Ocimum Basilicum Var Research Articles

Companion basil plants prime the tomato wound response through volatile signaling in a mixed planting system

Key messageVolatile compounds released from basil prime the tomato wound response by promoting jasmonic acid, mitogen-activated protein kinase, and reactive oxygen species signaling.Within mixed planting systems, companion plants can promote growth or enhance stress responses in target plants. However, the mechanisms underlying these effects remain poorly understood. To gain insight into the molecular nature of the effects of companion plants, we investigated the effects of basil plants (Ocimum basilicum var. minimum) on the wound response in tomato plants (Solanum lycopersicum cv. ‘Micro-Tom’) within a mixed planting system under environmentally controlled chamber. The results showed that the expression of Pin2, which specifically responds to mechanical wounding, was induced more rapidly and more strongly in the leaves of tomato plants cultivated with companion basil plants. This wound response priming effect was replicated through the exposure of tomato plants to an essential oil (EO) prepared from basil leaves. Tomato leaves pre-exposed to basil EO showed enhanced expression of genes related to jasmonic acid, mitogen-activated protein kinase (MAPK), and reactive oxygen species (ROS) signaling after wounding stress. Basil EO also enhanced ROS accumulation in wounded tomato leaves. The wound response priming effect of basil EO was confirmed in wounded Arabidopsis plants. Loss-of-function analysis of target genes revealed that MAPK genes play pivotal roles in controlling the observed priming effects. Spodoptera litura larvae-fed tomato leaves pre-exposed to basil EO showed reduced growth compared with larvae-fed control leaves. Thus, mixed planting with basil may enhance defense priming in both tomato and Arabidopsis plants through the activation of volatile signaling.

Studying the Response of Greek Basil Ocimum basilicum var. minimum to Treatment with High Doses of Selenium

Previous published literatures have been established the impact of selenium application in a trace amount on yield and active constituents of basil plants. In the current study, the effect of high doses of selenium application on growth of Greek basil Ocimum basilicum var. minimum growth and its essential oil compounds was investigated. Obtained result exhibited that the foliar application with (0, 40, 80, 120, 160) mg/L of selenium reduced the plants growth parameters and plant content of phytopigments and primary metabolites such as carbohydrates, protein, and proline. Refractive index of essential oil diminished post selenium application, while, specific gravity increased at 160 mg/L. Selenium application also caused alteration in the secondary metabolites profile. A reduction was obtained in the volatile compounds of essential oil such as Linalool, Eugenol and Methyleugenol with selenium treatment. On the other hand, unsaturated fatty acids such as Linolenic acid and phytosterols such as Campesterol, Stigmasterol and beta-Sitosterol increased with applicated selenium concentration.

Comparison Sunscreen Potential of Extract with Ethanol Extract Cream of Basil Leaves (Ocimum basilicum var. anisatum Benth) In Vitro

Sunscreens on the market are generally made of synthetic materials. However, many synthetic active substances can cause allergies and irritation. Along with the trend back to nature, the use of traditional medicine among the public is more in demand. Natural ingredients that have potential for sunscreen are basil leaves (Ocimum basilicum var. anisatum Benth). Cream preparations have the advantage of a fairly high aesthetic value and the level of comfort in use is quite good. This study aims to determine the sunscreen potency of the extract and cream of the ethanolic extract of basil leaves in vitro based on the values of %Te, %Tp and SPF. Determination of sunscreen potency was carried out by calculating %Te, %Tp and SPF values on ethanol extract of basil leaves and cream of ethanolic extract of basil leaves in vitro using UV-Vis spectrophotometry at a wavelength of 290-400 nm every 5 nm interval. The %Te value of basil leaf ethanol extract at a concentration of 100 ppm was not included in the category, at a concentration of 200 ppm and 300 ppm it was in the category of extra protection. And the value of %Te cream of basil leaf ethanol extract at a concentration of 100 ppm is not included in the category, at a concentration of 200 ppm it is in the regular suntan category, at a concentration of 300 ppm it is in the extra protection category. The %Tp value of ethanol extract of basil leaves and cream of ethanolic extract of basil leaves was included in the total block category. The SPF value of the ethanolic extract of basil leaves at concentrations of 100 ppm, 200 ppm and 300 ppm, respectively, is 3.873 (minimum); 12,163(maximum); and 40,736(ultra). While the SPF value of the cream of ethanol extract of basil leaves was 2.792 (minimum); 6,508(extra); and 12,259 (maximum).

