Antifungal and antimycotoxigenic properties of chemically characterised essential oil ofBoswellia serrataRoxb. ex Colebr

In vitro efficacy of Boswellia carterii resin extracts formulated as an emulsifiable concentrate against Tetranychus urticae and phytopathogenic fungi

Contemporary agriculture heavily relies on pesticides for pest eradication and disease management. Consequently, current study was carried out to assess the acaricidal/antifungal efficacy of emulsifiable concentrate (10 % EC) derived from Boswellia carterii (B. carterii) against adult females of Tetranychus urticae (T. urticae), and five fungal pathogens. The meticulous examination of the chemical constitution of the crude extracts derived from the resin of B. carterii was conducted through the employment of the venerable technique known as Gas-Liquid Chromatography (GLC). The formulated petroleum-ether extract (FPEE) and formulated ethyl-acetate extract (FEAE) of B. carterii at a concentration of 10 mg ml-1 exhibited notable antioxidant activity with rates of 62.0 % and 90.8 %, respectively. In vitro, the FEAE exhibited potent inhibition against all the tested phytopathogenic fungi at different concentrations, whereas FPEE showed comparatively less efficacy. Interestingly, at 4000 ppm concentration, FEAE completely ceased the mycelial growth compared with the control. Moreover, following a span of 72 h of intervention, FPEE exhibited a greater degree of toxicity towards mature females of the T. urticae. This was evidenced by the LC50 value of 422.52 parts per million (ppm) for FPEE, which surpassed the LC50 value of 539.50 ppm observed for FEAE. In summary, the present study indicates that B. carterii resin formulated as an emulsifiable concentrate (10 % EC) can offer a natural and effective alternative for integrated pest management, thereby reducing reliance on synthetic pesticides and offering a more environmentally sustainable strategy for pest control.

Antifungal activity of essential oils and their combinations against storage fungi

We aimed to evaluate the fungicidal activity of essential oils (EOs) from Baccharis dracunculifolia (Asteraceae), Baccharis uncinella (Asteraceae), Mentha arvensis (Lamiaceae), Salvia officinalis (Lamiaceae), Melaleuca alternifolia (Myrtaceae), and Cymbopogon nardus (Poaceae) in the in vitro control of mycotoxin-producing strains of Aspergillus niger, Aspergillus nomius, Aspergillus flavus, and Fusarium graminearum. EOs' chemical composition was analyzed by gas chromatography-mass spectrometry, and a total of 19, 21, 18, 20, 17, and 15 compounds were identified in B. dracunculifolia, B. uncinella, S. officinalis, M. arvensis, M. alternifolia, and C. nardus EOs, respectively. Contact and volatilization bioassays were performed, for which M. alternifolia and C. nardus EOs had the greatest fungicidal effect (> 90%). Therefore, these EOs were evaluated for minimum inhibitory concentration, medium inhibitory concentration, and sporulation. Effects from the combined use of EOs were also evaluated. EOs interacted in combination, displaying an additive effect against F. graminearum and A. flavus and an antagonistic effect against the remaining isolates. We conclude that C. nardus EO was effective in the control of storage pathogens and that combined EOs can improve their antifungal effects.

Unani medicinal herbs as potential air disinfectants: an evidence-based review

OBJECTIVES

Indoor air quality has a significant impact on our health and quality of life, as people spends 80-90% of their time indoors. Fumigation of several medicinal herbs has been recommended by Unani scholars to improve air quality, but their efficacy in air purification is still unknown. Hence, this article aims to discuss the applicability of proposed medicinal herbs in the light of current researches.

METHODS

A manual literature survey of classical Unani texts was conducted to collect information about the herbs recommended for air purification. In addition, research databases such as PubMed, Google Scholar, and ScienceDirect were extensively searched for evidence on the efficacy and mechanism of action of the suggested herbs in air purification.

RESULTS

In classical Unani texts, authors have found descriptions of 26 herbs that have been recommended for improving air quality. In-vitro studies have confirmed the antimicrobial activity of 19 of these herbs. Moreover, the efficacy of Styrax benzoin, Commiphora myrrha and Acorus calamus fumigation on aerial microbes have also been validated by studies.

