Ocimum Americanum Research Articles

Exploring of Chemical Profile and Biological Activities of Three Ocimum Species From Comoros Islands: A Combination of In Vitro and In Silico Insights.

Ocimum species have a great interest in different traditional medicinal systems. This study examined the chemical composition, antioxidant properties, enzyme inhibitory effects, and antibacterial and antifungal activities of the aerial parts of Ocimum gratissimum, Ocimum americanum, and Ocimum basilicum from the Comoros Islands. The extracts were analyzed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) to determine their chemical composition. Antioxidant activity was assessed using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), chelating ability, and phosphomolybdenum radical scavenging assays. Enzyme inhibitory activities against acetylcholinesterase (AChE), butrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase were evaluated using spectrophotometric methods. Antibacterial and antifungal activities were tested using the broth microdilution method against selected pathogenic microorganisms. The selected enzymes and proteins were evaluated using in silico methods with biomolecules from these plants. In addition, 111 different metabolites were identified in the tested extracts using advanced HPLC/MS techniques. The most significant number of detected compounds were derivatives of hydroxycinnamic acids, followed by flavonoid glycosides and aglycones and derivatives of hydroxybenzoic acids. All three Ocimum species exhibited significant antioxidant activities, O. gratissimum exhibited the best-reducing abilities in CUPRAC and FRAP assays. In addition, enzyme inhibitory assays revealed that O. americanum had the most potent inhibitory effect on tyrosinase (48.01 ± 3.89 mg kojic acid equivalent [KAE]/g), and amylase (1.08 ± 0.02 mmol acarbose equivalent [ACAE]/g). Antibacterial and antifungal tests demonstrated that the extracts possess broad-spectrum activity. Molecular docking results showed that compounds exhibited remarkable binding energies with target enzymes and proteins. The molecular dynamics simulations identified chicoric acid with MurE of Staphylococcus aureus complex as the most promising drug candidate. These findings support their traditional medical and nutraceutical uses and suggest possibilities for natural functional applications.

Green Silver Nanoparticles and Their Activity as Antifungal Agents Against Penicillium digitatum Causing Green Mould of Citrus

AbstractThe green synthesis of silver nanoparticles (SNPs) using aqueous extracts of five plants viz., Ocimum americanum, Azadirachta indica, Allium sativum, Eucalyptus hybrida, Zingiber officinale were evaluated for their antifungal property against Penicillium digitatum, a green mould pathogen of citrus fruits. The five plant species were selected from a screening of aqueous extracts from 16 plant species. The efficacy of aqueous extracts, at 50 % concentration, ranged from 14.44–68.52 % inhibition in mycelia growth of P. digitatum. Among SNPs, O. americanum was found most efficacious, at 1000 ppm concentration, with 80.7 % mycelial inhibition followed by A. indica with 77.4 % mycelial growth inhibition of fungal pathogen. Further, physical and structural characterization of SNPs of O. americanum and A. indica was carried out. The characterization analysis executed via transmission and scanning electron microscope revealed size distribution and nanoparticles were spherical to irregularly shaped ranging from 22.8–250 nm in O. americanum and 26.5–500 nm in A. indica. In UV‐visible spectrophotometer, the absolute absorption peak was recorded at 448 nm and 442 nm for O. americanum and A. indica, respectively. FTIR analysis of SNPs of A. indica and O. americanum confirmed the presence of carboxyl, amide group and secondary amines which were the main constituent of proteins. The novelty of the present study is in the green synthesis of silver nanoparticles with potential in the management of postharvest pathogens of fruit crops. The synthesis of SNPs used in this study is simple, environmentally benign and cost‐effective using aqueous extract of native plants.

Optimization of Microwave-Assisted Green Synthesis of Zinc oxide nanoparticles Using Ocimum americanum and Euphorbia hirta Extracts: In Vitro Evaluation of Antioxidant, Anti-inflammatory, Antibacterial, Cytotoxicity, and Wound Healing Properties

Optimization of Microwave-Assisted Green Synthesis of Zinc oxide nanoparticles Using Ocimum americanum and Euphorbia hirta Extracts: In Vitro Evaluation of Antioxidant, Anti-inflammatory, Antibacterial, Cytotoxicity, and Wound Healing Properties

Effect of Capsicum Chinense Powder in the Preservation of Maize and Groundnut Grains in Stock Against Sitophilus Zeamaïs and Aphis Craccivora, Case of the Boke Region (Republic of Guinea)

