Antibacterial properties of essential oils and methanol extracts of sweet basil Ocimum basilicum occurring in Bangladesh

Ocimum kilimandscharicum 4CL11 negatively regulates adventitious root development via accumulation of flavonoid glycosides

4-Coumarate-CoA Ligase (4CL) is an important enzyme in the phenylpropanoid biosynthesis pathway. Multiple 4CLs are identified in Ocimum species; however, their in planta functions remain enigmatic. In this study, we independently overexpressed three Ok4CL isoforms from Ocimum kilimandscharicum (Ok4CL7, -11, and -15) in Nicotiana benthamiana. Interestingly, Ok4CL11 overexpression (OE) caused a rootless or reduced root growth phenotype, whereas overexpression of Ok4CL15 produced normal adventitious root (AR) growth. Ok4CL11 overexpression in N. benthamiana resulted in upregulation of genes involved in flavonoid biosynthesis and associated glycosyltransferases accompanied by accumulation of specific flavonoid-glycosides (kaempferol-3-rhamnoside, kaempferol-3,7-O-bis-alpha-l-rhamnoside [K3,7R], and quercetin-3-O-rutinoside) that possibly reduced auxin levels in plants, and such effects were not seen for Ok4CL7 and -15. Docking analysis suggested that auxin transporters (PINs/LAXs) have higher binding affinity to these specific flavonoid-glycosides, and thus could disrupt auxin transport/signaling, which cumulatively resulted in a rootless phenotype. Reduced auxin levels, increased K3,7R in the middle and basal stem sections, and grafting experiments (intra and inter-species) indicated a disruption of auxin transport by K3,7R and its negative effect on AR development. Supplementation of flavonoids and the specific glycosides accumulated by Ok4CL11-OE to the wild-type N. benthamiana explants delayed the AR emergence and also inhibited AR growth. While overexpression of all three Ok4CLs increased lignin accumulation, flavonoids, and their specific glycosides were accumulated only in Ok4CL11-OE lines. In summary, our study reveals unique indirect function of Ok4CL11 to increase specific flavonoids and their glycosides, which are negative regulators of root growth, likely involved in inhibition of auxin transport and signaling.

Exploring Ocimum basilicum's Secondary Metabolites: Inhibition and Molecular Docking against Rhynchophorus ferrugineus for Optimal Action

The objective of our work is to create a practical procedure to produce in vitro cell suspensions of O. basilicum and to ascertain the factors that encourage enhanced secondary metabolite production. We investigated the impact of these metabolites on Rhynchophorus ferrugineus's adult and larval target enzymes. The explants were cultivated on Murashige and Skoog (MS) media with 0.1 to 1 mg/L plant growth regulators (PGRs) to create calluses. 2,4-Dichlorophenoxyacetic acid (2,4-D), kinetin, 1-naphthylacetic acid (NAA), and indole-3-butryic acid (IBA) at 0.5, 0.5, 0.1, and 1 mg/L, respectively, with 3% sucrose led to the highest biomass accumulation. In cell suspensions, the total phenolic content (TPC) and total flavonoid content (TFC) were 39.68 and 5.49 mg/g DW, respectively, with abiotic Verticillium dahliae as an activator. Rosmarinic acid, ursolic acid, nepetoidin A and B, salvigenin, and quercetin-3-O-rutinoside as flavonoids and phenolics were analyzed using UPLC-I TQD MS, with the highest concentrations reached after 40 days. The extract demonstrates insecticidal activity against the fourth-instar larvae of R. ferrugineus, with adults at 1197 µg/mL and 12.5 µg/larvae as LC50 and LD50 values. The extract inhibited acetylcholine esterase (AChE), acid phosphatases (ACPs), alkaline phosphatases (ALPs), and gamma-aminobutyric acid-transaminase (GABA-T) in larval tissue in vitro, with IC50 values of 124.2, 149.3, 157.8, and 204.8 µg/mL, and in vivo, with IC50 values of 157.2, 179.4, 185.3, and 241.6 µg/mL, after 24 h. Pure compounds identified the activity of the extract, showing the inhibition of AChE, ACPs, ALPs, and GABA-T with IC50 values ˂ 200 µg/mL (in vitro). The ABMET examination revealed good oral permeability, and docking tests showed that the compounds bind AChE, ACPs, ALPs, and GABA-T. These findings show that a green bioprocessing method such as an O. basilicum cell suspension is a quick and straightforward technique for producing phenolic compounds, and it may be used to develop sustainable bio-insecticides and new green procedures.

