Essential Oil Composition Analysis of Cymbopogon Species from Eastern Nepal by GC-MS and Chiral GC-MS, and Antimicrobial Activity of Some Major Compounds

Chemical composition and biological activity of lemongrass volatile oil and n-Hexane extract: GC/MS analysis, in vitro and molecular modelling studies

Lemon grass, formally identified as Cymbopogon citratus, is a plant that belongs to the Poaceae family. The present work aimed to examine the chemical composition by GC/MS analysis and assess the biological potential of C. citratus volatile oil and n-hexane extract. The volatile oil and n-hexane extract were evaluated for antioxidant potential and tested for their enzyme inhibition against tyrosinase, butyrylcholinesterase (BChE), acetylcholinesterase (AChE), α-amylase, and α-glucosidase. The chemical analysis of the lemongrass n-hexane extract (HE) and volatile oil (VO) revealed that the main constituents in the HE are aliphatic hydrocarbons (42.98%), triterpenoids (20.14%), and aromatic hydrocarbons (17.25%). Conversely, the main constituents of the (VO) are predominantly monoterpenes, namely α-citral (36.08%), β-citral (34.22%), and β-myrcene (13.84%). The oil showed more potent antioxidant potential in DPPH, ABTS, CUPRAC, FRAP, and phosphomolybdenum (10.18, 35.69 mg Trolox equivalent/g, 98.97 and 69.73 mg Trolox equivalent/g and 43.01 mmol Trolox equivalent/g). The HE displayed higher BChE (1.53 mg Galanthamine equivalent)/g), as well as α-amylase and α-glucosidase inhibitory activities (0.39 and 2.40 mmol Acarbose equivalent/g). The VO demonstrated more potent tyrosinase inhibitory activities (57.19 mg Kojic acid equivalent/g) along with acetyl and butyrylcholinesterase inhibition. Dominant compounds exhibited the ability to bind with high affinity to various target proteins, with a particular affinity for AChE and BChE. The volatile oil and n-hexane extract of C. citratus show significant promise as a viable choice for the advancement of novel therapeutic strategies aimed at addressing oxidative stress, neurodegeneration, and diabetes.

Larvicidal Effects of Cymbopogon commutatus Essential Oil and Its Based Nanoformulations on Culex pipiens: Chemical Profiling and Physicochemical Characterization

Cymbopogon commutatus has been used as an ingredient in the manufacturing of soap and mosquito repellent. Herein, the chemical profiling of the C. commutatus aerial parts essential oil (CCEO) was constructed on the basis of the multiplex of GC-MS and nuclear magnetic resonance (NMR). Four nanoformulations-EO nanoemulsions (CCEO@NE), chitosan-coated (CSNPs@NE), silver nanoparticle-loaded (AgNPs@NE), and iron oxide-loaded (Fe2O3NPs@NE)-were formulated. The larvicidal effects of CCEO, its major component, and its nanoformulations were evaluated on Culex pipiens. Twenty-seven components (99.77%)-including monoterpenes (78.36%) and sesquiterpenes (21.41%)-were tentatively identified, including geraniol (67.49%) and geranyl acetate (3.52%) as predominant constituents. Geraniol was isolated and confirmed via NMR spectroscopic analysis. The nanoformulations exhibited diverse characteristics, with particle sizes spanning from 81.28 ± 6.17 nm (CCEO@NE) to 128.67 ± 6.96 nm (Fe2O3NPs@NE) and encapsulation efficiencies ranging from 72.57% ± 4.05% (Fe2O3NPs@NE) to 83.73% ± 6.69% (CCEO@NE). Zeta potentials ranged from -21.38 ± 5.18 mV (AgNPs@NE) to +14.39 ± 2.19 mV (CSNPs@NE), indicating variations in surface charge stability. CCEO and geraniol showed the highest larvicidal effects, recording LC50 of 263.96 and 226.41 ppm, respectively, after 48 h of exposure. Nanoformulations showed latent effects and inhibitory activity in pupation and fly emergence. Consequently, CCEO and its nanoformulations may present good alternatives for controlling C. pipiens.