CONCLUSIONS

The findings of the literature review clearly demonstrated that the herbs recommended by Unani scholars for air purification have broad-spectrum antimicrobial activity, indicating that these herbs could be a potential candidate for air disinfectant. Therefore, authors recommend the further researches on proposed herbs to validate their efficiency against airborne pathogens in the vapour phase.

Influence of Technological Factors on the Quality of Chitosan Microcapsules with Boswellia serata L. Essential Oil

Essential oils contain many volatile compounds that are not stable and lose their pharmacological effect when exposed to the environment. The aim of this study is to protect Boswellia serrata L. essential oil from environmental factors by encapsulation and determine the influence of chitosan concentration and types (2%, 4%; medium and high molecular weights), essential oil concentration, different emulsifiers (Tween and Span), and technological factors (stirring time, launch height, drip rate) on the physical parameters, morphology, texture, and other parameters of the generated gels, emulsions, and microcapsules. For the first time, Boswellia serrata L. essential oil microcapsules with chitosan were prepared by coacervation. Hardness, consistency, stickiness, viscosity, and pH of chitosan gels were tested. Freshly obtained microcapsules were examined for moisture, hardness, resistance to compression, size, and morphology. Results show that different molecular weights and concentrations of chitosan affected gel hardness, consistency, stickiness, viscosity, mobility, and adhesion. An increase in chitosan concentration from 2% to 4% significantly changed the appearance of the microcapsules. It was found that spherical microcapsules were formed when using MMW and HMW 80/1000 chitosan. Chitosan molecular weight, concentration, essential oil concentration, and stirring time all had an impact on the hardness of the microcapsules and their resistance to compression.

Boswellic acids/Boswellia serrata extract as a potential COVID-19 therapeutic agent in the elderly

The most severe cases of COVID-19, and the highest rates of death, are among the elderly. There is an urgent need to search for an agent to treat the disease and control its progression. Boswellia serrata is traditionally used to treat chronic inflammatory diseases of the lung. This review aims to highlight currently published research that has shown evidence of potential therapeutic effects of boswellic acids (BA) and B. serrata extract against COVID-19 and associated conditions. We reviewed the published information up to March 2021. Studies were collected through a search of online electronic databases (academic libraries such as PubMed, Scopus, Web of Science, and Egyptian Knowledge Bank). Several recent studies reported that BAs and B. serrata extract are safe agents and have multiple beneficial activities in treating similar symptoms experienced by patients with COVID-19. Because of the low oral bioavailability and improvement of buccal/oral cavity hygiene, traditional use by chewing B. serrata gum may be more beneficial than oral use. It is the cheapest option for a lot of poorer people. The promising effect of B. serrata and BA can be attributed to its antioxidant, anti-inflammatory, immunomodulatory, cardioprotective, anti-platelet aggregation, antibacterial, antifungal, and broad antiviral activity. B. serrata and BA act by multiple mechanisms. The most common mechanism may be through direct interaction with IκB kinases and inhibiting nuclear factor-κB-regulated gene expression. However, the most recent mechanism proposed that BA not only inhibited the formation of classical 5-lipoxygenase products but also produced anti-inflammatory LOX-isoform-selective modulators. In conclusion a small to moderate dose B. serrata extract may be useful in the enhancing adaptive immune response in mild to moderate symptoms of COVID-19. However, large doses of BA may be beneficial in suppressing uncontrolled activation of the innate immune response. More clinical results are required to determine with certainty whether there is sufficient evidence of the benefits against COVID-19.

Activity of Liquid and Volatile Fractions of Essential Oils against Biofilm Formed by Selected Reference Strains on Polystyrene and Hydroxyapatite Surfaces

