Chemical composition and in-vitro antioxidant and antimicrobial activity of the essential oil of Citrus aurantifolia L. leaves grown in Eastern Oman

Quality Standards and Pharmacological Interventions of Natural Oils: Current Scenario and Future Perspectives

Medicinal plants are rich sources of natural oils such as essential and fixed oils used traditionally for nutritive as well as medicinal purposes. Most of the traditional formulations or phytopharmaceutical formulations contain oil as the main ingredient due to their own therapeutic applications and thus mitigating several pathogeneses such as fungal/bacterial/viral infection, gout, psoriasis, analgesic, antioxidant, skin infection, etc. Due to the lack of quality standards and progressive adulteration in the natural oils, their therapeutic efficacy is continuously deteriorated. To develop quality standards and validate scientific aspects on essential oils, several chromatographic and spectroscopic techniques such as HPTLC, HPLC, NMR, LC-MS, and GC-MS have been termed as the choices of techniques for better exploration of metabolites, hence sustaining the authenticity of the essential oils. In this review, chemical profiling and quality control aspects of essential or fixed oils have been explored from previously reported literature in reputed journals. Methods of chemical profiling, possible identified metabolites in essential oils, and their therapeutic applications have been described. The outcome of the review reveals that GC-MS/MS, LC-MS/MS, and NMR-based chromatographic and spectroscopic techniques are the most liable, economic, precise, and accurate techniques for determining the spuriousness or adulteration of oils based on their qualitative and quantitative chemical profiling studies. This review occupies the extensive information about the quality standards of several oils obtained from natural sources for their regulatory aspects via providing the detailed methods used in chemoprofiling techniques. Hence, this review helps researchers in further therapeutic exploration as well as quality-based standardization for their regulatory purpose.

Assessment of anticancer, antimicrobial, antidiabetic, anti-obesity and antioxidant activity of Ocimum Basilicum seeds essential oil from Palestine

BACKGROUND

Many modern pharmaceutical researchers continue to focus on the discovery and evaluation of natural compounds for possible therapies for obesity, diabetes, infections, cancer, and oxidative stress. Extraction of Ocimum basilicum seed essential oil and evaluation of its antioxidant, anti-obesity, antidiabetic, antibacterial, and cytotoxic activities were the goals of the current study.

METHOD

O. basilicum seed essential oil was extracted and evaluated for its anticancer, antimicrobial, antioxidant, anti-obesity, and anti-diabetic properties utilizing standard biomedical assays.

RESULTS

O. basilicum seed essential oil showed good anticancer activity against Hep3B (IC₅₀ 56.23 ± 1.32 µg/ml) and MCF-7 (80.35 ± 1.17 µg/ml) when compared with the positive control, Doxorubicin. In addition, the essential oil showed potent antibacterial (against Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Proteus mirabilis, and Pseudomonas aeruginosa) and antifungal (against Candida albicans) activities. Moreover, as for the anti-amylase test, IC₅₀ was 74.13 ± 1.1 µg/ml, a potent effect compared with the IC₅₀ of acarbose, which was 28.10 ± 0.7 µg/ml. On the other hand, for the anti-lipase test, the IC₅₀ was 112.20 ± 0.7 µg/ml a moderate effect compared with the IC₅₀ of orlistat, which was 12.30 ± 0.8 µg/ml. Finally, the oil had a potent antioxidant effect with an IC₅₀ of 23.44 ± 0.9 µg/ml compared with trolox (IC₅₀ was 2.7 ± 0.5 µg/ml).

CONCLUSION

This study has provided initial data that supports the importance of O. basilcum essential oil in traditional medicine. The extracted oil not only exhibited significant anticancer, antimicrobial, and antioxidant properties but also antidiabetic and anti-obesity effects, which provided a foundation for future research.

Unveiling Chemical, Antioxidant and Antibacterial Properties of Fagonia indica Grown in the Hail Mountains, Saudi Arabia

