Common garlic (Allium sativum L.) has potent Anti-Bacillus anthracis activity

Unveiling the Neem (Azadirachta indica) Effects on Biofilm Formation of Food-Borne Bacteria and the Potential Mechanism Using a Molecular Docking Approach

Biofilms currently represent the most prevalent bacterial lifestyle, enabling them to resist environmental stress and antibacterial drugs. Natural antibacterial agents could be a safe solution for controlling bacterial biofilms in food industries without affecting human health and environmental safety. A methanolic extract of Azadirachta indica (neem) leaves was prepared and analyzed using gas chromatography-mass spectrometry for the identification of its phytochemical constituents. Four food-borne bacterial pathogens (Bacillus cereus, Novosphingobium aromaticivorans, Klebsiella pneumoniae, and Serratia marcescens) were tested for biofilm formation qualitatively and quantitatively. The antibacterial and antibiofilm properties of the extract were estimated using liquid cultures and a microtiter plate assay. The biofilm inhibition mechanisms were investigated using a light microscope and molecular docking technique. The methanolic extract contained 45 identified compounds, including fatty acids, ester, phenols, flavonoids, terpenes, steroids, and antioxidants with antimicrobial, anticancer, and anti-inflammatory properties. Substantial antibacterial activity in relation to the extract was recorded, especially at 100 μg/mL against K. pneumoniae and S. marcescens. The extract inhibited biofilm formation at 100 μg/mL by 83.83% (S. marcescens), 73.12% (K. pneumoniae), and 54.4% (N. aromaticivorans). The results indicate efficient biofilm formation by the Gram-negative bacteria S. marcescens, K. pneumoniae, and N. aromaticivorans, giving 0.74, 0.292, and 0.219 OD at 595 nm, respectively, while B. cereus was found to have a low biofilm formation potential, i.e., 0.14 OD at 595 nm. The light microscope technique shows the antibiofilm activities with the biofilm almost disappearing at 75 μg/mL and 100 μg/mL concentrations. This antibiofilm property was attributed to DNA gyrase inhibition as illustrated by the molecular docking approach.

Ethnobotany, phytochemistry, and biological activities of Psidium guajava in the treatment of diarrhea: a review

Psidium guajava: is a tropical tree that is widely used in traditional medicine, especially for treating diarrhea. While P. guajava has been the subject of numerous reviews, none have specifically examined its ethnobotany, pharmacology, and phytochemistry in relation to its antidiarrheal activity. This review aims to summarize the evidence of effectiveness and safety of P. guajava in the treatment of diarrhea. Literature searches were conducted through Web of Science, PubMed, and ScienceDirect by using keywords "Psidium guajava" and "diarrhea" in October 2022. A total of 189 studies were included in this review. P. guajava is widely used in traditional medicine in 44 countries. Decoction and oral were the most represented method of preparation and administration, respectively, while leaves represented the most frequently cited part of the plant. Around 27 antidiarrheal or antibacterial compounds have been isolated and identified, including benzophenone glycosides, terpenes, polysaccharides, phenols, and flavonoids. This article presents ethnobotanical and pharmacological evidence for the efficacy of P. guajava leaves in the treatment of diarrhea and provides reference information for further investigation of this plant. However, despite the large number of publications on the topic, there are still some questions to answer: are quercetin and its glycosides the only ones to act as antidiarrheal agents? What is the mechanism of action of P. guajava antidiarrheal compounds? are the use of guava leaves safe in all types of populations including children, and at what dosage? To answer these questions, more complete phytochemical studies and systematic clinical trials are needed.

