Comprehensive Analysis of 11 Species of Euodia (Rutaceae) by Untargeted LC-IT-TOF/MS Metabolomics and In Vitro Functional Methods.

The Euodia genus comprises numerous untapped medicinal plants that warrant thorough evaluation for their potential as valuable natural sources of herbal medicine or food flavorings. In this study, untargeted metabolomics and in vitro functional methods were employed to analyze fruit extracts from 11 significant species of the Euodia genus. An investigation of the distribution of metabolites (quinolone and indole quinazoline alkaloids) in these species indicated that E. rutaecarpa (Euodia rutaecarpa) was the most widely distributed species, followed by E. compacta (Euodia compacta), E. glabrifolia (Euodia glabrifolia), E. austrosinensis (Euodia austrosinensis), and E. fargesii (Euodia fargesii). There have been reports on the close correlation between indole quinazoline alkaloids and their anti-tumor activity, especially in E. rutaecarpa fruits which exhibit effectiveness against various types of cancer, such as SGC-7901, Hela, A549, and other cancer cell lines. Additionally, the E. rutaecarpa plant contains indole quinazoline alkaloids, which possess remarkable antibacterial properties. Our results offer novel insights into the utilization of Euodia resources in the pharmaceutical industry.

Pulp or Peel? Comparative Analysis of the Phytochemical Content and Selected Cosmetic-Related Properties of Annona cherimola L., Diospyros kaki Thumb., Cydonia oblonga Mill. and Fortunella margarita Swingle Pulp and Peel Extracts.

Fruit peels might be a valuable source of active ingredients for cosmetics, leading to more sustainable usage of plant by-products. The aim of the study was to evaluate the phytochemical content and selected biological properties of hydroglycolic extracts from peels and pulps of Annona cherimola, Diospyros kaki, Cydonia oblonga, and Fortunella margarita as potential cosmetic ingredients. Peel and pulp extracts were compared for their antiradical activity (using DPPH and ABTS radical scavenging assays), skin-lightening potential (tyrosinase inhibitory assay), sun protection factor (SPF), and cytotoxicity toward human fibroblast, keratinocyte, and melanoma cell lines. The total content of polyphenols and/or flavonoids was significantly higher in peel than in pulp extracts, and the composition of particular active compounds was also markedly different. The HPLC-MS fingerprinting revealed the presence of catechin, epicatechin and rutoside in the peel of D. kaki, whereas kaempferol glucoside and procyanidin A were present only in the pulp. In A. cherimola, catechin, epicatechin and rutoside were identified only in the peel of the fruit, whereas procyanidins were traced only in the pulp extracts. Quercetin and luteolinidin were found to be characteristic compounds of F. margarita peel extract. Naringenin and hesperidin were found only in the pulp of F. margarita. The most significant compositional variety between the peel and pulp extracts was observed for C. oblonga: Peel extracts contained a higher number of active components (e.g., vicenin-2, kaempferol rutinoside, or kaempferol galactoside) than pulp extract. The radical scavenging potential of peel extracts was higher than of the pulp extracts. D. kaki and F. margarita peel and pulp extracts inhibited mushroom and murine tyrosinases at comparable levels. The C. oblonga pulp extract was a more potent mushroom tyrosinase inhibitor than the peel extract. Peel extract of A. cherimola inhibited mushroom tyrosinase but activated the murine enzyme. F. margarita pulp and peel extracts showed the highest in vitro SPF. A. cherimola, D. kaki, and F. margarita extracts were not cytotoxic for fibroblasts and keratinocytes up to a concentration of 2% (v/v) and the peel extracts were cytotoxic for A375 melanoma cells. To summarize, peel extracts from all analyzed fruit showed comparable or better cosmetic-related properties than pulp extracts and might be considered multifunctional active ingredients of skin lightening, anti-aging, and protective cosmetics.

Asiaticasics A-O, structurally intriguing coumarins from Toddalia asiatica with potential inflammatory inhibitory activity.