The Aja and Salma mountains in the Hail region are home to a variety of indigenous wild plants, some of which are used in Bedouin folk medicine to treat various ailments. The purpose of the current study was to unveil the chemical, antioxidant and antibacterial properties of Fagonia indica (Showeka) grown widely in these mountains, as data on the biological activities of this plant in this remote area are scarce. XRF spectrometry indicated the presence of some essential elements, which were in the order of Ca > S > K > AL > CL > Si > P > Fe > Mg > Na > Ti > Sr > Zn > Mn. Qualitative chemical screening revealed the presence of saponins, terpenes, flavonoids, tannins, phenols and cardiac glycosides in the methanolic extract (80% v/v). GC-MS showed the presence of 2-chloropropanoic acid 18.5%, tetrahydro-2-methylfuran 20.1%, tridecanoic acid 12-methyl-, methyl ester 2.2%, hexadecanoic acid, methyl ester 8.6%, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate 13.4%, methyl linoleate 7.0%, petroselinic acid methyl ester 15%, erucylamide 6.7% and diosgenin 8.5%. Total phenols, total tannins, flavonoids, DPPH, reducing power, -carotene and ABTS IC₅₀ (mg/mL) scavenging activity were used to measure the antioxidant capabilities of Fagonia indica, which exhibited prominent antioxidant properties at low concentrations when compared to ascorbic acid, butylate hydroxytoluene and beta-carotene. The antibacterial investigation revealed significant inhibitory effects against Bacillus subtilis MTCC121 and Pseudomona aeruginosa MTCC 741 with inhibition zones of 15.00 ± 1.5 and 12.0 ± 1.0 mm, respectively. The MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) ranged between 125 to 500 μg/mL. The MBC/MIC ratio indicated possible bactericidal efficacy against Bacillus subtilis and bacteriostatic activity against Pseudomona aeruginosa. The study also showed that this plant has anti-biofilm formation activity.

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.

The Development of the Antibacterial Microcapsules of Citrus Essential Oil for the Cosmetotextile Application: A Review

Essential oils (EOs) obtained from the Citrus genus were reported to exhibit good antimicrobial activity. Therefore, they can potentially be applied in daily necessities such as textile sectors as antibacterial functional fabric products. However, a packaging technique to retain such volatile and labile active substances is compulsory. In particular, microencapsulation was found to be a common coating technique employed to protect EOs from the effects of light, heat, humidity, stability, and controlled release of active substances. Various microencapsulation techniques have been introduced, but the most widely used method is complex coacervation, as it is simple, inexpensive, and capable of snaring high essential oils. Hence, this review focused on the microencapsulation of the most consumable citrus EOs with complex coacervation methods and their immobilization on commonly carried-out fabrics. In addition, it also discusses the isolation methods of the EOs, their chemical composition, and the mechanism of antibacterial action.

The Chemical Composition and Antibacterial and Antioxidant Activities of Five Citrus Essential Oils

Increasing concerns over the use of antimicrobial growth promoters in animal production has prompted the need to explore the use of natural alternatives such as phytogenic compounds and probiotics. Citrus EOs have the potential to be used as an alternative to antibiotics in animals. The purpose of this research was to study the antibacterial and antioxidant activities of five citrus EOs, grapefruit essential oil (GEO), sweet orange EO (SEO), bergamot EO (BEO), lemon EO (LEO) and their active component d-limonene EO (DLEO). The chemical composition of EOs was analyzed by gas chromatography–mass spectrometry (GC-MS). The antibacterial activities of the EOs on three bacteria (Escherichia coli, Salmonella and Lactobacillus acidophilus) were tested by measuring the minimum inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and inhibition zone diameter (IZD). The antioxidant activities of EOs were evaluated by measuring the free radical scavenging activities of DPPH and ABTS. We found that the active components of the five citrus EOs were mainly terpenes, and the content of d-limonene was the highest. The antibacterial test showed that citrus EOs had selective antibacterial activity, and the LEO had the best selective antibacterial activity. Similarly, the LEO had the best scavenging ability for DPPH radicals, and DLEO had the best scavenging ability for ABTS. Although the main compound of the five citrus EOs was d-limonene, the selective antibacterial and antioxidant activity of them might not be primarily attributed to the d-limonene, but some other compounds’ combined action.

Antibacterial Activity of Lemon Basil (Ocimum citriodorum) and Key Lime (Citrus aurantifolia S.) Extract Combination on Streptococcus mutants

BACKGROUND: Lots of plants that are used in Southeast Asian and Indonesian cuisine have antibacterial properties. AIM: This study aimed to find out the effectiveness of lemon basil (Ocimum citriodorum) and key lime (Citrus aurantifolia S.) extract combination on Streptococcus mutants’ inhibition. METHODS: Lemon Basil and Key Lime were extracted and combined with several following concentration, respectively, (30–70%, 40–60%, 50–50%, 60–40%, and 70–30%). S. mutants were cultured using Brain-heart Infusion Broth overnight. The inhibition range from the extract combination was measured and analyzed. RESULTS: All combinations except 60–40 showed significant effectivity against S. mutants compared to control (p < 0.05). Post hoc tests revealed that only the combination Lemon Basil-Key Lime 30–70% that has a significantly wider inhibition range compared to L50%-K50% (p = 0.034), L60%-K40% (p = 0.007), and L70%–K30% (p = 0.023). CONCLUSION: Combination extract of Lemon Basil and Key lime has effectivity against oral micro bacteria, especially S. mutants.