Screening and identification of antibacterial components in Artemisia argyi essential oil by TLC-direct bioautography combined with comprehensive 2D GC × GC-TOFMS

One of the primary components that contribute to Artemisia argyi 's effectiveness is essential oil, which has an exceptional antibacterial effect that has been well documented. The actual cause of its antibacterial activity and associated mechanism, however, are still not completely understood. For the first time, comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (2D GC × GC-TOFMS) and thin-layer chromatography-direct bioautography (TLC-DB) were employed to investigate its antibacterial components. The antibacterial properties of A. argyi essential oil were investigated, and the antibacterial activity of six compounds was evaluated, using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coil) as test microorganisms. TLC-direct bioautography was used to screen two bioactive clusters. Following 2D GC × GC-TOFMS identification of bioactive clusters, six compounds were evaluated for in vitro antibacterial activity verification. All the components tested displayed antibacterial action. Results showed that α-terpineol and eugenol had high potent antibacterial activity (MIC＜0.62 mg/mL, IC50＜2.00 mg/mL). For complex essential oils from traditional Chinese medicine, this method is efficient for quick screening and identifying antibacterial compounds.

Comparative Study on the Influence of Various Drying Techniques on Drying Characteristics and Physicochemical Quality of Garlic Slices

Effects of vacuum freeze drying (VFD), air impingement drying (AID), hot air drying based on temperature and humidity control (TH-HAD), pulsed vacuum drying (PVD), and medium- and short-wave infrared radiation drying (MSIRD) on the drying characteristics and physicochemical properties of garlic slices were investigated in the current work. Based on the experimental results, the Weibull model fitted the experimental results better (R2 > 0.99) than the Wang and Singh model. Samples dried with PVD showed the smallest color difference (ΔE*), better rehydration capacity and desirable reducing sugar content. In response to thermal effects and pressure pulsations, the cell walls gradually degraded, and the cell and organelle membranes ruptured. The allicin and soluble pectin contents of garlic slices treated with PVD were higher by 8.0–252.3% and 49.5–92.2%, respectively, compared to those of the samples dried by other techniques. VFD maintained a complete garlic slice structure with the minimum shrinkage and the best appearance. The MSIRD process produced the densest structure, and caused an additional loss of color and phytochemical contents. The findings in current work implied that PVD could be a promising drying technique for garlic slices.

Correlation Between Different Antidiarrheal Treatments and Changes in Chemical Components of Allii Sativi Bulbus Before and After Steaming Treatment Based on Flora Sequencing and In Vitro Experiments

We investigated the changes in the main active ingredients and pharmacodynamic differences in the therapeutic effect of garlic before and after steaming and the correlation between them. The main active ingredients in raw garlic products (RGPs) and steamed garlic products (SGPs) were determined by high-pressure liquid chromatography and ultraviolet spectroscopy. Acute rapid diarrhea (AD) and antibiotic-induced diarrhea (DD) models were established in rats, and each group was treated with RGP and SGP, respectively. The main chemical components of garlic changed before and after steaming. Garlicin and alliinase were only found in RGP, whereas only alliin was found in SGP. Both RGP and SGP contained garlic polysaccharides. For in vivo experiments on AD, the average rate of loose stools was 100.00 ± 0.00, 31.55 ± 11.76, and 19.14 ± 6.62 in the RGP high-dose and SGP high-dose treatment groups, respectively; in DD, the rates were 91.11 ± 14.40, 19.33 ± 3.63, and 30.56 ± 4.30, respectively (P < .01, treatment vs. model groups). In AD, the average grade of loose stools was 2.33 ± 0.52 and 1.83 ± 0.75 in the model and RGP high-dose treatment groups, respectively (P < .05); in DD, the values were 2.17 ± 0.41 in the model group and 1.67 ± 0.52 in the SGP high-dose treatment group (P < .05). RGP had a better therapeutic effect on AD, mainly related to the antibacterial effect of garlicin in RGP. SGP had a better therapeutic effect on DD, mainly related to the alliin and garlic polysaccharide in SGP. This study could provide evidence to support the clinical use of garlic.

