Search Results (11)

Natural products have long been recognized as invaluable resources in drug discovery. Essential oils have attracted widespread attention due to their broad spectrum of biological activities. Herein, we report the anti-kinetoplastid activity of Aloysia citrodora leaf essential oil through a bioassay-guided fractionation method against the etiological agents of Chagas disease and leishmaniasis. This approach has led to the isolation and structural identification of compound 1 (citral) as the main active constituent, with IC₅₀ values of 8.47 μM against Leishmania amazonensis and 12.90 μM against Trypanosoma cruzi. In addition, eight compounds (2–9) were synthesized and evaluated. Among these, citral 2,4-dinitrophenylhydrazone (9) exhibited the highest anti-kinetoplastid activity, with an IC₅₀ value of 10.62 μM against L. amazonensis, displaying a similar biological profile to citral and the reference drug. Structure–activity relationship studies revealed that the type of Schiff base and acylating agent played a crucial role in the activity. Mechanism of action studies demonstrated that compound 9 directly targets the apoptotic pathway, inducing programmed cell death through selective pathway inhibition. This work underscores the potential of A. citrodora essential oil and its compounds as prospective therapeutic leads against neglected tropical diseases. Full article

The mosquito Aedes albopictus is a vector of several harmful viruses, necessitating the development of safer and more sustainable repellents than DEET. This study evaluated the potential of plant-based EOs extracted via steam distillation from Aloysia citrodora and Bursera graveolens plants harvested in Ecuador. A. citrodora EO exhibited a high sensory pleasantness with a citral-like aroma, while B. graveolens EO had lower sensory appeal due to off-flavors. At 200 µL L⁻¹, B. graveolens EO demonstrated strong ovideterrent activity, reducing egg laying by 64%, whereas A. citrodora EO displayed the highest larvicidal activity with an LC₅₀ value of 88.54 µL L⁻¹. Both EOs, applied at 0.20 µL cm⁻² on human skin, provided comparable repellency for over 45 min. The RD₅₀ values were 0.104 µL cm⁻² for A. citrodora EO and 0.136 µL cm⁻² for B. graveolens EO. When compared to DEET at 0.04 µL cm⁻², no significant differences in repellency were observed within the first 15 min post-application. These findings suggest that both EOs are effective alternatives to synthetic repellents, and A. citrodora EO emerges as a promising candidate due to its superior sensory attributes and larvicidal activity. Full article

Drug discovery based on medicinal plants remains an important source of bioactive compounds, many of which have been the basis for new chemical structures for the pharmaceutical and food industries. According to the World Health Organization, about 80% of the worldwide population still depends on plant drugs, and several medicines have been obtained from medicinal plants. Unfortunately, the potential benefits of these plants have led to unscientific exploration of natural resources, a fact that is being globally observed. The aim of this study was to evaluate eleven aromatic medicinal plants and compare them to Azorean Camellia sinensis green tea in terms of antioxidant activity, total phenolics, and flavonoid content, and also to evaluate the possibility of their valorization as a nutraceutical material. The results revealed that Camellia sinensis presented higher values for free radical scavenging activity (FRSA, EC₅₀ = 3.43 µg/mL), ferric reducing antioxidant power (FRAP, EC₅₀ = 5.12 µg/mL), and total phenolic content (TPC, 294.43 mg acid gallic equivalents per g of dry extract (DE)). However, the aromatic medicinal plants also presented significant results in terms of FRSA and FRAP, particularly Aloysia citrodora, Mentha pulegium, and Stevia rebaudiana. For ferric ion chelating (FIC), the highest value was found in Cymbopogon citratus (80.60%). Mentha pulegium and Aloysia citrodora had significant values for TPC (199.15 and 187.15 mg GAE/g DE, respectively), but were lower than the values of Camellia sinensis. For flavonoid content (TFC), the highest value was shown in Achyrocline satureioides (265.75 mg rutin equivalents per g DE). This study revealed the importance of some aromatic medicinal plants in terms of bioactivities, and that their combination with green tea is a perfect blend for added value with beneficial nutraceutical effects for human health. Full article