In Guinea, forest resources (native plants) are of great importance to rural populations, who are highly dependent on these native species as they are used in addition to the conservation of agricultural produce for food, pharmacopoeia, fodder, handicrafts, housing and domestic energy. In our previous studies, a total of 14 native plant species were identified, to know Capsicum chinense, Capsicum frustescens, Capsicum annuum, Capsicum baccatum, Capsicum pubescens, Hyptis suaveolens, Hyptis spicigera, Ocimum americanum, Ocimum basilicium, Allium cepal, Zingiber officinal Rosc, Combretummicranthum, Cymbopogon schoenanthus and Azadirachta indica. Over the last two decades, a great deal of work has been carried out to find gentler food protection methods that respect human health and the environment. The most widely used for preserving agricultural produce is Capsicum chinense (98%). Post-harvest losses of these commodities in Guinea, and more particularly in the Boke Region, are still a real problem. The solutions found in this study to combat pests of agricultural stocks were the increasing use of doses (5g; 10g; 15g; 20g) of Capsicum chinense fruit powder against Sitophilus zeamaïs, a pest of maize grain, and Aphis craccivora, a pest of groundnut grain. During evaluation of the insecticidal effects of Capsicum chinense powder, the doses (5g; 10g; 15g and 20g) used per 100 kg of maize and per 100 kg of groundnuts resulted in considerable mortality of Sitophilus zeamaïs and Aphis craccivora.

Assessment of luminescent copper nanomaterials as anti-germs, anti-proliferation efficiencies using green nano-strategy.

For the first time, we suggest using leaf extract from Ocimum americanum as the economically viable bio-fabrication of copper nanomaterials. The residuals of leaf extract bio-capping provide the stability of the nanomaterials in-situ. UV-Vis and XRD confirmed the formation, with the UV-Vis spectrum of Cu-NMs revealing a surface plasmon resonance characteristic peak at 350 nm. FT-IR analysis was employed to examine the functional groups. FE-SEM with EDX was used to assess the morphology and carry out an elemental analysis of the nanomaterials. Diffusion and MTT assays were used to study the antimicrobial and anticancer activities. The synthesized copper nanomaterials exhibited in-vitro cytotoxicity against human skin cancer (A431) cell lines. Green nanomaterial was examined against the methylene blue dye, photodegradation was reduced by up to 90.6% within 50 minutes. The copper nanomaterials synthesized in our study exhibit promising applications in biomedicine and environmental pollution research.

Distribution, local use, and bio-prospecting opportunity of Ocimum americanum L. in Northwestern part of the Amhara Region, Ethiopia

Ocimum americanum (Basil) encompasses various uses. The plant is valued both as a food additive for its aromatic qualities and in folk medicine for treating various ailments. However, its uses, distribution, and the associated community knowledge have not been properly and systematically documented. Therefore, a survey was conducted to explore the bio-prospecting potential of Ocimum americanum and gather baseline information on its community knowledge. Purposive and proportional samplings were used to select districts, villages, users, and growers who participated in the study. The selected districts - Dembiya, Gonder Zuria, Takusa, Alefa, Bahir Dar city, and Bahir Dar Zuria Districts - were selected based on the plant’s growth potential and user availability. Data collection methods included semi-structured interviews, group discussions, and field observations. The findings revealed that basil is used for various purposes: ailment treatment (32.67%), food flavoring (26.6%), food preservative (7.7%), and to impart aroma to different foods (8.33%). Specifically, 32.67 % of the respondents used Ocimum americanum for traditional medicine purposes, primarily to treat depression/headaches, stomach aches, and ward off evil spirits. The methods for preparation and administration included concoction (21.05 %), direct application of plant parts (15.79%), grinding (15.79%), melting (5.26%), Fumigation (10.53%), and inhalation (31.58%). Medicinal dosage varied among users depending on the intensity, type, experience, and the severity of the disease. Nine traditional foods spiced, with basil were identified, with the highest fidelity level for basil use being food flavoring (18.33%) followed by preservation (18.33%). The direct matrix analysis indicated that chilli pepper spice was the most preferred local food sweetened by basil, followed by hot-spiced pepper. This study highlights the traditional foods spiced with basil and providesvaluable insights for bio-prospecting companies in the food and pharmacological industries.