Herbals and Plants in the Treatment of Pancreatic Cancer: A Systematic Review of Experimental and Clinical Studies

Background: Pancreatic cancer represents the most lethal malignancy among all digestive cancers. Despite the therapeutic advances achieved during recent years, the prognosis of this neoplasm remains disappointing. An enormous amount of experimental (mainly) and clinical research has recently emerged referring to the effectiveness of various plants administered either alone or in combination with chemotherapeutic agents. Apart from Asian countries, the use of these plants and herbals in the treatment of digestive cancer is also increasing in a number of Western countries as well. The aim of this study is to review the available literature regarding the efficacy of plants and herbals in pancreatic cancer. Methods: The authors have reviewed all the experimental and clinical studies published in Medline and Embase, up to June 2021. Results: More than 100 plants and herbals were thoroughly investigated. Favorable effects concerning the inhibition of cancer cell lines in the experimental studies and a favorable clinical outcome after combining various plants with established chemotherapeutic agents were observed. These herbals and plants exerted their activity against pancreatic cancer via a number of mechanisms. The number and severity of side-effects are generally of a mild degree. Conclusion: A quite high number of clinical and experimental studies confirmed the beneficial effect of many plants and herbals in pancreatic cancer. More large, double-blind clinical studies assessing these natural products, either alone or in combination with chemotherapeutic agents should be conducted.

Effect of Different Essential Oils on the Properties of Edible Coatings Based on Yam (Dioscorea rotundata L.) Starch and Its Application in Strawberry (Fragaria vesca L.) Preservation

Every year the world loses about 50% of fruits and vegetables post-harvest and in the supply chain. The use of biodegradable coatings and films with antioxidant properties has been considered an excellent alternative to extend the shelf life of food. Therefore, the objective of this work was to develop a coating based on yam (Dioscorea rotundata L.) starch-containing lime, fennel, and lavender essential oils to extend the shelf life of strawberries (Fragaria vesca l.). The tensile properties, barrier properties (water vapour permeability (WVP) and oxygen permeability (OP)), moisture content, water-solubility, absorption capacity, water contact angle, optical properties, the antioxidant activity of the resultant starch-based coatings were evaluated. After that, the active properties of the coatings were assessed on strawberries inoculated with Aspergillus niger during 14 days of storage at 25 °C. The results showed that the incorporation of essential oils improved the elongation and WVP and provided antioxidant capacity and antimicrobial activity in the films. In particular, the essential oil of lime showed higher antioxidant activity. This fact caused the unwanted modification of other properties, such as the decrease in tensile strength, elastic modulus and increase in OP. The present study revealed the potential use of lime, fennel, and lavender essential oils incorporated into a polymeric yam starch matrix to produce biodegradable active films (antioxidant and antimicrobial). Obtained films showed to be a viable alternative to increase the shelf life of strawberries and protect them against Aspergillus niger.

Journey of Limonene as an Antimicrobial Agent

Injudicious consumption of antibiotics in the past few decades has arisen the problem of resistance in pathogenic organisms against most antibiotics and antimicrobial agents. Scenarios of treatment failure are becoming more common in hospitals. This situation demands the frequent need for new antimicrobial compounds which may have other mechanisms of action from those which are in current use. Limonene can be utilized as one of the solutions to the problem of antimicrobial resistance. Limonene is a naturally occurring monoterpene with a lemon-like odor, which mainly present in the peels of citrus plants like lemon, orange, grapefruit, etc. The study aimed to enlighten the antimicrobial properties of limonene as per previous literature. Advantageous contributions have been made by various research groups in the study of the antimicrobial properties of limonene. Previous studies have shown that limonene not only inhibits disease-causing pathogenic microbes, however, it also protects various food products from potential contaminants. This review article contains information about the effectiveness of limonene as an antimicrobial agent. Apart from antimicrobial property, some other uses of limonene are also discussed such as its role as fragrance and flavor additive, as in the formation of nonalcoholic beverages, as solvent and cleaner in the petroleum industry, and as a pesticide. Antibacterial, antifungal, antiviral, and anti-biofilm properties of limonene may help it to be used in the future as a potential antimicrobial agent with minimal adverse effects. Some of the recent studies also showed the action of limonene against COVID-19 (Coronavirus). However, additional studies are requisite to scrutinize the possible mechanism of antimicrobial action of limonene.

