Among natural substances widespread in fruits, vegetables, spices, and medicinal plants, flavonoids and organic acids belong to the promising groups of bioactive compounds with strong antioxidant and anti-inflammatory properties. The aim of the present work was to evaluate the antibacterial activity of 13 common flavonoids (flavones, flavonols, flavanones) and 6 organic acids (aliphatic and aromatic acids). The minimal inhibitory concentrations (MICs) of selected plant substances were determined by the micro-dilution method using clinical strains of four species of pathogenic bacteria. All tested compounds showed antimicrobial properties, but their biological activity was moderate or relatively low. Bacterial growth was most strongly inhibited by salicylic acid (MIC = 250–500 μg/mL). These compounds were generally more active against Gram-negative bacteria: Escherichia coli and Pseudomonas aeruginosa than Gram-positive ones: Enterococcus faecalis and Staphylococcus aureus. An analysis of the antibacterial effect of flavone, chrysin, apigenin, and luteolin showed that the presence of hydroxyl groups in the phenyl rings A and B usually did not influence on the level of their activity. A significant increase in the activity of the hydroxy derivatives of flavone was observed only for S. aureus. Similarly, the presence and position of the sugar group in the flavone glycosides generally had no effect on the MIC values.

Curcumin, a principal bioactive substance of turmeric (Curcuma longa L.), is reported as a strong antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral agent. However, its antimicrobial properties require further detailed investigations into clinical and multidrug-resistant (MDR) isolates. In this work, we tested curcumin’s efficacy against over 100 strains of pathogens belonging to 19 species. This activity was determined by the broth microdilution method and by calculating the minimum inhibitory concentration (MIC). Our findings confirmed a much greater sensitivity of Gram-positive than Gram-negative bacteria. This study exhibited a significantly larger variation in the curcumin activity than previous works and suggested that numerous clinical strains of widespread pathogens have a poor sensitivity to curcumin. Similarly, the MICs of the MDR types of Staphylococcus aureus, S. haemolyticus, Escherichia coli, and Proteus mirabilis were high (≥2000 µg/mL). However, curcumin was effective against some species and strains: Streptococcus pyogenes (median MIC = 31.25 µg/mL), methicillin-sensitive S. aureus (250 µg/mL), Acinetobacter lwoffii (250 µg/mL), and individual strains of Enterococcus faecalis and Pseudomonas aeruginosa (62.5 µg/mL). The sensitivity of species was not associated with its affiliation to the genus, and it could differ a lot (e.g., S. pyogenes, S. agalactiae and A. lwoffii, A. baumannii). Hence, curcumin can be considered as a promising antibacterial agent, but with a very selective activity.

Despite much progress in the diagnosis and treatment of cancer, tumour diseases constitute one of the main reasons of deaths worldwide. The side effects of chemotherapy and drug resistance of some cancer types belong to the significant current therapeutic problems. Hence, searching for new anticancer substances and medicines are very important. Among them, bacterial proteins and peptides are a promising group of bioactive compounds and potential anticancer drugs. Some of them, including anticancer antibiotics (actinomycin D, bleomycin, doxorubicin, mitomycin C) and diphtheria toxin, are already used in the cancer treatment, while other substances are in clinical trials (e.g., p28, arginine deiminase ADI) or tested in in vitro research. This review shows the current literature data regarding the anticancer activity of proteins and peptides originated from bacteria: antibiotics, bacteriocins, enzymes, nonribosomal peptides (NRPs), toxins and others such as azurin, p28, Entap and Pep27anal2. The special attention was paid to the still poorly understood active substances obtained from the marine sediment bacteria. In total, 37 chemical compounds or groups of compounds with antitumor properties have been described in the present article.

Fucoxanthin is a carotenoid produced by brown algae and diatoms. This compound has several biological properties such as antioxidant, anti-obesity, anti-diabetic, anticancer, and antimicrobial activities. Unfortunately, until now the latter effect has been poorly confirmed. The aim of this study was an evaluation of fucoxanthin activity against 20 bacterial species. Antimicrobial effect of fucoxanthin was determined by using the agar disc-diffusion and micro-dilution methods. The studied carotenoid acted against 13 bacteria growing in aerobic conditions. It was observed to have a significantly stronger impact on Gram-positive than Gram-negative bacteria. Mean zones of growth inhibition (ZOIs) for Gram-positive bacteria ranged between 9.0 and 12.2 mm, while for Gram-negative were from 7.2 to 10.2 mm. According to the agar disc-diffusion method, the highest activity of fucoxanthin was exhibited against Streptococcus agalactiae (mean ZOI 12.2 mm), Staphylococcus epidermidis (mean ZOI 11.2 mm), and Staphylococcus aureus (mean ZOI 11.0 mm), and in the microdilution test towards Streptococcus agalactiae with the minimal inhibitory concentration (MIC) of 62.5 µg/mL. On the other hand, fucoxanthin was not active against strict anaerobic bacteria.

Fireweed (Epilobium angustifolium L., Onagraceae) is one of important medicinal plants used especially in the treatment of urogenital disorders, including benign prostatic hyperplasia (BPH) and prostatitis. The therapeutic effects of E. angustifolium extracts comprise antiproliferative, anti-inflammatory, immunomodulatory, antioxidant, and also antimicrobial activities. The aim of the present review was to provide the information on the botany, phytochemistry and traditional uses of E. angustifolium. This plant is a widespread circumboreal species of North America and Eurasia, tolerant in terms of habitat conditions, and often occupying man-made open habitats. Phytochemical studies on E. angustifolium resulted in the identification of about 250 different metabolites, including about 170 substances found for the first time in this plant in the last six years (2014)(2015)(2016)(2017)(2018)(2019). Fireweed has an abundance of polyphenolic compounds, particularly ellagitannins. Oenothein B and quercetin-3-O-glucuronide are proposed as markers for the identification and standardization of the plant raw material. E. angustifolium exhibits significant phytochemical variability in relation to the geographical origin, plant part and time of harvest/vegetation phase. Survey of the ethnobotanical literature showed that the above-mentioned species has been widely used not only as a medicinal, but also as an edible, honey and decorative plant. BOTANY TaxonomyEpilobium (Chamerion) angustifolium is classified to the Onagraceae family, which consists of 22 genera and approximately 650 species. The genus Chamerion (Raf.) Raf. ex Holub (syn. Chamaenerion Ség.) with eight species restricted to the northern hemisphere (mainly in Eurasia) belongs to the Onagroideae subfamily and Epilobieae tribe [18]. Relatively often, it is included in Epilobium L., which is the largest genus in the Onagraceae [19][20][21][22]. However, Chamerion clearly differs from Epilobium in terms of flower structure, leaf arrangement and other features [18,[23][24][25]. Molecular data also show that Chamerion is a separate monophyletic group of plants [26][27][28]. SynonymsThe Plant List [22] provides more than 40 synonyms of the species described, with three of these being the most commonly used: Epilobium angustifolium L., Chamerion angustifolium (L.) Holub and Chamaenerion angustifolium (L.) Scop. According to Holub [23], Chamerion should be considered the correct Latin name of this genus, while Chamaenerion is an illegitimate name. On the other hand, Sennikov [25] recently presented arguments for the restoration of the older name Chamaenerion. However, in Recently, the number of publications concerning the above-mentioned species has increased significantly. Screening of the Scopus database with the keywords of 'Epilobium/Chamerion/Chamaenerion angustifolium' found 416 document results, including 80 articles published in the years of 2014-2019. A new detailed summary is required not only for phytochemistry and pharmacology of E. angustifolium, but also in ...