Dihydrochalcones in Sweet Tea: Biosynthesis, Distribution and Neuroprotection Function

Effects of apples (Malus domestica) and their derivatives on metabolic conditions related to inflammation and oxidative stress and an overview of by-products use in food processing

Apple (Malus domestica) is the third most produced fruit worldwide. It is a well-known source of bioactive compounds mainly represented by hydroxycinnamic acids, flavan-3-ols, dihydrochalcones, dehydroascorbic acid, carotenoids, chlorogenic acid, epicatechin, and phloridzin. Due to the lack of a recent evaluation of the clinical trials associated with apple consumption, this review investigated the effects of this fruit on metabolic conditions related to inflammation and oxidative stress and reviewed the applications of apple waste on food products. Thirty-three studies showed that apples or its derivatives exhibit anti-inflammatory and antioxidant actions, improve blood pressure, body fat, insulin resistance, dyslipidemia, and reduce cardiovascular risks. Apples have a great economic impact due to its several applications in the food industry and as a food supplement since it has impressive nutritional value. Dietary fiber from the fruit pomace can be used as a substitute for fat in food products or as an improver of fiber content in meat products. It can also be used in bakery and confectionary products or be fermented to produce alcohol. Pomace phytocompounds can also be isolated and applied as antioxidants in food products. The potential for the use of apples and by-products in the food industry can reduce environmental damage.

A narrative review on the mechanism of natural flavonoids in improving glucolipid metabolism disorders

Glucolipid metabolism disorder (GLMD) is a complex chronic disease characterized by glucose and lipid metabolism disorders with a complex and diverse etiology and rapidly increasing incidence. Many studies have identified the role of flavonoids in ameliorating GLMD, with mechanisms related to peroxisome proliferator-activated receptors, nuclear factor kappa-B, AMP-activated protein kinase, nuclear factor (erythroid-derived 2)-like 2, glucose transporter type 4, and phosphatidylinositol-3-kinase/protein kinase B pathway. However, a comprehensive summary of the flavonoid effects on GLMD is lacking. This study reviewed the roles and mechanisms of natural flavonoids with different structures in the treatment of GLMD reported globally in the past 5 years and provides a reference for developing flavonoids as drugs for treating GLMD.

Rapid and green quantification of phloridzin and trilobatin in Lithocarpus litseifolius (Hance) Chun (sweet tea) using an online pressurized liquid extraction high-performance liquid chromatography at equal absorption wavelength method

Sweet tea is a functional herbal tea with anti-inflammatory, anti-diabetic, and other effects, in which phloridzin and trilobatin are two functional compounds. However, the current methods for their quantification are time-consuming, costly, and environmentally unfriendly. In this paper, we propose a rapid method that integrates online pressurized liquid extraction and high-performance liquid chromatography featuring a superficially porous column for fast separation. Moreover, we employ an equal absorption wavelength method to eliminate using multiple standard solutions and relative calibration factors. Our verification process corroborated the technique's selectivity, accuracy, precision, linearity, and detection limitations. Separately, our methodology demonstrated excellent analytical efficiency, cost-effectiveness, and environmental friendliness. Practical application using six distinct batches of sweet tea samples yielded results in congruence with the external standard method. The analytical rate of this technique is up to over 18 times faster than traditional methods, and organic solvent consumption has been reduced to less than 1.5 mL. Therefore, this method provides a valuable way to achieve quality control and green analysis of sweet tea and other herbal teas.

Optimizing Trilobatin Production via Screening and Modification of Glycosyltransferases

Trilobatin (TBL) is a key sweet compound from the traditional Chinese sweet tea plant (Rubus suavissimus S. Lee). Because of its intense sweetness, superior taste profile, and minimal caloric value, it serves as an exemplary natural dihydrochalcone sweetener. It also has various health benefits, including anti-inflammatory and glucose-lowering effects. It is primarily produced through botanical extraction, which impedes its scalability and cost-effectiveness. In a novel biotechnological approach, phloretin is used as a precursor that is transformed into TBL by the glycosyltransferase enzyme ph-4'-OGT. However, this enzyme's low catalytic efficiency and by-product formation limit the large-scale synthesis of TBL. In our study, the enzyme Mdph-4'-OGT was used to screen 17 sequences across species for TBL synthesis, of which seven exhibited catalytic activity. Notably, PT577 exhibited an unparalleled 97.3% conversion yield within 3 h. We then optimized the reaction conditions of PT577, attaining a peak TBL bioproduction of 163.3 mg/L. By employing virtual screening, we identified 25 mutation sites for PT577, thereby creating mutant strains that reduced by-products by up to 50%. This research enhances the enzymatic precision for TBL biosynthesis and offers a robust foundation for its industrial-scale production, with broader implications for the engineering and in silico analysis of glycosyltransferases.

Chromosome-scale genome assembly of sweet tea (Lithocarpus polystachyus Rehder)

Lithocarpus, with >320 species, is the second largest genus of Fagaceae. However, the lack of a reference genome limits the molecular biology and functional study of Lithocarpus species. Here, we report the chromosome-scale genome assembly of sweet tea (Lithocarpus polystachyus Rehder), the first Lithocarpus species to be sequenced to date. Sweet tea has a 952-Mb genome, with a 21.4-Mb contig N50 value and 98.6% complete BUSCO score. In addition, the per-base consensus accuracy and completeness of the genome were estimated at 60.6 and 81.4, respectively. Genome annotation predicted 37,396 protein-coding genes, with repetitive sequences accounting for 64.2% of the genome. The genome did not undergo whole-genome duplication after the gamma (γ) hexaploidy event. Phylogenetic analysis showed that sweet tea diverged from the genus Quercus approximately at 59 million years ago. The high-quality genome assembly and gene annotation resources enrich the genomics of sweet tea, and will facilitate functional genomic studies in sweet tea and other Fagaceae species.

Progress and Prospects of Natural Glycoside Sweetener Biosynthesis: A Review

To achieve an adequate sense of sweetness with a healthy low-sugar diet, it is necessary to explore and produce sugar alternatives. Recently, glycoside sweeteners and their biosynthetic approaches have attracted the attention of researchers. In this review, we first outlined the synthetic pathways of glycoside sweeteners, including the key enzymes and rate-limiting steps. Next, we reviewed the progress in engineered microorganisms producing glycoside sweeteners, including de novo synthesis, whole-cell catalysis synthesis, and in vitro synthesis. The applications of metabolic engineering strategies, such as cofactor engineering and enzyme modification, in the optimization of glycoside sweetener biosynthesis were summarized. Finally, the prospects of combining enzyme engineering and machine learning strategies to enhance the production of glycoside sweeteners were discussed. This review provides a perspective on synthesizing glycoside sweeteners in microbial cells, theoretically guiding the bioproduction of glycoside sweeteners.