Antimicrobial activity of flavonoids from Piper lanceaefolium and other Colombian medicinal plants against antibiotic susceptible and resistant strains of Neisseria gonorrhoeae

Ethnomedicine, phytochemistry, and pharmacological activities of Uvaria chamae P. Beauv.: A comprehensive review

The use of medicinal plants as food and medicine has been a common practice in the world, especially in tropical African countries. One such plant in West Africa is Uvaria chamae, also known as Bush banana, renowned for its diverse ethnomedicinal applications and, more recently, for its pharmacological activities attributed to a rich array of phytochemical constituents. Various parts of the plant have been traditionally employed for the treatment of diverse health issues such as digestive disorders, fever, dysmenorrhea, cancer, wound healing, and many more. To unravel the bioactive compounds responsible for these medicinal properties, a comprehensive phytochemical analysis has been undertaken. Notable isolates include chamanetin, dichamanetin, uvaretin, and uvarinol from different parts of the plant. The pharmacological evaluation of these compounds has revealed significant anticancer and antimicrobial properties. Therefore, this review provides a thorough examination of the phytochemicals derived from Uvaria chamae, detailing their associated pharmacological activities both in vitro and in vivo. The review emphasizes the potential of Uvaria chamae as a valuable source of lead compounds for cancer chemotherapy and antimicrobial drug discovery.

Isolation and biological activity of natural chalcones based on antibacterial mechanism classification

Bacterial infection, which is still one of the leading causes of death in humans, poses an enormous threat to the worldwide public health system. Antibiotics are the primary medications used to treat bacterial diseases. Currently, the discovery of antibiotics has reached an impasse, and due to the abuse of antibiotics resulting in bacterial antibiotic resistance, researchers have a critical desire to develop new antibacterial agents in order to combat the deteriorating antibacterial situation. Natural chalcones, the flavonoids consisting of two phenolic rings and a three-carbon α, β-unsaturated carbonyl system, possess a variety of biological and pharmacological properties, including anti-cancer, anti-inflammatory, antibacterial, and so on. Due to their potent antibacterial properties, natural chalcones possess the potential to become a new treatment for infectious diseases that circumvents existing antibiotic resistance. Currently, the majority of research on natural chalcones focuses on their synthesis, biological and pharmacological activities, etc. A few studies have been conducted on their antibacterial activity and mechanism. Therefore, this review focuses on the antibacterial activity and mechanisms of seventeen natural chalcones. Firstly, seventeen natural chalcones have been classified based on differences in antibacterial mechanisms. Secondly, a summary of the isolation and biological activity of seventeen natural chalcones was provided, with a focus on their antibacterial activity. Thirdly, the antibacterial mechanisms of natural chalcones were summarized, including those that act on bacterial cell membranes, biological macromolecules, biofilms, and quorum sensing systems. This review aims to lay the groundwork for the discovery of novel antibacterial agents based on chalcones.

Flavonoid Components, Distribution, and Biological Activities in Taxus: A review

Taxus, also known as "gold in plants" because of the famous agents with emphases on Taxol and Docetaxel, is a genus of the family Taxaceae, distributed almost around the world. The plants hold an important place in traditional medicine in China, and its products are used for treating treat dysuria, swelling and pain, diabetes, and irregular menstruation in women. In order to make a further study and better application of Taxus plants for the future, cited references from between 1958 and 2022 were collected from the Web of Science, the China National Knowledge Internet (CNKI), SciFinder, and Google Scholar, and the chemical structures, distribution, and bioactivity of flavonoids identified from Taxus samples were summed up in the research. So far, 59 flavonoids in total with different skeletons were identified from Taxus plants, presenting special characteristics of compound distribution. These compounds have been reported to display significant antibacterial, antiaging, anti-Alzheimer's, antidiabetes, anticancer, antidepressant, antileishmaniasis, anti-inflammatory, antinociceptive and antiallergic, antivirus, antilipase, neuronal protective, and hepatic-protective activities, as well as promotion of melanogenesis. Flavonoids represent a good example of the utilization of the Taxus species. In the future, further pharmacological and clinical experiments for flavonoids could be accomplished to promote the preparation of relative drugs.