Different essential oils can inhibit Candida albicans biofilm formation on acrylic resin by suppressing aspartic proteinase: In vitro and in silico approaches

INTRODUCTION

Cymbopogon martini, Syzygium aromaticum, and Cupressus sempervirens are used for antimicrobial purposes in the worldwide. Both their extracts and essential oil contents are rich in active ingredients.

OBJECTIVE

The aim of this study was to investigate the inhibitory effect of Cymbopogon martini essential oil (CMEO), Syzygium aromaticum essential oil (SAEO) and Cupressus sempervirens essential oil (CSEO) on Candida albicans biofilm formation on heat-polymerized polymethyl methacrylate (PMMA) samples in vitro and in silico.

MATERIALS AND METHODS

Essential oil contents with anticandidal potential were determined by Gas Chromatography-Mass Spectrometry. Following C. albicans adhesion, PMMA samples were treated independently with Corega® and each essential oil. The anticandidal activity of the essential oils was determined by spectrophotometric absorbance measurement at 600 nm, taking into account the cultures of each sample. The cytotoxicity evaluation of essential oils was performed by MTT Colorimetric assay. The software package AutoDockTools (1.5.6) was used for the in silico studies. The effect of essential oil content on the inhibition of Secreted aspartic proteinase (SAP2) was evaluated considering the Ligand@SAP2 complex formation.

RESULTS

2% of CMEO and 5% of SAEO exhibited higher anticandidal activity than Corega® (p < 0.05), whereas Corega® had higher anticandidal activity than 2% and 5% of CSEO (p < 0.05). The cytotoxicity of essential oils on NIH/3T3 cells after 24 h was found to be 2.41 for CSEO, 2.84 for CMEO, and 2.85 µg/mL for SAEO. The results of the in silico study showed that citronellol from CMEO, chavibetol (m-eugenol) from SAEO and β-pinene from CSEO each had the highest effect on the inhibition of SAP2. The highest binding affinity value was found for citronellol at -5.3 kcal/mol.

CONCLUSIONS

The biofilm formation of C. albicans onto acrylic resin was inhibited by CMEO, SAEO and CSEO at a concentration of 2% through in vitro assay. The most effective inhibition was determined to be due to citronellol in CMEO through in silico analysis.

Dynamics of linalool and its derivatives enantiomers in Camellia sinensis var. A ssamica "Hainan dayezhong"

We here analyzed changes in the proportion and content of chiral isomers of linalool and its derivatives in "Hainan dayezhong" throughout its life cycle from tea tree growth and tea manufacturing to brewing. The chiral isomers of aromatic compounds present in fresh tea leaves were found to undergo substantial diurnal and seasonal changes during tea tree growth, and their proportions varied slightly across different leaf positions. The chiral isomer content of linalool and its derivatives was consistently higher in stems than in leaves. Pest and disease stress significantly increased the proportion and content of type-R aroma. The proportion of chiral isomers underwent no considerable change during black tea manufacturing. However, their content varied dramatically among different processes. Diversity in the proportion and content of chiral isomers was observed in the wild tea tree. Further research should focus on breeding "Hainan dayezhong" wild resources to generate clones with high aroma quality.

The effects of varying ingredients combination and boiling time on total phenolic content, antioxidant activity, and antimicrobial properties of lemongrass-ginger tea

