaloids.

CONCLUSIONS

Investigation of the phytochemical profile of sunflower meal produced in Brazil pointed to several secondary metabolites reported for the first time in sunflower samples, including phenolic compounds, alkaloids, and terpenes. The use of activated charcoal in an alkaline medium as an adsorbent for the concentration of these phytochemicals, from an aqueous extract, generated a potentially cost-effective, ecofriendly extract, enriched in minor metabolites, indicating a possible innovative way to selectively obtain these compounds from sunflower meal. © 2022 Society of Chemical Industry.

Phytochemicals and anti-tyrosinase activities of Paeonia ostii leaves and roots

Tree peony (sect. Moutan) is a kind of Traditional Chinese Medicine and ornamental plant, which has been widely cultivated and utilized for thousands of years. To further study the active components of Paeonia ostii (Moutan, Fengdan), six fractions (soluble free (F), soluble esterification, soluble glycosylation, insoluble bound, insoluble esterification and insoluble glycosylation) were extracted from the leaves and roots by alkaline and acid treatment for the first time. Twenty-one typical compounds were identified and quantified by HPLC-MS. The results showed that total phenolic content (TPC) in peony roots (PR) and peony leaves (PL) were as high as 125.48 and 280.38 mg GAE·g^-1 dw, which maximizes the extraction efficiency of phenolic compounds, especially leaves, compared with the conventional method. PR-F and PL-F had the highest TPC, antioxidant and anti-tyrosinase activities. Paeoniflorin was the main compounds in PL and PR. It and pentagalloylglucose (PGG) almost reached the anti-tyrosinase level of kojic acid, but they showed different inhibitory mechanisms by molecular docking. On the whole, PR-F, PL-F, PGG and paeoniflorin might be potential for skin whitening products.

Lab Scale Extracted Conditions of Polyphenols from Thinned Peach Fruit Have Antioxidant, Hypoglycemic, and Hypolipidemic Properties

Thinned peach polyphenols (TPPs) were extracted by ultrasonic disruption and purified using macroporous resin. Optimized extraction conditions resulted in a TPPs yield of 1.59 ± 0.02 mg GAE/g FW, and optimized purification conditions resulted in a purity of 43.86% with NKA-9 resin. TPPs composition was analyzed by UPLC-ESI-QTOF-MS/MS; chlorogenic acid, catechin, and neochlorogenic acid were the most abundant compounds in thinned peaches. Purified TPPs exhibited scavenging activity on DPPH, ABTS, hydroxyl radical, and FRAP. TPPs inhibited α-amylase and α-glucosidase by competitive and noncompetitive reversible inhibition, respectively. TPPs also exhibited a higher binding capacity for bile acids than cholestyramine. In summary, TPPs from thinned peaches are potentially valuable because of their high antioxidant, hypoglycemic, and hypolipidemic capacities, and present a new incentive for the comprehensive utilization of thinned peach fruit.

Comprehensive Utilization of Thinned Unripe Fruits from Horticultural Crops

Fruit thinning is a cultivation technique that is widely applied in horticulture in order to obtain high-quality horticultural crops. This practice results in the discarding of a large number of thinned unripe fruits in orchards each year, which produces a great waste of agricultural resources and causes soil pollution that may be an important reservoir for pest and plant diseases. Current studies showed that bioactive compounds such as polyphenols, organic acids, monosaccharides and starches are present in unripe fruits. Therefore, we reviewed the bioactive components obtained from thinned unripe fruits, their revalorization for the food industry, their beneficial effects for human health and the methods for obtaining these components. We also performed a calculation of the costs and benefits of obtaining these bioactive compounds, and we proposed future research directions. This review provides a reference for the effective utilization and industrial development of thinned unripe fruits obtained from horticultural crops. Furthermore, revalorizing the waste from this cultural practice may increase the economic benefits and relieve the environmental stress.