Antioxidant and Antimicrobial Potencies of Chemically-Profiled Essential Oil from Asteriscus graveolens against Clinically-Important Pathogenic Microbial Strains

Chemical Composition and Biological Activities of the Essential Oil from Citrus reticulata Blanco Peels Collected from Agrowastes

Citrus fruits have a thick outer coat which is often discarded due to its low economic value and usually contributes to the waste. So this work focused on exploring the potential pharmacological properties of the discarded citrus peels. In the present study, we extracted the essential oil from peel wastes of Citrus reticulata Blanco (CREO) from the local market. The antioxidant, antibacterial, and anticancer properties of essential oil were evaluated. The CREO exhibited a strong antioxidant property with DPPH radical scavenging, ABTS radical scavenging, H2 O2 radical scavenging, Ferric reducing antioxidant power and for Lipid peroxidation inhibition respectively. Antibacterial properties of CREO was indicated against different pathogenic microbial strains like E. coli, P. aeruginosa, S. aureus, and S. enterica in terms of disc diffusion method and minimum inhibitory concentration (MIC). Further, anticancer properties studied on breast cancer cell lines MCF7 and MDA-MB-231 showed dose-dependent cytotoxicity with IC50 of 56.67±3.12 μg/mL and 76.44±2.53 μg/mL respectively. The GC-MS analysis of CREO revealed the presence of major compounds like S-limonene, α-pinene, α-myrcene, and cis-terpinene which might have played a significant role in strong antioxidant, antibacterial and anticancer properties. The study thus identified the potential health benefits of Citrus reticulata peel waste.

The Assessment of Antimicrobial and Anti-Biofilm Activity of Essential Oils against Staphylococcus aureus Strains

The increase in antimicrobial resistance and tolerance over the years has become a serious public health problem, leading to the inevitable development of alternative antimicrobial agents as substitutes for industrial pharmaceutical antibiotics targeting humans and animals under the concept of one health. Essential oils (EOs) extracted from aromatic and pharmaceutical plants incorporate several bioactive compounds (phytochemicals) that positively affect human and animal health. Herein, this work aimed to examine a standardized chemical composition and screen the antimicrobial and anti-biofilm activity of Thymus sibthorpii, Origanum vulgare, Salvia fruticosa, and Crithmum maritimum EOs against three different Staphylococcus aureus strains by gold-standard disc diffusion, broth microdilution, and microtiter plate biofilm assays. Therefore, the evaluation of the above-mentioned EOs were considered as substitutes for antibiotics to combat the ever-mounting antimicrobial resistance problem. The observed bacterial growth inhibition varied significantly depending on the type and concentration of the antimicrobials. Thymus sibthorpii was determined as the strongest antimicrobial, with 0.091 mg/mL minimum inhibitory concentration (MIC) and a 14-33 mm diameter inhibition zone at 5% (v/v) concentration. All tested EOs indicated almost 95% inhibition of biofilm formation at their half MIC, while gentamicin sulfate did not show sufficient anti-biofilm activity. None of the methicillin-resistant strains showed resistance to the EOs compared to methicillin-sensitive strains. Thymus sibthorpii and Origanum vulgare could be potential alternatives as antimicrobial agents to overcome the problem of microbial resistance. The tested EOs might be incorporated into antimicrobial products as safe and potent antimicrobial and anti-biofilm agents.

Chemical Composition, Antioxidant, Anti-Bacterial, and Anti-Cancer Activities of Essential Oils Extracted from Citrus limetta Risso Peel Waste Remains after Commercial Use

Citrus plants are widely utilized for edible purposes and medicinal utility throughout the world. However, because of the higher abundance of the antimicrobial compound D-Limonene, the peel waste cannot be disposed of by biogas production. Therefore, after the extraction of D-Limonene from the peel wastes, it can be easily disposed of. The D-Limonene rich essential oil from the Citrus limetta risso (CLEO) was extracted and evaluated its radical quenching, bactericidal, and cytotoxic properties. The radical quenching properties were DPPH radical scavenging (11.35 ± 0.51 µg/mL) and ABTS scavenging (10.36 ± 0.55 µg/mL). There, we observed a dose-dependent antibacterial potential for the essential oil against pathogenic bacteria. Apart from that, the essential oil also inhibited the biofilm-forming properties of E. coli, P. aeruginosa, S. enterica, and S. aureus. Further, cytotoxicity was also exhibited against estrogen receptor-positive (MCF7) cells (IC₅₀: 47.31 ± 3.11 µg/mL) and a triple-negative (MDA-MB-237) cell (IC₅₀: 55.11 ± 4.62 µg/mL). Upon evaluation of the mechanism of action, the toxicity was mediated through an increased level of reactive radicals of oxygen and the subsequent release of cytochrome C, indicative of mitotoxicity. Hence, the D-Limonene rich essential oil of C. limetta is useful as a strong antibacterial and cytotoxic agent; the antioxidant properties exhibited also increase its utility value.