Methods of Isolation of Active Substances from Garlic (Allium sativum L.) and Its Impact on the Composition and Biological Properties of Garlic Extracts

Garlic (Allium sativum L.) is widely used in the human diet and in scientific research due to its biological properties. Various factors, e.g., temperature, pressure, extraction method, type of solvent, size, and territorial origin of garlic, affect the amount and type of bioactive compounds obtained from garlic extracts. In turn, the content of bioactive compounds correlates with the biological activity of the extracts. Therefore, the aim of this review was to summarize the current state of knowledge of the methods and effectiveness of isolation of active substances from garlic and their impact on the garlic extract composition and, consequently, biological properties. According to the literature, extracts obtained using water as a solvent are mainly responsible for antimicrobial properties, which is related to, inter alia, the high content of allicin. The use of alcohols, such as methanol or ethanol, is associated with the outstanding antioxidant power of extracts resulting from the presence of phenolic compounds. In turn, due to the presence of diallyl disulfide and disulfide trisulfide, garlic oil has anticancer potential. Acetone is the most effective organic solvent; however, it is not suitable for immediate consumption.

The Antimicrobial Potential of the Neem Tree Azadirachta indica

Azadirachta indica (A. Juss), also known as the neem tree, has been used for millennia as a traditional remedy for a multitude of human ailments. Also recognized around the world as a broad-spectrum pesticide and fertilizer, neem has applications in agriculture and beyond. Currently, the extensive antimicrobial activities of A. indica are being explored through research in the fields of dentistry, food safety, bacteriology, mycology, virology, and parasitology. Herein, some of the most recent studies that demonstrate the potential of neem as a previously untapped source of novel therapeutics are summarized as they relate to the aforementioned research topics. Additionally, the capacity of neem extracts and compounds to act against drug-resistant and biofilm-forming organisms, both of which represent large groups of pathogens for which there are limited treatment options, are highlighted. Updated information on the phytochemistry and safety of neem-derived products are discussed as well. Although there is a growing body of exciting evidence that supports the use of A. indica as an antimicrobial, additional studies are clearly needed to determine the specific mechanisms of action, clinical efficacy, and in vivo safety of neem as a treatment for human pathogens of interest. Moreover, the various ongoing studies and the diverse properties of neem discussed herein may serve as a guide for the discovery of new antimicrobials that may exist in other herbal panaceas across the globe.

Recent advances in research on Allium plants: functional ingredients, physiological activities, and applications in agricultural and food sciences

Fruits and vegetables (FVs) have long been a major source of nutrients and dietary phytochemicals with outstanding physiological properties that are essential for protecting humans from chronic diseases. Moreover, the growing demand of consumers for nutritious and healthy foods is greatly promoting the increased intake of FVs. Allium (Alliaceae) is a perennial bulb plant genus of the Liliaceae family. They are customarily utilized as vegetable, medicinal, and ornamental plants and have an important role in agriculture, aquaculture, and the pharmaceutical industry. Allium plants produce abundant secondary metabolites, such as organosulfur compounds, flavonoids, phenols, saponins, alkaloids, and polysaccharides. Accordingly, Allium plants possess a variety of nutritional, biological, and health-promoting properties, including antimicrobial, antioxidant, antitumor, immunoregulatory, antidiabetic, and anti-inflammatory effects. This review aims to highlight the advances in the research on the bioactive components, physiological activities and clinical trials, toxicological assessment for safety, and applications of different Allium plants. It also aims to cover the direction of future research on the Allium genus. This review is expected to provide theoretical reference for the comprehensive development and utilization of Allium plants in the fields of functional foods, medicine, and cosmetics.

Antibiotic Isoflavonoids, Anthraquinones, and Pterocarpanoids from Pigeon Pea (Cajanus cajan L.) Seeds against Multidrug-Resistant Staphylococcus aureus