Green Synthesis of Silicon Quantum Dots Using Ocimum basilicum var. Purpurascens as an Organic Reductor Agent

Green Synthesis of Silicon Quantum Dots Using Ocimum basilicum var. Purpurascens as an Organic Reductor Agent

A Culinary and Medicinal Gem: Exploring the Phytochemical and Functional Properties of Thai Basil.

This study aimed to comprehensively evaluate the potential health benefits of Thai basil extracts from two species, Ocimum basilicum var. thyrsiflorum and Ocimum basilicum cv. Jumbo 4320, by investigating their bioactivities, phytochemical composition, and in vitro antioxidant, antimicrobial, and antithrombotic activities. Thai basil extracts from two species (Ocimum basilicum var. thyrsiflorum and cv. Jumbo 4320) were obtained using water, ethanol, and ethyl acetate. Phytochemical analysis revealed chlorophylls, carotenoids, and diverse phenolic compounds. Its water extract boasted the highest total phenolics (459.62 ± 3.07 mg GAE/100 g), outperforming ethanol and ethyl acetate extracts (171.20 ± 1.10 and 66.02 ± 0.99 mg GAE/100 g, respectively). The ethanol extract of Jumbo 4320 also reigned supreme in total flavonoids (557.12 ± 14.27 mg CE/100 g), surpassing its counterparts (209.07 ± 23.31 and 131.41 ± 0.37 mg CE/100 g). O. basilicum cv. Jumbo 4320 extracts exhibited superior antioxidant activity by various assays. Jumbo 4320's water extract further dominated in the DPPH assay (IC50 48.52 ± 1.15 mg/mL), demonstrating superior free radical scavenging compared to ethanol and ethyl acetate extracts (IC50 60.54 ± 0.52 and 82.09 ± 3.18 mg/mL), respectively. While thyrsiflorum's ethanol extract claimed the top spot in the FRAP assay (0.0186 ± 0.00 mmol Fe2+/g), Jumbo 4320's water extract showcased the highest cellular antioxidant activity (80.62 ± 0.00% relative fluorescence intensity) in the DCFH-DA assay. Interestingly, Ocimum basilicum var. thyrsiflorum extracts demonstrated stronger antithrombotic activity at prolonging the prothrombin time at 78.3 ± 17.56 s. While the antimicrobial activity against most tested pathogens was limited, both species' extracts inhibited Bacillus cereus. These findings suggest the potential of Thai basil extracts, particularly from Jumbo 4320, as functional food ingredients with antioxidant and antithrombotic properties.

Chloroplast genome of Ocimum basilicum var. purpurascens Bentham 1830 (Lamiaceae)

Ocimum basilicum var. purpurascens Bentham 1830 (Red Rubin Basil) is an aromatic herb belonging to the family Lamiaceae and is known for its medicinal uses. It is commonly used in traditional medicine to treat cardiovascular diseases and obesity. It possesses anti-inflammatory, antioxidant, antifungal, and anti-spasmodic properties. In our recent study, we assembled the chloroplast genome sequence of O. basilicum var. purpurascens using Illumina paired-end sequencing technology. The assembled chloroplast genome was 152,407 base pairs (bp), inclusive of a large single-copy (LSC) region accounting for 83,409 bp and a small single-copy (SSC) region spanning 17,604 bp. Two inverted repeats (IRs) interspersed these regions, each 25,697 bp long. The chloroplast genome harbored 132 genes, comprising 88 protein-coding genes, 36 transfer RNA (tRNA), and eight rRNA genes. Among these, nine genes encompassed a single intron, two presented with two introns, with the remaining devoid of any introns. The overall GC content of the chloroplast genome was determined to be 38%. The GC content in the LSC, SSC, and IR regions was 35.9%, 31.6%, and 43.1%, respectively. Our phylogenetic exploration of the chloroplast genomes elucidated that O. basilicum var. purpurascens exhibits close genetic affinity with O. basilicum var. basilicum and other constituents of the Ocimum genus within the Lamiaceae family.