Ethyl acetate fraction of Toddalia asiatica was fractionated to yield fifteen previously undescribed prenylated coumarins, asiaticasics A-O (1-15) along with nine (16-24) known derivatives. The structures of these undescribed coumarins were established by spectroscopic analysis and reference data. Biological activity evaluation showed that compound 3 with the IC50 value of 2.830 µM and compound 12 with the IC50 value of 0.682 µM owned anti-inflammatory activity by detecting the rate of lactate dehydrogenase release in pyroptosis J774A.1 cells. The results showed that the expression of Caspase-1 and IL-1ß was decreased in a dose-dependent manner in the compound 12 treatment group, suggesting that compound 12 may reduce pyroptosis by inhibiting NLRP3 inflammasome. To further determine that compound 12 treatment can inhibit macrophage pyroptosis, morphological observation was performed and the results were consistent with the bioactivity evaluation.

Haplophyllum tuberculatum (Forssk.) A. Juss Essential Oils: Seasonal Contents Variation, Bioactivity of the Traditionally-favored, High-yield and Frequent-use Summer Season Oil.

Haplophyllum tuberculatum (Forssk.) A.Juss. volatile oils were obtained by distillation of the aerial parts of the plant growing in Libya during the summer and spring seasons. A yield and componential analysis revealed that the summer season oil, which is frequently used in traditional medicaments by North African communities, was high in yield (0.858%) compared to the spring season oil (0.47%), and distinguished by the presence of major and various diverse constituents, some of which are considered chemical markers. Owing to the traditional and high incidence of use of the summer-produced essential oil for the treatment of several disorders, including hepatic diseases, and fatigue, the oil was pharmacologically investigated for its varied bioactivities of anti-microbial, in vivo anti-oxidant, and in vitro anti-cancer properties. Thirty-three compounds were identified and represented 96.2% of the peaks in the GCchromatogram of the summer oil, in which the major volatile constituents were δ-3-carene (21.5%), bornyl acetate (16.9%), and limonene aldehyde (15.2%). The summer-based essential oil of the plant demonstrated moderate anti-bacterial activity against Gram-positive bacteria and a relatively strong antibacterial effect against Gram-negative bacteria as compared to the positive antibacterial controls, ampicillin and gentamicin, respectively. Also, antifungal activity against Aspergillus sp. was observed. The summerproduced oil also exhibited in vivo antioxidant and in vitro anti-cancer activities.

Limonoids and alkaloids from Tetradium austrosinense (Hand.-Mazz.) T.G.Hartley.

A pair of new enantiomeric indolopyridoquinazoline-type alkaloids, (+)-1,7S,8R- and (-)-1,7R,8S-trihydroxyrutaecarpine (3a and 3b), and a new limonoid-tyrosamine hybrid, austrosinin (8), along with six known alkaloids and limonoids, were isolated from the stems with leaves of Tetradium austrosinense. Their structures were elucidated on the basis of analysis of MS, NMR, ECD and time-dependent density functional theory-based electronic circular dichroism (TDDFT-ECD) calculations, as well as proposed biosynthetic pathway. An anti-inflammatory bioassay in vitro showed 8 had significant immunosuppressive effect against the production of pro-inflammatory cytokine TNF-α in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

A Review of the Ethnomedicinal, Phytochemical, and Anticancer Properties of Melicope Species.

