Airborne antituberculosis activity of Eucalyptus citriodora essential oil

Chemometric-based drug discovery approaches from natural origins using hyphenated chromatographic techniques

INTRODUCTION

Isolation and characterization of bioactive components from complex matrices of marine or terrestrial biological origins are the most challenging issues for natural product chemists. Biochemometric is a new potential scope in natural product analytical science, and it is a methodology to find the compound's correlation to their bioactivity with the help of hyphenated chromatographic techniques and chemometric tools.

OBJECTIVES

The present review aims to evaluate the application of chemometric tools coupled to chromatographic techniques for drug discovery from natural resources.

METHODS

The searching keywords "biochemometric," "chemometric," "chromatography," "natural products bioassay," and "bioassay" were selected to search the published articles between 2010-2023 using different search engines including "Pubmed", "Web of Science," "ScienceDirect," and "Google scholar."

RESULTS

An initial stage in natural product analysis is applying the chromatographic hyphenated techniques in conjunction with biochemometric approaches. Among the applied chromatographic techniques, liquid chromatography (LC) techniques, have taken up more than half (53%) and also, mass spectroscopy (MS)-based chromatographic techniques such as LC-MS are the most widely used techniques applied in combination with chemometric methods for natural products bioassay. Considering the complexity of dataset achieved from chromatographic hyphenated techniques, chemometric tools have been increasingly employed for phytochemical studies in the context of determining botanicals geographical origin, quality control, and detection of bioactive compounds.

CONCLUSION

Biochemometric application is expected to be further improved with advancing in data acquisition methods, new efficient preprocessing, model validation and variable selection methods which would guarantee that the applied model to have good prediction ability in compound relation to its bioactivity.

The Ethnopharmacology, Phytochemistry and Bioactivities of the Corymbia Genus (Myrtaceae)

Plants have been vital to human survival for aeons, especially for their unique medicinal properties. Trees of the Eucalyptus genus are well known for their medicinal properties; however, little is known of the ethnopharmacology and bioactivities of their close relatives in the Corymbia genus. Given the current lack of widespread knowledge of the Corymbia genus, this review aims to provide the first summary of the ethnopharmacology, phytochemistry and bioactivities of this genus. The Scopus, Web of Science, PubMed and Google Scholar databases were searched to identify research articles on the biological activities, phytochemistry and ethnomedical uses of Corymbia species. Of the 115 Corymbia species known, 14 species were found to have ethnomedical uses for the leaves, kino and/or bark. Analysis of the references obtained for these 14 Corymbia spp. revealed that the essential oils, crude extracts and compounds isolated from these species possess an array of biological activities including anti-bacterial, anti-fungal, anti-protozoal, anti-viral, larvicidal, insecticidal, acaricidal, anti-inflammatory, anti-oxidant, anti-cancer and anti-diabetic activities, highlighting the potential for this under-studied genus to provide lead compounds and treatments for a host of medical conditions.

Ethnobotanical study of nutraceutical plants used to manage opportunistic infections associated with HIV/AIDS in Acholi sub-region, Northern Uganda

BACKGROUND

Nutraceutical plants play a potential role as supportive treatment with antiretroviral drugs in the management of opportunistic infections associated with HIV/AIDS. There is limited documentation of nutraceutical plants in Northern Uganda and limited literature addressing processes to be adopted for quality assurance of herbal formulations in Uganda. This study aimed to document plant species with nutritional and medicinal properties used for managing opportunistic infections associated with HIV/AIDS by traditional medicine practitioners (TMPs), who included professional herbalists, herbal farmers and herbal sellers in Acholi sub region, Northern Uganda.

METHODS

An ethnobotanical study was carried out in Amuru, Gulu and Pader districts, Northern Uganda. Cross-sectional data were collected using purposive and snowball sampling techniques. A total of four hundred (378 women and 22 men) informants were selected. Data were collected using semistructured interviews, focus group discussions and direct observation. Data were analysed using descriptive statistics, familiarity index (FI), fidelity level (FL) and informant consensus factor (ICF).