Effect of Different Concentrations of Chitosan on Germination and Growth of Sweet Thai Basil

Sweet Thai basil, Ocimum basilicum var. thyrsiflora is a medicinal plant that is widely used in many industries due to its richness in phytochemical contents. The present study was carried out to improve the germination growth and of sweet Thai basil. In the current research sweet Thai basil seeds were treated with different concentrations of chitosan (0, 2, 4 and 6 ml/L). The result showed that treatment at 4 ml/ L chitosan produced seed germination percentage 100, seed germination speed (1.51), vigor index (6.93) taller seedlings (7.69 cm in height), with bigger stem diameter (0.90 mm), leaf area (1.59 cm2/leaf), and root length (3.19 cm). However, 4 ml/L chitosan concentration was best compare to 0, 2 and 4 ml/L concentration of chitosan. On the other hand, it is recommended for the seeds of sweet Thai basil to be treated with 4 ml/L of chitosan with different plant density.

Application timing and duration of LED and HPS supplements differentially influence yield, nutrient bioaccumulation, and light use efficiency of greenhouse basil across seasons.

Three primary factors that impact plant growth and development are light quantity, quality, and duration. Commercial growers can manipulate these parameters using light-emitting diodes (LEDs) to optimize biomass yield and plant quality. There is significant potential to synergize supplemental lighting (SL) parameters with seasonal variation of ambient sunlight to optimize crop light use efficiency (LUE), which could increase biomass while reducing SL electricity costs. To determine the best lighting characteristics and durations for different crops, particularly for enhancing the yield and nutritional quality of high-value specialty crops produced in greenhouses during the winter, a thorough efficacy comparison of progressive incremental daily light integrals (DLIs) using LED and high-pressure sodium (HPS) sources is required. The purpose of this study was to compare the effects of differential application timing and DLIs of supplemental blue (B)/red (R) narrowband wavelengths from LED lighting systems and HPS lamps on greenhouse hydroponic basil (Ocimum basilicum var. 'Genovese') production. We assessed edible biomass, nutrient bioaccumulation, and LUE. Nine light treatments included: one non-supplemented natural light (NL) control, two end-of-day (EOD) HPS treatments applied for 6h and 12h, five EOD 20B/80R LED treatments applied for 3h, 6h, 9h, 12h, 18h, and one continuous LED treatment (24h). Each SL treatment provided 100 µmol·m-2·s-1. The DLI of the NL control averaged 9.9mol·m-2·d-1 during the growth period (ranging from 4 to 20mol·m-2·d-1). SL treatments and growing seasons significantly impacted biomass and nutrient bioaccumulation; some SL treatments had lower yields than the non-supplemented NL control. January growing season produced the lowest fresh mass (FM) and dry mass (DM) values compared to November, which had the highest. Mineral analyses revealed that both growing seasons and lighting types impacted macro and micronutrient accumulation. Additionally, the efficiency of each treatment in converting electrical energy into biomass varied greatly. EOD supplements using LED and HPS lighting systems both have merits for efficiently optimizing yield and nutrient accumulation in basil; however, biomass and nutrient tissue concentrations highly depend on seasonal variation in ambient sunlight in conjunction with a supplement's spectral quality, DLI, and application schedule.

Effects of biochar and compost addition in potting substrates on growth and volatile compounds profile of basil (Ocimum basilicum L.).

Despite the optimal characteristics of peat, more environmental-friendly materials are needed in the nursery sector, although these must guarantee specific quantitative and qualitative commercial standards. In the present study, we evaluated the influence of biochar and compost as peat surrogates on yield and essential oil profile of two different varieties of basil (Ocimum basilicum var. Italiano and Ocimum basilicum var. minimum). In two 50-day pot experiments, we checked the performances of biochar from pruning of urban trees and composted kitchen scraps, both mixed in different proportions with commercial peat (first experiment), and under different nitrogen (N) fertilization regimes (second experiment), in terms of plant growth and volatile compounds profile of basil. Total or high substitution of peat with biochar (100% and 50% v.v.) or compost (100%) resulted in seedling death a few days from transplantation, probably because the pH and electrical conductivity of the growing media were too high. Substrates with lower substitution rates (10-20%) were underperforming in terms of plant growth and color compared to pure commercial peat during the first experiment, whereas better performances were obtained by the nitrogen-fertilized mixed substrates in the second experiment, at least for one variety. We identified a total of 12 and 16 aroma compounds of basil (mainly terpenes) in the two experiments. Partial replacement of peat did not affect basil volatile organic compounds content and composition, whereas N fertilization overall decreased the concentration of these compounds. Our results support a moderate use of charred or composted materials as peat surrogates. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Differential Antioxidant Response to Supplemental UV-B Irradiation and Sunlight in Three Basil Varieties.