The genus Melicope, which consists of 230 species, stands out as the largest genus within the Rutaceae family. Melicope species are characterized by their evergreen nature and can range from shrubs to predominantly dioecious trees. The Melicope species have been utilized in traditional medicine to address a wide range of ailments, including fever, colds, cramps, and inflammation. These plants have gained significant attention due to their noteworthy ethnopharmacological and ethnomedicinal significance. Researchers have isolated numerous biologically active secondary metabolites from different Melicope species, which include polymethoxylated flavonoids, furanocoumarins, acetophenones, benzenoids, and quinolone alkaloids. These compounds exhibit diverse biological activities, such as antibacterial, antidiabetic, antifungal, and antiproliferative properties against human cancer cell lines. This review provides an update on the chemical constituents of the selected species of Melicope. The study also highlights the anticancer and cytotoxicity properties of the plant extracts and phytochemical constituents from Melicope species. Furthermore, the molecular mechanisms underlying the anticancer effects are elucidated. Overall, this review contributes to understanding the significant pharmacological potential of Melicope species and unlocking their chemical composition, emphasizing their relevance in the development of therapeutic agents, particularly in the field of cancer research.

Six new coumarins from the roots of Toddalia asiatica and their anti-inflammatory activities.

We reported the discovery of six novel coumarins, toddasirins A-F (1-6), each endowed with modified isoprenyl or geranyl side chains, derived from the roots of Toddalia asiatica. Comprehensive structural elucidation was achieved through multispectroscopic analyses, single-crystal X-ray diffraction experiments, and advanced quantum mechanical electronic circular dichroism (ECD) calculations. Furthermore, the anti-inflammatory activity of these compounds was assessed. Notably, compounds 1-3 and 6 demonstrated notable inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells, with 50% inhibitory concentration (IC50) values of 3.22, 4.78, 8.90, and 4.31 µmol·L-1, respectively.

Bael (Aegle marmelos L. Correa) fruit extracts encapsulated alginate nanoparticles as a potential dietary supplement with improved bioactivities.

Nanoencapsulated bael fruit (Aegle marmelos L. Correa (Family: Rutaceae)) extracts reveal novel prospects in the development of dietary supplements with improved biological activities in the field of the food industry. The main objectives of this study were to prepare and characterize aqueous, ethanol, 50% ethanol, and 50% acetone extracts of bael fruit encapsulated alginate nanoparticles and investigate the effect of encapsulation on in vitro release of polyphenols, antidiabetic, antioxidant, and anti-inflammatory activities, and their stability. Bael fruit extracts encapsulated alginate nanoparticles were prepared using the ionic gelation method. Characterization, in vitro release profiles of polyphenols, determination of antidiabetic, anti-inflammatory, antioxidant activity, and accelerated stability were conducted. The results of the characterization confirmed the successful encapsulation of extracts of bael fruit in the alginate matrix. The aqueous extract of bael fruit encapsulated alginate nanoparticles exhibited a more controlled slow-release profile, accounting for 21.82% ± 1.17% and 48.14% ± 0.52% of polyphenols at solutions of pH 1.2 and pH 6.8, respectively. In general, the results of the bioactivity assessment suggested that nanoencapsulation could facilitate the enhancement of its antidiabetic, antioxidant, and anti-inflammatory properties. The results of thermogravimetric analysis and thin layer chromatography fingerprint showed the stability of aqueous bael fruit extract encapsulated alginate nanoparticles at 27 and 4°C over a month. In summary, the results of this study revealed the potency of nanoencapsulated aqueous extract of bael fruit to develop a dietary supplement with improved antidiabetic, antioxidant, and anti-inflammatory activities. PRACTICAL APPLICATION: The encapsulation of bael fruit extracts into a nanocarrier enhances bioactivities and promotes the controlled release of bioactive compounds. This could be useful in the future food industry, based on scientifically proven data, and inspire the market by means of the development of dietary supplements. Overall, the results would facilitate the formulation of novel commercially elegant nanoencapsulated dietary supplements with improved potential to manage a healthy life.

Characteristics of wood apple (Limonia acidissima L.) and soybean powder jelly for emergency food alternatives.