RESULTS

This study recorded a total of 84 nutraceutical plant species, which are used to manage opportunistic infections associated with HIV/AIDS. Most abundant families were Leguminoceae, Asteraceae and Solanaceae. Six nutraceutical plants that had higher fidelity level and familiarity index values included Momordica foetida Schumach, Erigeron floribundus (Kunth) Sch. Bip, Mangifera indica L, Cajanus cajan L. Millsp, Eucalyptus globulus Labill and Cucurbita pepo L. Respondents' knowledge on nutraceutical plants had a positive significant correlation with age (R2 = 0.0524, p ≤ 0.01). The popular mode of preparation are decoctions/boiling in water (70%), while the most used route of administration is oral (76%). TMPs tried to ensure that during collection and processing, plant materials were free from contamination. TMPs reported limited knowledge on preservation techniques.

CONCLUSIONS

This study demonstrates the availability and diversity of nutraceutical plants in Uganda and reports methods of processing and administration used by TMPs. Both men and women used nutraceutical plants to manage opportunistic infections associated with HIV/AIDS and showed great extent of their traditional knowledge. Most of the nutraceutical plants in study area are wild and abundant; however, high percentage use of plant roots and bark threatens the sustainable use from the wild.

Encapsulation of Zataria multiflora essential oil in polyvinyl alcohol/chitosan/gelatin thermo-responsive hydrogel: Synthesis, physico-chemical properties, and biological investigations

Zataria multiflora essential oil is a natural volatile plant product whose therapeutic applications require a delivery platform. Biomaterial-based hydrogels have been extensively used in biomedical applications, and they are promising platforms to encapsulate essential oils. Among different hydrogels, intelligent hydrogels have recently attracted many interests because of their response to environmental stimuli such as temperature. Herein, Zataria multiflora essential oil is encapsulated in a polyvinyl alcohol/chitosan/gelatin hydrogel as a positive thermo-responsive and antifungal platform. According to the optical microscopic image, the encapsulated spherical essential oil droplets reveal a mean size of 1.10 ± 0.64 μm, which are in consistent with the SEM imaging results. Encapsulation efficacy and loading capacity are 98.66 % and 12.98 %, respectively. These results confirm the successful efficient encapsulation of the Zataria multiflora essential oil within the hydrogel. The chemical compositions of the Zataria multiflora essential oil and the fabricated hydrogel are analyzed by gas chromatography-mass spectroscopy (GC-MS) and Fourier transform infrared (FTIR) techniques. It is found that thymol (44.30 %) and γ-terpinene (22.62 %) are the main constituents of the Zataria multiflora essential oil. The produced hydrogel inhibits the metabolic activity of Candida albicans biofilms (~60-80 %), which can be related to the antifungal activity of the essential oil constituents and chitosan. Based on the rheological results, the produced thermo-responsive hydrogel shows a gel-sol viscoelastic transition at a temperature of 24.5 °C. This transition leads to a facile release of the loaded essential oil. The release test depicts that about 30 % of Zataria multiflora essential oil is released during the first 16 min. In addition, 2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay demonstrates that the designed thermo-sensitive formulation is biocompatible with high cell viability (over 96 %). The fabricated hydrogel can be deemed as a potential intelligent drug delivery platform for controlling cutaneous candidiasis due to antifungal effectiveness and less toxicity, which can be a promising alternative to traditional drug delivery systems.

Helichrysum italicum: From Extraction, Distillation, and Encapsulation Techniques to Beneficial Health Effects

Helichrysum italicum (family Asteraceae), due to its various beneficial health effects, represents an important plant in the traditional medicine of Mediterranean countries. Currently, there is a renewed interest in this medicinal plant, especially in investigations involving the isolation and identification of its bioactive compounds from extracts and essential oils, as well as in experimental validation of their pharmacological activities. In this paper, we review the current knowledge on the beneficial health effects of Helichrysum italicum extracts, essential oils, and their major bioactive polyphenolic compounds, ranging from antioxidative, anti-inflammatory, and anticarcinogenic activities to their antiviral, antimicrobial, insecticidal, and antiparasitic effects. This review also provides an overview of the most promising extraction and distillation techniques for obtaining high-quality extracts and essential oils from Helichrysum italicum, as well as methods for determining their antioxidative, antimicrobial, anti-inflammatory, and anticarcinogenic activities. Finally, new ideas for in silico studies of molecular mechanisms of bioactive polyphenols from Helichrysum italicum, together with novel suggestions for their improved bioavailability through diverse encapsulation techniques, are introduced.