Sweet Basil (Ocimum basilicum L.)-A Review of Its Botany, Phytochemistry, Pharmacological Activities, and Biotechnological Development

An urgent demand for natural compound alternatives to conventional medications has arisen due to global health challenges, such as drug resistance and the adverse effects associated with synthetic drugs. Plant extracts are considered an alternative due to their favorable safety profiles and potential for reducing side effects. Sweet basil (Ocimum basilicum L.) is a valuable plant resource and a potential candidate for the development of pharmaceutical medications. A single pure compound or a combination of compounds exhibits exceptional medicinal properties, including antiviral activity against both DNA and RNA viruses, antibacterial effects against both Gram-positive and Gram-negative bacteria, antifungal properties, antioxidant activity, antidiabetic potential, neuroprotective qualities, and anticancer properties. The plant contains various phytochemical constituents, which mostly consist of linalool, eucalyptol, estragole, and eugenol. For centuries, community and traditional healers across the globe have employed O. basilicum L. to treat a wide range of ailments, including flu, fever, colds, as well as issues pertaining to digestion, reproduction, and respiration. In addition, the current research presented underscores the significant potential of O. basilicum-related nanotechnology applications in addressing diverse challenges and advancing numerous fields. This promising avenue of exploration holds great potential for future scientific and technological advancements, promising improved utilization of medicinal products derived from O. basilicum L.

Natural Compounds with Antimicrobial Properties in Cosmetics

Currently, the cosmetic industry is a very intensively growing part of the economy. Consumer demands are adapted to the current lifestyle, which is based on technological innovations and awareness of the impact of various factors on human health and fitness. There is growing interest in cosmetics based on environmentally friendly natural compounds exerting health-promoting effects. Chemicals with antimicrobial properties used as ingredients in cosmetics ensure their durability and safety. Polyphenolic compounds, peptides, essential oils, and plant extracts characterized by these properties are natural ingredients that can replace synthetic components of cosmetics. The advantage of these compounds is that they exhibit antioxidant, anti-inflammatory, and soothing properties, enhancing the product value in addition to their antimicrobial properties. This review article describes the antimicrobial properties of natural compounds that can protect cosmetics and can replace previously used preservative agents. Various studies indicate that the use of these compounds increases consumer interest in these products and has a positive impact on the environment.

Determination of Chemical Composition and Investigation of Biological Activities of Ocimum basilicum L

This study aimed to determine the chemical composition of the essential oils (EOs) of Ocimum basilicum L., as well as to evaluate the antibacterial, antidiabetic, dermatoprotective, and anti-inflammatory properties, and the EOs and aqueous extracts of O. basilicum. The antibacterial activity was evaluated against bacterial strains, Gram-positive and Gram-negative, using the well diffusion and microdilution methods, whereas the antidiabetic activity was assessed in vitro using two enzymes involved in carbohydrate digestion, α-amylase and α-glucosidase. On the other hand, the dermatoprotective and anti-inflammatory activities were studied by testing tyrosinase and lipoxygenase inhibition activity, respectively. The results showed that the chemical composition of O. basilicum EO (OBEO) is dominated by methyl chavicol (86%) and trans-anethol (8%). OBEO exhibited significant antibacterial effects against Gram-negative and Gram-positive strains, demonstrated by considerable diameters of the inhibition zones and lower MIC and MBC values. In addition, OBEO exhibited significant inhibition of α-amylase (IC50 = 50.51 ± 0.32 μg/mL) and α-glucosidase (IC50 = 39.84 ± 1.2 μg/mL). Concerning the anti-inflammatory activity, OBEO significantly inhibited lipoxygenase activity (IC50 = 18.28 ± 0.03 μg/mL) compared to the aqueous extract (IC50 = 24.8 ± 0.01 μg/mL). Moreover, tyrosinase was considerably inhibited by OBEO (IC50 = 68.58 ± 0.03 μg/mL) compared to the aqueous extract (IC50 = 118.37 ± 0.05 μg/mL). The toxicological investigations revealed the safety of O. basilicum in acute and chronic toxicity. The finding of in silico analysis showed that methyl chavicol and trans-anethole (main compounds of OBEO) validate the pharmacokinetics of these compounds and decipher some antibacterial targets.