The substitution of wood apple juice and soybean powder in the seaweed jelly product can be used as an alternative to emergency supplementary feeding (ESF) for children under five years of age, which contains high protein, fiber, and calories. This study aimed to determine the effect of adding wood apple juice and soybean powder to the nutrition content, vitamin C, zinc, magnesium, total phenol, antioxidant activity, acceptability, and shelf-life of seaweed jelly products. This study was an experimental study with a completely randomized design with two treatment factors, which consisted of making seaweed jelly products with three different ratios of wood apple juice and soybean powder, 60:40 (F1), 50:50 (F2), and 40:60 (F3), dried at 40 °C (T1) and 50 °C (T2). Macronutrients were determined using proximate analysis. The total phenol and vitamin C were measured using Folin-ciocalteu reagent and UV-Vis spectrophotometry. Antioxidant activity was analyzed by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH). The contents of zinc and magnesium were evaluated through Atomic Absorption Spectrophotometry (AAS). Estimation of shelf life was determined with Accelerated Shelf-Life Test (ASLT) method and Arrhenius equation model. The best formula based on proximate analysis was F3, which contained 361.98 kcal of energy and 33.79 g of protein. The best formula (F1) dried at 40 °C; contains 56.28 mg/100 g vitamin C; zinc was 1.55 mg/100 g; magnesium was 79.25 mg/100 g; antioxidant activity (IC50) was 88.39 µg/mL; and total phenol was 8.59 mg GAE/g. The quality attributes of the best formula show the potential of the jelly as an emergency food despite its short shelf-life.

Behavioral and electrophysiological (ECoG) effects of haplophyllum robustum and TRPA1 antagonist in adult male wistar rats.

This article aimed to investigate the effects of Haplophyllum robustum hydroalcoholic extract on animals' behavioral and electrocorticographic changes. This plant is mainly found in Turkey, Iran, and Central Asia, and is reported to have convulsive effects. In this article, we worked on the effects of its hydroalcoholic extract on electrocorticography (ECoG), along with changes induced by intracerebroventricular administration of GABAA antagonists. Furthermore, the effects of low doses of this extract on behavioral depression were examined. Four animal sets were used to compare ECoG in Wistar rats. A group of negative control, a group of positive control (PTZ), and two groups received an injection of plant extract (500 mg/kg, ip), with or without administration of Diazepam (5 mg/kg). Also, three sets were applied to compare receiving and not receiving intracerebroventricular (icv) injection of Transient receptor potential ankyrin 1 antagonist (HC-030031) (2 µg/kg) on plant-induced seizure delay and animal death. Two groups of control and a group with plant extract together with TRPA1 antagonist were administrated. Furthermore, in the present study, the forced swimming test (FST) was used as a model of depression. The behaviors of animals in three groups of negative control and positive control (Fluoxetine) and plant extract (200 mg/kg, ip) were compared. According to the ECoG, high doses of extract of plants led to seizures similar to PTZ, which were then reduced by diazepam injection. At this dose, injection of TRPA1 antagonist did not significantly delay the onset of seizures or the death of the animals. Further, a subconvulsive dose of hydroalcoholic plant extracts was equally effective in treating depression as Fluoxetine injections.

Effectiveness of kumquat decoction for the improvement of cough caused by SARS-CoV-2 Omicron variants, a multicentre, prospective observational study.

