Volatile Organic Compounds from Basil Essential Oils: Plant Taxonomy, Biological Activities, and Their Applications in Tropical Fruit Productions

Evaluation of basil essential oils for antifungal and anti-aflatoxigenic activity against Aspergillus flavus

Essential oils of basil herbs such as nyazbo or sweet basil (Ocimum basilicum), holy basil or tulsi (O. tenuiflorum), and African or clove basil (O. gratissimum) have traditionally been used for their therapeutic potential. These medicinal herbs are being cultivated and consumed globally, and the increasing demand for antimicrobial and antifungal natural products has led to the assessment of the potential of essential oils of medicinal plants to inhibit mycelial growth rather than synthetic fungicides. Thus, the present study explored natural alternatives to inhibit mycelial growth (Aspergilus flavus) and aflatoxin production. Linalool (25.40%), methyl chavicol (37.63%), and eugenol (39.52%) were identified as chief compounds in the EOs of O. basilicum, O. tenuiflorum, and O. gratissimum respectively. Ocimum tenuiflorum EO demonstrated the highest inhibitory activity at 0.75 µL mL- 1 against Aspergillus flavus and totally inhibited the synthesis of aflatoxin B1 (AFB1). The AFB2 production was completely inhibited at 0.25 µL mL- 1 by O. tenuiflorum EO, while O. basilicum and O. gratissimum EOs showed inhibition against AFB2 at 0.50 µL mL- 1, and 1.0 µL mL- 1, respectively. The present study suggests that EOs of basil herbs could be a potential natural alternative of synthetic fungicides to inhibit the fungal growth and aflatoxin production.

Low-pressure cold plasma pretreatment: Impact on quality attributes of "Fan Retief" guava and efficacy against Colletotrichum gloeosporioides

This work investigated the impact of low-pressure cold plasma (CP) as a pretreatment with polyethylene terephthalate (PET) plastic trays or open corrugated cardboard (OCC) boxes on the overall quality of "Fan Retief" guava fruits stored for 28 days at 13°C. Untreated samples placed in PET and OCC served as control. Guava fruits followed typical climacteric responses, but CP-treated samples significantly slowed down respiration (RRCO2) and ethylene production rate during storage (p ≤ 0.05). On day 28, CP-treated samples retained the highest titratable acidity and total phenolics compared to untreated samples (p ≤ 0.05). Overall, CP pretreatment better maintained the relative abundance of characteristic volatile compounds for guava fruits during storage, effectively delayed decay incidence, and inhibited the growth of Colletotrichum gloeosporioides in vivo compared to control. PRACTICAL APPLICATION: This study demonstrated low-pressure cold plasma as a potential alternative phytosanitary tool for the postharvest handling of guava fruit.

Enhancing french basil growth through synergistic Foliar treatment with copper nanoparticles and Spirulina sp

BACKGROUND

This study investigates a novel idea about the foliar application of nanoparticles as nanofertilizer combined with a natural stimulant, blue-green algae Spirulina platensis L. extract, as a bio-fertilizer to achieve safety from using nanoparticles for enhancement of the growth and production of the plant. Thus, this experiment aimed to chemically synthesize copper nanoparticles via copper sulfate in addition to evaluate the impact of CuNPs at 500, 1000, and 1500 mg/L and the combination of CuNPs with or without microalgae extract at 0.5, 1, and 1.5 g/L on the morphological parameters, photosynthetic pigments accumulation, essential oil production, and antioxidant activity of French basil.

RESULTS

The results revealed that foliar application of CuNPs and its interaction with spirulina extract significantly increased growth and yield compared with control, the treatments of 1000 and 1500 mg/L had less impact than 500 mg/L CuNPs. Plants treated with 500 mg/L CuNPs and 1.5 g/L spirulina extract showed the best growth and oil production, as well as the highest accumulation of chlorophylls and carotenoids. The application of CuNPs nanofertilizer caused a significant increase in the antioxidant activity of the French basil plant, but the combination of CuNPs with spirulina extract caused a decrease in antioxidant activity.

CONCULOSION

Therefore, foliar application of natural bio-fertilizer with CuNPsis necessary for obtaining the best growth and highest oil production from the French basil plant with the least damage to the plant and the environment.