Green synthesis of silver nanoparticle prepared with Ocimum species and assessment of anticancer potential

Silver nanoparticles (AgNPs) have gained much attention due to their unique physical, and chemical properties. Integration of phytochemicals in nanoformulation might have higher applicability in healthcare. Current work demonstrates the synthesis of green AgNPs with O. gratissimum (gr-AgNPs) O. tenuiflorum (te-AgNPs) and O. americanum (am-AgNPs) followed by an evaluation of their antimicrobial and anticancer properties. SEM analysis revealed spherical-shaped particles with average particle sizes of 69.0 ± 5 nm for te-AgNPs, 46.9 ± 9 nm for gr-AgNPs, and 58.5 ± 18.7 nm for am-AgNPs with a polydispersity index below 0.4. The synthesized am-AgNPs effectively inhibited Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, Aspergillus niger, and Candida albicans with 23 ± 1.58 mm, 20 ± 1.68 mm, 22 ± 1.80 mm, 26 ± 1.85 mm, and 22 ± 1.40 nm of zone of inhibition respectively. Synthesized AgNPs also induced apoptotic cell death in MCF-7 in concentration-dependent manner. IC50 values for am-AgNPs, te-AgNPs, and gr-AgNPs were 14.78 ± 0.89 µg, 18.04 ± 0.63 and 15.41 ± 0.37 µg respectively which suggested that am-AgNPs were the most effective against cancer. At higher dose size (20 µg) AgNPs were equally effective to commercial standard Doxorubicin (DOX). In comparison to te-AgNPs and gr-AgNPs, am-AgNPs have higher in vitro anticancer and antimicrobial effects. The work reported Ocimum americanum for its anticancer properties with chemical profile (GCMS) and compared it with earlier reported species. The activity against microbial pathogens and selected cancer cells clearly depicted that these species have distinct variations in activity. The results have also emphasized on higher potential of biogenic silver nanoparticles in healthcare but before formulation of commercial products, detailed analysis is required with human and animal models.

Toxicological Evaluation of Sub-Chronic Administration of Ethanol Leaf Extract of <i>Ocimum canum</i> on Lipid Parameters, Heart Histology and Feed Consumption of Wistar Rats

Ocimum canum is a plant that is commonly used in many parts of SubSaharan Africa to treat ailments such as infection, discomfort, and diarrhea. The study was aimed to evaluate the sub-chronic toxicity of Ocimum canum on the heart, lipid profile and feed consumption in Wister rats after oral administration of the leaf extract. Animals of either sexes were chosen. Group 1 received distilled water (10 ml/kg), while groups 2, 3, and 4 received 100, 200, and 400 mg/kg of Ocimum canum, respectively. Animals were kept in conventional cages and provided oral access to the extract, water, and food for 28 days before being weighed and slaughtered. Blood was drawn via heart puncture and immediately sent for hematological and chemopathological investigation. The plant's histological cardiotoxic potential was investigated using the haematoxylin and eosin (H&E) staining technique. There was a significant (P<0.05) drop in RBC, HGB, and MCV, but no change in neutrophils, basophils, eosinophils, or platelets. The extract did not cause a significant (P<0.05) change in cholesterol, LDL, or triglyceride levels, but it did induce a substantial increase in HDL levels. Histological examination of cardiac tissue confirms other parameters. The results indicated that the plant may not be cardiotoxic.

Ocimum basilicum and Ocimum americanum: A Systematic Literature Review on Chemical Compositions and Antimicrobial Properties

Objectives This systematic review aimed to evaluate the chemical compositions and Pharmacological applications of Ocimum basilicum, known as sweet basil, and Ocimum americanum, known as hoary basil, to assess their antimicrobial properties. Both plants are renowned for their culinary uses and medicinal properties, with studies suggesting potential therapeutic benefits due to their rich essential oil. Methods A systematic approach was adopted to gather and analyze the relevant literature on the chemical profiles and pharmacological activities of Ocimum basilicum and Ocimum americanum. Electronic databases including Web of Science, ScienceDirect, Google Scholar, and PubMed were searched using keywords such as chemical composition of Ocimum basilicum, chemical composition of Ocimum americanum, antimicrobial activities of Ocimum basilicum, and antimicrobial activities of Ocimum americanum. Results Ninety-nine articles meeting the determined inclusion criteria were incorporated in this systematic review. Several studies have consistently demonstrated the antimicrobial activities of these 2 plants, although the specific compounds responsible for this activity vary between the 2 species. Conclusion The diverse array of bioactive molecules present in these plants contributes to their pharmacological effects, suggesting avenues for further research into their therapeutic applications. This review supports the continued exploration of the medicinal properties and potential development of sweet basil and hoary basil as antimicrobial agents.