BACKGROUND: Kumquat decoction is a traditional Chinese medicine formula and has been widely used to alleviate the coronavirus disease 2019 (COVID-19)-related cough in China. However, the effectiveness and safety of kumquat decoction remain unclear. PURPOSE: To assess the effectiveness and safety of kumquat decoction for COVID-19-related cough. STUDY DESIGN: A multicentre, prospective observational study. METHODS: We enrolled consecutive patients with mild-to-moderate COVID-19 from December 31, 2022, to January 3, 2023, during the Omicron phase in Yangshuo County, China. The primary outcome was the time from study baseline to sustained cough resolution by the last follow-up day on January 31, 2023. The effectiveness was evaluated by Cox proportional hazards models based on propensity score analyses. The secondary outcomes were the resolution of cough and other COVID-19-related symptoms by Days 3, 5, and 7. RESULTS: Of 1434 patients, 671 patients were excluded from the analysis of cough resolution. Among the remaining 763 patients, 481 (63.04%) received kumquat decoction, and 282 (36.96%) received usual care. The median age was 38.0 (interquartile range [IQR] 29.0, 50.0) years, and 55.7% were women. During a median follow-up of 7.000 days, 68.2% of patients in the kumquat group achieved sustained cough resolution (93.77 per 1000 person-days) compared to 39.7% in the usual care group (72.94 per 1000 person-days). The differences in restricted mean survival time (RMST) (kumquat decoction minus usual care group) for cough resolution were -0.742 days (95% CI, -1.235 to -0.250, P = 0.003) on Day 7. In the main analysis using propensity-score matching, the adjusted hazard ratio (HR) for cough resolution (kumquat decoction vs. usual care group) was 1.94 (95% CI, 1.48 to 2.53, P < 0.001). Similar findings were found in multiple sensitivity analyses. In addition, the use of kumquat decoction was associated with the resolution of cough, and a stuffy nose on Days 5 and 7, as well as the resolution of sore throat on Day 7 following medication. CONCLUSION: In this study among patients with COVID-19-related cough, receiving kumquat decoction was associated with an earlier resolution of cough symptoms.

Phytochemistry and Biological Activities of Murraya Species.

Murraya is a plant genus within the Rutaceae family comprising over 17 species, which are widely distributed in Asia, Australia, and the Pacific Islands. Furthermore, these species have been used in traditional medicine to treat fever, pain, and dysentery. Several reports have also extensively studied the leaves, seeds, stembark, and bark of Murraya from 1965 to 2023 to explore their natural product composition. Various phytochemical studies have revealed the isolation of 413 compounds recorded, comprising coumarins, terpenoids, flavonoids, and aromatics, as well as alkaloids, which constitute the largest proportion (46.9%). These isolated compounds have long been known to exhibit different bioactivities, such as cytotoxic and anti-inflammatory properties. Cytotoxic activity has been observed against HCT 116, HeLa, HepG2, and other cell lines. Previous studies have also reported the presence of antifungal, hepatoprotective, antihyperlipidemic, antidiarrheal, and antioxidant effects. Therefore, this review provides a comprehensive overview of Murraya species, highlighting their phytochemistry, biological activities, and potential as a source of active natural compounds.

Antibacterial and antibiotic potentiating capabilities of extracts isolated from Burkillanthus malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus against human pathogenic bacteria.

Antibiotics which once a boon in medicine and saved millions of lives are now facing an ever-growing menace of antibacterial resistance, which desperately needs new antibacterial drugs which are innovative in chemistry and mode of action. For many years, the world has turned to natural plants with antibacterial properties to combat antibiotic resistance. On that basis, we aimed to identify plants with antibacterial and antibiotic potentiating properties. Seventeen different extracts of 3 plants namely Burkillanthus malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus were tested against multi-drug resistant Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Methicillinresistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA). Antibacterial activity of hexane, methanol and chloroform extracts of bark, seed, fruit, flesh and leaves from these plants were tested using, disk diffusion assay, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Antibiotic potentiating capabilities were tested using time-kill assay. B. malaccensis fruit chloroform extract showed the biggest zone of inhibition against MRSA (13.00±0.0 mm) but C. bracteosus bark methanol extract showed the biggest inhibition zone against MSSA (15.33±0.6 mm). Interestingly, bark methanol extract of C. bracteosus was active against MRSA (8.7±0.6 mm), MSSA (7.7±0.6 mm) (Gram-positive) and A. baumannii (7.7±0.6 mm) (Gram-negative). Overall, the leaf methanol and bark methanol extract of C. bracteosus warrants further investigation such as compound isolation and mechanism of action for validating its therapeutic use as antibiotic potentiator importantly against MRSA and A. baumannii.