This study was aimed at exploring the effect of varying lemongrass-ginger combinations, and boiling time on total phenolic contents (TPC), antioxidant activity, and antimicrobial efficacy of lemongrass-ginger tea. Lemongrass-ginger tea was produced by varying the percentage of lemongrass (25 %, 50 %, and 75 %) and boiling times (5, 10, and 15 min). The antioxidant activity of the lemongrass-ginger tea samples was investigated using the DPPH and ABTS assays whereas the TPC was determined using the Folin-Ciocalteau method. The antimicrobial activities were investigated by measuring the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) of the tea against selected microorganisms, and its combinatory effects with antimicrobial drugs. The lemongrass-ginger combination and the boiling time significantly affected antioxidant potential, TPC, and antimicrobial activities. TPC measured ranged between 966.7 ± 90.20 to 1761.3 ± 81.70 μgGAE/g whereas DPPH antioxidant activities varied from 43.97 ± 14.99 % to 75.20 ± 8.55 %. The highest values of TPC and DPPH were 1761.3 ± 81.70 μgGAE/g and 75.20 ± 8.55 % and were recorded by 75 % lemongrass-ginger combination boiled for 15 min. Furthermore, differences in lemongrass-ginger combination and boiling times resulted in varying antimicrobial activities against the test microorganisms. The lowest MBC was recorded for 50 % lemongrass boiled for 10 min against C. albicans, 75 % lemongrass boiled for 15 min against K. pneumoniae and S. typhi, and 25 % lemongrass against E. coli. Additionally, varying ingredient proportions and boiling times affected the combinatory effect of the tea with antimicrobial drugs. However, the exact effect depends on the proportion of ingredients used and the boiling times.

Antioxidant Potential of Medicinal Plants in the Treatment of Scabies Infestation

Oxidative stress, characterized by an overproduction of reactive oxygen species that overwhelm the body's physiological defense mechanisms, is a key factor in the progression of parasitic diseases in both humans and animals. Scabies, a highly contagious dermatological condition caused by the mite Sarcoptes scabiei var. hominis, affects millions globally, particularly in developing regions. The infestation leads to severe itching and skin rashes, triggered by allergic reactions to the mites, their eggs, and feces. Conventional scabies treatments typically involve the use of scabicidal agents, which, although effective, are often associated with adverse side effects and the increasing threat of resistance. In light of these limitations, there is growing interest in the use of medicinal plants as alternative therapeutic options. Medicinal plants, rich in bioactive compounds with antioxidant properties, offer a promising, safer, and potentially more effective approach to treatment. This review explores the role of oxidative stress in scabies pathogenesis and highlights how medicinal plants can mitigate this by reducing inflammation and oxidative damage, thereby alleviating symptoms and improving patient outcomes. Through their natural antioxidant potential, these plants may serve as viable alternatives or complementary therapies in the management of scabies, especially in cases where resistance to conventional treatments is emerging.

Characterization and antimicrobial activity of essential oils extracted from lemongrass (Cymbopogon flexuosus) using microwave-assisted hydro distillation

Lemongrass (Cymbopogon flexuosus) essential oil (LGEO) contains α-citral, β-citral and other phytochemicals extracted using various methods. This research extracted essential oils using steam distillation (SD) and microwave-assisted hydro distillation (MAHD) to maximize quantity and purity. LGEO was tested for antibacterial properties. LGEO was extracted using SD and compared to MAHD output based on oil production and chemical composition. We performed GCMS to characterize LGEO. Fourier transform infrared spectroscopy (FTIR) used for quantum chemical analysis. Spectroscopic analysis showed that SD extracted secondary metabolites (ethyl-linalool, isogeranial, β-citral, α-citral, geranyl acetate, and caryophyllene) yielded 9.7 %, 11.5 %, 35.4 %, 13.4 %, 6.4 %, and 6.4 %, respectively, while MAHD yielded 10.2 %, 13.4 %, 43.2 %, 17.3 %, 6.9 %, and 7.3 %. MAHD extracted α and β citral content was better than SD extraction technique. FTIR spectroscopy and quantum chemistry analysis showed extracted oil chemical composition, electronic structure of α and β citral isomers. In the disc-diffusion experiment, both extracts were effective against Gram-positive and Gram-negative bacteria and harmful fungi. LGEO from SD and MAHD extraction (30 mg/mL) demonstrated disc diffusion assay antibacterial efficacy against microorganisms. The two extracts effectively inhibited microorganisms with MIC values of 3.75 and 7.5 μg/mL. It can be concluded that, LGEO have greater antimicrobial activity in MAHD extraction.