In vitro and in silico β-lactamase inhibitory properties and phytochemical profile of Ocimum basilicum cultivated in central delta of Egypt

CONTEXT

Some studies reported the chemical content and antimicrobial properties of Ocimum basilicum L. (Lamiaceae), relevant to the ecological variations in some areas of Egypt and other countries, yet no research was conducted on the plant cultivated in the central delta region of Egypt. Also, no previous data reported on inhibition of β-lactamases by O. basilicum.

OBJECTIVE

To assess β-lactamases inhibition by O. basilicum extracts and the individual constituents.

MATERIALS AND METHODS

Dried aerial parts of O. basilicum were extracted by hydrodistillation for preparation of essential oil and by methanol for non-volatile constituents. Essential oil content and the methanol extract were analysed by GC-MS and UPLC-PDA-MS/MS, respectively. Methyl cinnamate was isolated and analysed by NMR. Broth microdilution method was used to investigate the antimicrobial against resistant clinical isolates of Escherichia coli identified by double disc synergy, combination disc tests and PCR. The most active oil content was further tested with a nitrocefin kit for β-lactamase inhibition and investigated by docking.

RESULTS

O. basilicum was found to contain methyl cinnamate as the major content of the essential oil. More interestingly, methyl cinnamate inhibited ESBL β-lactamases of the type CTX-M. The in vitro IC₅₀ using nitrocefin kit was 11.6 µg/mL vs. 8.1 µg/mL for clavulanic acid as a standard β-lactamase inhibitor.

DISCUSSION AND CONCLUSIONS

This is the first study to report the inhibitory activity of O. basilicum oil and methyl cinnamate against β-lactamase-producing bacteria. The results indicate that methyl cinnamate could be a potential alternative for β-lactamase inhibition.

The in vitro and in vivo antibacterial activities of uniflorous honey from a medicinal plant, Scrophularia ningpoensis Hemsl., and characterization of its chemical profile with UPLC-MS/MS

ETHNOPHARMACOLOGICAL RELEVANCE

According to the Compendium of Materia Medica, honey has been used as a traditional medicine in treatment against mucositis, tinea, hemorrhoids and psoriasis. In complementary medicine, due to its significant antimicrobial activity, honey has been widely used as a remedy for skin wounds and gastrohelcosis for thousands of years.

AIM OF THE STUDY

This study is aimed at exploring the antimicrobial activity and mechanisms of honey sourced from medicinal plants, and revealing the composition-activity relationship, to facilitate their complementary and alternative application in the therapy of bacterial infectious diseases.

MATERIALS AND METHODS

Eight kinds of medicinal plant-derived uniflorous honey, native to China, were gathered. Their antimicrobial activities were evaluated in vitro, and then in vivo with the systemically infected mouse model and the acute skin infection model. SYTOX uptake assay, scanning electron microscopy, DNA binding assay, and quantitative real-time PCR, were carried out to elucidate the antibacterial mechanisms. This was followed by an investigation of the componential profile with the UPLC-MS/MS technique.

RESULTS

It was found that Scrophularia ningpoensis Hemsl. (figwort) honey (S. ningpoensis honey) exhibited broad-spectrum and the strongest antibacterial potency (MICs of 7.81-125.00%, w/v), comparable to manuka honey. In the in vivo assays, S. ningpoensis honey significantly decreased the bacterial load of the muscles under the acute MRSA-infected skin wounds; the sera level of TNF-α in the S. aureus and P. aeruginosa-infected mice decreased by 45.38% and 51.75%, respectively, after the treatment of S. ningpoensis honey (125 mg/10 g). It was capable of killing bacteria through disrupting the cell membranes and the genomic DNA, as well as down-regulating the expression of genes associated with virulence, biofilm formation and invasion, including icaA, icaD, eno, sarA, agrA, sigB, fib and ebps in S. aureus, and lasI, lasR, rhlI, rhlR and algC in P. aeruginosa. Apart from H₂O₂, some other nonperoxide compounds such as adenosine, chavicol, 4-methylcatechol, trehalose, palmitoleic acid and salidroside, might play a vital role in the antibacterial properties of S. ningpoensis honey.

CONCLUSIONS

This is the first study to thoroughly investigate the antibacterial activity, mode of action, and componential profile of S. ningpoensis honey. It suggested that S. ningpoensis honey might be a potential supplement or substitute for manuka honey, for the prevention or treatment of bacterial infections. It will facilitate the precise application of medicinal plant-sourced honey, provide a new thread for the development of antibacterial drugs, and assist in the distinction of different kinds of honey.