Plant as an Alternative Source of Antifungals against Aspergillus Infections: A Review

Aspergillus species consists of a group of opportunistic fungi that is virulent when the immunity of the host is compromised. Among the various species, Aspergillus fumigatus is the most prevalent species. However, the prevalence of fungal infections caused by non-fumigatus Aspergillus has been increasing. Polyenes, echinocandins and azoles are the three main classes of antifungal agents being used for the treatment of aspergillosis. Nevertheless, the incidence of resistance towards these three classes has been rising over the years among several Aspergillus spp. The side effects associated with these conventional antifungal agents have also limited their usage. This urges the need for the discovery of a safe and effective antifungal agent, which presents a major challenge in medicine today. Plants present a rich source of bioactive molecules which have been proven effective against a wide range of infections and conditions. Therefore, this present review intends to examine the current literature available regarding the efficacy and mechanism of action of plant extracts and their compounds against Aspergillus spp. In addition, novel drug delivery systems of plant extracts against Aspergillus spp. were also included in this review.

Chemical Composition and Biological Activities of the Leaf Essential Oils of Curcuma longa, Curcuma aromatica and Curcuma angustifolia

Curcuma species are widely used as a food additive and also in various medicinal purposes. The plant is a rich source of essential oil and is predominantly extracted from the rhizomes. On the other hand, the leaves of the plants are usually considered as an agrowaste. The valorization of these Curcuma leaf wastes into essential oils is becoming accepted globally. In the present study, we aim to extract essential oils from the leaves of Curcuma longa (LEO), C. aromatica (REO), and C. anguistifolia (NEO). The chemical composition of these essential oils was analyzed by GC-MS. Free radical scavenging properties were evaluated against the radical sources, including DPPH, ABTS, and hydrogen peroxide. The antibacterial activity was assessed by the disc diffusion method and Minimum inhibitory concentration analysis against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica) bacteria. Results identified the compounds α-phellandrene, 2-carene, and eucalyptol as predominant in LEO. The REO was predominated by camphor, 2-bornanone, and curdione. The main components detected in NEO were eucalyptol, curzerenone, α-lemenone, longiverbenone, and α-curcumene. Antioxidant properties were higher in the LEO with IC50 values of 8.62 ± 0.18, 9.21 ± 0.29, and 4.35 ± 0.16 µg/mL, against DPPH, ABTS, and hydrogen peroxide radicals. The cytotoxic activity was also evident against breast cancer cell lines MCF-7 and MDA-MB-231 cells; the LEO was found to be the most active against these two cell lines (IC50 values of 40.74 ± 2.19 and 45.17 ± 2.36 µg/mL). Likewise, the results indicated a higher antibacterial activity for Curcuma longa essential oil with respective IC50 values (20.6 ± 0.3, 22.2 ± 0.3, 20.4 ± 0.2, and 17.6 ± 0.2 mm). Hence, the present study confirms the possible utility of leaf agrowastes of different Curcuma spp. as a possible source of essential oils with pharmacological potential.

An Update on Effectiveness and Practicability of Plant Essential Oils in the Food Industry

Consumer awareness and demands for quality eco-friendly food products have made scientists determined to concentrate their attention on sustainable advancements in the utilization of bioactive compounds for increasing safety and food quality. Essential oils (EOs) are extracted from plants and exhibit antimicrobial (antibacterial and antifungal) activity; thus, they are used in food products to prolong the shelf-life of foods by limiting the growth or survival of microorganisms. In vitro studies have shown that EOs are effective against foodborne bacteria, such as Escherichia coli, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus. The growing interest in essential oils and their constituents as alternatives to synthetic preservatives has been extensively exploited in recent years, along with techniques to facilitate the implementation of their application in the food industry. This paper’s aim is to evaluate the current knowledge on the applicability of EOs in food preservation, and how this method generally affects technological properties and consumers’ perceptions. Moreover, essential aspects concerning the limitation of the available alternatives are highlighted, followed by a presentation of the most promising trends to streamline the EOs’ usability. Incorporating EOs in packaging materials is the next step for green and sustainable foodstuff production and a biodegradable method for food preservation.

Evaluation of the Cardiac Electrophysiological and Haemodynamic Effects of Elsholtzia ciliata Essential Oil on Swine

The demand for the development of novel medicines with few side effects and no proarrhythmic properties is increasing. Extensive research on herbal extracts has been conducted with the expectation that the compounds will exert precise effects without harmful side effects. Elsholtzia ciliata (Thunb.) Hyl. essential oil (EO) possesses antiarrhythmic properties similar to those of class 1B antiarrhythmics, such as prolonging myocardial activation of the QRS complex and shortening the QT interval. In this study, we determined the kinetic profile of EO phytocompounds and the effects of EO on heart electrical activity and arterial blood pressure. For this study, we chose to use local breed pigs that were anaesthetized. The effects of an intravenous bolus of EO on ECG parameters, arterial blood pressure, heart rate variability, and blood levels of haematological and biochemical parameters were registered and evaluated. Following an intravenous injection of a bolus, EO exerted a vasodilatory effect, resulting in significant reductions in arterial blood pressure. EO also increased the heart rate and altered ECG parameters. The bolus of EO prolonged the QRS complex, shortened the QT interval, and nonmonotonically altered the PQ interval. After the administration of a bolus of EO, the activity of the autonomic nervous system was altered. This study confirms that EO possesses similar properties to class 1B antiarrhythmics and exerts a hypotensive effect; it reduces arterial blood pressure possibly by modulating peripheral vascular resistance.