Current advances on the therapeutic potential of pinocembrin: An updated review

Pinocembrin (5,7-dihydroxyflavone) is a major flavonoid found in many plants, fungi and hive products, mainly honey and propolis. Several in vitro and preclinical studies revealed numerous pharmacological activities of pinocembrin including antioxidant, anti-inflammatory, antimicrobial, neuroprotective, cardioprotective and anticancer activities. Here, we comprehensively review and critically analyze the studies carried out on pinocembrin. We also discuss its potential mechanisms of action, bioavailability, toxicity, and clinical investigations. The wide therapeutic window of pinocembrin makes it a promising drug candidate for many clinical applications. We recommend some future perspectives to improve its pharmacokinetic and pharmacodynamic properties for better delivery that may also lead to new therapeutic advances.

Bacteriospermia and Male Infertility: Role of Oxidative Stress

Male infertility is one of the major challenging and prevalent diseases having diverse etiologies of which bacteriospermia play a significant role. It has been estimated that approximately 15% of all infertility cases are due to infections caused by uropathogens and in most of the cases bacteria are involved in infection and inflammation leading to the development of bacteriospermia. In response to bacterial load, excess infiltration of leukocytes in the urogenital tract occurs and concomitantly generates oxidative stress (OS). Bacteria may induce infertility either by directly interacting with sperm or by generating reactive oxygen species (ROS) and impair sperm parameters such as motility, volume, capacitation, hyperactivation. They may also induce apoptosis leading to sperm death. Acute bacteriospermia is related with another clinical condition called leukocytospermia and both compromise male fertility potential by OS-mediated damage to sperm leading to male infertility. However, bacteriospermia as a clinical condition as well as the mechanism of action remains poorly understood, necessitating further research in order to understand the role of individual bacterial species and their impact in male infertility.

Antibacterial Effects of Flavonoids and Their Structure-Activity Relationship Study: A Comparative Interpretation

According to the latest report released by the World Health Organization, bacterial resistance to well-known and widely available antibacterial drugs has become a significant and severe global health concern and a grim challenge to tackle in order to cure infections associated with multidrug-resistant pathogenic microorganisms efficiently. Consequently, various strategies have been orchestrated to cure the severe complications related to multidrug-resistant bacteria effectively. Some approaches involved the retardation of biofilm formation and multidrug-resistance pumps in bacteria as well as the discovery of new antimicrobial agents demonstrating different mechanisms of action. In this regard, natural products namely alkaloids, terpenoids, steroids, anthraquinone, flavonoids, saponins, tannins, etc., have been suggested to tackle the multidrug-resistant bacterial strains owing to their versatile pharmacological effects. Amongst these, flavonoids, also known as polyphenolic compounds, have been widely evaluated for their antibacterial property due to their tendency to retard the growth of a wide range of pathogenic microorganisms, including multidrug-resistant bacteria. The hydroxylation of C5, C7, C3′, and C4′; and geranylation or prenylation at C6 have been extensively studied to increase bacterial inhibition of flavonoids. On the other hand, methoxylation at C3′ and C5 has been reported to decrease flavonoids’ antibacterial action. Hence, the latest information on the antibacterial activity of flavonoids is summarized in this review, with particular attention to the structure–activity relationship of this broad class of natural compounds to discover safe and potent antibacterial agents as natural products.

Efficiency of cow dung based vermi-compost on seed germination and plant growth parameters of Tagetes erectus (Marigold)

Vermi-composting is an environmental friendly and economic process to decompose organic waste. The objective of this study was to produce vermi-compost using E isenia fetida and to investigate the impact of vermi-compost (VC) and organic manure (cow dung) on seed germination, seedlings, and growth parameters of Tagetes erecta. Physio-chemical parameters of vermi-compost and organic manure were recorded. A potting experiment was designed, germination medium containing soil, sand, and various concentrations of vermi-composts. The composition of germinating media was: TO (Sand + Soil), TCC (Sand + Soil + Cow dung), 10% VC (Sand + Soil + 0.1 kg VC), 15% VC (Sand + Soil + 0.15 kg VC), 20% VC (Sand + Soil + 0.2 kg VC), 25% VC (Sand + Soil + 0.25 kg VC), 30% VC (Sand + Soil + 0.3 kg VC), and 35% VC (Sand + Soil + 0.35 kg VC). Seed germination, seedling, vegetative plant growth, and flowering parameters were evaluated in different germinating media. Pre and post-physio-chemical parameters of germination media were also recorded to check their stability and quality. Results showed that 20% VC was effective for the early initiation of seed germination (2.0 ± 0.0 days) and all growth parameters of marigold seedlings. The germination percentage at 20% VC was recorded as 87.5 ± 1.40 %. The best vegetative plant growth and flowering parameters of marigold plants were observed with 35% VC after transplantation. Findings showed that vermi-compost is the best-suited germination and growing media, which not only improved the soil health but also promoted seed germination and plant growth. Our study undoubtedly indicates that vermi-compost is a more encouraging and advantageous bio-fertilizer and can be used as a powerful and effective for immediate marigold production.