Selected Phytochemicals to Combat Lungs Injury: Natural Care

The human has two lungs responsible for respiration and drug metabolism. Severe lung infection caused by bacteria, mycobacteria, viruses, fungi, and parasites may lead to lungs injury. Smoking and tobacco consumption may also produce lungs injury. Inflammatory and pain mediators are secreted by alveolar macrophages. The inflammatory mediators, such as cytokines, interleukin (IL)-1, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α, neutrophils, and fibroblasts are accumulated in the alveoli sac, which becomes infected. It may lead to hypoxia followed by severe pulmonary congestion and the death of the patient. There is an urgent need for the treatment of artificial respiration and ventilation. However, the situation may be the worst for patients suffering from lung cancer, pulmonary tuberculosis, and acute pneumonia caused by acute respiratory distress syndrome (ARDS). Re-urgency has been happening in the case of coronavirus disease of 2019 (COVID-19) patients. Therefore, it is needed to protect the lungs with the intake of natural phytomedicines. In the present review, several selected phyto components having the potential role in lung injury therapy have been discussed. Regular intake of natural vegetables and fruits bearing these constituents may save the lungs even in the dangerous attack of SARS-CoV-2 in lung cancer, pulmonary TB, and pneumatic patients.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

Antimycobacterial Activity and Safety Profile Assessment of Alpinia galanga and Tinospora cordifolia

Tuberculosis (TB) remains a common deadly infectious disease and worldwide a major health problem. The current study was therefore designed to investigate the in vitro antimycobacterial activity of different extracts of Alpinia galanga and Tinospora cordifolia. Moreover, a safety assessment for both plants was carried out. Dichloromethane and ethanolic extracts of each plant were examined against H37Rv INH-sensitive and resistant INH strains of Mycobacterium tuberculosis. The safety assessment of both plants has been performed through in vivo acute and chronic toxicity studies in animal model. Body weight, food consumption, water intake, organ's weight, and haematological and biochemical parameters of blood and serum were evaluated. The extracts of A. galanga and T. cordifolia produced significant and dose-dependent inhibitory activity with maximum effect of 18-32% at 50 μg/ml against both strains of M. tuberculosis. No effect on the body weight or food and water consumption was observed but A. galanga caused significantly an increase in the relative weight of the heart, liver, spleen, and kidney. Haematological studies of both plants revealed a slight but significant fall in the RBC and WBC level as well as haemoglobin and platelets. In addition, A. galanga extracts increased significantly liver enzymes and bilirubin and glucose.

Suppression of inflammatory and infection responses in lung macrophages by eucalyptus oil and its constituent 1,8-cineole: Role of pattern recognition receptors TREM-1 and NLRP3, the MAP kinase regulator MKP-1, and NFκB

