Efficacy of photoactivated Myrciaria cauliflora extract against Staphylococcus aureus infection – A pilot study

Evaluation of the antimicrobial potential of extracts Myrciaria cauliflora in strains of Staphylococcus aureus ATCC and Staphylococcus aureus BLAC

Bacteria of medical interest have increasingly acquired resistance to available antimicrobials over the years. This resistance makes these microorganisms a challenge for conventional medicine treatments, and new research is focusing on herbal medicine to fight these pathogens. The present work aimed to evaluate the cytotoxic activity of Myrciaria cauliflora and Genipa americana extracts, considering an in vitro bacterial inhibition, using a modified antibiogram technique, the extracts were studied in strains of Staphylococcus aureus ATCC 29213 and Staphylococcus aureus BLAC, where inhibition was observed in the two strains studied by the extract. This study observed that the M. cauliflora bark extract has antimicrobial potential when tested in vitro on S. aureus ATCC 29213 and S. aureus BLAC strains, indicating it is a potential herbal medicine for infections by this pathogen.

Biocultural heritage of the Caatinga: a systematic review of Myrtaceae and its multiple uses

The Caatinga, an exclusively Brazilian biome, stands as a reservoir of remarkable biodiversity. Its significance transcends ecological dimensions, given the direct reliance of the local population on its resources for sustenance and healthcare. While Myrtaceae, a pivotal botanical family within the Brazilian flora, has been extensively explored for its medicinal and nutritional attributes, scant attention has been directed towards its contextual relevance within the Caatinga's local communities. Consequently, this inaugural systematic review addresses the ethnobotanical roles of Myrtaceae within the Caatinga, meticulously anchored in the PRISMA 2020 guidelines. We searched Scopus, MEDLINE/Pubmed, Scielo, and LILIACS. No date-range filter was applied. An initial pool of 203 articles was carefully scrutinized, ultimately yielding 31 pertinent ethnobotanical studies elucidating the utility of Myrtaceae amongst the Caatinga's indigenous populations. Collectively, they revealed seven distinct utilization categories spanning ~54 species and 11 genera. Psidium and Eugenia were the genera with the most applications. The most cited categories of use were food (27 species) and medicinal (22 species). The importance of accurate species identification was highlighted, as many studies did not provide enough information for reliable identification. Additionally, the potential contribution of Myrtaceae fruits to food security and human health was explored. The diversity of uses demonstrates how this family is a valuable resource for local communities, providing sources of food, medicine, energy, and construction materials. This systematic review also highlights the need for more ethnobotanical studies to understand fully the relevance of Myrtaceae species in the Caatinga, promoting biodiversity conservation, as well as support for local populations.

Phytochemical Composition and Antimicrobial and Antibiofilm Effect of Myrciaria cauliflora Hydroethanolic Extract against Staphylococcus aureus and Acinetobacter baumannii

Staphylococcus aureus and Acinetobacter baumannii are opportunistic pathogens, and both are involved in different oral infections. This work aimed to analyze the phytochemical composition of Myrciaria cauliflora hydroethanolic extract and to evaluate its antimicrobial and antibiofilm action against Staphylococcus aureus (ATCC 6538) and Acinetobacter baumannii (ATCC 19606; multi-resistant clinical strains 58004, 50098, 566006, and H557). Myrciaria cauliflora hydroethanolic extract was prepared, and the content of soluble solids, flavonoids, and phenols was quantified. High-performance liquid chromatography (HPLC) was performed later. The minimum inhibitory concentration was determined using the broth microdilution method according to the Clinical and Laboratory Standards Institute, standard M7-A6, and subsequently, its minimum bactericidal concentration was determined. Then, the most effective concentrations were analyzed against biofilms. Statistical analysis was performed using the ANOVA method with Tukey's test. The soluble solids content in the prepared hydroethanolic extract of M. cauliflora was 2.22%. Additionally, the total flavonoid content, measured using the quercetin standard curve, was 0.040 mg/mL. Furthermore, the total phenol content, determined using the gallic acid standard curve, was 0.729 mg/mL. HPLC analysis presented peaks of gallic acid (11.80 m), p-coumaric acid (12.09 m), cinnamic acid derivative (19.02 m), and ellagic acid (29.83 m). The extract demonstrated antimicrobial and antibiofilm action against all tested strains. However, the most effective antibacterial concentration against all the tested bacteria was 5.55 mg/mL. Therefore, these chemical components justify that M. cauliflora hydroethanolic extract is effective in reducing biofilm formation in S. aureus (standard strain) and A. baumannii (standard and clinical strains).