Effect of Chemical and Granular Organic Fertilizer with Hormone Mixed Formula (HO) for Quality And Productivity on Hoary Basil (Ocimum Americanum L.)

Purpose: This research study aimed to develop chemical and granular organic fertilizers with hormone mixed formula (HO) and examine its effect on growth, productivity and active principles of hoary basil (Ocimum americanum L.) and the effect of HO fertilizer on soil properties. Method: Experiments were conducted in an RCBD with 6 treatments 4 replications on 1.2x4 m plots with 32 seedlings on each. The soil properties before and after experiments, growth rate, yield and active principles were analyzed by ANOVA, and compared by a DMRT method at the reliability of 95%. The experiments were conducted between September 2020 and September 2021. Results and Conclusion: The results showed that the HO fertilizers (T4, T5 and T6) improved organic matter, the soil pH, bulk density, soil porosity and water holding capacity. The HO fertilizers also significantly increased secondary and micronutrients. The plants with the HO fertilizers, especially with T6 and T5, showed the highest growth in terms of height, stem size, number of branches and canopy size, with statistically significant differences compared to the other treatments. In terms of yield productivity, T6 had the highest yield (3,192.7), followed by T2 (2,920.5), T5 (2,728.8), T4 (2,667.7), T3(1,952.1) and T1(1,735.8 kg/rai.). According to the active principle analysis, eugenol and methyl eugenol were found highest under T6 (HO-3). As for the net profit in hoary basil production, T6 showed the highest profit of 94,965 baht/rai. Implications of the Research: It was concluded that the HO fertilizers, as environmentally friendly fertilizing options, could sustainably improve soil quality and HO-3, in particular, has proved to be suitable for hoary basil production to provide high quality, safe products for both domestic and international markets. Originality/Value: This study highlights the effectiveness of HO fertilizers on increasing yields, yield component and active principles of hoary basil.

Chemical composition and mosquitocidal properties of essential oil from Indian indigenous plants Ocimum tenuiflorum L. and Ocimum americanum L. against three vector mosquitoes

Mosquitoes stand out as the most perilous and impactful vectors on a global scale, transmitting a multitude of infectious diseases to both humans and other animals. The primary objective of the current research was to assess the effectiveness of EOs from Ocimum tenuiflorum L. and Ocimum americanum L. in controlling Anopheles stephensi Liston. Culex quinquefasciatus Say and Aedes aegypti L. mosquitoes. The larvae, pupae and eggs of the mosquitoes were exposed to four different concentrations (6.25–50 ppm). The tested EOs resulted in >99–100 % mortality at 120 h for the eggs of all examined mosquito species. It also showed robust larvicidal and pupicidal activity with LC50 and LC90 values of 17–39, 23–60 ppm and 46–220, and 73–412 ppm against Aedes, Culex and Anopheles mosquito species, respectively, at 24 h of treatment. The Suitability Index or Predator Safety Factor demonstrated that the EOs extracted from O. tenuiflorum L. and O. americanum L. did not cause harm to P. reticulata, D. indicus (water bug), G. affinis and nymph (dragonfly). GC-MS analysis identified the major probable constituents of the oil, including Phenol, 2-Methoxy-4-(1-Propenyl)- (28.29 %); 1-Methyl-3-(1′-Methylcyclopropyl) Cyclopentene (46.46 %); (E,E,E)-3,7,11,15-Tetramethylhexadeca-1,3,6,10,14-Pentaene (18.91 %) and 1,3-Isobenzofurandione, 3a,4,7,7a-Tetrahydro-4,7-Dimethyl (33.02 %). These constituents may play a significant role in the mosquitocidal activity of the oil. The same results were identified in the formulation prepared from the EOs. This marks the first report confirming the successful utilization of EOs derived from O. tenuiflorum L. and O. americanum L. in mosquito population control initiatives.