Eucalyptus oil (EO) used in traditional medicine continues to prove useful for aroma therapy in respiratory ailments; however, there is a paucity of information on its mechanism of action and active components. In this direction, we investigated EO and its dominant constituent 1,8–cineole (eucalyptol) using the murine lung alveolar macrophage (AM) cell line MH-S. In an LPS-induced AM inflammation model, pre-treatment with EO significantly reduced (P ≤0.01or 0.05) the pro-inflammatory mediators TNF-α, IL-1 (α and β), and NO, albeit at a variable rate and extent; 1,8-cineole diminished IL-1 and IL-6. In a mycobacterial-infection AM model, EO pre-treatment or post-treatment significantly enhanced (P ≤0.01) the phagocytic activity and pathogen clearance. 1,8-cineole also significantly enhanced the pathogen clearance though the phagocytic activity was not significantly altered. EO or 1,8-cineole pre-treatment attenuated LPS-induced inflammatory signaling pathways at various levels accompanied by diminished inflammatory response. Among the pattern recognition receptors (PRRs) involved in LPS signaling, the TREM pathway surface receptor (TREM-1) was significantly downregulated. Importantly, the pre-treatments significantly downregulated (P ≤0.01) the intracellular PRR receptor NLRP3 of the inflammasome, which is consistent with the decrease in IL-1β secretion. Of the shared downstream signaling cascade for these PRR pathways, there was significant attenuation of phosphorylation of the transcription factor NF-κB and p38 (but increased phosphorylation of the other two MAP kinases, ERK1/2 and JNK1/2). 1,8-cineole showed a similar general trend except for an opposite effect on NF-κB and JNK1/2. In this context, either pre-treatment caused a significant downregulation of MKP-1 phosphatase, a negative regulator of MAPKs. Collectively, our results demonstrate that the anti-inflammatory activity of EO and 1,8-cineole is modulated via selective downregulation of the PRR pathways, including PRR receptors (TREM-1 and NLRP3) and common downstream signaling cascade partners (NF-κB, MAPKs, MKP-1). To our knowledge, this is the first report on the modulatory role of TREM-1 and NLRP3 inflammasome pathways and the MAPK negative regulator MKP-1 in context of the anti-inflammatory potential of EO and its constituent 1,8-cineole.

Antibacterial Properties of Flavonoids from Kino of the Eucalypt Tree, Corymbia torelliana

Traditional medicine and ecological cues can both help to reveal bioactive natural compounds. Indigenous Australians have long used kino from trunks of the eucalypt tree, Corymbia citriodora, in traditional medicine. A closely related eucalypt, C. torelliana, produces a fruit resin with antimicrobial properties that is highly attractive to stingless bees. We tested the antimicrobial activity of extracts from kino of C. citriodora, C. torelliana × C. citriodora, and C. torelliana against three Gram-negative and two Gram-positive bacteria and the unicellular fungus, Candida albicans. All extracts were active against all microbes, with the highest activity observed against P. aeruginosa. We tested the activity of seven flavonoids from the kino of C. torelliana against P. aeruginosa and S. aureus. All flavonoids were active against P. aeruginosa, and one compound, (+)-(2S)-4',5,7-trihydroxy-6-methylflavanone, was active against S. aureus. Another compound, 4',5,7-trihydroxy-6,8-dimethylflavanone, greatly increased biofilm formation by both P. aeruginosa and S. aureus. The presence or absence of methyl groups at positions 6 and 8 in the flavonoid A ring determined their anti-Staphylococcus and biofilm-stimulating activity. One of the most abundant and active compounds, 3,4',5,7-tetrahydroxyflavanone, was tested further against P. aeruginosa and was found to be bacteriostatic at its minimum inhibitory concentration of 200 µg/mL. This flavanonol reduced adhesion of P. aeruginosa cells while inducing no cytotoxic effects in Vero cells. This study demonstrated the antimicrobial properties of flavonoids in eucalypt kino and highlighted that traditional medicinal knowledge and ecological cues can reveal valuable natural compounds.

Evaluation of Chemical Composition and Antileishmanial and Antituberculosis Activities of Essential Oils of Piper Species

Essential oils from fresh Piperaceae leaves were obtained by hydrodistillation and analyzed by gas chromatography mass spectrometry (GC-MS), and a total of 68 components were identified. Principal components analysis results showed a chemical variability between species, with sesquiterpene compounds predominating in the majority of species analyzed. The composition of the essential oil of Piper mosenii was described for the first time. The cytotoxicity of the essential oils was evaluated in peritoneal macrophages and the oils of P. rivinoides, P. arboretum, and P. aduncum exhibited the highest values, with cytotoxic concentration at 50% (CC50) > 200 µg/mL. Both P. diospyrifolium and P. aduncum displayed activity against Leishmania amazonensis, and were more selective for the parasite than for the macrophages, with a selectivity index (SI) of 2.35 and >5.52, respectively. These SI values were greater than the 1 for the standard drug pentamidine. The antileishmanial activity of the essential oils of P. diospyrifolium and P. aduncum was described for the first time. P. rivinoides, P. cernuum, and P. diospyrifolium displayed moderate activity against the Mycobacterium tuberculosis H37Rv bacillus, with a minimum inhibitory concentration (MIC) of 125 µg/mL. These results are relevant and suggests their potential for therapeutic purposes. Nevertheless, further studies are required to explain the exact mechanism of action of these essential oils.