Phloroglucinol derivatives, coumarins and an alkaloid from the roots of Evodia lepta Merr.

Two previously undescribed phloroglucinol derivatives [(±) evolephloroglucinols A and B], five unusual coumarins [evolecoumarins A and B and (±) evolecoumarins C-E], and one novel enantiomeric quinoline-type alkaloid [(±) evolealkaloid A], along with 20 known compounds, were isolated from the EtOH extract of the roots of Evodia lepta Merr. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of the undescribed compounds were determined by X-ray diffraction or computational calculations. Their anti-neuroinflammatory effects were assayed. Among the identified compounds, compound 5a effectively reduced nitric oxide (NO) production with an EC50 value of 22.08 ± 0.46 µM. Hence, it could indeed inhibit the lipopolysaccharide (LPS)-induced Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome.

Novel studies on Isolation, purification and characterization of dibenzonitro compound from Glycosmis pentaphylla (Retz.) DC. and effect in downregulating neuronal cancers.

To isolate Letrozole from Glycosmis pentaphylla (Retz.) DC. and to determine its effect on regulating the proliferation, cell cycle distribution, apoptosis and key mechanisms in human neuroblastoma cell lines. Letrozole was isolated through column chromatographic technique and its effect was checked on human neuroblastoma cell lines, IMR 32. The effects of Letrozole on cell viability were measured by MTT assay, and the cell cycle distribution was determined by flow cytometry. The expression changes in mRNA of proliferating cell nuclear antigen (PCNA), cyclin D1 and Bcl-xL were taken from real-time PCR analysis and the protein levels were detected by Western blotting. The results of the present study showed that Letrozole, isolated from leaves of G. pentaphylla could cause significant inhibitory effect on proliferation of IMR 32 cells in a dose dependent manner. Cell arrest was obtained at S phase with the treatment of Letrozole. Apart from this, the expression of PCNA, cyclin D1 and Bcl-xL were decreased both at mRNA and protein levels for the same treatment. Letrozole can inhibit proliferation, induce cell arrest and cause apoptosis in IMR 32 cell lines. The decreased expression of PCNA, cyclin D1 and Bcl-xL induced by Letrozole contributes to the above effects in vitro. This is the first report on the isolation of Letrozole from G. pentaphylla.

Insulin sensitization by Feronia elephantum in fructose-induced hyperinsulinemic rats: Insights from computational and experimental pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Feronia elephantum corr. (synonym: Feronia limonia, Murraya odorata, Schinus Limonia, or Limonia acidissima; common names: Bela, Kath, Billin, and Kavitha), belonging to the family Rutaceae has been known for clinical conditions such as pruritus, diarrhea, impotence, dysentery, heart diseases, and is also used as a liver tonic. However, the effect of the fruit pulp of F. elephantum on insulin resistance has yet not been reported. AIM OF THE STUDY: The present study aimed to assess the effect of hydroalcoholic extract/fraction of F. elephantum fruit pulp on fasting blood glucose, oral glucose tolerance test, and glucose uptake in fructose-induced insulin-resistant rats and predict the gene-set enrichment of lead hits of F. elephantum with targets related to insulin resistance. MATERIAL AND METHODS: System biology tools were used to predict the best category of fraction and propose a possible mechanism. Docking was carried out with adiponectin and its receptor (hub genes). Further, fructose supplementation was used for the induction of insulin resistance. Later, three doses of extract (400, 200, and 100 mg/kg) and a flavonoid-rich fraction (63 mg/kg) were used for treatment along with metformin as standard. The physical parameters like body weight, food intake, and water intake were measured along with oral glucose tolerance test, insulin tolerance test, glycogen content in skeletal muscles and liver, glucose uptake by rat hemidiaphragm, lipid profiles, anti-oxidant biomarkers, and histology of the liver and adipose tissue. RESULTS: Network pharmacology reflected the potency of F. elephantum to regulate adiponectin which may promote the reversal of insulin resistance and inhibit α-amylase and α-glucosidase. Vitexin was predicted to modulate the most genes associated with diabetes mellitus. Further, F. elephantum ameliorated the exogenous glucose clearance, promoted insulin sensitivity, reduced oxidative stress, and improved glucose and lipid metabolism. HPLC profiling revealed the presence of apigenin and quercetin in the extract for the first time. CONCLUSION: The fruit pulp of F. elephantum reverses insulin resistance by an increase in glucose uptake and a decrease in gluconeogenesis which may be due to the regulation of multiple proteins via multiple bio-actives.