The antioxidant and antimicrobial activity of ethanolic extract in roots, stems, and leaves of three commercial Cymbopogon species

BACKGROUND

Cymbopogon is a member of the family Poaceae and has been explored for its phytochemicals and bioactivities. Although the antimicrobial activities of Cymbopogon spp. extracts have been extensively studied, comprehensive analyses are required to identify promising compounds for the treatment of antimicrobial resistance. Therefore, this study investigated the antioxidant and antimicrobial properties of Cymbopogon spp. ethanolic extracts in every single organ.

METHODS

Ethanolic extracts were obtained from three Indonesian commercial species of Cymbopogon spp., namely Cymbopogon citratus (L.) Rendle, Cymbopogon nardus (DC.) Spatf., and Cymbopogon winterianus Jowitt. The leaf, stem, and root extracts were evaluated via metabolite profiling using gas chromatography-mass spectrometry (GC-MS). In silico and in vitro analyses were used to evaluate the antioxidant and antimicrobial properties of the Cymbopogon spp. ethanolic extracts. In addition, bioactivity was measured using cytotoxicity assays. Antioxidant assays were performed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis [3-ethylbenzothiazoline-6-sulfonic acid (ABTS) to determine toxicity to Huh7it-1 cells using a tetrazolium bromide (MTT) assay. Finally, the antimicrobial activity of these extracts was evaluated against Candida albicans, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli using a well diffusion assay.

RESULTS

GC-MS analysis revealed 53 metabolites. Of these, 2,5-bis(1,1-dimethylethyl)- phenol (27.87%), alpha-cadinol (26.76%), and 1,2-dimethoxy-4-(1-propenyl)-benzene (20.56%) were the predominant compounds. C. winterianus and C. nardus leaves exhibited the highest antioxidant activity against DPPH and ABTS, respectively. Contrastingly, the MTT assay showed low cytotoxicity. C. nardus leaf extract exhibited the highest antimicrobial activity against E. coli and S. aureus, whereas C. winterianus stem extract showed the highest activity against B. substilis. Furthermore, computational pathway analysis predicted that antimicrobial activity mechanisms were related to antioxidant activity.

CONCLUSIONS

These findings demonstrate that the leaves had strong antioxidant activity, whereas both the leaves and stems showed great antimicrobial activity. Furthermore, all Cymbopogon spp. ethanolic extracts showed low toxicity. These findings provide a foundation for future studies that assess the clinical safety of Cymbopogon spp. as novel drug candidates.

Antibacterial and Antifungal Activities of Cimbopogon winterianus and Origanum syriacum Extracts and Essential Oils against Uropathogenic Bacteria and Foodborne Fungal Isolates

This study focused on testing the antibacterial and antifungal activity of Origanum syriacum (O. syriacum) and Cimbopogon winterianus (C. winterianus) extracts and their essential oils (EOs). The bacteria were isolated from urine samples and identified by a VITEK assay, and the fungi were isolated from spoiled food samples and further identified by MALDI-TOF. The susceptibility of the microbial isolates was assessed by determining the bacteriostatic and bactericidal/fungicidal effects by the minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) broth microdilution assay and time-kill test. The antibiofilm activities were assessed by the antibiofilm screening assays. The bacterial isolates included three Gram-negative isolates (Escherichia coli, Klebsiella pneumonia, and Citrobacter freundii) and two Gram-positive isolates (Staphylococcus aureus and Streptococcus intermedius). The fungal isolates included Candida albicans and Aspergillus niger. The O. syriacum and C. winterianus extracts exhibited bacteriostatic and fungistatic activities (MIC 1.25-2.5 mg/mL for the bacterial isolates and 2.5-5 mg/mL for the fungal isolates). However, their EOs exhibited bactericidal (MBC 5-20%) and fungicidal (MFC 1.25-10%) activities, meaning that the EOs had a better antimicrobial potential than the extracts. The antibiofilm activities of the mentioned extracts and their EOs were relatively weak. The O. syriacum extract inhibited S. aureus, S. intermedius, and K. pneumonia biofilms at a concentration of 0.3125 mg/mL and C. albicans and A. niger biofilms at 0.625 mg/mL. No antibiofilm activity was recorded for C. winterianus extract. In addition, the packaging of grapes with C. winterianus extract preserved them for about 40 days. The results reflect the significant antimicrobial activity of O. syriacum and C. winterianus extracts and their EOs, thus suggesting their potential in food packaging and preservation.