Antimicrobial photodynamic therapy with Brazilian green propolis controls intradermal infection induced by methicillin-resistant Staphylococcus aureus and modulates the inflammatory response in a murine model

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of skin and soft tissue infections worldwide. This microorganism has a wide range of antibiotics resistance, a fact that has made the treatment of infections caused by MRSA difficult. In this sense, antimicrobial photodynamic therapy (aPDT) with natural products has emerged as a good alternative in combating infections caused by antibiotic-resistant microorganisms. The objective of the present study was to evaluate the effects of aPDT with Brazilian green propolis against intradermal MRSA infection in a murine model. Initially, 24 Balb/c mice were infected intradermally in the ears with 1.5 × 108 colony-forming units of MRSA 43300. After infection, they were separated into 4 groups (6 animals per group) and treated with the vehicle, only Brazilian green propolis, only blue LED light or with the aPDT protocol (Brazilian green propolis + blue LED light). It was observed in this study that aPDT with Brazilian green propolis reduced the bacterial load at the site of infection. Furthermore, it was able to inhibit weight loss resulting from the infection, as well as modulate the inflammatory response through greater recruitment of polymorphonuclear cells/neutrophils to the infected tissue. Finally, aPDT induced an increase in the cytokines IL-17A and IL-12p70 in the draining retromaxillary lymph node. Thus, aPDT with Brazilian green propolis proved to be effective against intradermal MRSA infection in mice, reducing bacterial load and modulating the immune response in the animals. However, more studies are needed to assess whether such effects are repeated in humans.

A Review of Phototoxic Plants, Their Phototoxic Metabolites, and Possible Developments as Photosensitizers

This study provides a comprehensive overview of the current knowledge regarding phototoxic terrestrial plants and their phototoxic and photosensitizing metabolites. Within the 435,000 land plant species, only around 250 vascular plants have been documented as phototoxic or implicated in phototoxic occurrences in humans and animals. This work compiles a comprehensive catalog of these phototoxic plant species, organized alphabetically based on their taxonomic family. The dataset encompasses meticulous details including taxonomy, geographical distribution, vernacular names, and information on the nature and structure of their phototoxic and photosensitizing molecule(s). Subsequently, this study undertook an in-depth investigation into phototoxic molecules, resulting in the compilation of a comprehensive and up-to-date list of phytochemicals exhibiting phototoxic or photosensitizing activity synthesized by terrestrial plants. For each identified molecule, an extensive review was conducted, encompassing discussions on its phototoxic activity, chemical family, occurrence in plant families or species, distribution within different plant tissues and organs, as well as the biogeographical locations of the producer species worldwide. The analysis also includes a thorough discussion on the potential use of these molecules for the development of new photosensitizers that could be used in topical or injectable formulations for antimicrobial and anticancer phototherapy as well as manufacturing of photoactive devices.

Characterization of Brazilian green propolis as a photosensitizer for LED light-induced antimicrobial photodynamic therapy (aPDT) against methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-intermediate Staphylococcus aureus (VISA)