Enhancing growth, vitality, and aromatic richness: unveiling the dual magic of silicon dioxide and titanium dioxide nanoparticles in Ocimum tenuiflorum L

Ocimum tenuiflorum, commonly known as "Holy basil," is renowned for its notable medicinal and aromatic attributes. Its unique fragrance attributes to specific volatile phytochemicals, primarily belonging to terpenoid and/or phenylpropanoid classes, found within their essential oils. The use of nanoparticles (NPs) in agriculture has attracted attention among plant researchers. However, the impact of NPs on the modulation of morpho-physiological aspects and essential oil production in medicinal plants has received limited attention. Consequently, the present study aimed to explore the effect of silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles at various concentrations (viz., DDW (control), Si50+Ti50, Si100+Ti50, Si100+Ti100, Si200+Ti100, Si100+Ti200 and Si200+Ti200 mg L-1) on growth, physiology and essential oil production of O. tenuiflorum at 120 days after planting (DAP). The results demonstrated that the combined application of Si and Ti (Si100+Ti100 mg L-1) exhibited the most favourable outcomes compared to the other combinational treatments. This optimal treatment significantly increased the vegetative growth parameters (root length (33.5%), shoot length (39.2%), fresh weight (62.7%) and dry weight (28.5%)), photosynthetic parameters, enzymatic activities (nitrate reductase and carbonic anhydrase), the overall area of PGTs (peltate glandular trichomes) and essential oil content (172.4%) and yield (323.1%), compared to the control plants. Furthermore, the GCMS analysis showed optimal treatment (Si100+Ti100) significantly improved the content (43.3%) and yield (151.3%) of eugenol, the primary active component of the essential oil. This study uncovers a remarkable and optimal combination of SiO2 and TiO2 nanoparticles that effectively enhances the growth, physiology, and essential oil production in Holy basil. These findings offer valuable insights into maximizing the potential benefits of its use in industrial applications.

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

BACKGROUND

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.

RESULTS

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.

CONCLUSION

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.

Comprehensive Metabolomic Fingerprinting Combined with Chemometrics Identifies Species- and Variety-Specific Variation of Medicinal Herbs: An Ocimum Study

Identification of plant species is a crucial process in natural products. Ocimum, often referred to as the queen of herbs, is one of the most versatile and globally used medicinal herbs for various health benefits due to it having a wide variety of pharmacological activities. Despite there being significant global demand for this medicinal herb, rapid and comprehensive metabolomic fingerprinting approaches for species- and variety-specific classification are limited. In this study, metabolomic fingerprinting of five Ocimum species (Ocimum basilicum L., Ocimum sanctum L., Ocimum africanum Lour., Ocimum kilimandscharicum Gurke., and Hybrid Tulsi) and their varieties was performed using LC-MS, GC-MS, and the rapid fingerprinting approach FT-NIR combined with chemometrics. The aim was to distinguish the species- and variety-specific variation with a view toward developing a quality assessment of Ocimum species. Discrimination of species and varieties was achieved using principal component analysis (PCA), partial least squares discriminate analysis (PLS-DA), data-driven soft independent modelling of class analogy (DD-SIMCA), random forest, and K-nearest neighbours with specificity of 98% and sensitivity of 99%. Phenolics and flavonoids were found to be major contributing markers for species-specific variation. The present study established comprehensive metabolomic fingerprinting consisting of rapid screening and confirmatory approaches as a highly efficient means to identify the species and variety of Ocimum, being able to be applied for the quality assessment of other natural medicinal herbs.

Analysis of Volatile Secondary Metabolites in Ocimum basilicum Cell Suspensions: Inhibition, In Silico Molecular Docking, and an ADMET Analysis against Proteolytic Enzymes of Rhynchophorus ferrugineus

Our study's overarching goal was to determine which O. basilicum cell suspensions approach yielded the most insecticidal and R. ferrugineus-inhibitory volatile secondary metabolites. After inoculation with Verticillium dahliae as an activator, the growth kinetics were measured, and the extract was identified using GC-MS. Validation was achieved for the insecticidal efficacy of a volatile extract, the pure phenolic content against larva and adult R. ferrugineus, and the inhibitory effect on proteases (in vivo and in vitro). The volatile extract achieved an LC₅₀ of 1229 µg/mL and an LD₅₀ of 13.8 µg/larva. The LC₅₀ values for β-bergamotene, α-eudesmol, β-farnesene, linalool, 1,8-cineole, eugenol, α-guaiene, and β-caryophyllene were 1294, 1312, 1356, 1398, 1426, 1459, 1491, and 1523 g/mL, respectively. The LD₅₀ activities of α-eudesmol, linalool, 1,8-cineole, eugenol, and nerol were 12.4, 13.7, 13.9, 14.2, and 15.6 g/larva, respectively. Active volatile extract of O. basilicum inhibited trypsin proteinase, elastase, cysteine, overall protease, and metalloprotease activity with IC₅₀ values of 89.4, 101.7, 394.7, 112.4, and 535.2 µg/mL and 178.5, 192.4, 547.3, 208.3, and 924.8 µg/mL, in vitro and in vivo, respectively. There was evidence of action against total proteases (in vitro) with IC₅₀ values of 78.9, 81.2, 88.6, 90.7, 91.5, 97.6, 107.4, and 176.3 µg/mL for β-bergamotene, α-eudesmol, β-farnesene, linalool, 1,8-cineole, eugenol, α-guaiene, and β-caryophyllene, respectively. Total proteases (in vivo) are inhibited by the α-eudesmol, linalool, 1,8-cineole, eugenol, nerol, and (E)-β-ocimene, with IC₅₀ values of 162.3, 192.7, 193.1, 201.4, 248.6, and 273.2 µg/mL, respectively. ADMET and molecular docking modeling were the only two methods used to conduct in-depth computational analyses of compounds. The study recommended using an efficient cell suspension method to produce a volatile extract rich in useful secondary metabolites that may be utilized as a bio-insecticide.

