An assessment of the evidence for antibacterial activity of stinging nettle (Urtica dioica) extracts

Exploring the synergistic potential of wild nettle and olive oil: bioactive compounds, antioxidant capacity, and antibacterial properties

This study delved into the incorporation of wild nettle (Urtica dioica L.) leaves powder with virgin olive oil, exploring its potential to enhance nutritional value and health benefits. The antioxidant, antibacterial, and mineral-enrichment attributes of the resultant nettle-infused olive oil were investigated. Phenolic composition analysis revealed that an optimal maceration time of 30-40 minutes leads to maximal phenolic and flavonoid contents (57.66 mg GAE/100 g and 67.18 mg QE/100 g, respectively). The infused oil demonstrated superior radical scavenging activity (DPPH and ABTS assays) compared to virgin olive oil. Notably, nettle infusion significantly elevates zinc (10.12 mg/kg) and iron (13.85 mg/kg) contents. Antibacterial assays exhibited enhanced inhibition diameters and lower MIC and MBC values for nettle-infused oil against various bacterial strains. The study's findings underscore the potential of nettle infusion to enhance the nutritional and functional attributes of olive oil, holding promise for novel culinary and health applications.

Nepali oral microbiomes reflect a gradient of lifestyles from traditional to industrialized

Background

Lifestyle plays an important role in shaping the gut microbiome. However, its contributions to the oral microbiome remains less clear, due to the confounding effects of geography and methodology in investigations of populations studied to date. Furthermore, while the oral microbiome seems to differ between foraging and industrialized populations, we lack insight into whether transitions to and away from agrarian lifestyles shape the oral microbiota. Given the growing interest in so-called 'vanishing microbiomes' potentially being a risk factor for increased disease prevalence in industrialized populations, it is important that we distinguish lifestyle from geography in the study of microbiomes across populations.

Results

Here, we investigate salivary microbiomes of 63 Nepali individuals representing a spectrum of lifestyles: foraging, subsistence farming (individuals that transitioned from foraging to farming within the last 50 years), agriculturalists (individuals that have transitioned to farming for at least 300 years), and industrialists (expatriates that immigrated to the United States within the last 20 years). We characterize the role of lifestyle in microbial diversity, identify microbes that differ between lifestyles, and pinpoint specific lifestyle factors that may be contributing to differences in the microbiomes across populations. Contrary to prevailing views, when geography is controlled for, oral microbiome alpha diversity does not differ significantly across lifestyles. Microbiome composition, however, follows the gradient of lifestyles from foraging through agrarianism to industrialism, supporting the notion that lifestyle indeed plays a role in the oral microbiome. Relative abundances of several individual taxa, including Streptobacillus and an unclassified Porphyromonadaceae genus, also mirror lifestyle. Finally, we identify specific lifestyle factors associated with microbiome composition across the gradient of lifestyles, including smoking and grain source.

Conclusion

Our findings demonstrate that by controlling for geography, we can isolate an important role for lifestyle in determining oral microbiome composition. In doing so, we highlight the potential contributions of several lifestyle factors, underlining the importance of carefully examining the oral microbiome across lifestyles to improve our understanding of global microbiomes.

Anti-BPH lignans from Urtica triangularis subsp. pinnatifida (Hand.-Mazz.) C.J.Chen

A new lignan named (-)-ginkgool-9-O-β-glucopyranoside (1) together with eight known lignans (2-9) were isolated from Urtica triangularis subsp. pinnatifida (Hand.-Mazz.) C.J.Chen. According to the mass spectrometry and spectroscopic analyses, the gross structure and absolute configuration of the new lignan were elucidated. The cytotoxic effects of compounds 1-9 on BPH-1 cells and the docking results on type II 5α-reductase were analysed to evaluate their anti-BPH activity. The results showed better anti-BPH activity that compound 4 displaying an IC50 of 79.75 ± 3.68 μM than finasteride presenting an IC50 of 91.8 ± 3.74 μM. Compounds 1, 2 and 5 had moderate anti-BPH activity compared with finasteride.

Urtica dioica Extract Leads to Cyst Reduction, Enhanced Cell-Mediated Immune Response, and Antioxidant Activity in Experimental Toxoplasmosis

BACKGROUND

Toxoplasmosis is a cosmopolitan parasitic infection caused by Toxoplasma gondii which is commonly treated by pyrimethamine (PYR) plus sulfadiazine (SDZ) with several adverse side effects. The present study evaluated the therapeutic effects of Urtica dioica L. aqueous extract (UDE) on acute and chronic toxoplasmosis in mice.

METHODS

For this purpose, mice were infected with 20 cysts (acute infection) or 10 cysts (chronic infection) of T. gondii (Me49 strain). The mice were treated with 200 mg/kg of UDE intraperitoneally (IP) and intragastric route (IG). The UDE-treated mice were compared with the PYR + SDZ treatment. The histopathological changes, cyst count, total antioxidant capacity (TAC), malondialdehyde (MDA) assay, and serum INF-γ were also evaluated.