Three basil plant varieties (Ocimum basilicum var. Genovese, Ocimum × citriodorum, and Ocimum basilicum var. purpurascens) were grown under moderate light (about 300 µmol photons m-2 s-1) in a glasshouse or growth chamber and then either transferred to an open field (average daily dose: 29.2 kJ m-2 d-1) or additionally exposed to UV-B irradiation in a growth chamber (29.16 kJ m-2 d-1), to reveal the variety-specific and light-specific acclimation responses. Total antioxidant capacity (TAC), phenolic profile, ascorbate content, and class III peroxidase (POD) activity were used to determine the antioxidant status of leaves under all four light regimes. Exposure to high solar irradiation at the open field resulted in an increase in TAC, total hydroxycinnamic acids (HCAs, especially caffeic acid), flavonoids, and epidermal UV-absorbing substances in all three varieties, as well as a two-fold increase in the leaf dry/fresh weight ratio. The supplemental UV-B irradiation induced preferential accumulation of HCAs (rosmarinic acid) over flavonoids, increased TAC and POD activity, but decreased the ascorbate content in the leaves, and inhibited the accumulation of epidermal flavonoids in all basil varieties. Furthermore, characteristic leaf curling and UV-B-induced inhibition of plant growth were observed in all basil varieties, while a pro-oxidant effect of UV-B was indicated with H2O2 accumulation in the leaves and spotty leaf browning. The extent of these morphological changes, and oxidative damage depended on the basil cultivar, implies a genotype-specific tolerance mechanism to high doses of UV-B irradiation.

Antioxidant and antimicrobial activities of <em>Ocimum basilicum var. thyrsiflora</em> against some oral microbes

The accumulation of free radicals is the root cause of many dangerous diseases. Several studies are being conducted to identify plant-based natural antioxidants and antimicrobial elements. Ocimum basilicum var. thyrsiflora exhibits anti-inflammatory, antioxidant, antiulcer, antiviral, hypoglycemic, hypolipidemic, antimicrobial, anticancer, wound-healing, etc. This research aimed to determine the in vitro antioxidant activity of essential oils extracted from the leaves and seeds of Ocimum basilicum var. thyrsiflora by hydroxyl radical, nitric oxide, 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical, and azino-bis (3-ethylbenthiazoline-6-sulphonic acid (ABTS) assays. The antibacterial activity of essential oils extracted from leaves and seeds of Ocimum basilicum var. thyrsiflora was evaluated by the disc diffusion method against E. coli, P. aeruginosa, Acinetobacter, S. epidermis, K. pneumoniae, S. aureus, E. faecalis, and P. mirabilis. According to the findings, the hydroxyl radical (HO•) scavenging assay method revealed more potent antioxidant activity in Ocimum basilicum var. thyrsiflora essential oils than in other methods. The hydroxyl radical scavenging assay was found to have IC50 values of 115.20 ± 6.45 and 128.35 ± 6.20 for seeds and leaves, respectively. Ocimum basilicum var. thyrsiflora essential oils exhibited a strong antibacterial effect against all the tested microorganisms. The highest antibacterial activity was measured in the essential oil extracted from seeds against P. aeruginosa (20.06±0.30) at a concentration of 50% of essential oil, and the lowest activity was observed in the essential oil extracted from leaves against P. mirabilis (7.46±0.45) at a concentration of 12.5% of essential oil. As a result, it can be a potent natural source of antioxidants to treat many stress and anxiety-related diseases and would be a better alternative for the development of new antimicrobial medications to treat a variety of infectious ailments caused by microbes.

Effects of Ulva intestinalis Linnaeus seaweed liquid extract on plant growth, photosynthetic performance and water status of two hydroponically grown Lamiaceae species: Peppermint (Mentha × piperita L.) and purple basil (Ocimum basilicum var. purpurascens Benth.)