Seventy-one healthy subjects with sleep disturbances participated in a randomized, double-blind controlled trial in which dietary supplementation with an extract of Aloysia citrodora (lemon verbena) (n = 33) or placebo (n = 38) was administered for 90 days. There were between-group differences in favor of the experimental group in the visual analogue scale (VAS) for sleep quality (6.5 ± 1.6 vs. 5.5 ± 2.1, p = 0.021) as well as in the overall score (5.8 ± 2.4, p = 0.008) and scores for sleep latency (1.6 ± 1.0 vs. 1.9 ± 0.7, p = 0.027) and sleep efficiency (84.5 ± 12.8 vs. 79.8 ± 13.6, p = 0.023) in the Pittsburgh Sleep Quality Index (PSQI). Sleep-related variables (latency, efficiency, wakefulness after sleep onset, awakenings) assessed by actigraphy also showed better scores in the experimental group (p = 0.001). Plasma nocturnal melatonin levels also increased significantly in the experimental group (199.7 ± 135.3 vs. 174.7 ± 115.4 pg/mL, p = 0.048). Changes in anthropometric parameters and physical activity levels were not found. In summary, a dietary supplement of lemon verbena administered for 3 months was associated with a significant improvement in sleep quality as compared with placebo in a population of healthy subjects with sleep problems. Full article

Cistus ladanifer L., Acacia dealbata L., and Aloysia citrodora Paláu were subject to an optimization procedure for two extraction techniques (heat-assisted extraction (HAE) and ultrasound-assisted extraction (UAE)). The extracts were then analyzed by HPLC-DAD-ESI/MS for their phenolic profile (cistus—15 compounds, acacia—21 compounds, and lemon verbena—9 compounds). The response surface methodology was applied, considering four varying factors: ethanol percentage; extraction time; temperature/power; and S/L ratio, generating two responses (the major phenolic compound, or family of compounds, and the extraction yield). For cistus, both techniques optimized the extraction yield of punicalagins, with UAE proving to be the most efficient extraction method (3.22% ethanol, 22 min, 171 W, and 35 g/L). For acacia, HAE maximized the extraction of procyanidin (74% ethanol, 86 min, 24 °C, and 50 g/L), and UAE maximized the content of myricetin (65% ethanol, 8 min, 50 W, and 50 g/L). For lemon verbena, HAE favored the extraction of martynoside (13% ethanol, 96 min, 49 °C and 17 g/L) and forsythiaside UAE (94% ethanol, 25 min, 399 W, and 29 g/L). The optimal conditions for the extraction of compounds with high added value and potential for use in pharmaceuticals and nutraceuticals were defined. Full article

A member of the Verbenaceae family, Aloysia citrodora, or lemon verbena, is a medicinal herb with antioxidant compounds. The aim of this study was to develop a green, optimized method for the bioactive compound (carotenoids, ascorbic acid, and polyphenols) extraction from lemon verbena leaves through response surface methodology (RSM). The bioactive compound recovery was shown to be significantly affected by the extraction technique (both with pulsed electric field and ultrasound-assisted extraction), along with an extraction solvent, based on partial least squares analysis. Consequently, the maximum polyphenol yield required a double-assisted extraction with a relatively low extraction duration (60 min) at a high temperature (80 °C), with a moderate-polarity extraction solvent (50% v/v ethanol). With the optimized method, the total polyphenol content (TPC) was measured at 175.03 mg gallic acid equivalents/g, whereas chromatographic analysis revealed that verbascoside was the most prevalent polyphenol (132.61 mg/g). The optimum extract provided a high antioxidant capacity through the measurements of FRAP (1462.17 μmol ascorbic acid equivalents (AAE)/g), DPPH (1108.91 μmol AAE/g), and H₂O₂ (1662.93 μmol AAE/g). Total carotenoids were measured at 499.61 μg/g, with ascorbic acid at 8.36 μg/g. Correlation analyses revealed a negative correlation of the latter compound with color coordinates. This study highlights the potential of lemon verbena leaves to be used in pharmaceutical and food industries. Full article