RESULTS

In the acute toxoplasmosis, UDE by IP and IG administration significantly reduced the number of brain cysts by 93.74 and 92.55%, respectively, and increased the survival rate to 80% compared with 60% in untreated controls. In the chronic infection, cyst burden decreased at 88.2 and 83.4%, respectively, for IP and IG treatments. Moreover, UDE significantly increased INF- γ levels in acute and chronic toxoplasmosis. Tissue inflammatory lesions were reduced in the UDE-treated subgroups compared to the untreated group. UDE treatment significantly reduced MDA levels and elevated TAC in both acute and chronic infections.

CONCLUSION

The results show that U. dioica possesses significant immunostimulant and antioxidant activity with a higher cyst reduction in the brain during acute toxoplasmosis. Further studies are required to investigate the fractionations of UDE against T. gondii and its combination with other standard drugs.

Bioassay-Guided Assessment of Antioxidative, Anti-Inflammatory and Antimicrobial Activities of Extracts from Medicinal Plants via High-Performance Thin-Layer Chromatography

Natural products and their analogues have contributed significantly to treatment options, especially for anti-inflammatory and infectious diseases. Thus, the primary objective of this work was to compare the bioactivity profiles of selected medicinal plants that are historically used in folk medicine to treat inflammation and infections in the body. Chemical HPTLC fingerprinting was used to assess antioxidant, phenolic and flavonoid content, while bioassay-guided HPTLC was used to detect compounds with the highest antibacterial and anti-inflammatory activities. The results of this study showed that green tea leaf, walnut leaf, St. John's wort herb, wild thyme herb, European goldenrod herb, chamomile flower, and immortelle flower extracts were strong radical scavengers. Green tea and nettle extracts were the most active extracts against E. coli, while calendula flower extract showed significant potency against S. aureus. Furthermore, green tea, greater celandine, and fumitory extracts exhibited pronounced potential in suppressing COX-1 activity. The bioactive compounds from the green tea extract, as the most bioactive, were isolated by preparative thin-layer chromatography and characterized with their FTIR spectra. Although earlier studies have related green tea's anti-inflammatory properties to the presence of catechins, particularly epigallocatechin-3-gallate, the FTIR spectrum of the compound from the most intense bioactive zone showed the strongest anti-inflammatory activity can be attributed to amino acids and heterocyclic compounds. As expected, antibacterial activity in extracts was related to fatty acids and monoglycerides.

Sweet and sour synergy: exploring the antibacterial and antibiofilm activity of acetic acid and vinegar combined with medical-grade honeys

Oxymel, a combination of honey and vinegar, has been used as a remedy for wounds and infections in historical and traditional medical settings. While honey is now clinically used to treat infected wounds, this use of a complex, raw natural product (NP) mixture is unusual in modern western medicine. Research into the antimicrobial activity of NPs more usually focuses on finding a single active compound. The acetic acid in vinegar is known to have antibacterial activity at low concentrations and is in clinical use to treat burn wound infections. Here, we investigated the potential for synergistic activity of different compounds present in a complex ingredient used in historical medicine (vinegar) and in an ingredient mixture (oxymel). We conducted a systematic review to investigate published evidence for antimicrobial effects of vinegars against human pathogenic bacteria and fungi. No published studies have explicitly compared the activity of vinegar with that of a comparable concentration of acetic acid. We then characterized selected vinegars by HPLC and assessed the antibacterial and antibiofilm activity of the vinegars and acetic acid, alone and in combination with medical-grade honeys, against Pseudomonas aeruginosa and Staphylococcus aureus. We found that some vinegars have antibacterial activity that exceeds that predicted by their acetic acid content alone, but that this depends on the bacterial species being investigated and the growth conditions (media type, planktonic vs. biofilm). Pomegranate vinegars may be particularly interesting candidates for further study. We also conclude that there is potential for acetic acid, and some vinegars, to show synergistic antibiofilm activity with manuka honey.

A case study of the Ancientbiotics collaboration

Interdisciplinary collaboration is regarded as a desirable way of researching and, in some instances, even a requirement for academic teams and funding proposals. This paper explores the possibilities, but also the problems, of collaboration between different disciplines through a case study of the Ancientbiotics team. This team explores the potential of natural products contained in historical medical recipes. The search for clinically useful natural products in unusual places, such as historical medical practices, is a well-established endeavor in the scientific disciplines. The Ancientbiotics collaboration, largely based across UK institutions, takes this path a step forward in combining modern scientific knowledge of natural products with expertise from humanities to identify ingredient combinations. After 7 years of practice, the research has produced a variety of outcomes. This perspective will explore how the team worked within an interdisciplinary framework to advance investigation and application of historical medical recipes.