Investigation of the Antibacterial Activity and Subacute Toxicity of a Quercus crassifolia Polyphenolic Bark Extract for its Potential Use in Functional Foods

Pharmacognostic standardization and evaluation of antiulcer potential of Olax psittacorum leaf extract

The modern medicine has received many plants as a gift from ethnobotany. It is an efficient method of discovering new medicines. The leaves of Olax psittacorum (Lam.) Vahl. were extracted with ethanol, and the phytoconstituents present in the leaf extract were identified using Gas chromatography-mass spectrometric analysis (GC-MS), followed by determination of physico-chemical parameters and anti-ulcer properties. The leaf ethanolic extract (LEE) yield was observed to be 43.2%. The quantitative surface microscopy analysis revealed a stomatal index of 30 and 22 epidermal cells and qualitatively confirms presence of quinone, flavonoid, phenol, carbohydrate, tannin, saponin and absence of alkaloids using various screening techniques. The LEE confirms its anti-ulcer potency by inhibiting ulceration by 58% and 75% respectively, thus proving the hypothesis. These identified parameters may be helpful in developing some botanical standards for the standardisation and identification of O. psittacorum leaves with anti-ulcer properties.

Antioxidants in Oak (Quercus sp.): Potential Application to Reduce Oxidative Rancidity in Foods

This review explores the antioxidant properties of oak (Quercus sp.) extracts and their potential application in preventing oxidative rancidity in food products. Oxidative rancidity negatively impacts food quality, causing changes in color, odor, and flavor and reducing the shelf life of products. The use of natural antioxidants from plant sources, such as oak extracts, has gained increasing interest due to potential health concerns associated with synthetic antioxidants. Oak extracts contain various antioxidant compounds, including phenolic acids, flavonoids, and tannins, which contribute to their antioxidative capacity. This review discusses the chemical composition of oak extracts, their antioxidative activity in different food systems, and the safety and potential challenges related to their application in food preservation. The potential benefits and limitations of using oak extracts as an alternative to synthetic antioxidants are highlighted, and future research directions to optimize their application and determine their safety for human consumption are suggested.

Bioactive Molecules from Myrianthus arboreus, Acer rubrum, and Picea mariana Forest Resources

Forest trees are the world's most important renewable natural resources in terms of their dominance among other biomasses and the diversity of molecules that they produce. Forest tree extractives include terpenes and polyphenols, widely recognized for their biological activity. These molecules are found in forest by-products, such as bark, buds, leaves, and knots, commonly ignored in forestry decisions. The present literature review focuses on in vitro experimental bioactivity from the phytochemicals of Myrianthus arboreus, Acer rubrum, and Picea mariana forest resources and by-products with potential for further nutraceutical, cosmeceutical, and pharmaceutical development. Although these forest extracts function as antioxidants in vitro and may act on signaling pathways involved in diabetes, psoriasis, inflammation, and skin aging, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods. Traditional forest management systems focused on wood must evolve towards a holistic approach, allowing the use of these extractives for developing new value-added products.

Biological Activity of Bark Extracts from Northern Red Oak (Quercus rubra L.): An Antioxidant, Antimicrobial and Enzymatic Inhibitory Evaluation

The northern red oak (Quercus rubra L.) is an ornamental oak species native to eastern America, being an invasive species in Europe, with increasing coverage. The aim of this work was to evaluate the biological potential of red oak bark extracts. Aqueous and ethanolic preparations were obtained by two extraction methods: ultrasonic-assisted extraction (UAE) and microwave assisted extraction (MAE). The total phenolic and tannin contents were measured using spectrophotometric methods. The antioxidant activity was evaluated by two complementary methods (DPPH and ABTS). Antimicrobial potential was tested against five bacteria and three Candida species, and the effect on biofilm formation and synergism with gentamicin was also evaluated. Finally, enzyme inhibitory properties were assessed for α-glucosidase, tyrosinase, and acetylcholinesterase. The results indicated a higher phenolic content for the extracts obtained through MAE, while UAE bark extracts were rich in tannins. All the extracts exhibited antioxidant, anti-glucosidase, and anti-tyrosinase activity, while the antibacterial potential was mostly observed for the MAE extracts, especially against S. aureus, C. parapsilopsis, and C. krusei; inhibition of biofilm formation was observed only for MRSA. These findings show that the red oak bark might be an important source of bioactive compounds with antioxidant and antimicrobial properties.

Hypolipidemic activity and safety evaluation of a rhamnan-type sulfated polysaccharide-chromium (III) complex

BACKGROUND

Hyperlipidaemia is a chronic disorder characterized by imbalance of energy metabolism and high blood lipid level. The rhamnan-type sulfated polysaccharide is an excellent metal-ion chelating ligands. In this study, hypolipidemic activity and safety evaluation of a rhamnan-type sulfated polysaccharide-chromium (III) complex (RSPC) were studied.

METHODS

Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the structure of RSPC. The effects of the RSPC on lipid metabolism in hyperlipidemic mice were evaluated by lipid contents, histopathological observation, immunofluorescent analysis, and adipocytokine levels. Moreover, sub-acute toxicity evaluation of RSPC was carried out on ICR mice.