The production and consumption of organic products have been increasing in Portugal, as well as in the European Union as a whole. The main objective of this work is to understand the consumption habits of organic medicinal and aromatic plants (OMAPs) among Portuguese adults. An online questionnaire was distributed using social networks, resulting in the collection and statistical analysis of 300 responses. Of the participants who reported consuming OMAPs, 44.3% showed a daily consumption pattern. The most frequently mentioned OMAPs for fresh consumption were parsley (Petrosselinum crispum L., 92%), garlic (Allium sativum L., 84.1%), and coriander (Coriandrum sativum L., 78.1%). The most commonly mentioned OMAP for consumption as dried plants were oregano (Origanum vulgare L., 74.6%), lemon balm (Melissa officinalis L., 49.2%), and lemon verbena (Aloysia citrodora L., 46.8%). The main reasons cited for using OMAPs were their benefits to health (58.7% of participants), benefits to the environment (33.2%), and reduced salt consumption (29.5%). Among these, the main health benefits mentioned included anti-inflammatory properties (45.0%), prevention of cardiovascular diseases (41.6%), and prevention of high cholesterol (39.9%). Furthermore, 82.5% of respondents considered themselves sufficiently, well, or excellently informed about the nutritional properties of OMAPs. This research initiates a discussion about whether profiling OMAP consumption habits can serve as a valuable tool for promoting organic farming in Portugal, increasing OMAP production and consumption, and strengthening the connection between these products and potential positive human health effects. Full article

Plant extracts contain valuable sources of biologically active molecules and, lately, have attracted scientific and industrial interest as inhibitors of food-borne pathogens and growth stimulators of beneficial microbes. In this vein, the aim of this study was to explore and exploit the effect of Aloysia citrodora extracts as potent functional regulators of food microbiota by stimulating the growth of probiotic strains and by suppressing the evolution of common food-spoilage and pathogenic bacteria. Aqueous and ethanolic extracts of A. citrodora, rich in polyphenols, were prepared and their phytochemical composition was unveiled by LC-triple quadruple and LC-QToF mass spectrometry. The growth stimulatory activity of a wild-type Lacticaseibacillus rhamnosus strain, along with L. rhamnosus GG, used as a control, was assessed by monitoring cell growth in the presence of sodium chloride, bile salts, thermal stress, and alcohol. We found that the aqueous extract stimulated the growth of probiotic strains at 0.5 mg/mL. At the same concentration, stimulatory activity was observed for the wild-type L. rhamnosus in the presence of bile salts and alcohol and for L. rhamnosus GG in the presence of NaCl and under thermal stress. The ethanolic extract of A. citrodora exhibited prebiotic activity at 0.25 mg/mL, but did not promote the growth of the strains under the stress conditions tested. In addition, minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) against food-spoilage and pathogenic microbes were determined. The strongest growth inhibitory activity of foodborne pathogens was noted by the A. citrodora ethanolic extract, while the aqueous A. citrodora extract had no effect against Escherichia coli. Importantly, the spoilage and pathogenic microbes tested were more sensitive to the extracts than the probiotic strains, indicating a significant contribution to the functional regulation of food microbiota, provided that they are used at the optimum concentration. Full article

The nutritional profiles of common and lemon verbena leaves were analyzed (proximate constituents, free sugars, organic acids, tocopherols, and fatty acids) and the leaves were prepared in hydromethanolic and aqueous (decoctions and infusions) extracts. The phenolic compound composition and antioxidant activity (2,2-Diphenyl-1-picrylhydrazyl (DPPH); 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric-reducing antioxidant power (FRAP); and cupric-reducing antioxidant capacity (CUPRAC) assays) of the extracts were characterized. The nutritional composition varied between the studied species, with lemon verbena showing higher amounts of protein, ash, and fat than common verbena, whereas the opposite trend was recorded for the dietary fiber content. The main free sugars detected in both species were fructose, glucose, and sucrose, which were present in higher amounts in the common verbena samples. Succinic acid was the most abundant organic acid in both species while high amounts of oxalic acid were detected in lemon verbena. The main fatty acids in both species were α-linolenic, palmitic, and linoleic acid. Regarding the phenolic compound content, the extracts of lemon verbena presented higher amounts of total phenolic compounds (TPCs), total flavonoids (TFs) and total phenolic acids (TPAs) than the common verbena extracts while the aqueous extracts (infusions and decoctions) were richer in TPCs, TFs, and TPAs than the hydromethanolic ones in both species. Nine phenolic compounds were identified and quantified, including seven phenolic acids and two flavonoids. The lemon verbena samples were characterized by higher antioxidant activity compared to the common verbena samples while the aqueous extracts showed higher antioxidant efficacy than the hydromethanolic ones. In conclusion, both species showed promising results in terms of the nutritional value, chemical composition, and antioxidant activities, which were positively correlated with the phenolic compound contents. Moreover, the extraction protocol may affect the chemical composition and bioactive properties of both species, with aqueous extracts showing better results than hydromethanolic ones. Full article