Efficacy and Mechanism of Traditional Medicinal Plants and Bioactive Compounds against Clinically Important Pathogens

Traditional medicinal plants have been cultivated to treat various human illnesses and avert numerous infectious diseases. They display an extensive range of beneficial pharmacological and health effects for humans. These plants generally synthesize a diverse range of bioactive compounds which have been established to be potent antimicrobial agents against a wide range of pathogenic organisms. Various research studies have demonstrated the antimicrobial activity of traditional plants scientifically or experimentally measured with reports on pathogenic microorganisms resistant to antimicrobials. The antimicrobial activity of medicinal plants or their bioactive compounds arising from several functional activities may be capable of inhibiting virulence factors as well as targeting microbial cells. Some bioactive compounds derived from traditional plants manifest the ability to reverse antibiotic resistance and improve synergetic action with current antibiotic agents. Therefore, the advancement of bioactive-based pharmacological agents can be an auspicious method for treating antibiotic-resistant infections. This review considers the functional and molecular roles of medicinal plants and their bioactive compounds, focusing typically on their antimicrobial activities against clinically important pathogens.

Antimicrobial Effects of Chemical Compounds Isolated from Traditional Chinese Herbal Medicine (TCHM) Against Drug-Resistant Bacteria: A Review Paper

Infectious diseases caused by pathogenic bacteria seriously threaten human lives. Although antibiotic therapy is effective in the treatment of bacterial infections, the overuse of antibiotics has led to an increased risk of antibiotic resistance, putting forward urgent requirements for novel antibacterial drugs. Traditional Chinese herbal medicine (TCHM) and its constituents are considered to be potential sources of new antimicrobial agents. Currently, a series of chemical compounds purified from TCHM have been reported to fight against infections by drug-resistant bacteria. In this review, we summarized the recent findings on TCHM-derived compounds treating drug-resistant bacterial infections. Further studies are still needed for the discovery of potential antibacterial components from TCHM.

Antibacterial activity of flavonoids and their structure-activity relationship: An update review

Based on World Health Organization reports, resistance of bacteria to well-known antibiotics is a major global health challenge now and in the future. Different strategies have been proposed to tackle this problem including inhibition of multidrug resistance pumps and biofilm formation in bacteria and development of new antibiotics with novel mechanism of action. Flavonoids are a large class of natural compounds, have been extensively studied for their antibacterial activity, and more than 150 articles have been published on this topic since 2005. Over the past decade, some promising results were obtained with the antibacterial activity of flavonoids. In some cases, flavonoids (especially chalcones) showed up to sixfold stronger antibacterial activities than standard drugs in the market. Some synthetic derivatives of flavonoids also exhibited remarkable antibacterial activities with 20- to 80-fold more potent activity than the standard drug against multidrug-resistant Gram-negative and Gram-positive bacteria (including Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). This review summarizes the ever changing information on antibacterial activity of flavonoids since 2005, with a special focus on the structure-activity relationship and mechanisms of actions of this broad class of natural compounds.

A Survey of the Chemical Compounds of Piper spp. (Piperaceae) and Their Biological Activities

The genus Piper is one of the largest genera in the Piperaceae, with most species widely distributed globally, covering all continents. To date, many Piper species have been scientifically investigated for their chemical diversities and interesting broad spectrum of bioactivities, including central nervous system (CNS), pesticidal, antifungal and antibacterial effects. This review systematically summarizes the scaffolds of the alkaloids reported, the major chemicals isolated from Piper spp., and their biological activities. Besides the alkaloids, some neolignans with rearranged skeletons show structural diversities, while the chalcones, flavonoids and kava-pyrones have some potential activities. Herein, the sesquiterpenes and phenolic compounds from Piper species and their bioactivities are also surveyed.