Biological Profiling of Essential Oils and Hydrolates of Ocimum basilicum var. Genovese and var. Minimum Originated from Serbia

The genus Ocimum has many species that are used to treat diverse kinds of illnesses and sicknesses from ancient times. One of them, Ocimum basilicum L., commonly known as basil, has a vital role due to its various medicinal goods. It is best known as a plant with pharmacological activities, but also as an antioxidant, antimicrobial, and larvicidal agent. Although it has been traditionally used in Serbia in traditional medicine for centuries as an insecticidal, antibacterial, and antifungal plant as well as a traditional culinary plant, none of the O. basilicum varieties have been commercialised until today. There are significant numbers of information across the world that oils and by-products are part of the global market, but no references to the essential oil composition of Serbian plants were found. Therefore, the objective of this work was to evaluate the antioxidant and antimicrobial potentials of essential oil and hydrolate of two different varieties: O. basilicum var. genovese and Ocimum. basilicum var. minimum originating from Serbia for further industrial production of antimicrobial- and/or antioxidant-valued products. The results of this study confirm that essential oils of O. basilicum var. genovese and var. minimum represent a significant source of bioactive compounds, especially linalool, with a high rate of biological activities. Similar behaviour is observed for hydrolates, which are the by-product of the essential oil distillation process and can be utilised as bioactive-rich waste in further investigation.

In Vitro and In Silico Screening of Anti-Vibrio spp., Antibiofilm, Antioxidant and Anti-Quorum Sensing Activities of Cuminum cyminum L. Volatile Oil

Cuminum cyminum L. essential oil (cumin EO) was studied for its chemical composition, antioxidant and vibriocidal activities. Inhibition of biofilm formation and secretion of some virulence properties controlled by the quorum sensing system in Chromobacterium violaceum and Pseudomonas aeruginosa strains were also reported. The obtained results showed that cuminaldehyde (44.2%) was the dominant compound followed by β-pinene (15.1%), γ-terpinene (14.4%), and p-cymene (14.2%). Using the disc diffusion assay, cumin EO (10 mg/disc) was particularly active against all fifteen Vibrio species, and the highest diameter of growth inhibition zone was recorded against Vibrio fluvialis (41.33 ± 1.15 mm), Vibrio parahaemolyticus (39.67 ± 0.58 mm), and Vibrio natrigens (36.67 ± 0.58 mm). At low concentration (MICs value from 0.023–0.046 mg/mL), cumin EO inhibited the growth of all Vibrio strains, and concentrations as low as 1.5 mg/mL were necessary to kill them (MBCs values from 1.5–12 mg/mL). Using four antioxidant assays, cumin EO exhibited a good result as compared to standard molecules (DPPH = 8 ± 0.54 mg/mL; reducing power = 3.5 ± 0.38 mg/mL; β-carotene = 3.8 ± 0.34 mg/mL; chelating power = 8.4 ± 0.14 mg/mL). More interestingly, at 2x MIC value, cumin EO inhibited the formation of biofilm by Vibrio alginolyticus (9.96 ± 1%), V. parahaemolyticus (15.45 ± 0.7%), Vibrio cholerae (14.9 ± 0.4%), and Vibrio vulnificus (18.14 ± 0.3%). In addition, cumin EO and cuminaldehyde inhibited the production of violacein on Lauria Bertani medium (19 mm and 35 mm, respectively). Meanwhile, 50% of violacein inhibition concentration (VIC50%) was about 2.746 mg/mL for cumin EO and 1.676 mg/mL for cuminaldehyde. Moreover, elastase and protease production and flagellar motility in P. aeruginosa were inhibited at low concentrations of cumin EO and cuminaldehyde. The adopted in-silico approach revealed good ADMET properties as well as a high binding score of the main compounds with target proteins (1JIJ, 2UV0, 1HD2, and 3QP1). Overall, the obtained results highlighted the effectiveness of cumin EO to prevent spoilage with Vibrio species and to interfere with the quorum sensing system in Gram-negative bacteria by inhibiting the flagellar motility, formation of biofilm, and the secretion of some virulence enzymes.