Physiological responses and variation in secondary metabolite content among Thai holy basil cultivars (Ocimum tenuiflorum L.) grown under controlled environmental conditions in a plant factory

Holy basil (Ocimum Tenuiflorum L.) is a widely used herb containing several bioactive compounds of interest for the food and pharmaceutical industries. Plant factories using artificial lighting (PFAL) is a modern agricultural system that offers opportunity to improve crop production and stabilizes productivity in many herbal plants. However, little is known about the variation among holy basil varieties that can be cultivated and provide reasonable biomass and bioactive compounds in PFAL. We therefore evaluated 10 Thai accessions and two commercial cultivars in a PFAL (with hydroponic cultivation) to categorize cultivar characteristics by investigating physiological responses and secondary metabolite variation at plant flowering stage. Among Thai varieties, net photosynthetic rate (Pn) was significantly highest in varieties OC059 and OC081. The greatest growth and biomass measures were observed in OC064. Antioxidant capacity also varied, with the greatest accumulation of total phenolic compounds (TPC), flavonoids, and antioxidant activity by DPPH assay in OC064, and highest terpenoid content in OC194. The accumulation of major compounds confirmed by showing the highest levels of eugenol in OC057, OC063, OC194, and OC195 and methyl eugenol in OC072 and OC081. The highest α-humulene content was found in OC059. PCA based on physiological responses and secondary metabolites indicate that OC064 was clearly distinguished from other cultivars/accessions. These findings demonstrate variation across holy basil accessions for physiologic responses, antioxidant capacity, and secondary compounds in PFAL. These insights lead to identification of suitable varieties which is the most important step of developing an efficient method for producing high quality raw materials of Thai holy basil for supplying the foods and pharmaceutical industries.

Influence of black rice (Oryza sativa L.) bran derived anthocyanin-extract on growth rate, immunological response, and immune-antioxidant gene expression in Nile tilapia (Oreochromis niloticus) cultivated in a biofloc system

This study investigated the effects of dietary supplementation with anthocyanin extracted from black rice bran (AR) on the growth rate, immunological response, and expression of immune and antioxidant genes in Nile tilapia raised in an indoor biofloc system. A total of 300 Nile tilapia fingerlings (15.14 ± 0.032 g) were maintained in 150 L tanks and acclimatized for two weeks. Five experimental AR diets (0, 1, 2, 4, and 8 g kg^-1) with various anthocyanin doses were used to feed the fish. We observed that the growth and feed utilization of fish fed with different dietary AR levels increased significantly after eight weeks (p < 0.05). In addition, the serum immunity of fish fed AR diets was much greater than that of those fed non-AR diets (p < 0.05). However, there were little or no difference in between fish fed AR enriched diets and the control AR-free diet (p > 0.05). After eight weeks, fish fed AR-supplemented diets had significantly higher mRNA transcript levels in immune (interleukin [IL]-1, IL-8, and liposaccharide-binding protein [LBP]) and antioxidant (glutathione transferase-alpha [GST-α] and glutathione reductase [GSR]) genes compared to control fish fed the AR-free diet, with the greatest enhancement of mRNA transcript levels (in the case of IL-8 by up to about 5.8-fold) in the 4 g kg^-1 AR diet. These findings suggest that dietary inclusion of AR extract from black rice bran at 4-8 g kg^-1 could function as a herbal immunostimulant to enhance growth performance, feed consumption, and immunity in Nile tilapia.