Biofilms are surface-attached, structured microbial communities displaying higher tolerance to antimicrobial agents in comparison to planktonic cells. An estimated 80% of all infections are thought to be biofilm-related. The drying pipeline of new antibiotics efficient against biofilm-forming pathogens urges the search for alternative routes of treatment. Essential Oils (EOs), extracted from medicinally important plants, are a reservoir of bioactive compounds that may serve as a foothold in investigating novel antibiofilm compounds. The aim of this study was to compare antimicrobial activity of liquid and volatile fractions of tested EOs against biofilm-forming pathogens using different techniques. In this research, we tested five EOs, extracted from Syzygium aromaticum L., Boswelia serrata Roxb., Juniperus virginiana L., Pelargonium graveolens L. and Melaleuca alternifolia Cheel., against planktonic and biofilm forms of five selected reference strains, namely Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. To obtain cohesive results, we applied four various methodological approaches: to assess the activity of the liquid fraction of EOs, disc diffusion and the microdilution method were applied; to test EOs’ volatile fraction, the AntiBioVol assay and modified Antibiofilm Dressing Activity Measurement (A.D.A.M.) were used. The molecular composition and dynamics of antimicrobial substances released from specific EOs was measured using Gas Chromatography–Mass Spectrometry (GC-MS). The antimicrobial potency of EO’s volatile fraction against biofilm formed by tested strains differed from that of the liquid fraction and was related to the molecular weight of volatile compounds. The liquid fraction of CW-EO and volatile fraction of F-EO acted in the strongest manner against biofilm of C. albicans. The addition of 0.5% Tween 20 to liquid phase, enhanced activity of G-EO against E. coli and K. pneumoniae biofilm. EO activity depended on the microbial species it was applied against and the chosen assessment methodology. While all tested EOs have shown a certain level of antimicrobial and antibiofilm effect, our results indicate that the choice of EO to be applied against a specific biofilm-forming pathogen requires careful consideration with regard to the above-listed aspects. Nevertheless, the results presented in this research contribute to the growing body of evidence indicating the beneficial effects of EOs, which may be applied to fight biofilm-forming pathogens.

Plant Phytochemicals in Food Preservation: Antifungal Bioactivity: A Review

Synthetic food additives generate a negative perception in consumers. This fact generates an important pressure on food manufacturers, searching for safer natural alternatives. Phytochemicals (such as polyphenols and thiols) and plant essential oils (terpenoids) possess antimicrobial activities that are able to prevent food spoilage due to fungi (e.g., Aspergillus, Penicillium) and intoxications (due to mycotoxins), both of which are important economic and health problems worldwide. This review summarizes industrially interesting antifungal bioactivities from the three main types of plant nutraceuticals: terpenoids (as thymol), polyphenols (as resveratrol) and thiols (as allicin) as well as some of the mechanisms of action. These phytochemicals are widely distributed in fruits and vegetables and are very useful in food preservation as they inhibit growth of important spoilage and pathogenic fungi, affecting especially mycelial growth and germination. Terpenoids and essential oils are the most abundant group of secondary metabolites found in plant extracts, especially in common aromatic plants, but polyphenols are a more remarkable group of bioactive compounds as they show a broad array of bioactivities.

Influence of Two Garlic-Derived Compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), on Growth and Mycotoxin Production by Fusarium Species In Vitro and in Stored Cereals

Two garlic-derived compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), were examined for their efficacy against mycotoxigenic Fusarium species (F. graminearum, F. langsethiae, F. verticillioides). The objectives were to assess the inhibitory effect of these compounds on growth and mycotoxin production in vitro, and in situ in artificially inoculated wheat, oats and maize with one isolate of each respectively, at different water activity (a_w) conditions when stored for up to 20 days at 25 °C. In vitro, 200 ppm of either PTS or PTSO reduced fungal growth by 50-100% and mycotoxin production by >90% depending on species, mycotoxin and a_w conditions on milled wheat, oats and maize respectively. PTS was generally more effective than PTSO. Deoxynivalenol (DON) and zearalenone (ZEN) were decreased by 50% with 80 ppm PTSO. One-hundred ppm of PTS reduced DON and ZEN production in wheat stored at 0.93 a_w for 20 days, although contamination was still above the legislative limits. Contrasting effects on T-2/HT-2 toxin contamination of oats was found depending on a_w, with PTS stimulating production under marginal conditions (0.93 a_w), but at 0.95 a_w effective control was achieved with 100 ppm. Treatment of stored maize inoculated with F. verticilliodies resulted in a stimulation of total fumonsins in most treatments. The potential use of such compounds for mycotoxin control in stored commodities is discussed.