Insights into the anti-Candida albicans properties of natural phytochemicals: An in vitro and in vivo investigation

Invasive candidiasis, attributed to Candida albicans, has long been a formidable threat to human health. Despite the advent of effective therapeutics in recent decades, the mortality rate in affected patient populations remains discouraging. This is exacerbated by the emergence of multidrug resistance, significantly limiting the utility of conventional antifungals. Consequently, researchers are compelled to continuously explore novel solutions. Natural phytochemicals present a potential adjunct to the existing arsenal of agents. Previous studies have substantiated the efficacy of phytochemicals against C. albicans. Emerging evidence also underscores the promising application of phytochemicals in the realm of antifungal treatment. This review systematically delineates the inhibitory activity of phytochemicals, both in monotherapy and combination therapy, against C. albicans in both in vivo and in vitro settings. Moreover, it elucidates the mechanisms underpinning the antifungal properties, encompassing (i) cell wall and plasma membrane damage, (ii) inhibition of efflux pumps, (iii) induction of mitochondrial dysfunction, and (iv) inhibition of virulence factors. Subsequently, the review introduces the substantial potential of nanotechnology and photodynamic technology in enhancing the bioavailability of phytochemicals. Lastly, it discusses current limitations and outlines future research priorities, emphasizing the need for high-quality research to comprehensively establish the clinical efficacy and safety of phytochemicals in treating fungal infections. This review aims to inspire further contemplation and recommendations for the effective integration of natural phytochemicals in the development of new medicines for patients afflicted with C. albicans.

Identification of essential oils with strong activity against stationary phase Mycobacterium abscessus

Purpose

To identify essential oils (EOs) active against non-growing stationary phase Mycobacterium abscessus and multidrug-resistant M. abscessus strains.

Methods

The activity of EOs against both stationary and log phase M. abscessus was evaluated by colony forming unit (CFU) assay and minimum inhibitory concentration (MIC) testing.

Results

We assessed the activity of 80 EOs against stationary phase M. abscessus and found 12 EOs (Cinnamon, Satureja montana, Palmarosa, Lemon eucalyptus, Honey myrtle, Combava, Health shield, Mandarin, Thyme, Rosewood, Valerian Root and Basil) at 0.5% concentration to be active against both growing and non-growing stationary phase M. abscessus. Among them, Satureja montana essential oil and Palmarosa essential oil could eliminate all stationary phase M. abscessus at 0.125% and Cinnamon essential oil could eliminate stationary phase bacteria at 0.063% after 1-day treatment. Interestingly, these EOs also exhibited promising activity against multidrug-resistant M. abscessus clinical strains.

Conclusions

Our study indicates that some EOs display outstanding effectiveness against both drug susceptible M. abscessus and multidrug-resistant M. abscessus isolates. These findings may be significant for the treatment of persistent M. abscessus infections.

Lemongrass (Cymbopogon flexuosus) growth rate, essential oil yield and composition as influenced by different soil conditioners under two watering regimes