Nigerian polyherbal-based hydrotherapy: a panacea to infectious diseases

A global society, including developed countries, continues to struggle with fatal diseases that are difficult to treat with Western medicine. A variety of infectious diseases have existed for ages, but in Africa they had been limited thanks to the Indigenous Knowledge System (IKS) prior to the introduction of cosmopolitan medicine. Influenza virus repression has been demonstrated by a number of herbal antivirals, yet the invaluable therapeutic potential of herbal medicine has been underestimated. Despite various reliable methods offered by Western medicine, the globally destructive COVID-19 pandemic requires a successful fight. The wisdom of African IKS used in tackling epidemics that have broken out in the past is brought to mind again. Pneumonia – a COVID-19 symptom, could be treated with polyherbal fomentation. Selected plants cultivated across Nigeria for hydrotherapy are under consideration to be used in proper doses. Given the potential associated with IKS, a multi-disciplinary approach involving experts in phytomedicine, ethnobotany, phytochemistry, plant physiology and ecology is necessary to unlock the therapeutic potential of traditional medicine.

Essential oils as Potential Source of Anti-dandruff Agents: A Review

BACKGROUND

Dandruff is a frequently occurring scalp problem that causes significant discomfort to approximately 50% population at some stage of life, especially post-puberty and pre-adult age.

OBJECTIVE

This review aims to summarize the recent findings regarding the anti-fungal properties of herbal essential oils against pathogens involved in dandruff prognosis.

METHODS

A literature search of studies published between 2000 and 2020 was conducted over databases: PubMed, Google Scholar, Scopus, and Science direct. Literature was explored using the guidelines given in Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Dandruff, characterized by clinical symptoms of dryness, pruritis, scaly, and flaky scalp, is considered a pri-mary manifestation of seborrheic dermatitis. Amongst various etiological and pathophysiological factors, a significant role of yeasts, primarily species of Malassezia, Candida, has been strongly correlated with dandruff. At the same time, incidences of M. furfur, M. restricta, and M. globosa are high compared to others. Due to relapse of symptoms with the withdrawal of conventional anti-dandruff products. Essential oils of herbal origin, such as tea tree oil, lime oil, rose-mary oil, have gained global importance in dermatology. These oils are rich in secondary aromatic metabolites, espe-cially terpenes and phenolic components that impart substantial antimicrobial properties and resisting biofilm production.

CONCLUSION

Based on the available information, we can conclude that essential oils have tremendous potential to be developed as anti-dandruff products; however, further studies are warranted to establish their efficacy in dandruff cures.

Encapsulated Limonene: A Pleasant Lemon-Like Aroma with Promising Application in the Agri-Food Industry. A Review

Limonene, mainly found as a major component in Citrus spp., has been proven to possess a valuable potential as sustainable replacement to synthetic pesticides and food preservatives. This review intends to give a clear overview of the principal emerging applications of limonene in the agri-food industry as antimicrobial, herbicidal and antioxidant agent. To successfully use limonene in a greener agri-food industry, its preservation had become a top concern for manufacturers. In order to elucidate the most efficient and sustainable manner to encapsulate limonene, the different techniques and materials tested up to the present are also reviewed. In general, encapsulation conserves and protects limonene from outside aggressions, but also allows its controlled release as well as enhances its low water solubility, which can be critical for the discussed applications. Other parameters such as scalability, low cost and availability of equipment will need to be taken into account. Further efforts would likely be oriented to the elucidation of encapsulating sustainable systems obtained by cost-efficient elaboration processes, which can deliver effective concentrations of limonene without affecting crops and food products.

Citrus Essential Oils (CEOs) and Their Applications in Food: An Overview

Citrus is a genus belonging to the Rutaceae family and includes important crops like orange, lemons, pummelos, grapefruits, limes, etc. Citrus essential oils (CEOs) consist of some major biologically active compounds like α-/β-pinene, sabinene, β-myrcene, d-limonene, linalool, α-humulene, and α-terpineol belonging to the monoterpenes, monoterpene aldehyde/alcohol, and sesquiterpenes group, respectively. These compounds possess several health beneficial properties like antioxidant, anti-inflammatory, anticancer, etc., in addition to antimicrobial properties, which have immense potential for food applications. Therefore, this review focused on the extraction, purification, and detection methods of CEOs along with their applications for food safety, packaging, and preservation. Further, the concerns of optimum dose and safe limits, their interaction effects with various food matrices and packaging materials, and possible allergic reactions associated with the use of CEOs in food applications were briefly discussed, which needs to be addressed in future research along with efficient, affordable, and "green" extraction methods to ensure CEOs as an ecofriendly, cost-effective, and natural alternative to synthetic chemical preservatives.