Blowflies are vectors of microorganisms and human pathogens, and their maggots cause myiasis in vertebrates and infest and spoil meat and fish products. Essential oils (EOs) from spices were proven to be a safer and more sustainable alternative to synthetic insecticides for the control of blowflies and are suitable for protecting food from such pests. However, some EOs are not acceptable for environmental or topical applications due to their strong, unpleasant odour. In this study, we measured the acute toxicity and the repellence of two EOs extracted from the Andean plants Aloysia citrodora Palau and Bursera graveolens (Kunth) Triana and Planch., both known for their pleasant odour, against the blue blowfly Calliphora vomitoria (L.) (Diptera: Calliphoridae). We also compared their bioactivity with that of the Allium sativum L. EO, which is very effective but bad-smelling. The A. citrodora EO was mainly rich in oxygenated monoterpenes, the most abundant of which were geranial (26.8%) and neral (21.0%). The B. graveolens EO was chiefly composed of monoterpene hydrocarbons, mostly represented by limonene (46.2%). According to the sensory description, the best odour profile was associated with the A. citrodora EO, while the olfactory expression of the EO from B. graveolens was negatively affected by a strong odour of “mouldy lemon”. The behavioural test showed that the A. citrodora EO was more repellent than that of A. sativum and, on the contrary, that the B. graveolens EO was attractive. The toxicity tests showed that the EOs of both Andean plants have a clear toxic effect on the C. vomitoria eggs and adults. In terms of ovicidal activity, there were no significant differences among the effects of the three tested EOs. On the adult flies, the toxicity of the two EOs of the Andean plants was much lower than that of A. sativum (LC₅₀ fumigation = 1.86 μL EO L⁻¹ air; LC₅₀ ingestion = 8.10 μL EO mL⁻¹ gel) both by fumigation (LC₅₀ = 23.66 and 25.30 μL EO L⁻¹ air for A. citrodora and B. graveolens, respectively) and ingestion (LC₅₀ = 36.65 and 44.97 μL EO mL⁻¹ gel for A. citrodora and B. graveolens, respectively), while, by contact, the A. citrodora EO (LD₅₀ = 0.27 μL EO insect⁻¹) was more toxic than the A. sativum EO (LD₅₀ = 0.46 μL EO insect⁻¹). Full article

The aim of this study was to evaluate the in vitro antimicrobial activity of medicinal methanolic plant extracts against multidrug-resistant bacteria to determine the cytotoxicity of these extracts on eukaryotic cells, and to confirm their efficacy against Methicillin-Resistant Staphylococcus aureus (MRSA) in experimental animals. The effects of the methanol extract of sixty folk plants were investigated on; MRSA, Extended Spectrum Beta-Lactamase E. coli and MDR Pseudomonas aeruginosa by disc diffusion and MIC assay. Cytotoxicity was determined using MTT and hemolysis of human erythrocytes. Three plant extracts with the highest antimicrobial activities were tested using a challenge experiment on mice. Systemic infection was performed by intraperitoneal inoculation of (5 × 10⁶ CFU/mL) of MRSA isolate. Then mice received 300 mg/kg body weight of the plant extracts daily for seven days. The efficacy of plant extracts was evaluated by general health, mortality rate, gross lesion, and histopathology study of inoculated mice. Only ten plants showed activities against different MDR bacteria with inhibitory zones ranging from (8 to 22 mm) in diameter. Of the ten medicinal plant extracts, Camellia sinensis and Aloysia citrodora showed the highest activities against MRSA and MSSA isolates, with MIC value ranging from 0.5 to 1.5 mg/ml, followed by Hibiscus sabdariffa, Thymus vulgaris, and Glycyrrhiza glabra. Furthermore, the extract of the effective plants showed low toxicity against Vero and fibroblasts cell lines, along with inhibitory activities to erythrocytes membrane disruption. The in vivo study demonstrated that Camellia sinensis showed significant activity against MRSA infections in mice. The results validate that these plants are effective and safe antibacterial agents against multidrug-resistance bacteria, and have the potential to be utilized as an alternative to antibiotics for the treatment of bacterial infections. Full article