Natural products have been known for their antimicrobial factors since time immemorial. Infectious diseases are a worldwide burden that have been deteriorating because of the improvement of species impervious to various anti-infection agents. Hence, the distinguishing proof of antimicrobial specialists with high-power dynamic against MDR microorganisms is central to conquer this issue. Successful treatment of infection involves the improvement of new drugs or some common source of novel medications. Numerous naturally occurring antimicrobial agents can be of plant origin, animal origin, microbial origin, etc. Many plant and animal products have antimicrobial activities due to various active principles, secondary metabolites, or phytochemicals like alkaloids, tannins, terpenoids, essential oils, flavonoids, lectins, phagocytic cells, and many other organic constituents. Phytocomplexes' antimicrobial movement frequently results from a few particles acting in cooperative energy, and the clinical impacts might be because of the direct effects against microorganisms. The restorative plants that may furnish novel medication lead the antimicrobial movement. The purpose of this study is to investigate the antimicrobial properties of the phytocomplexes and natural extracts of the plants that are ordinarily being utilized as conventional medications and then recommended the chance of utilizing them in drugs for the treatment of multiple drug-resistant disease.

Multifunctional Therapeutic Potential of Phytocomplexes and Natural Extracts for Antimicrobial Properties.

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

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Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

The present study was conducted to evaluate a natural extract, obtained from the Beta vulgaris plant, for its phytochemical composition and its beneficial health effects. Therefore, total phenolic and flavonoid contents, as well as identification and quantification of phenolic compounds by HPLC, were assessed in leaves’ extract. Moreover, antioxidant activities were investigated using free radical scavenging tests, (ABTS+ and DPPH+) and reducing power assay (FRAP) as well as ferrous ions’ (Fe2+) chelating activity. The Antiglycation effect was also evaluated, using the BSA-fructose model, and the antidiabetic effect was determined by inhibition of α-amylase and α-glucosidase enzymes. Additionally, the in vitro antitumor effect was quantified using the MTT assay, and the antibacterial activity was evaluated using the agar disc diffusion and broth microdilution methods. Both aqueous and methanolic extracts exhibited potential antioxidant capacity with a higher effect for the methanolic extract. Furthermore, the in vitro antitumor activity of the methanolic extracts exhibited potent cytotoxic effects against two breast cancer cell lines, MDA-MB-468 and MCF-7. Moreover, Beta vulgaris extracts inhibit not only α-amylase and α-glucosidase, but also advanced glycation end-products’ (AGEs) formation, which would prevent diabetes’ complications. Beta vulgaris methanolic extract revealed also a high antibacterial effect against Proteus mirabilis and Bacillus subtilis. Taken together, these results revealed that Beta vulgaris leaves’ extracts constitute a valuable food and natural source of bioactive molecules that could be used for the development of new, natural drugs against cancer and diabetes.

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Beta vulgaris subsp. maritima: A Valuable Food with High Added Health Benefits

Background Plants are a rich source of therapeutic compounds that have tremendous applications in the pharmaceutical industry. This study aimed to identify the phytochemicals present in the seven selected medicinal plants as well as their antioxidant and antimicrobial activities. Methods Phytochemical screening, total phenolic, and flavonoid contents were determined using standard methods. The antioxidant activity of plant extracts was determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), and nitric oxide (NO) radical scavenging assays. The antimicrobial activity of the plant extracts was determined by the broth microdilution method. Results The results of phytochemical analysis showed the presence of phenols, flavonoids, and steroids in all plant extracts. The extract of Psychotria peduncularis showed the highest total phenolic and flavonoid contents (5.57 ± 0.22 mg GAE/g and 1.38 ± 0.06 mg QE/g, respectively). All plant extracts showed very strong antioxidant activity against DPPH and NO radical scavenging with IC50 values ranging from 0.55 to 49.43 µg/mL and 0.65 to 13.7 µg/mL, respectively. The extracts of Tristemma mauritianum and P. peduncularis displayed significant antibacterial activity with MIC values ranging from 16 to 1024 µg/mL. T. mauritianum extract showed bactericidal activity against all tested species. The extracts of Alsophila manianna and P. peduncularis showed significant antifungal activity (MIC = 64 µg/mL) against Candida albicans strain. Conclusion The screened extracts of medicinal plants used in our study can be used as potential antioxidant and antimicrobial agents, and resources for the development of new drugs.

https://downloads.hindawi.com/journals/aps/2022/1998808.pdf

Phytochemical Screening, Antioxidant, and Antimicrobial Activities of Seven Underinvestigated Medicinal Plants against Microbial Pathogens

Mastitis is the most prevalent global illness affecting dairy cows. This bacterial infection damages and inflames the udder tissues. Several plant extracts have demonstrated synergistic antibacterial activities with standard drugs in mastitis treatment. Scant information exists on Ocimum tenuiflorum L. This study evaluated the antibacterial activity of O. tenuiflorum extract and its interaction with antibacterial drugs against common mastitis pathogens including Staphylococcus aureus, coagulase-negative Staphylococci (CNS), Streptococcus agalactiae, and Escherichia coli. Anti-inflammatory activities in LPS-stimulated RAW264.7 macrophage cells were also studied. The O. tenuiflorum extract exhibited antibacterial activities against S. aureus, CNS, and S. agalactiae with minimum inhibitory concentration (MIC) ranging from 3.9 to 31.2 µg/mL and minimum bactericidal concentration (MBC) ranging from 15.6 to 500 µg/mL. Combinations of O. tenuiflorum with penicillin or amoxicillin-clavulanic acid showed synergistic effects against all tested strains but an additive effect with cefazolin and gentamicin. Pretreatment of the extract significantly decreased the expression of inflammatory molecules (IL-6, TNF-α, IL-1β, iNOS, COX-2, and PGE2) generated by LPS in macrophages. Results suggested O. tenuiflorum effectiveness against various Gram-positive mastitis bacteria, with the potential to reduce antibacterial doses and combat inflammation.

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Synergistic Antibacterial and Anti-inflammatory Activities of Ocimum tenuiflorum Ethanolic Extract against Major Bacterial Mastitis Pathogens

Microbial resistance has progressed rapidly and is becoming the leading cause of death globally. The spread of antibiotic-resistant microorganisms has been a significant threat to the successful therapy against microbial infections. Scientists have become more concerned about the possibility of a return to the pre-antibiotic era. Thus, searching for alternatives to fight microorganisms has become a necessity. Some bacteria are naturally resistant to antibiotics, while others acquire resistance mainly by the misuse of antibiotics and the emergence of new resistant variants through mutation. Since ancient times, plants represent the leading source of drugs and alternative medicine for fighting against diseases. Plants are rich sources of valuable secondary metabolites, such as alkaloids, quinones, tannins, terpenoids, flavonoids, and polyphenols. Many studies focus on plant secondary metabolites as a potential source for antibiotic discovery. They have the required structural properties and can act by different mechanisms. This review analyses the antibiotic resistance strategies produced by multidrug-resistant bacteria and explores the phytochemicals from different classes with documented antimicrobial action against resistant bacteria, either alone or in combination with traditional antibiotics.

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Najwan Jubair

Papers

Review on the Antibacterial Mechanism of Plant-Derived Compounds against Multidrug-Resistant Bacteria (MDR).