Chemical Composition and Antioxidant Potential of Leaf Essential Oils of Ocimum Canum Sims Harvested at Various Times Daily

Fresh Ocimum canum leaves were harvested five times at interval of three hours in a twelve hour-cycle daily (7:00, 10:00, 13:00, 16:00, and 19:00 hours). The leaves from each harvest were separately subjected to hydrodistillation for three hours in a Clevenger-type apparatus. The oils obtained were analyzed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Cluster analysis was used (based on the data, select variables > 0.2% of 43 oil components from five harvest times) to classify the oils. Antioxidant potential of the oils were determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and Sodium Nitroprusside (SNP)-Induced Lipid Peroxidation assays. The oils afforded yield in the range of 0.15-0.23% (w/w), with the highest and lowest yields observed at 7:00 and 13:00 hours respectively. A total of 23-40 compounds, representing 99.4-99.8% of the total oils were identified from their mass spectra with predominance of oxygenated monoterpenoids (50-65.7%), hydrogenated monoterpenoids accounted for 5.4-19.1%, whereas hydrogenated sesquiterpenoids constituted between 10.1-21.4% of the total oils. The most abundant compound was linalool (46.7-52.4%), other major compounds identified were terpinen-4-ol (8.5-9.5%), eugenol (1.9-10%) and trans-α-bergamotene (5.5-10.2%). Cluster analysis revealed a significant variability within the oil samples obtained from various harvest times. The oils presented a considerable antioxidant activity (IC50 of 5.45-10.87µg/ml compared with 4.05-6.11µg/ml for BHT standard) for DPPH assay; and (3.86- 5.36 µg/ml compared with 2.12-4.33 µg/ml for BHA standard) for SNP-Induced lipid peroxidation assay. The oil obtained from 10:00 hours harvest had the best antioxidant activity at IC50 for both assays. Chemical composition and antioxidant activity of the oils varied significantly with harvest times. The oils exhibited antioxidant property comparable to those of standards, hence could serve as cheaper and safer alternative to synthetic drugs to ameliorate oxidative stress after clinical trials.

Effect of Some Medicinal Plants Aqueous Extracts on Two Species of Two Plant Pathogenic Bacteria Pseudomonas savastanoi and Xanthomonas campestris

Mouhanna, A.M., M.A.R. Drakly, M.A. Abou Hasan and H.N.H. Al-Obaydi. 2024. Effect of Some Medicinal Plants Aqueous Extracts on Two Species of Two Plant Pathogenic Bacteria Pseudomonas savastanoi and Xanthomonas campestris. Arab Journal of Plant Protection, 42(3): 382-386. https://doi.org/10.22268/AJPP-001254 This study aimed to evaluate the effect of aqueous extracts of some medicinal plants naturally present in Jableh region, Lattakia governorate on two plant pathogenic bacteria, Pseudomonas savastanoi and Xanthomonas campestris. The inhibitory effect of the bacteria was measured by the diameter length of the inhibition zone around the disc treated with the extract. The aqueous extracts of Ocimum canum, Salvia sclarea, Origamum tytthanthum and Thymus serpyllum showed a significantly higher inhibitory effect on P. savastanoi compared to their effect on X. campestris. Aqueous extracts of Coridothymus capitatus and Majorana syriaca showed similar inhibition effect on the two studied bacteria species. The highest inhibition rate was 99.975 and 99.997% for Coridothymus capitatus and Majorana syriaca extracts against X. campestris and P. savastanoi, respectively, whereas the lowest inhibition rate was for Thymus serpyllum extracts with 25.0 and 16.7% inhibition rate against P. savastanoi and X. campestris, respectively. Results indicate the importance of using these aqueous extracts in the control of bacterial plant diseases. However, such laboratory tests need to be confirmed by extended field trials. Keywords: Aqueous extracts, plant pathogenic bacteria, Pseudomonas savastanoi, Xanthomonas campestris, inhibitory effect.

Isolation, characterization and docking analysis of insecticidal compound from Ocimum canum methanolic leaf extracts and its potential against three mosquito vectors

Vector management is an important challenge and burden to developing countries. Frequent and indiscriminate application of chemical insecticides for vector control has resulted in the development of resistance and undesirable effects on beneficial organisms. Hence an alternative approach is needed for the mosquito control programme. The present study investigated the insecticidal activity and spectral analysis of Ocimum canum methanol leaf extract against three mosquito species. One out of four fractions (F1-F4), the 4th fraction, revealed showed good insecticidal activity in larva and adult Cx. quinquefasciatus, Ae. aegypti and An. stephensi (0.114, 0.325 and 0.173 ppm) and (1.798, 1.061 and 0.871 ppm). The mortality was found to be dosage dependant. Spectral analysis of 1H NMR and 13C NMR indicates the presence of 6 protons at δH value of 7.45 (s) and 3 protons at δH value of 7.85 (s) ppm. FT-IR identified the possible band near the capping region at 3417.16 cm-1. LC-MS confirmed the eugenol compound with 99.79% purity at the molecular weight of 164. Further, eugenol docking analysis revealed high homology similarity with insect odorant binding protein 3OGN and AchE protein 2BG9. Overall, the result suggests that isolated eugenol compounds were found to be effective for the eco-friendly management of mosquito vectors. These findings could be useful for designing an efficient mosquitocidal compound in the future.