RESULTS

SEM and AFM further demonstrated formation of the polysaccharide-chromium (III) complex and revealed the intertwined network of RSPC. The RSPC significantly (p < 0.05) regulated lipid levels in the mice. The RSPC inhibited over-growth of adipocytes and reduced inflammatory infiltration induced by hyperlipidemia. The RSPC promoted differentiation of white adipose tissue into beige adipocytes and increased expression of uncoupling protein 1 (UCP1), thereby eliminating fat accumulation. Moreover, RSPC (5 mg/kg for mice; equivalent to 924 µg/d for adults) promoted secretion of adiponectin and suppressed resistin, leptin, and tumor necrosis factor alpha. Sub-acute toxicity evaluation showed that 1500 mg/kg of RSPC exhibited no apparent adverse effects on the mice.

CONCLUSION

These results indicated that RSPC could be safely used to prevent hyperlipidemia and inflammation and may provide a new idea for the prevention of hyperlipidaemia and the related metabolic disorders.

Antibacterial activity and mechanism of chloroform fraction from aqueous extract of mugwort leaves (Artemisia argyi L.) against Staphylococcus aureus

In this work, the antibacterial activity and mechanism of chloroform fraction obtained from aqueous extract of mugwort leaves against Staphylococcus aureus were investigated. The extract showed obvious antibacterial activity against S. aureus which the minimum inhibitory concentration and minimum bactericidal concentration were determined to be 3·0 and 6·0 mg ml^-1 respectively. The mechanism study suggested that the extract could destroy the integrity of the S. aureus cell walls and increase the permeability of cell membrane in a certain concentration, but it could not kill S. aureus in a short time. Instead, the extract could make bacteria in a state of apoptosis for a long time, interfere with the normal physiological metabolism of bacteria, and eventually make bacteria die, which was confirm by scanning electronic microscope.

Optimization of Microwave Assisted Extraction Conditions to Improve Phenolic Content and In Vitro Antioxidant and Anti-Microbial Activity in Quercus cerris Bark Extracts

The species of the Quercus genus, including Quercus cerris L., are widely used and their wood represents a valuable material utilized for various purposes. The intense industrial processing of wood results in a considerable amount of poorly-used natural by-products, such as bark, and a loss of potentially useful raw materials. Thus, the aim of our study was to evaluate the phytochemical characteristics and potential biological activities of Quercus cerris bark extracts obtained by optimizing the parameters of microwave assisted extraction (MAE). The optimum conditions for MAE were determined using a design of experiments (DoE) model, which set the experimental variables (irradiation time and microwave power) and their values. Aqueous and hydroalcoholic extractions were performed and the optimum parameters of extraction were determined for both solvents. The total polyphenolic and tannin contents were determined. The biological activities representative of antioxidant capacity were determined using two free radical scavenging methods, the DPPH and ABTS methods, and the antibacterial activity was assessed with the microdilution method. The results showed different optimal extraction conditions for aqueous (30 min at 850 W) and hydroalcoholic (18 min at 650 W) extracts. A higher yield of total polyphenols was observed in the hydroalcoholic bark extract (403.73 ± 7.35 mg gallic acid equivalents/g dried weight); however a lower level of tannins was registered in comparison to the aqueous extract. In addition, both extracts exerted high antioxidant activities, with the aqueous extracts having a stronger inhibitory effect against the DPPH radical. Moreover, the extracts exhibited antibacterial activity against the tested bacterial strains, especially against the Gram-positive strains and Klebsiella pneumoniae, with the hydroalcoholic extracts being more efficient overall. To conclude, the optimized MAE was an efficient method to extract phytochemical compounds with potential biological effects from Quercus cerris bark.

A Comprehensive Review of Phytochemistry and Biological Activities of Quercus Species

The Quercus genus provides a large amount of biomaterial with many applications in fields like pharmaceutics, cosmetics, and foodstuff areas. Due to the worldwide dissemination of the genus, many species were used for centuries in traditional healing methods or in the wine maturing process. This review aims to bring together the results about phytoconstituents from oak extracts and their biological applicability as antioxidants, antimicrobial, anticancer, etc. The literature data used in this paper were collected via PubMed, Scopus, and Science Direct (2010–June 2020). The inclusion criteria were papers published in English, with information about phytoconstituents from Quercus species (leaves, bark and seeds/acorns) and biological activities such as antioxidant, antibacterial, antiobesity, anti-acne vulgaris, antifungal, anticancer, antiviral, antileishmanial, antidiabetic, anti-inflammatory. The exclusion criteria were the research of other parts of the Quercus species (e.g., galls, wood, and twigs); lack of information about phytochemistry and biological activities; non-existent Quercus species reported by the authors. The most studied Quercus species, in terms of identified biomolecules and biological activity, are Q. brantii, Q. infectoria and Q. robur. The Quercus species have been reported to contain several phytoconstituents. The main bioactive phytochemicals are phenolic compounds, volatile organic compounds, sterols, aliphatic alcohols and fatty acids. The, Quercus species are intensely studied due to their antioxidant, anti-inflammatory, antimicrobial, and anticancer activities, provided by their phytochemical composition. The general conclusion is that oak extracts can be exploited for their biological activity and can be used in research fields, such as pharmaceutical, nutraceutical and medical.