Seaweed extracts are considered as marine biostimulants and have been successfully used in agriculture to improve the growth and tolerance to different environmental stress conditions of many crops. Therefore, the present study was carried out for the first time and aimed to determine the effects of a seaweed liquid extract on growth and photosynthetic performance as well as the water status of hydroponically-grown peppermint and purple basil plants. For this purpose, the experiment was conducted under greenhouse conditions and plants were cultivated in hydroponic systems according to the nutrient film technique. A seaweed liquid extract at 10% was prepared from the green marine macroalgae Ulva intestinalis and then added to the nutrient solution of the hydroponic system. Based on our experimental data, the main results have proven that Ulva intestinalis seaweed liquid extract could be successfully used as a biostimulant in the hydroponic cultivation of peppermint for its enhancing effect on some plant growth and photosynthetic as well as water status parameters. However, it is not recommended to add the seaweed liquid extract of Ulva intestinalis to the hydroponic culture of purple basil since most of the parameters analyzed were shown to be negatively affected by the seaweed liquid extract treatment. Furthermore, the results of this study could be practical for enhancing the production of medicinal and aromatic plants by adding the Ulva intestinalis seaweed liquid extract to the nutrient solution of the hydroponic system.

Variation in supplemental lighting quality influences key aroma volatiles in hydroponically grown 'Italian Large Leaf' basil.

The spectral quality of supplemental greenhouse lighting can directly influence aroma volatiles and secondary metabolic resource allocation (i.e., specific compounds and classes of compounds). Research is needed to determine species-specific secondary metabolic responses to supplemental lighting (SL) sources with an emphasis on variations in spectral quality. The primary objective of this experiment was to determine the impact of supplemental narrowband blue (B) and red (R) LED lighting ratios and discrete wavelengths on flavor volatiles in hydroponic basil (Ocimum basilicum var. Italian Large Leaf). A natural light (NL) control and different broadband lighting sources were also evaluated to establish the impact of adding discrete and broadband supplements to the ambient solar spectrum. Each SL treatment provided 8.64 mol.m-2.d-1 (100 µmol.m-2.s-1, 24 h.d-1) photon flux. The daily light integral (DLI) of the NL control averaged 11.75 mol.m-2.d-1 during the growth period (ranging from 4 to 20 mol.m-2.d-1). Basil plants were harvested 45 d after seeding. Using GC-MS, we explored, identified, and quantified several important volatile organic compounds (VOCs) with known influence on sensory perception and/or plant physiological processes of sweet basil. We found that the spectral quality from SL sources, in addition to changes in the spectra and DLI of ambient sunlight across growing seasons, directly influence basil aroma volatile concentrations. Further, we found that specific ratios of narrowband B/R wavelengths, combinations of discrete narrowband wavelengths, and broadband wavelengths directly and differentially influence the overall aroma profile as well as specific compounds. Based on the results of this study, we recommend supplemental 450 and 660 nm (± 20 nm) wavelengths at a ratio of approximately 10B/90R at 100-200 µmol.m-2.s-1, 12-24 h.d-1 for sweet basil grown under standard greenhouse conditions, with direct consideration of the natural solar spectrum and DLI provided for any given location and growing season. This experiment demonstrates the ability to use discrete narrowband wavelengths to augment the natural solar spectrum to provide an optimal light environment across variable growing seasons. Future experiments should investigate SL spectral quality for the optimization of sensory compounds in other high-value specialty crops.

Optimization of Microwave-Assisted Extraction of Mucilage from Ocimum basilicum var. album (L.) Seed

Microwave-assisted extraction (MAE) is an effective green extraction method of value-added and bioactive compounds. The impact of different extraction times (2-7 min), microwave power (360-760 W), and solvent-to-sample ratio (20 : 1-40 : 1 ml/g) on the extraction yield of Ocimum basilicum var. album L. using MAE was investigated. Maximum extraction yield ( 17.00 ± 0.14 %) was obtained at optimal conditions for extraction using response surface methodology, including extraction time of 4.33 min, power of 570.32 W, and the solvent-to-sample ratio of 40 : 1 ml/g, which was very close to the model prediction (17.01%). The yield of the conventional extraction (CE) method (50°C, 100 rpm, 1 h extraction time, and solvent-to-sample ratio of 40 : 1 ml/g) was 14.53 ± 0.25 %. Comparisons were made between the functional and structural characteristics of the mucilage extracted under optimal conditions and the CE method. Fourier transforms infrared (FTIR) spectroscopy was utilized to study the changes in functional groups, and scanning electron microscopy (SEM) was used to determine the morphological characteristics. Emulsion stability against heat, water absorption capacity, foaming capacity, and foaming stability of the extracted mucilage under optimal conditions were 80.73 ± 0.08 %, 48.71 ± 0.32 g/g, 24.55 ± 0.42 %, and 91.6 ± 0.49 %, respectively, which were higher than the CE method. SEM results showed a more porous structure in mucilage obtained by the MAE method, while no changes were observed by FTIR analysis between the functional groups of extracted mucilage obtained from the utilized extraction methods. Therefore, the application of the MAE method was superior to CE in terms of yield, structural and functional characteristics, and significantly shorter extraction time. The findings show the great potential of microwave processing in commercial and laboratory extraction of mucilage without deteriorative effects on the structural and functional properties of the extracted material.

