GC-MS-based metabolomics, antibacterial and anti-inflammatory investigations to characterize the quality of essential oil obtained from dried Xylopia aethiopica fruits from Ghana and Nigeria

Evidence for the efficacy of anti-inflammatory plants used in Brazilian traditional medicine with ethnopharmacological relevance

ETHNOPHARMACOLOGICAL RELEVANCE

When exacerbated, inflammatory processes can culminate in physical and emotional disorders and, if not stopped, can be lethal. The high prevalence of inflammation has become a public health problem, and the need for new drugs to treat this pathology is imminent. The use of medicinal plants has emerged as an alternative, and a survey of data that corroborates its application in inflammatory diseases is the starting point. Furthermore, Brazil harbors a megadiversity, and the traditional use of plants is relevant and needs to be preserved and carefully explored for the discovery of new medicines.

AIM OF THE STUDY

This review sought to survey the medicinal plants traditionally used in Brazil for the treatment of inflammatory processes and to perform, in an integrative way, a data survey of these species and analysis of their phytochemical, pharmacological, and molecular approaches.

MATERIALS AND METHODS

Brazilian plants that are traditionally used for inflammation (ophthalmia, throat inflammation, orchitis, urinary tract inflammation, ear inflammation, and inflammation in general) are listed in the DATAPLAMT database. This database contains information on approximately 3400 native plants used by Brazilians, which were registered in specific documents produced until 1950. These inflammatory disorders were searched in scientific databases (PubMed/Medline, Scopus, Web of Science, Lilacs, Scielo, Virtual Health Library), with standardization of DECS/MESH descriptors for inflammation in English, Spanish, French, and Portuguese, without chronological limitations. For the inclusion criteria, all articles had to be of the evaluated plant species, without association of synthesized substances, and full articles free available in any of the four languages searched. Duplicated articles and those that were not freely available were excluded.

RESULTS

A total of 126 species were identified, culminating in 6181 articles in the search. After evaluation of the inclusion criteria, 172 articles representing 40 different species and 38 families were included in the study. Comparison of reproducibility in intra-species results became difficult because of the large number of extraction solvents tested and the wide diversity of evaluation models used. Although the number of in vitro and in vivo evaluations was high, only one clinical study was found (Abrus precatorius). In the phytochemical analyses, more than 225 compounds, mostly phenolic compounds, were identified.

CONCLUSION

This review allowed the grouping of preclinical and clinical studies of several Brazilian species traditionally used for the treatment of many types of inflammation, corroborating new searches for their pharmacological properties as a way to aid public health. Furthermore, the large number of plants that have not yet been studied has encouraged new research to revive traditional knowledge.

Chemical Constituents and Antimicrobial and Antioxidant Activities of Essential Oil from Dried Seeds of Xylopia aethiopica

The study aimed to investigate the chemical composition and antimicrobial and antioxidant activities of the essential oil from dried seeds of Xylopia aethiopica. The essential oil was obtained by hydrodistillation and analyzed by GC/FID and GC/MS. The essential oil yield was 1.35%. Forty-nine compounds were identified in the essential oil with 1,8-cineole (16.3%), β-pinene (14.8%), trans-pinocarveol (9.1%), myrtenol (8.3%), α-pinene (5.9%), and terpinen-4-ol (5.6%) as major components. The antimicrobial activity of this essential oil was studied using disk diffusion and broth microdilution methods on four bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa) and one fungus (Candida albicans). The essential oil exhibited excellent activity against S. aureus, E. faecalis, and C. albicans and moderate activity against E. coli. Among all strains tested, C. albicans showed the best sensitivity with a MIC of 50 mg/mL. The antioxidant activity was examined using a DPPH-free radical scavenging assay. The essential oil of X. aethiopica showed low antioxidant activity (IC50 = 784.604 ± 0.320 mg/mL) compared to that of ascorbic acid and the reference compound (IC50 = 0.163 ± 0.003 mg/mL). The results indicate that consumption of X. aethiopica seeds can reduce the virulence of food-borne pathogens and their resistance to antibiotics.