Antimicrobial and Larvicidal Activities of Different Ocimum Essential Oils Extracted by Ultrasound-Assisted Hydrodistillation

Infectious diseases and their vectors have remained a concern for human population from their historical origin. Microbial pathogens have also emerged as a potent threat to the healthcare systems even in developed countries. Essential oils remain a less explored method for infectious disease control; besides, the ultrasound-assisted extraction (UAE) of essential oil production has emerged as promising source of bioactive volatiles over conventional methods. This study analyzed the possible use of UAE- Essential oils (EOs) from different species of Ocimum plants (Ocimum basilicum (OB), O. gratissimum (OG), O. tenuiflorum (OT), and O. canum (OC)) in the management of microbial pathogens and mosquito larval control. The antibacterial activity was estimated in terms of a disc diffusion assay and minimum inhibitory concentrations against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enteritidis. The larvicidal property was found using three important mosquito vectors and the LC50 value was determined. Furthermore, antioxidant and anti-inflammatory properties were estimated in terms of radical scavenging activities and the inhibition of lipoxygenase enzyme activity. The EOs exhibited significant DPPH radical scavenging (high in OG), hydrogen-peroxide scavenging (OB) and lipoxygenase inhibition (OB). The antibacterial activity was high in OB and OG (p < 0.05) and the larvicidal activity was of higher sensitivity against Aedis and Culex, whereas Armigeres was more resistant. However, no sign of toxicity in the Allium cepa model or non-targeted organism Guppy fishes was observed. Overall, the UAE extracted Ocimum essential oils were found to be effective against various human pathogenic microbial organisms, with OB and OG being highly active. Likewise, the EOs was also able to induce mortality in the larval forms of various mosquito vectors.

Comparative studies of eco-friendly compounds like humic acid, salicylic, and glycyrrhizic acids and their nanocomposites on French basil (Ocimum basilicum L. cv. Grand verde)

As the green tactics for enhancing plant growth and production using naturally occurring materials are highly needed, it is important to use the nanoformulation of these materials as an attractive novel technique. Therefore, this research has been performed to evaluate the plants' morphological traits, the qualitative parameters, and molecular genetic characteristics using random amplified polymorphic DNA (RAPD) of French basil independence on growth biostimulators and their nanocomposite. The treatments included normal formulations and nanocomposite formulation of humic acid (5 mM HA), salicylic acid (1.4 mM SA), and glycyrrhizic acid ammonium salt (0.4 mM GA) and control treatment (water application). The results show that foliar spray with HA, SA, GA, and their nanocomposites significantly increased (p ≤ 0.05) on all vegetative growth characters, photosynthetic pigments, oil yield/plant, mineral content, and antibacterial activity as compared with control plants. Also, 1,1-diphenyl-2-picrylhydrazyl (DPPH) values of different samples used varied from 70.63 to 74.93%, with a significant increase compared to untreated plants. The most marked increases have been observed in treated plants with biostimulants in the nanocomposites form than in the natural form. On the other hand, GA and its nanocomposite showed variable effects on basil plants and gave the lowest increase values in all parameters than the other biostimulant but have high antimicrobial activity. For the molecular study, ten selected primers displayed a total of 288 amplified fragments scored per primer ranging from 7 to 46 fragments; 157 bands were polymorphic with 69% polymorphism. It could be concluded that humic acid and its nanocomposite are the most effective biostimulants that increased plant productivity and oil content.

In Vitro and In Silico Evaluation for the Inhibitory Action of O. basilicum Methanol Extract on α-Glucosidase and α-Amylase

Diabetes mellitus is a metabolic disease that predominates, nowadays. It causes hyperglycemia and consequently major health complications. Type II diabetes is the most common form and is a result of insulin resistance in the target tissues. To treat this disease, several mechanisms have been proposed. The most direct route is via inhibiting the intestinal enzymes, e.g., α-glucosidase and α-amylase, responsible for intestinal polysaccharide digestion that therefore would reduce the absorption of monosugars through the intestinal walls. In this study, we shed the light on this route by testing the inhibitory effect of Ocimum basilicum extract on the enzymes α-glucosidase and α-amylase in vitro and in silico. Experimental procedures were performed to test the effect of the O. basilicum methanol extract from aerial parts followed by the in silico docking. 500 μg/mL of the extract led to 70.2% ± 8.6 and 25.4% ± 3.3 inhibition on α-glucosidase and α-amylase activity, respectively. Similarly, the effect of caffeic acid, a major extract ingredient, was also tested, and it caused 42.7% ± 3.0 and 47.1% ± 4.0 inhibition for α-amylase and α-glucosidase, respectively. Docking experiments were performed to predict the phytochemicals responsible for this robust inhibitory activity in the O. basilicum extracts. Several compounds have shown variable levels of inhibition, e.g., caffeic acid, pyroglutamic acid, and uvasol. The results indicated that O. basilicum can be a potent antidiabetic drug.