Studi Kepustakaan Pengendalian Infeksi Soil Transmitted Helminth Pada Ruminansia Di Lahan Kering Nusa Tenggara Timur Secara Kimia Dan Non-Kimia

Soil Transmitted Helminth (STH) is an intestinal nematode which in its life cycle requires soil for the maturation process. STH infection is classified as neglected disease, which is an infection that is not noticed and is chronic in nature because it does not cause typical clinical symptoms and the effects are only seen in the long term. The purpose of this study was to determine chemical and non-chemical control of STH infection on ruminants in dry land of NTT. The method used is a qualitative descriptive method with a literature study approach. Based on the results of the study, it was found that the chemical control of STH infection on ruminants in the dry land of NTT is from the benzimidazole group because it is easy to obtain, easy to apply and has good effectiveness, some of which are albendazole, mebendazole, levamisole, piperazine, pyrantel pamoate, and tiabendazole. Meanwhile, non-chemical effective control of STH infection can use several types of plants, including Putri malu extract (Mimosa pudica Linn.), katuk leaf extract, basil leaf extract (Ocimum americanum Linn.), soursop leaf extract (Annona muricata L.), alamanda leaf extract (Allamanda cathartica L.), mango arumanis (mangifera indica L.), and moringa leaf (Moringaoleifera L.) which have been studied contain chemical compounds that are beneficial such as anthelmintics, namely saponins, mimosin and tannins.

Evaluation of synergism in essential oils against the cattle tick Rhipicephalus microplus in Burkina Faso

The cattle tick Rhipicephalus microplus affects animal production economically by reducing weight gain and milk production and causing diseases, such as babesiosis and anaplasmosis. Using synthetic acaricides to reduce their incidence has caused the emergence of resistant tick populations. The present study aimed to assess the in vitro acaricidal activity of combinations of essential oils (EOs) from Ocimum americanum, Ocimum gratissimum, and Lippia multiflora against R. microplus larvae. In fact, numerous biological properties have been reported on EOs from these three plants, including acaricidal properties. Hence, a larval immersion test was performed using a population of R. microplus resistant to synthetic acaricides used in Burkina Faso. Results revealed that EO from O. gratissimum was the most effective on R. microplus larvae with LC50 and LC90 values at 10.36 and 15.51 mg/mL, respectively. For EO combinations, the most significant synergistic effect was obtained by combination 6 (1/3 O. americanum + 2/3 O. gratissimum +1/6 L. multiflora), with a combination index value of 0.44. All combinations presented dose reduction index >1, indicating a favorable dose reduction. According to the literature, this is the first study to determine the combination effect of EOs from the abovementioned plants in controlling R. microplus activity in vitro. Thus, the combination of these EOs is an alternative to control the resistant populations of invasive cattle ticks.

Local perceptions and endogenous knowledge of Hoary Basil (Ocimum americanum L.) in Burkina Faso

Local perceptions and endogenous knowledge of Hoary Basil (Ocimum americanum L.) in Burkina Faso

<i>In vitro</i> assessment of the efficacy of three essential oils of aromatic plants against <i>Magnaporthe oryzae</i> B.C. Couch, a rice blast pathogen in Burkina Faso