Artificial Neural Network and Response Surface-Based Combined Approach to Optimize the Oil Content of Ocimum basilicum var. thyrsiflora (Thai Basil).

Ocimum basilicum var. thyrsiflora is valuable for its medicinal properties. The barriers to the commercialization of essential oil are the lack of requisite high oil-containing genotypes and variations in the quantity and quality of essential oils in different geographic areas. Thai basil's essential oil content is significantly influenced by soil and environmental factors. To optimize and predict the essential oil yield of Thai basil in various agroclimatic regions, the current study was conducted. The 93 datasets used to construct the model were collected from samples taken across 10 different agroclimatic regions of Odisha. Climate variables, soil parameters, and oil content were used to train the Artificial Neural Network (ANN) model. The outcome showed that a multilayer feed-forward neural network with an R squared value of 0.95 was the most suitable model. To understand how the variables interact and to determine the optimum value of each variable for the greatest response, the response surface curves were plotted. Garson's algorithm was used to discover the influential predictors. Soil potassium content was found to have a very strong influence on responses, followed by maximum relative humidity and average rainfall, respectively. The study reveals that by adjusting the changeable parameters for high commercial significance, the ANN-based prediction model with the response surface methodology technique is a new and promising way to estimate the oil yield at a new site and maximize the essential oil yield at a particular region. To our knowledge, this is the first report on an ANN-based prediction model for Ocimum basilicum var. thyrsiflora.

Identification of Key Aromatic Compounds in Basil (Ocimum L.) Using Sensory Evaluation, Metabolomics and Volatilomics Analysis.

Basil (Ocimum L.) is widely used as a flavor ingredient, however research on basil flavor is limited. In the current study, nine basil species were selected, including Ocimum basilicum L.var. pilosum (Willd.) Benth., Ocimum sanctum, Ocimum basilicum cinnamon, Ocimum gratissimum var. suave, Ocimum tashiroi, Ocimum basilicum, Ocimum americanum, Ocimum basilicum ct linalool, and Ocimum basilicum var. basilicum, and their fragrance and flavor characteristics were assessed by sensory evaluation. The results indicated that Ocimum basilicum var. basilicum and Ocimum gratissimum var. suave have a strong clove smell and exhibited a piquant taste. Metabolomics and volatilomics analyses measured 100 nonvolatile metabolites and 134 volatiles. Differential analysis showed that eugenol, γ-terpinene, germacrene D and malic acid were among the most varied metabolites in basil species. Combined with sensory evaluation results, correlation analysis revealed that β-pinene and γ-cadinene contributed to the piquant smell, while eugenol and germacrene D contributed to the clove smell, and malic acid and L-(−)-arabitol contributed to the sweet flavor in basil. This study provided comprehensive flavor chemistry profiles of basil species and could be used as a guide for basil flavor improvement. The better understanding of objective sensory attributes and chemical composition of fresh basil could introduce the improved cultivars with preponderant traits, which is also in accordance with the various demands of breeders and growers, food producers, and consumers.

Impact of Foliar Application of Some Growth stimulants on the vegetative growth and the Essential oil characters of Ocimum basilicum var. thyrsiflorum (L.)

Impact of Foliar Application of Some Growth stimulants on the vegetative growth and the Essential oil characters of Ocimum basilicum var. thyrsiflorum (L.)