Impact of Zinc Excess on Germination, Growth Parameters and Oxidative Stress of Sweet Basil (Ocimum basilicum L.)

In the present study, the effects of elevated zinc concentrations on germination, physiological and biochemical parameters were investigated in basil (Ocimum basilicum L.). Results indicate that zinc excess (1-5 mM ZnSO₄) did not affect germination process, but it drastically reduced vigor index and radicle elongation, and induced oxidative stress. Exposure of basil plants to 400 and 800 µM Zn decreased aerial parts and roots dry biomass, root length and leaf number. Under these conditions, the reduction of plant growth was associated with the formation of branched and abnormally shaped brown roots. Translocation factor < 1 and bioconcentration factor > 1 was observed for 100 µM Zn suggested the possible use of basil as a phytostabiliser. Excess of Zn supply (> 100 µM) decreased chlorophyll content, total phenol and total flavonoid contents. Additionally, an increased TBARS levels reflecting an oxidative burst was observed in Zn-treated plants. These findings suggest that excess Zn adversely affects plant growth, photosynthetic pigments, phenolic and flavonoid contents, and enhances oxidative stress in basil plants.

A Systematic Review of Plants With Antibacterial Activities: A Taxonomic and Phylogenetic Perspective

Background: Antimicrobial resistance represents a serious threat to human health across the globe. The cost of bringing a new antibiotic from discovery to market is high and return on investment is low. Furthermore, the development of new antibiotics has slowed dramatically since the 1950s' golden age of discovery. Plants produce a variety of bioactive secondary metabolites that could be used to fuel the future discovery pipeline. While many studies have focused on specific aspects of plants and plant natural products with antibacterial properties, a comprehensive review of the antibacterial potential of plants has never before been attempted. Objectives: This systematic review aims to evaluate reports on plants with significant antibacterial activities. Methods: Following the PRISMA model, we searched three electronic databases: Web of Science, PubMed and SciFinder by using specific keywords: "plant," "antibacterial," "inhibitory concentration." Results: We identified a total of 6,083 articles published between 1946 and 2019 and then reviewed 66% of these (4,024) focusing on articles published between 2012 and 2019. A rigorous selection process was implemented using clear inclusion and exclusion criteria, yielding data on 958 plant species derived from 483 scientific articles. Antibacterial activity is found in 51 of 79 vascular plant orders throughout the phylogenetic tree. Most are reported within eudicots, with the bulk of species being asterids. Antibacterial activity is not prominent in monocotyledons. Phylogenetic distribution strongly supports the concept of chemical evolution across plant clades, especially in more derived eudicot families. The Lamiaceae, Fabaceae and Asteraceae were the most represented plant families, while Cinnamomum verum, Rosmarinus vulgaris and Thymus vulgaris were the most studied species. South Africa was the most represented site of plant collection. Crude extraction in methanol was the most represented type of extraction and leaves were the main plant tissue investigated. Finally, Staphylococcus aureus was the most targeted pathogenic bacteria in these studies. We closely examine 70 prominent medicinal plant species from the 15 families most studied in the literature. Conclusion: This review depicts the current state of knowledge regarding antibacterials from plants and provides powerful recommendations for future research directions.

Formulation and evaluation of Ocimum basilicum-based emulgel for wound healing using animal model