The vast cultivation of lemongrass (Cymbopogon flexuosus) as an essential oil-bearing plant worldwide relies heavily on its compound citral that holds immense industrial potential. Soil fertility practices greatly affect the growth and quality of these plants, with a majority of the agricultural land globally grappling with water scarcity. In this respect, field experiments were conducted at the University of Embu research farm during the November 2021-September 2022 growing period and aimed to investigate the influence of two different factors, namely; (i) two watering regimes (rainfed and irrigated) and (ii) four soil conditioner levels (control (T1), cow manure (T2), cow manure plus NPK fertilizer (T3), and NPK fertilizer alone (T4)) on the growth and essential oil parameters of C. flexuosus. The field trials were arranged in a split-plot design with three replicates for each treatment. The essential oil from C. flexuosus was obtained using steam distillation method and analyzed for quality using gas chromatography with mass spectrometry (GC-MS) technique. Results revealed that treatments T4 and T3 improved the growth of C. flexuosus under rain-fed conditions, implying the plant's sensitivity to soil fertility practices and watering regimes. Herbage from rain-fed plants harvested after 120 days had high oil content, ranging from 0.17 to 0.23 %, while herbage from irrigated plants harvested after 180 days had the lowest oil content, ranging from 0.11 to 0.17 %. Using GC-MS, the main components of C. flexuosus oil were citral (75.97-87.70 %), geranyl acetate (0.80-4.91 %), geraniol (0.80-4.26 %), isogeranial (1.83-3.45 %), and isoneral (1.29-2.78 %). Notably, citral, a racemic mixture of geranial and neral, was found in a high concentration (87.70 %), meeting the acceptable international market standards for its use. Altogether, the major oil compounds, oil yield and growth properties of C. flexuosus in this experiment differed as a function of different soil conditioners under the two watering regimes, and so with the time scale. The outcomes of this research highlight implications for enhancing and bolstering the production of high-value lemongrass oil in Kenya, where it holds potential significance as a vital economic and export-oriented crop.

Microfluidizing Technique Application for Algerian Cymbopogon citratus (DC.) Stapf Effects Enhanced Volatile Content, Antimicrobial, and Anti-Mycotoxigenic Properties

Medicinal plant extracts are a promising source of bioactive minor contents. The present study aimed to evaluate the distinguished volatile content of Algerian Cymbopogon citratus (DC.) Stapf before and after the microfluidization process and their related antimicrobial and anti-mycotoxigenic impacts and changes. The GC-MS apparatus was utilized for a comparative examination of Algerian lemongrass essential oil (LGEO) with its microfluidization nanoemulsion (MF-LGEO) volatile content. The MF-LGEO was characterized using Zetasizer and an electron microscope. Cytotoxicity, antibacterial, and antifungal activities were determined for the LGEO and MF-LGEO. The result reflected changes in the content of volatiles for the MF-LGEO. The microfluidizing process enhanced the presence of compounds known for their exceptional antifungal and antibacterial properties in MF-LGEO, namely, neral, geranial, and carvacrol. However, certain terpenes, such as camphor and citronellal, were absent, while decanal, not found in the raw LGEO, was detected. The droplet diameter was 20.76 ± 0.36 nm, and the polydispersity index (PDI) was 0.179 ± 0.03. In cytotoxicity studies, LGEO showed higher activity against the HepG2 cell line than MF-LGEO. Antibacterial LGEO activity against Gram-positive bacteria recorded an inhibitory zone from 41.82 ± 2.84 mm to 58.74 ± 2.64 mm, while the zone ranged from 12.71 ± 1.38 mm to 16.54 ± 1.42 mm for Gram-negative bacteria. Antibacterial activity was enhanced to be up to 71.43 ± 2.54 nm and 31.54 ± 1.01 nm for MF-LGEO impact against Gram-positive and Gram-negative pathogens. The antifungal effect was considerable, particularly against Fusarium fungi. It reached 17.56 ± 1.01 mm and 13.04 ± 1.37 mm for LGEO and MF-LGEO application of a well-diffusion assay, respectively. The MF-LGEO was more promising in reducing mycotoxin production in simulated fungal growth media due to the changes linked to essential compounds content. The reduction ratio was 54.3% and 74.57% for total aflatoxins (AFs) and ochratoxin A (OCA) contents, respectively. These results reflect the microfluidizing improvement impact regarding the LGEO antibacterial, antifungal and anti-mycotoxigenic properties.