Staphylococcus aureus is the primary cause of skin and soft tissue infections. Its significant adaptability and the development of resistance are the main factors linked to its spread and the challenges in its treatment. Antimicrobial photodynamic therapy emerges as a promising alternative. This work aimed to characterize the antimicrobial photodynamic activity of Brazilian green propolis, along with the key bioactive compounds associated with this activity. Initially, a scanning spectrometry was conducted to assess the wavelengths with the potential to activate green propolis. Subsequently, reference strains of methicillin-resistant Staphylococcus aureus (MRSA ATCC 43300) and vancomycin-intermediate Staphylococcus aureus (VISA ATCC 700699) were exposed to varying concentrations of green propolis: 1 µg/mL, 5 µg/mL, 10 µg/mL, 50 µg /mL and 100 µg/mL and were stimulated by blue, green or red LED light. Finally, high-performance liquid chromatography coupled with a diode array detector and tandem mass spectrometry techniques, along with classic molecular networking analysis, was performed to identify potential bioactive molecules with photodynamic activity. Brazilian green propolis exhibits a pronounced absorption peak and heightened photo-responsiveness when exposed to blue light within the range of 400 nm and 450 nm. This characteristic reveals noteworthy significant photodynamic activity against MRSA and VISA at concentrations from 5 µg/mL. Furthermore, the propolis comprises compounds like curcumin and other flavonoids sourced from flavone, which possess the potential for photodynamic activity and other antimicrobial functions. Consequently, Brazilian green propolis holds promise as an excellent bactericidal agent, displaying a synergistic antibacterial property enhanced by light-induced photodynamic effects.

Natural versus synthetic curcuminoids as photosensitizers: photobleaching and antimicrobial photodynamic therapy evaluation

Antimicrobial photodynamic therapy (aPDT) has been studied as an alternative to combat bacterial resistance to the commonly used antibiotics. aPDT requires the use of a photosensitizer and curcumin is one of the more promising, though the usage of natural curcumin can be inconsistent in certain biomedical uses due to differences in soil condition and turmeric age, besides a large quantity of the plant is necessary to obtain useful amounts of the actual molecule. As such, a synthetic analogue is preferred as it is pure, and its components are better characterized. The present work studied photophysical differences in both natural and synthetic curcumin using photobleaching experiments and searched for whether differences existed in aPDT studies against Staphylococcus aureus. The results showed a faster O₂ consumption and a singlet oxygen's generation rate lower by the synthetic curcumin, in comparison with the natural derivative. However, no statistical difference was observed when inactivating S. aureus and these results were following a concentration-based pattern. Thus, the use of synthetic curcumin is indicated, as it can be obtained in controlled amounts and with less environmental impact. Although there are small changes in a photophysical context comparing natural versus synthetic curcumins, we did not observe statistical differences in the photoinactivation of S.aureus bacteria, and reproducibility in biomedical contexts is better achieved with the synthetic analogue.

Physical activity reduces intradermal bacterial load in a murine model submitted to forced swim training - a pilot study

Regular exercise is beneficial to health. This study evaluated the effects of moderate and intense physical exercise modalities on intradermal infection by Staphylococcus aureus in a murine model. Mice that practiced moderate exercise had lower bacterial load on lymph nodes and less inflammatory infiltrate in dermis. They presented greater weight, however, less amount of epididymal fat: the weight was increased while they had fat diminished. A positive correlation was observed between lipid content and bacterial load in mice trained at moderate intensity. Animals that were under high intensity exercises presented superior bacterial load on the lymph nodes, increased neutrophil count and circulating lymphocytes, and had leukocyte recruitment to the dermis augmented, when compared to the ones in moderate exercise. These findings suggest that moderate physical activity modulates the immune response in dermal infection caused by S. aureus in a murine model.

The Enhancement of the Photodynamic Therapy and Ciprofloxacin Activity against Uropathogenic Escherichia coli Strains by Polypodium vulgare Rhizome Aqueous Extract

Antibiotic therapy and photodynamic therapy (PDT) are commonly used to treat bacterial infections. Unfortunately, these methods are often ineffective. Therefore, agents that could effectively support antibiotic therapy and PDT in the inactivation of pathogens are being sought. Phytotherapy seems to be a good solution. The aim of the current research was to examine whether Polypodium vulgare extract (PvE) would improve the effectiveness of PDT and ciprofloxacin (CIP), an antibiotic that is commonly used to treat urinary tract infections in humans. UHPLC-MS analysis was performed to establish the PvE content. Chlorin e6 has been used as a photosensitizer in the PDT method. Biofilm production was established using the spectrophotometric method. The live cell count in planktonic and biofilm consortia was determined with the microdilution method and DAPI staining. The decrease of the bacterial survival, biofilm mass synthesis, and morphological changes of the bacteria under the combined treatments: PDT+PvE and CIP+PvE was noted. The results clearly indicate that the PvE can be used as a good agent for improving the efficacy of both PDT and the CIP activity to inactivate uropathogenic Escherichia coli strains. The obtained results are of particular value in the era of widespread and still-increasing drug resistance among bacterial pathogens.