Combination of cassava starch biopolymer and essential oils for coating table eggs

This work aimed to evaluate the eggshell microbiota and the internal egg quality after coatings with cassava starch biopolymer enriched with different essential oils during 35 days of storage at 20°C. A total of 369 brown table eggs were used and distributed in the following treatments: uncoated eggs, coated with cassava starch + Ginger essential oil (CS+GIN), cassava starch + Lemongrass essential oil (CS+LEM), and cassava starch + Tahiti lemon essential oil (CS+TAH). The count of total aerobic mesophilic bacteria on coated eggshells at 0 and 35 days of storage were similar to each other (mean 0.70 ± 0.37 and 0.91 ± 0.22 log10 CFU/mL) and significantly lower compared to uncoated eggs (2.21 ± 0.17 and 3.17 ± 0.22 log10 CFU/mL), in that order. On the 35th day, coated eggs showed similar Haugh unit (HU) values between them (mean 70.61 ± 5.35; classified as A - high quality) and significantly higher than uncoated eggs (51.60 ± 4.28; classified as B - average quality). Cassava starch coatings added with essential oils preserved the internal quality of the eggs during storage for 5 weeks at 20°C, reducing the eggshell microbiota and effectively keeping it at low levels during storage.

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

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

In Vitro and In Vivo Anticancer Activity of Basil (Ocimum spp.): Current Insights and Future Prospects

Simple Summary

Basil (Ocimum basilicum) is a medicinal herb of the family Lamiaceae that contains a variety of potential bioactive compounds, such as polyphenols, flavonoids, phenolics, and essential oils. Ocimum basilicum can boost phagocytic action of neutrophils and immunostimulant effect, antimicrobial activity due to linalool by having inhibitory action toward all tested microorganism, and additionally, rosmarinic acid shows inhibition in DNA synthesis, as well as protein synthesis when experimented on hepatoma-derived cell line (HepG2), this resulted by lower DNA fragments plus suppression on caspase-3 activation, which blocks apoptosis. The aim of this review is to spotlight and discuss the anti-cancer activity of basil (Ocimum) and its implications in cancer prevention and treatment. Antioxidants and other bioactive compounds in basil leaves show important potential anti-cancer activity regards to cell death and viability inhibition, cytotoxicity, inducing apoptosis, slowing down tumor growth and especially on cell cycle arrest both in vivo and in vitro.

Abstract

Background: Cancer is an irregular proliferation of cells that starts with a gene mutation that alters cellular function, is triggered by several factors, and can be inherited or acquired. The aim of this review is to discuss the anticancer activity of basil and its components’ strength, focusing on its implication in cancer prevention and treatment. Methods: This systematic review involves all of the studies published from 1 January 2010 through 1 January 2022. Results: In this review, 16 research articles are included to discuss the potential anticancer ability of the extracts of various Ocimum basilicum varieties at various dosages, applied to different cancer cells. Of those 16 articles, 2 were in vivo studies, 13 were in vitro studies, and 1 study conducted both in vivo and in vitro experiments. Antioxidants and other bioactive compounds in basil leaves show important potential anticancer activity at dosage of 4 mg/mL as aqueous extract or essential oil up to 200 µg/mL could slow-down tumor growth and progression with regards to cell death and viability inhibition. At dosages from 50 to 500 µg/mL is effective as anti-proliferative activities. cytotoxicity, inducing apoptosis, slowing down tumor growth, and especially cell cycle arrest, both in vivo and in vitro. Human studies show effects at dosages from 1 to 2.5 mg/daily on general vital activities and on reducing cytokines activity. Conclusions: Based on 16 published studies, basil demonstrates important anticancer activities in vivo and vitro models, and it could act as a potential cancer.

Functional Coatings by Natural and Synthetic Agents for Insect Control and Their Applications

Insect repellent textiles offer protection against disease-causing vectors such as mosquitoes, flies, and ticks. Protection is based on the incorporation of insect repellent compounds present in plant oil derivatives or synthetic oils. The effectiveness and application of natural insect repellents such as citronella grass, lemongrass, rosemary, peppermint, holy basil, tea tree, neem, lavender, thyme, lemon eucalyptus, clove, and cinnamon oils, as well as synthetic compounds permethrin, allethrin, malathion, DEET, DETA, IR3535, and picaridin, are compared here. The insect repellent and insecticidal effectiveness of natural compounds in their pure form are very low due to their high volatility. The effectiveness has been greatly improved through slow-release systems such as encapsulation of the essential oils and is comparable to synthetic compounds used for insect control purposes. Due to the lasting toxicity of synthetic compounds to humans and the environment, the use of natural compounds should become a more preferred method of insect control.