Cajanus cajan L. (pigeon pea, locally known in the Philippines as kadios) seed is a functional food with health benefits that extend beyond their nutritional value. C. cajan seeds contain highly diverse secondary metabolites with enriched beneficial properties, such as antibacterial, anticancer, and antioxidant activities. However, the antibacterial activities of secondary metabolites from Philippine-grown C. cajan, against multidrug-resistant Staphylococcus aureus have not been thoroughly described. Here, we investigated the in vitro antibacterial properties of C. cajan seed against multidrug-resistant S. aureus ATCC BAA-44 (MDRSA) and three other S. aureus strains (S. aureus ATCC 25923, S. aureus ATCC 6538, and coagulase-negative S. aureus) and, subsequently, identified the antibiotic markers against S. aureus strains using mass spectrometry. Secondary metabolites from C. cajan seeds were extracted using acetone, methanol, or 95% ethanol. Antibacterial screening revealed antibiotic activity for the C. cajan acetone extract. Bioassay-guided purification of the C. cajan acetone extract afforded three semi-pure high-performance liquid chromatography (HPLC) fractions exhibiting 32–64 µg/mL minimum inhibitory concentration (MIC) against MDRSA. Chemical profiling of these fractions using liquid chromatography mass spectrometry (LCMS) identified six compounds that are antibacterial against MDRSA. High-resolution mass spectrometry (HRMS), MS/MS, and dereplication using Global Natural Products Social Molecular Networking (GNPS)™, and National Institute of Standards and Technology (NIST) Library identified the metabolites as rhein, formononetin, laccaic acid D, crotafuran E, ayamenin A, and biochanin A. These isoflavonoids, anthraquinones, and pterocarpanoids from C. cajan seeds are potential bioactive compounds against S. aureus, including the multidrug-resistant strains.

Garlic: A systematic review of the effects on cardiovascular diseases

Allium sativum (garlic) certainly is one of the oldest horticultural crops in the world and presents bioactive compounds that are related to the garlic's effects on human health. Several authors have shown beneficial effects on diabetes, hypertension, dyslipidemia, obesity, and cardiovascular diseases (CVD), which are among the most relevant causes of mortality in the world. The aim of this systematic review was to evaluate the effects of garlic in the risk factors of CVD and evaluate its economic importance. MEDLINE-PubMed, COCHRANE, EMBASE, and Google Scholar databases were searched. The included studies showed that the use of garlic can reduce blood pressure, waist circumference, body mass index, LDL-c, non-HDL-c, total cholesterol, triglycerides, and inflammatory markers. It also can increase the levels of HDL-c and can improve cardiovascular parameters such as coronary artery calcium, microcirculation, epicardial and periaortic adipose tissue, post occlusive reactive hyperemia, low attenuation plaque, carotid intima-media thickness; and carotid intima-media thickness. Due to these reasons, garlic can be considered in the prevention and treatment of CVD risk factors.

Antibiotic resistance modifying ability of phytoextracts in anthrax biological agent Bacillus anthracis and emerging superbugs: a review of synergistic mechanisms

Background and objectives

The chemotherapeutic management of infections has become challenging due to the global emergence of antibiotic resistant pathogenic bacteria. The recent expansion of studies on plant-derived natural products has lead to the discovery of a plethora of phytochemicals with the potential to combat bacterial drug resistance via various mechanisms of action. This review paper summarizes the primary antibiotic resistance mechanisms of bacteria and also discusses the antibiotic-potentiating ability of phytoextracts and various classes of isolated phytochemicals in reversing antibiotic resistance in anthrax agent Bacillus anthracis and emerging superbug bacteria.

Methods

Growth inhibitory indices and fractional inhibitory concentration index were applied to evaluate the in vitro synergistic activity of phytoextract-antibiotic combinations in general.

Findings

A number of studies have indicated that plant-derived natural compounds are capable of significantly reducing the minimum inhibitory concentration of standard antibiotics by altering drug-resistance mechanisms of B. anthracis and other superbug infection causing bacteria. Phytochemical compounds allicin, oleanolic acid, epigallocatechin gallate and curcumin and Jatropha curcas extracts were exceptional synergistic potentiators of various standard antibiotics.

Conclusion

Considering these facts, phytochemicals represents a valuable and novel source of bioactive compounds with potent antibiotic synergism to modulate bacterial drug-resistance.