Antimicrobial photodynamic therapy (aPDT) with curcumin controls intradermal infection by Staphylococcus aureus in mice with type 1 diabetes mellitus: a pilot study

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main pathogens that cause infections in diabetic individuals. In this paper, we report the outcomes of our investigation on the intradermal application of antimicrobial photodynamic therapy (PDT) with curcumin in an infection induced by MRSA ATCC 43300 strain in the ear of mice with Type 1 Diabetes Mellitus (T1DM). A solution containing 100 μg of curcumin was photoactivated ex vivo with a LED light (450 nm) delivering a fluency of 13.5 J/cm3. This solution was administered in the ear intradermally, at the same inoculum site as the MRSA ATCC 43300 strain (PDT Group). This study also included the use of two control groups (both infected): One was treated with saline and the other was treated with non-photoactivated curcumin. The animals were euthanized 24 h after these treatments and samples of draining lymph node and treated ear were collected for examination. The PDT group showed lower bacterial load in the draining lymph node when compared to the saline and curcumin groups (p-value <0.05) 24 h after treatment. In addition to bacterial load, the PDT group presented a higher concentration of nitrates and nitrites in the draining lymph node when compared to the saline and curcumin groups (p-value <0.001). Examining the infectious site, despite apparently having similar inflammatory cell recruitment compared with the control groups, the PDT group showed a profile with less intense activity in the myeloperoxidase expression when compared to the saline group (p-value <0.001). Additionally, the detected concentration of cytokines such as IL-1β, IL-12, and IL-10 was significantly lower in the PDT group when compared to the saline group (p-value <0.01; p-value <0.05; p-value <0.05, respectively), thus presenting a less intense inflammatory response during infection resolution. Our pilot study showed for the first time the therapeutic potential of PDT using curcumin when administered intradermally in the treatment of infections caused by S. aureus in mice with T1DM.

Jaboticaba berry: A comprehensive review on its polyphenol composition, health effects, metabolism, and the development of food products

Jaboticaba, a popular Brazilian berry, has been studied due to its relevant polyphenol composition, health benefits and potential use for the development of derived food products. Considering that around 200 articles have been published in recent years, this review aims to provide comprehensive and updated information, as well as a critical discussion on: (i) jaboticaba polyphenolic composition and extraction methods for their accurate determination; (ii) jaboticaba polyphenol's metabolism; (iii) biological effects of the fruit and the relationship with its polyphenols and their metabolites; (iv) challenges in the development of jaboticaba derived products. The determination of jaboticaba polyphenols should employ hydrolysis procedures during extraction, followed by liquid chromatographic analysis. Jaboticaba polyphenols, mainly anthocyanins and ellagitannins, are extensively metabolized, and their metabolites are probably the most important contributors to the relevant health effects associated with the fruit, such as antioxidant, anti-inflammatory, antidiabetic, hepatoprotective and hypolipidemic. Most of the technological processing of jaboticaba fruit and its residues is related to their application as a colorant, antioxidant, antimicrobial and source of polyphenols. The scientific literature still lacks studies on the metabolism and bioactivity of polyphenols from jaboticaba in humans, as well as the effect of technological processes on these issues.

Potential Synergistic Action of Bioactive Compounds from Plant Extracts against Skin Infecting Microorganisms

The skin is an important organ that acts as a physical barrier to the outer environment. It is rich in immune cells such as keratinocytes, Langerhans cells, mast cells, and T cells, which provide the first line of defense mechanisms against numerous pathogens by activating both the innate and adaptive response. Cutaneous immunological processes may be stimulated or suppressed by numerous plant extracts via their immunomodulatory properties. Several plants are rich in bioactive molecules; many of these exert antimicrobial, antiviral, and antifungal effects. The present study describes the impact of plant extracts on the modulation of skin immunity, and their antimicrobial effects against selected skin invaders. Plant products remain valuable counterparts to modern pharmaceuticals and may be used to alleviate numerous skin disorders, including infected wounds, herpes, and tineas.