The main aim of the topically applied drugs is to provide local drug contact to the skin and minimize general absorption of drugs. Ocimum basilicum (OB) is popular for folk medicines, having official acceptance in many countries. The aim of this study was to formulate and evaluate the efficacy of topical application of OB-based emulgel on wound healing in animal model. The prepared formulations (OB emulgel) were assessed for FTIR analysis, stability studies, physical appearance, rheological behavior, spreadability, patch/sensitivity test and in vitro drug release. The in vivo wound healing effect was evaluated and compared with commercially available Silver Sulfadiazine cream Quench® in wound-induced rabbits by macroscopic and histopathological evidence. The OB extract/drug was compatible with the selected polymer and other excipients and indicated the suitability of the polymers/excipients for preparation of topical emulgel. The formulated OB emulgel exhibited good physical properties. The release profile of emulgel was satisfactory and released 81.71 ± 1.7% of the drug in 250 min. In vivo wound healing studies showed that OB emulgel exhibited the highest percent wound contraction similar to the commercial product (p > 0.05). This activity was statistically significant (p < 0.05) in comparison to control. Histopathological assessment showed marked improvement in the skin histological architecture after 16 days of OB emulgel treatment. In conclusion, the data demonstrated here signify the prospective of 5% OB emulgel as an innovative therapeutic approach in wound healing.

Molecular docking studies of phytochemicals against trehalose–6–phosphate phosphatases of pathogenic microbes

Background

Many of the pathogenic microbes use trehalose–6–phosphate phosphatase (TPP) enzymes for biosynthesis of sugar trehalose from trehalose–6–phosphate (T6P) in their pathway of infection and proliferation. Therefore, the present work is an approach to design new generation candidate drugs to inhibit TPP through in silico methods.

Results

Blast P and Clustal Omega phylogenetic analysis of TPP sequences were done for 12 organisms that indicate and confirm the presence of three conserved active site regions of known TPPs. Docking studies of 3D model of TPP with 17 phytochemicals revealed most of them have good binding affinity to an enzyme with rutin exhibiting highest affinity (Binding energy of − 7 kcal/mole). It has been found that during docking, phytochemical leads bind to active site region 3 of TPP sequences which coordinates Mg2+ and essential for catalysis.

Conclusions

Binding poses and distance measurement of TPP-phytochemical complexes of rutin, carpaine, stigmasterol, β-caryophyllene, and α-eudesmol reveals that the lead phytochemicals were in close proximity with most of the active site amino acids of region 3 (distance range from 1.796 to 2.747 Ao). This confirms the tight binding between enzyme and leads which may pave way for the discovery of new generation drugs against TPP producing pathogenic microbes to manage diseases.

Rapid Screening of Volatile Organic Compounds from Aframomum danielli Seeds Using Headspace Solid Phase Microextraction Coupled to Gas Chromatography Mass Spectrometry

Volatile organic compounds (VOCs) derived from plants have been used in the fragrance industry since time immemorial. Herein we report on the rapid screening of VOCs from seeds of ripe Aframomum danielli (family, Zingiberaceae) using a polydimethylsiloxane fibre headspace solid phase microextraction coupled to a gas chromatography mass spectrometry (SPME-GC/MS) instrument. Portions of 0.25, 0.35, and 0.50 g of ground sample were weighed and extraction of volatile organic compounds (VOCs) was achieved using a 100 μm polydimethylsiloxane solid phase microextraction (PDMS SPME) fibre, with the equilibrium time of 40 minutes and extraction temperature of 50°C; the following compounds with their respective relative abundances were obtained as the top ten most abundant and annotated ones using NIST, Wiley, and Fragrances Libraries: eucalyptol (58%); β-pinene (22%); α-pinene (7.5%); α-terpineol (4%), α-terpinyl acetate (2%); α-bergamotene (1%); pinocarveol (0.39%); α-copaene (0.35%); caryophyllene (0.34); and β-bisabolene (0.31%). These compounds have been reported elsewhere in the literature and listed in the Fragrances Library, incorporated into the Saturn QP2020 GCMS Solution® software used for their analysis.

Evaluation of antimicrobial activity and efficacy of herbal oils and extracts in disinfection of gutta percha cones before obturation

Objectives

Literature has shown that micro-organisms contaminate gutta percha (GP) during storage and manipulation. Till date herbal extracts are not explored as an alternative medicament for pre-operative chairside disinfection of GP cones. The purpose of our study was to evaluate the antimicrobial activity and efficacy of lemon grass oil (LG), basil oil (BO), and obicure tea extract (OT) in disinfecting GP cones before obturation.

Materials and Methods

Agar diffusion method was used to evaluate the antimicrobial efficacy of LG, BO, OT, and sodium hypochlorite (control) against common contaminants, namely, Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. One hundred and twenty GP cones were contaminated and cut into 2. First half was placed in the broth and incubated; whereas the second was treated with herbal extracts for 1 minute and then incubated for 24 hours in the broth. Any inhibition in bacterial growth was noted with presence/absence of turbidity. Two-way analysis of variance and χ² test were used to assess the effectiveness of herbal extracts to decontaminate GP.