Screening for drought tolerance in cultivars of the ornamental genus Tagetes (Asteraceae)

Drought tolerance was evaluated in twelve cultivars of three ornamental Tagetes species (T. patula, T. tenuifolia and T. erecta). A stress treatment was performed by completely stopping watering of plants maintained in controlled greenhouse conditions. After three weeks, several plant growth parameters (stem length (SL), fresh weight (FW) and water content (WC)), photosynthetic pigments (chlorophylls and carotenoids (Car)), osmolytes (proline (Pro), glycine betaine (GB) and total soluble sugars (TSS)), an oxidative stress maker (malondialdehyde (MDA)) and antioxidants (total phenolic compounds (TPC) and total flavonoids (TF)) were measured. Considerable differences in the evaluated traits were found among the control and drought-stressed plants. Drought stress generally caused a marked reduction in plant growth and carotenoid pigments, and an increase in soluble solutes and oxidative stress. For most cultivars, proline levels in stressed plants increased between 30 and 70-fold compared to the corresponding controls. According to the different measured parameters, on average T. erecta proved to be more tolerant to drought than T. patula and T. tenuifolia. However, a considerable variation in the tolerance to drought was found within each species. The traits with greater association to drought tolerance as well as the most tolerant cultivars could be clearly identified in a principal components analysis (PCA). Overall, our results indicate that drought tolerant cultivars of Tagetes can be identified at early stages using a combination of plant growth and biochemical markers.

New environmentally-friendly antimicrobials and biocides from Andean and Mexican biodiversity

Persistent application of pesticides often leads to accumulation in the environment and to the development of resistance in various organisms. These chemicals frequently degrade slowly and have the potential to bio-accumulate across the food chain and in top predators. Cancer and neuronal damage at genomic and proteomic levels have been linked to exposure to pesticides in humans. These negative effects encourage search for new sources of biopesticides that are more "environmentally-friendly" to the environment and human health. Many plant or fungal compounds have significant biological activity associated with the presence of secondary metabolites. Plant biotechnology and new molecular methods offer ways to understand regulation and to improve production of secondary metabolites of interest. Naturally occurring crop protection chemicals offer new approaches for pest management by providing new sources of biologically active natural products with biodegradability, low mammalian toxicity and environmentally-friendly qualities. Latin America is one of the world's most biodiverse regions and provide a previously unsuspected reservoir of new and potentially useful molecules. Phytochemicals from a number of families of plants and fungi from the southern Andes and from Mexico have now been evaluated. Andean basidiomycetes are also a great source of scientifically new compounds that are interesting and potentially useful. Use of biopesticides is an important component of integrated pest management (IPM) and can improve the risks and benefits of production of many crops all over the world.

The Natural Flavonoid Pinocembrin: Molecular Targets and Potential Therapeutic Applications

Pinocembrin is a natural flavonoid compound extracted from honey, propolis, ginger roots, wild marjoram, and other plants. In preclinical studies, it has shown anti-inflammatory and neuroprotective effects as well as the ability to reduce reactive oxygen species, protect the blood-brain barrier, modulate mitochondrial function, and regulate apoptosis. Considering these pharmaceutical characteristics, pinocembrin has potential as a drug to treat ischemic stroke and other clinical conditions. In this review, we summarize its pharmacologic characteristics and discuss its mechanisms of action and potential therapeutic applications.

Antimicrobial resistance in Neisseria gonorrhoeae in the 21st century: past, evolution, and future

Neisseria gonorrhoeae is evolving into a superbug with resistance to previously and currently recommended antimicrobials for treatment of gonorrhea, which is a major public health concern globally. Given the global nature of gonorrhea, the high rate of usage of antimicrobials, suboptimal control and monitoring of antimicrobial resistance (AMR) and treatment failures, slow update of treatment guidelines in most geographical settings, and the extraordinary capacity of the gonococci to develop and retain AMR, it is likely that the global problem of gonococcal AMR will worsen in the foreseeable future and that the severe complications of gonorrhea will emerge as a silent epidemic. By understanding the evolution, emergence, and spread of AMR in N. gonorrhoeae, including its molecular and phenotypic mechanisms, resistance to antimicrobials used clinically can be anticipated, future methods for genetic testing for AMR might permit region-specific and tailor-made antimicrobial therapy, and the design of novel antimicrobials to circumvent the resistance problems can be undertaken more rationally. This review focuses on the history and evolution of gonorrhea treatment regimens and emerging resistance to them, on genetic and phenotypic determinants of gonococcal resistance to previously and currently recommended antimicrobials, including biological costs or benefits; and on crucial actions and future advances necessary to detect and treat resistant gonococcal strains and, ultimately, retain gonorrhea as a treatable infection.

