Growth stimulation/inhibition effect of medicinal plants on human intestinal microbiota

A Systematic Review of Plants With Antibacterial Activities: A Taxonomic and Phylogenetic Perspective

Background: Antimicrobial resistance represents a serious threat to human health across the globe. The cost of bringing a new antibiotic from discovery to market is high and return on investment is low. Furthermore, the development of new antibiotics has slowed dramatically since the 1950s' golden age of discovery. Plants produce a variety of bioactive secondary metabolites that could be used to fuel the future discovery pipeline. While many studies have focused on specific aspects of plants and plant natural products with antibacterial properties, a comprehensive review of the antibacterial potential of plants has never before been attempted. Objectives: This systematic review aims to evaluate reports on plants with significant antibacterial activities. Methods: Following the PRISMA model, we searched three electronic databases: Web of Science, PubMed and SciFinder by using specific keywords: "plant," "antibacterial," "inhibitory concentration." Results: We identified a total of 6,083 articles published between 1946 and 2019 and then reviewed 66% of these (4,024) focusing on articles published between 2012 and 2019. A rigorous selection process was implemented using clear inclusion and exclusion criteria, yielding data on 958 plant species derived from 483 scientific articles. Antibacterial activity is found in 51 of 79 vascular plant orders throughout the phylogenetic tree. Most are reported within eudicots, with the bulk of species being asterids. Antibacterial activity is not prominent in monocotyledons. Phylogenetic distribution strongly supports the concept of chemical evolution across plant clades, especially in more derived eudicot families. The Lamiaceae, Fabaceae and Asteraceae were the most represented plant families, while Cinnamomum verum, Rosmarinus vulgaris and Thymus vulgaris were the most studied species. South Africa was the most represented site of plant collection. Crude extraction in methanol was the most represented type of extraction and leaves were the main plant tissue investigated. Finally, Staphylococcus aureus was the most targeted pathogenic bacteria in these studies. We closely examine 70 prominent medicinal plant species from the 15 families most studied in the literature. Conclusion: This review depicts the current state of knowledge regarding antibacterials from plants and provides powerful recommendations for future research directions.

Applications of microencapsulated Bifidobacterium longum with Eleutherine americana in fresh milk tofu and pineapple juice

Bifidobacterium longum was microencapsulated by extrusion technique and added in fresh milk tofu and pineapple juice. Microencapsulation of B. longum with Eleutherine americana extract, oligosaccharides extract, and commercial fructo-oligosaccharides was assessed for the bacterial survival after sequential exposure to simulated gastric and intestinal juices, and refrigeration storage. Microencapsulated B. longum with the extract and oligosaccharides extract in the food products showed better survival than free cells under adverse conditions. Sensory analysis demonstrated that the products containing co-encapsulated bacterial cells were more acceptable by consumers than free cells. Pineapple juice prepared with co-encapsulated cells had lower values for over acidification, compared with the juice with free cells added. This work suggested that microencapsulated B. longum with E. americana could enhance functional properties of fresh milk tofu and pineapple juice.

Plantago maxima leaves extract inhibits adipogenic action of a high-fat diet in female Wistar rats

PURPOSE

The primary objective of this study is to investigate the content of biologically active compounds producing an antioxidant effect in Plantago maxima and their influence on main mechanisms of dietary obesity development.

METHODS

Biologically active compounds in P. maxima were tested using paper chromatography. In in vivo experiment, high-fat-fed Wistar rats obtained P. maxima water extract for 3 months. Morphometric parameters, weight gain, serum adipokines, and cytokines, as well as oxidative stress biomarkers in rats’ tissues were evaluated. Gut microflora was also examined.

RESULTS

Plantago maxima leaves used in the experiment contained significant amount of flavonoids, iridoids, phenol carboxylic acids, and tannins and ascorbic acid. Our in vivo experiment data demonstrate that P. maxima water extract prevents excessive adiposity in a diet-induced model. P. maxima consumption reduced serum leptin (twofold), macrophage chemoattractant protein-1 (sevenfold), tumornecrosis factor-α (25%), and interleukine-6 (26%) levels. P. maxima water extract decreased adipose tissue oxidative stress biomarkers in rats fed a high-fat diet. In addition, increased bacterial growth in the diet-induced obesity model was reversed by the P. maxima extract treatment.

CONCLUSION

Plantago maxima water extract possessed antiadipogenic, antidiabetic, antiinflammatory, antioxidant activity, and normalized gut microflora in a rat model of diet-induced excessive adiposity due to a high content of biologically active compounds.

Preparation of Eleutherine americana-alginate complex microcapsules and application in Bifidobacterium longum

Microencapsulation using extrusion and emulsion techniques was prepared for Bifidobacterium longum protection against sequential exposure to simulated gastric and intestinal juices, refrigeration storage and heat treatment. Eleutherine americana was used as the co-encapsulating agent. Hydrolysis of E. americana by gastric and intestinal juices was also determined. E. americana and its oligosaccharide extract demonstrated their resistance to low pH and partial tolerance to human α-amylase. Microencapsulated B. longum with E. americana and oligosaccharide extract prepared by the extrusion technique survived better than that by the emulsion technique under adverse conditions. Survival of microencapsulated cells after exposure to the juices and refrigeration storage was higher than free cells at Weeks 2 and 4. In addition, the viability of microencapsulated cells was better than free cells at 65 °C for 15 min. This work suggested that microencapsulated B. longum with E. americana offers the effective delivery of probiotics to colon and maintains their survival in food products.