Antimicrobial activity of Xylopia pancheri Baill. Leaf extract against susceptible and resistant Staphylococcus aureus

Antibacterial activity of Xylopia pancheri Baill. (Annonaceae) leaf extract was investigated against susceptible Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and extended-spectrum-β-lactamase (ESBL)-producing Pseudomonas aeruginosa. Results showed that X. pancheri leaf extract displayed antibacterial activity against S. aureus with higher inhibitory effect on MRSA compared to control gentamycin antibiotic, and IC₅₀ value of 36.97 μg/mL [95%CI:29.59-46.18] against MRSA.

Essential Oils of Aromatic Plant Species from the Atlantic Rainforest Exhibit Extensive Chemical Diversity and Antimicrobial Activity

Microbial resistance, caused by the overuse or inadequate application of antibiotics, is a worldwide crisis, increasing the risk of treatment failure and healthcare costs. Plant essential oils (EOs) consist of hydrophobic metabolites with antimicrobial activity. The antimicrobial potential of the chemical diversity of plants from the Atlantic Rainforest remains scarcely characterized. In the current work, we determined the metabolite profile of the EOs from aromatic plants from nine locations and accessed their antimicrobial and biocidal activity by agar diffusion assays, minimum inhibitory concentration, time-kill and cell-component leakage assays. The pharmacokinetic properties of the EO compounds were investigated by in silico tools. More than a hundred metabolites were identified, mainly consisting of sesqui and monoterpenes. Individual plants and botanical families exhibited extensive chemical variations in their EO composition. Probabilistic models demonstrated that qualitative and quantitative differences contribute to chemical diversity, depending on the botanical family. The EOs exhibited antimicrobial biocidal activity against pathogenic bacteria, fungi and multiple predicted pharmacological targets. Our results demonstrate the antimicrobial potential of EOs from rainforest plants, indicate novel macromolecular targets, and contribute to highlighting the chemical diversity of native species.

Data handling and data analysis in metabolomic studies of essential oils using GC-MS

Gas chromatography electron impact ionization mass spectrometry (GC-EI-MS) has been, and remains, the most widely applied analytical technique for metabolomic studies of essential oils. GC-EI-MS analysis of complex samples, such as essential oils, creates a large volume of data. Creating predictive models for such samples and observing patterns within complex data sets presents a significant challenge and requires application of robust data handling and data analysis methods. Accordingly, a wide variety of software and algorithms has been investigated and developed for this purpose over the years. This review provides an overview and summary of that research effort, and attempts to classify and compare different data handling and data analysis procedures that have been reported to-date in the metabolomic study of essential oils using GC-EI-MS.

Diversity of Essential Oil-Secretory Cells and Oil Composition in Flowers and Buds of Magnolia sirindhorniae and Its Biological Activities

Magnolia sirindhorniae Noot. & Chalermglin produces fragrant flowers. The volatile oil secretary cells, quantity and quality as well as antioxidant and antimicrobial activities of the oils extracted from buds and flowers, have been investigated. The distribution of essential oil secretory cell in bud and flower revealed that the density and size of the oil cells were significantly higher in flowers compared to buds. In different floral parts, carpel has a higher oil cell density followed by gynophore and tepal. The histochemical analysis revealed the essential oil is synthesized in oil secretory cells. The volatile oil yield was 0.25 % in the buds and 0.50 % in flowers. GC/FID and GC/MS analysis identified 33 compounds contributing 83.2-83.5 % of the total essential oil composition. Linalool is the main constituent contributing 58.9 % and 51.0 % in the buds and flowers oils, respectively. The essential oil extracted from the flowers showed higher antimicrobial efficacy against Klebsiella pneumoniae and Staphylococcus aureus. Similarly, the essential oil isolated from the flowers depicts higher free radical scavenging, and antioxidant activity compared to buds' oil.

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.