Studies on the Yield and Chemical Composition of the Herb of Plants of the Genus Ocimum Depending on the Development Stage of the Plant

The research aimed to present the possibility of cultivating selected plants of the genus Ocimum in central-eastern Poland and to assess the chemical composition of the obtained raw material, considering the development stage of the plant. The research object consisted of six selected plants from the genus Ocimum: Ocimum basilicum, Ocimum basilicum var. purpurescens, Ocimum basilicum × citrodorum, Ocimum basilicum ‘Cinnamon’, Ocimum basilicum ‘Siam Queen’, Ocimum basilicum var. minimum ‘Minette’. The herb was harvested on the following dates: mid-June (vegetative stage), mid-July (beginning of flowering), late July/early August (full flowering), end of August (late flowering). The research showed that plants of genus Ocimum sp. can be successfully introduced to cultivation in central-eastern Poland. The yield of these plants was at a high level (average yield of fresh herb—1.15 kg m−2 and average marketable yield—0.14 kg m−2). Plants of genus Ocimum sp. accumulated the least essential oil, flavonoids, and tannins in the vegetative stage (mean: essential oil—0.86%, flavonoids—0.60%, tannins—0.41%). The highest content of all tested secondary metabolites was found in the variety O. basilicum var. minimum “Minette”. The variability of the content of the analyzed compounds depending on the growth and flowering stage of the plants under study is diversified. For this reason, the date of harvesting raw materials from these plants should be selected individually to obtain a high-quality product.

The Effect of Leaf Wounding on Basil Plants of Different Developmental Stages.

Leaf wounding is a common stress that triggers a great number of plant mechanisms, while the overall plant status and age could also be critical for these mechanisms. However, there are not sufficient data about plants’ physiological responses after leaf wounding that has been imposed at different developmental stages. In this study, physiological parameters, such as photosynthesis, transpiration, and stomatal conductance, as well as the chlorophyll and anthocyanin leaf contents, of Ocimum basilicum var. minimum L. plants were measured for seven days on wounded plants during three different developmental stages (vegetative, budding, and flowering). All of the measurements were conducted on control and wounded plants, while on the latter they were conducted on both wounded and intact leaves. The physiological parameters mentioned above revealed a remarkable decrease in wounded leaves of the budding and flowering plants, while they seemed to be only partially affected on the leaves of vegetative plants. The physiological parameters’ decrease was not only an immediate plant response that was observed 1–2 h after wounding, but, in general, it was constant (during the seven days of treatments) and diurnal (from 8 a.m. to 8 p.m.). The wounded leaves revealed an immediate and constant anthocyanin content decrease during all of the developmental stages, while the corresponding chlorophyll decrease was mainly evident in the flowering plants. Regarding the intact leaves, they exhibited, in general, a similar profile to that of the control ones. The results above reveal that at the vegetative stage, basil plants are more tolerant to leaf wounding than those at the budding and flowering stages, implying that the plant’s response to wounding is a phenomenon that depends on the plant’s developmental stage.

Studies on the Phytochemical Profile of Ocimum basilicum var. minimum (L.) Alef. Essential Oil, Its Larvicidal Activity and In Silico Interaction with Acetylcholinesterase against Aedes aegypti (Diptera: Culicidae).

Aedes aegypti L. (Diptera: Culicidae) is an important transmitter of diseases in tropical countries and controlling the larvae of this mosquito helps to reduce cases of diseases such as dengue, zika and chikungunya. Thus, the present study aimed to evaluate the larvicidal potential of the essential oil (EO) of Ocimum basilicum var. minimum (L.) Alef. The EO was extracted by stem distillation and the chemical composition was characterized by gas chromatography coupled with mass spectrometry (GC/MS and GC-FID). The larvicidal activity of EO was evaluated against third instar Ae. aegypti following World Health Organization (WHO) standard protocol and the interaction of the major compounds with the acetylcholinesterase (AChE) was evaluated by molecular docking. The predominant class was oxygenated monoterpenes with a concentration of 81.69% and the major compounds were limonene (9.5%), 1,8-cineole (14.23%), linalool (24.51%) and methyl chavicol (37.41%). The O. basilicum var. minimum EO showed unprecedented activity against third instar Ae. aegypti larvae at a dose-dependent relationship with LC50 of 69.91 (µg/mL) and LC90 of 200.62 (µg/mL), and the major compounds were able to interact with AChE in the Molecular Docking assay, indicating an ecological alternative for mosquito larvae control.