Blast, caused by Magnaporthe oryzae B.C.Couch, is the main fungal disease in the rice fields in Burkina Faso. Three pure essential oils at different concentrations of Cymbopogon schoenanthus, Ocimum americanum and Lippia multiflora, and four of their combinations were tested in vitro to evaluate their inhibition properties on mycelial growth, sporulation, and spore germination of M. oryzae. The contact method and the fumigation method were used for the different tests at doses of 0.05 μl/ml, 0.1 μl/ml, 0.3 μl/ml, 0.6 μl/ml, 0.9 μl/ml, 1.2 μl/ml, 1.5 μl/ml, 1.8 μl/ml, 2.1 μl/ml and 2.4 μl/ml. Two chemical fungicides, mancozeb and azoxystrobin and an absolute control were used in the trials. The results showed that the pure essential oil of L. multiflora and its combination with that of C. schoenanthus presented the most effective minimum doses of inhibition in the contact and fumigation method. These doses ranged from 0.1 μl/ml to 0.3 μl/ml for 100% inhibition of radial growth, sporulation, and spore germination of Magnaporthe oryzae. Mancozeb inhibited 100% of all parameters evaluated, while azoxystrobin was ineffective. The essential oil of L. multiflora and its combination with that of C. schoenanthus can be tested in a real environment to control rice blast.

Chemical compositions, antioxidant, antimicrobial, and mosquito larvicidal activity of Ocimum americanum L. and Ocimum basilicum L. leaf essential oils

BackgroundOcimum americanum L. (O. americanum) and Ocimum basilicum L. (O. basilicum) are highly valued aromatic medicinal plants. Their leaves are widely used as spices in traditional cuisine. Their essential oils (EOs) are extensively used in food, cosmetic, and pharmaceutical industries. This study aimed to investigate the main chemical profiles of O. americanum and O. basilicum leaf EOs and assess their effects on antibacterial, antioxidant, and larvicidal properties.MethodsEOs were extracted from the leaves of O. basilicum and O. americanum using steam distillation in a Clevenger-type apparatus. The chemical constituents of the EOs were analyzed using gas chromatography–mass spectrometry. 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and metal-chelating techniques were used to assess the free-radical scavenging capability of the oils. The extracted oils were also tested for their antibacterial activities via a disk-diffusion test and the broth microdilution method. Furthermore, the mosquito larvicidal (Aedes aegypti) activity was tested using standard protocols.ResultsCamphor (33.869%), limonene (7.215%), longifolene (6.727%), caryophyllene (5.500%), and isoledene (5.472%) were the major compounds in O. americanum leaf EO. The EO yield was 0.4%, and citral (19.557%), estragole (18.582%) camphor (9.224%) and caryophyllene (3.009%) were the major compounds found among the 37 chemical constituents identified in O. basilicum oil. O. basilicum exhibited a more potent antioxidant activity in DPPH, FRAP, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid tests than O. americanum. The zones of inhibition and minimum inhibitory concentration of the oils in the microdilution and disk diffusion methods were 8.00 ± 0.19 mm to 26.43 ± 2.19 mm and 3.12–100 µg/mL, respectively. At 400 ppm, O. basilicum and O. americanum EOs demonstrated larvicidal activity, with mortality ratios of 73.60% ± 0.89% and 78.00% ± 1.00%, respectively. Furthermore, after 30 min of exposure to O. americanum and O. basilicum EOs, the larval death rates were 73.60% ± 0.89% and 78.00% ± 1.00%, respectively.ConclusionsThe findings revealed that the EOs extracted from the leaves of O. basilicum and O. americanum exhibited reasonable antioxidant, antibacterial, and mosquito larvicidal potentials, and can be used as alternative medicine for the treatment of human health and larvicidal mosquito control.

The complete chloroplast genome of Ocimum americanum Linnaeus 1755 and phylogenetic analysis among the Lamiaceae family

Ocimum americanum Linnaeus 1755 (Lemon basil) is an essential medicinal species in the Ocimum genus. Its leaf decoction is traditionally used to treat diabetes, constipation, diarrhea, piles, and dysentery. The essential oils from this species have intense fungicidal activity. The complete chloroplast genome sequence of O. americanum was assembled from Illumina paired-end sequencing data. The O. americanum chloroplast genome was 152,460 bp in length, containing a large single copy (LSC) region of 83,459 bp and a small single copy (SSC) region of 17,607 bp, separated by a pair of inverted repeats (IRs) of 25,697 bp. The genome contained 134 unique genes, including 89 protein-coding, 37 tRNA, and eight rRNA genes. Among them, nine genes had a single intron, and two genes contained two introns. The overall GC content of the chloroplast genome was 38%, while the corresponding values of LSC, SSC, and IR regions were 35.8%, 31.7%, and 43.1%, respectively. In the phylogenetic analysis, all the Ocimum species formed a group closely related to Plectranthus barbatus. O. americanum was more closely related to O. gratissimum and O. basilicum than the other species of Ocimum included in this study.