Bacteriocins and other bioactive substances of probiotic lactobacilli as biological weapons against Neisseria gonorrhoeae

In the search of new antimicrobial agents against Neisseria gonorrhoeae, the bacteriocins-producing probiotic lactobacilli deserve special attention. The inhibitory effects of biosubstances such as organic acids, hydrogen peroxide and each bacteriocin-like inhibitory substance (BLIS) L23 and L60 on the growth of different gonococcal strains were investigated. Different non-treated and treated cell-free supernatants of two probiotic lactobacilli containing these metabolites were used. The aims of this work were (i) to evaluate the antimicrobial activity of the biosubstances produced by two probiotic lactobacilli, estimating the proportion in which each of them is responsible for the inhibitory effect, (ii) to define their minimum inhibitory concentrations (MICs) and, (iii) to determine the potential interactions between these biosubstances against N. gonorrhoeae. The main antimicrobial metabolites were the BLIS-es L23 and L60 in comparison with other biosubstances. Proportionally, their contributions to the inhibition on the gonococcal growth were 87.28% and 80.66%, respectively. The MIC values of bacteriocins were promising since these substances, when diluted, showed considerable inhibitory activity for all gonococci. In the interaction between bacteriocins, 100% of synergism was found on the gonococcal growth. In summary, this study indicates that both L23 and L60 could potentially serve to design new bioproducts against N. gonorrhoeae.

Using crude whole-genome assemblies of Neisseria gonorrhoeae as a platform for strain analysis: clonal spread of gonorrhea infection in Saskatchewan, Canada

Using crude whole-genome assemblies, we analyzed 25 isolates of Neisseria gonorrhoeae by using a high-resolution single nucleotide polymorphism (SNP) approach for nine housekeeping genes, characterizing penA alleles, and antimicrobial susceptibility phenotypes coupled with population structure analysis. Two clonal complexes, characterized by their spatial and geographical persistence, were identified. In addition, the clonal spread of penicillin-resistant/intermediate phenotypes and a novel introduction of the azithromycin resistance phenotype in Saskatchewan, Canada, were ascertained using this method.

A systematic review on biological activities of prenylated flavonoids

CONTEXT

Prenylated flavonoids are a unique class of naturally occurring flavonoids that exist especially for the plant's self-defensive strategy. This special class of flavonoids increases the bioactivities of their backbone flavonoids with non-prenylation; therefore, prenylated flavonoids have more potential to be developed and utilized.

OBJECTIVE

The number, position and type of the prenyl group on the flavonoids backbone structure may have close relationships with the bioactivities of flavonoids.

METHODS

PubMed and WEB OF KNOWLEDGE® were used to search articles published in English between 1 January 2002 and 31 December 2012, which discuss the structure-activity relationship between prenylated flavonoids and their bioactivities.

RESULTS

It is proposed that the prenyl-moiety makes the backbone compound more lipophilic, which leads to its high affinity with cell membranes. The prenylation brings the flavonoids with enhancement of antibacterial, anti-inflammatory, antioxidant, cytotoxicity, larvicidal as well as estrogenic activities. However, it is reported that the prenyl-moiety decreases the bioavailability and plasma absorption of prenylated flavonoids.

CONCLUSION

The prenyl group affects the bioactivities of flavonoids in certain ways, while the action mechanisms and the structure-activity relationship as well as more in vivo studies even clinical validation trials need to be further investigated.

Pinocembrin: a novel natural compound with versatile pharmacological and biological activities

Pinocembrin (5,7-dihydroxyflavanone) is one of the primary flavonoids isolated from the variety of plants, mainly from Pinus heartwood, Eucalyptus, Populus, Euphorbia, and Sparattosperma leucanthum, in the diverse flora and purified by various chromatographic techniques. Pinocembrin is a major flavonoid molecule incorporated as multifunctional in the pharmaceutical industry. Its vast range of pharmacological activities has been well researched including antimicrobial, anti-inflammatory, antioxidant, and anticancer activities. In addition, pinocembrin can be used as neuroprotective against cerebral ischemic injury with a wide therapeutic time window, which may be attributed to its antiexcitotoxic effects. Pinocembrin exhibits pharmacological effects on almost all systems, and our aim is to review the pharmacological and therapeutic applications of pinocembrin with specific emphasis on mechanisms of actions. The design of new drugs based on the pharmacological effects of pinocembrin could be beneficial. This review suggests that pinocembrin is a potentially promising pharmacological candidate, but additional studies and clinical trials are required to determine its specific intracellular sites of action and derivative targets in order to fully understand the mechanism of its anti-inflammatory, anticancer, and apoptotic effects to further validate its medical applications.