β-Citronellol, an alcoholic monoterpene with inhibitory properties on the contractility of rat trachea

β-Citronellol is an alcoholic monoterpene found in essential oils such Cymbopogon citratus (a plant with antihypertensive properties). β-Citronellol can act against pathogenic microorganisms that affect airways and, in virtue of the popular use of β-citronellol-enriched essential oils in aromatherapy, we assessed its pharmacologic effects on the contractility of rat trachea. Contractions of isolated tracheal rings were recorded isometrically through a force transducer connected to a data-acquisition device. β-Citronellol relaxed sustained contractions induced by acetylcholine or high extracellular potassium, but half-maximal inhibitory concentrations (IC50) for K(+)-elicited stimuli were smaller than those for cholinergic contractions. It also inhibited contractions induced by electrical field stimulation or sodium orthovanadate with pharmacologic potency equivalent to that seen against acetylcholine-induced contractions. When contractions were evoked by selective recruitment of Ca2+ from the extracellular medium, β-citronellol preferentially inhibited contractions that involved voltage-operated (but not receptor-operated) pathways. β-Citronellol (but not verapamil) inhibited contractions induced by restoration of external Ca2+ levels after depleting internal Ca2+ stores with the concomitant presence of thapsigargin and recurrent challenge with acetylcholine. Treatment of tracheal rings with L-NAME, indomethacin or tetraethylammonium did not change the relaxing effects of β-citronellol. Inhibition of transient receptor potential vanilloid subtype 1 (TRPV1) or transient receptor potential ankyrin 1 (TRPA1) receptors with selective antagonists caused no change in the effects of β-citronellol. In conclusion, β-citronellol exerted inhibitory effects on rat tracheal rings, with predominant effects on contractions that recruit Ca2+ inflow towards the cytosol by voltage-gated pathways, whereas it appears less active against contractions elicited by receptor-operated Ca2+ channels.

Essential oils in the treatment of respiratory tract diseases highlighting their role in bacterial infections and their anti-inflammatory action: a review

The appearance of multidrug resistant bacteria and growing antibiotic resistance is leading to a continuous need for discovering new drugs and alternative treatments against infections. The investigation of the antibacterial effect of essential oils (EOs), which are commonly used nowadays in cosmetics, health care, traditional medicine and food industry, could be one of the promising solutions for this worldwide problem. EOs have a complex mode of action due to their multiple composition. Respiratory tract diseases (RTDs) associated with bacterial infection and inflammation affect a large number of people from every age group worldwide. Because of volatility, EOs can easily reach the upper and lower parts of the respiratory tract via inhalation. Moreover, due to their antimicrobial and anti-inflammatory potency, they offer an effective treatment in respiratory tract infections (RTIs). The purpose of this review is to describe the most frequently developing infections of the upper and lower respiratory tract and to show methods used for the determination of the antibacterial activity of EOs by gaseous contact. The mode of action of EOs on bacterial cells and their anti-inflammatory action are also discussed. Results coming from recently performed in vivo animal studies as well as human trials are also reported. Patents deal with the role of EOs and their volatile constituents in the treatment of RTIs are also introduced. On the whole, this review aimed at showing EOs as potential antimicrobials and as anti-inflammatory agents to alleviate symptoms and signs of RTDs including RTIs. Copyright © 2015 John Wiley & Sons, Ltd.

Countercurrent Separation of Natural Products: An Update

This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 2008, 71, 1489-1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.