Photoactivated resveratrol controls intradermal infection by Staphylococcus aureus in mice: a pilot study

Staphylococcus aureus is one of the main causative agent of infections acquired in both community and hospital environment. In this context, photodynamic therapy (PDT) consists in using a photosensitizer that, activated by light, evokes the formation of reactive oxygen species (ROS), which lead to the death of microorganisms due to oxidative damage; it is useful tool since this action, harmful to pathogens, does not significantly injure human cells. In view of this, this work proposes a more in-depth study on the use of resveratrol (RSV) as a possible photosensitizer. It was observed, in the intradermal infection model in animals' ear dermis, that photoactivated resveratrol promotes an increase in myeloperoxidase expression with reduced bacterial load in the draining lymph node. Besides that, the draining lymph node of the animals treated with photoactivated RSV controls inflammation through IL-10 production. These are pioneers data and this work being a pilot study; then, other works must be conducted with the objective of elucidate the photoactivated resveratrol mechanism of action.

Photodamage on Staphylococcus aureus by natural extract from Tetragonia tetragonoides (Pall.) Kuntze: Clean method of extraction, characterization and photophysical studies

Photodynamic therapy (PDT) is a clinical modality that allows the destruction of tumor cells and microorganisms by reactive oxygen species, formed by the combination of photosensitizer (PS), molecular oxygen and adequate wavelength light. This research, through a clean methodology that involves pressurized liquids extraction (PLE), obtained a highly antimicrobial extract of Tetragonia tetragonoides, which rich in chlorophylls as photosensitizers. The Chlorophylls-based extract (Cbe-PLE) presented pharmacological safety, through the maintenance of cellular viability. In addition, Cbe-PLE showed great efficacy against Staphylococcus aureus, with severe dose-dependent damage to the cell wall of the pathogen. The obtained product has a high potential for the development of photostimulated phytotherapic formulations for clinical applications in localized infections, as a complementary therapeutic alternative to antibiotics.

Plinia cauliflora (Mart.) Kausel: A comprehensive ethnopharmacological review of a genuinely Brazilian species

ETHNOPHARMACOLOGICAL RELEVANCE

Plinia cauliflora (Mart.) Kausel is widespread in alluvial plains and open forests in Brazil, Argentina, and Paraguay. The fruits of P. cauliflora are used as food, and almost all parts of this species have long been used as a traditional Brazilian medicine for the treatment of skin irritations, flu, diarrhea, labyrinthitis, genito-urinary problems, and asthma.

THE AIM OF THE REVIEW

This review provides comprehensive and up-to-date information on P. cauliflora with regard to its ethnopharmacological uses, constituents, biological activities, and toxicology, all of which are useful for future research and the development of new drugs.

MATERIALS AND METHODS

The information and data on P. cauliflora were collected from ethnobotanical textbooks and scientific databases, such as PubMed, Scopus, EBSCO, Science Direct, Google, and Google Scholar.

RESULTS

The main chemical constituents in P. cauliflora preparations were depsides, flavonoids, and hydrolysable tannins. The main medicinal use of the species in Brazil is for the treatment of diarrhea. Although antimicrobial potential of this species has been demonstrated, data on gastrointestinal motility are still incipient and need further investigation. Studies that indicate the efficacy of its traditional use for sore throat, pelvic hemorrhage, uterine wounds, vaginal discharge, and flu are nonexistent. The scientific literature does not describe any toxic effects of its popular use. However, the available data do not allow us to conclude that the ethnomedicinal use of this species is safe, with a lack of well-designed preclinical tests and randomized clinical trials.

CONCLUSION

This review summarizes research on the traditional use, phytochemistry, biological activities, and toxicology of P. cauliflora. Although P. cauliflora possesses significant biological activities, much of its ethnomedicinal use has not been scientifically evaluated. Well-designed pharmacological and toxicological assays and randomized clinical trials are still needed to validate its ethnopharmacological use as an herbal medicine.