Results

LG showed the highest inhibition zones (29.9 ± 6.9 mm) for all tested organisms, followed by OT extract (16.3 ± 1.8 mm), sodium hypochlorite (16.0 ± 1.6 mm), and BO (14.5 ± 5.3 mm). Statistically significant difference was observed between LG and other herbal extracts (p < 0.05).

Conclusions

All extracts proved to be potential rapid chairside disinfectants of GP cones with LG showing the highest antimicrobial activity.

Isolation and characterization of antimicrobial compound from the stem-bark of the traditionally used medicinal plant Adenium obesum

BACKGROUND

Medicinal plants constitute a natural reservoir for medicines worldwide. They serve mainstream therapeutics and are central in folklore medicine. In case of Adenium obesum (Lav, Apocynaceae), indigenous people of Oman use it for the treatment of venereal diseases, wounds, skin diseases, headaches, muscle pain as well as joint pain; yet, the active ingredients have not been classified. To screened the antioxidant and antimicrobial activities of an identified compound that we isolated from the highest active chloroform extract.

METHODS

The antioxidant and antimicrobial activities of the extracts and the isolated compound were determined by diphenyl-1-picrylhydrazyl (DPPH) and disc diffusion methods. To characterize the compound, we used TLC, column, 1H-NMR, 13C-NMR, 2D-NMR, IR and MS.

RESULTS

The highest antioxidant activity was found in chloroform extract with EC50 value of 28.32 μg/ml followed by water, methanol, butanol, ethyl acetate and hexane extracts, their IC50 being 29.95, 39.17, 42.40, 43.20 and 57.00 μg/ml respectively. All crude extracts and pure compound displayed moderate antimicrobial activity against one Gram positive Staphylococcus aureus and three Gram negative Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris within growth inhibition range of 0-13 mm. The active metabolite was identified as 3,4-dihydroxycinnamic acid (R)-1-carboxy-2-(3,4-dihydroxyphenyl) ethyl ester which is a common plant ingredient known as rosmarinic acid.

CONCLUSION

The results indicate that walnut chloroform fraction may contain effective compounds with a broad spectrum of curative applications. This is the first report on isolation and characterization of a compound from chloroform crude extract of A. obesum.

Chemical composition, antioxidant, antimicrobial and cytotoxic activities of Tagetes minuta and Ocimum basilicum essential oils

Chemical composition, antioxidant, antimicrobial and cytotoxic activities of Tagetes minuta (TM) essential oil (TMO) and Ocimum basilicum (OB) essential oil (OBO) were examined. The main components for TMO were dihydrotagetone (33.9%), E-ocimene (19.9%), tagetone (16.1%), cis-β-ocimene (7.9%), Z-ocimene (5.3%), limonene (3.1%) and epoxyocimene (2.03%). The main components for OBO were methylchavicol (46.9%), geranial (19.1%), neral (15.15%), geraniol (3.0%), nerol (3.0%), caryophyllene (2.4%). Inhibitory concentrations (IC₅₀) for reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenging were 12–17 and 200–250 μg/mL of TMO and OBO, respectively. Minimal inhibitory concentration (MIC) against Salmonella typhi,Escherichia coli,Staphylococcus aureus,Bacillus subtilis,Aspergillus niger, and Candida albicans were 150 ± 8, 165 ± 9, 67 ± 8, 75 ± 7, 135 ± 15, and 115 ± 8 μg/mL of TMO, respectively. MIC for S. typhi,E. coli,S. aureus,B. subtilis,A. niger, and C. albicans were 145 ± 8, 160 ± 7, 45 ± 4, 40 ± 3, 80 ± 9, and 95 ± 7 μg/mL of OBO, respectively. IC₅₀ for nasopharyngeal cancer cell line (KB) and liver hepatocellular carcinoma cell line (HepG2) were 75 ± 5 and 70 ± 4 μg/mL of TMO, respectively. IC₅₀ for KB and HepG2 were 45 ± 4 and 40 ± 3 μg/mL of OBO, respectively. Thus, they could be used as an effective source of natural antioxidant and antibacterial additive to protect foods from oxidative damages and foodborne pathogens. Furthermore, they could be promising candidate for antitumor drug design.