Variation in microbial feature perception in the Rutaceae family with immune receptor conservation in citrus.

Although much is known about the responses of model plants to microbial features, we still lack an understanding of the extent of variation in immune perception across members of a plant family. In this work, we analyzed immune responses in Citrus and wild relatives, surveying 86 Rutaceae genotypes with differing leaf morphologies and disease resistances. We found that responses to microbial features vary both within and between members. Species in 2 subtribes, the Balsamocitrinae and Clauseninae, can recognize flagellin (flg22), cold shock protein (csp22), and chitin, including 1 feature from Candidatus Liberibacter species (csp22CLas), the bacterium associated with Huanglongbing. We investigated differences at the receptor level for the flagellin receptor FLAGELLIN SENSING 2 (FLS2) and the chitin receptor LYSIN MOTIF RECEPTOR KINASE 5 (LYK5) in citrus genotypes. We characterized 2 genetically linked FLS2 homologs from "Frost Lisbon" lemon (Citrus ×limon, responsive) and "Washington navel" orange (Citrus ×aurantium, nonresponsive). Surprisingly, FLS2 homologs from responsive and nonresponsive genotypes were expressed in Citrus and functional when transferred to a heterologous system. "Washington navel" orange weakly responded to chitin, whereas "Tango" mandarin (C. ×aurantium) exhibited a robust response. LYK5 alleles were identical or nearly identical between the 2 genotypes and complemented the Arabidopsis (Arabidopsis thaliana) lyk4/lyk5-2 mutant with respect to chitin perception. Collectively, our data indicate that differences in chitin and flg22 perception in these citrus genotypes are not the results of sequence polymorphisms at the receptor level. These findings shed light on the diversity of perception of microbial features and highlight genotypes capable of recognizing polymorphic pathogen features.

Preliminary Study on Insecticidal Potential and Chemical Composition of Five Rutaceae Essential Oils against Thrips flavus (Thysanoptera: Thripidae).

To meet the demand for novel pest management strategies to combat the development of insecticide resistance, plant essential oils may be a promising alternative source. This study investigated the insecticidal activity of five essential oils from the Rutaceae plant family against Thrips flavus Schrank (Thysanoptera: Thripidae) under laboratory conditions. The plant essential oils were citrus oil (Citrus reticulata Blanco), Chuan-shan pepper oil (Zanthoxylum piasezkii Maxim.), zanthoxylum oil (Zanthoxylum bungeanum Maxim.), pomelo peel oil (Citrus maxima (Burm.) Merr.) and orange leaf oil (Citrus sinensis (L.) Osbeck). Among the essential oils evaluated, orange leaf oil (LC50 = 0.26 g/L), zanthoxylum oil (LC50 = 0.27 g/L), and pomelo peel oil (LC50 = 0.44 g/L) resulted in a higher gastric toxicity under laboratory conditions. The results of the pot experiment also showed that orange leaf oil (93.06 ± 3.67% at 540.00 g a.i.·hm-2, 97.22 ± 1.39% at 720 g a.i.·hm-2, 100.00% at 900.00 g a.i.·hm-2) zanthoxylum oil (98.73 ± 1.27% at 900 g a.i.·hm-2), and pomelo peel oil (100.00% at 900 g a.i.·hm-2) exhibited a higher control efficacy, being the most effective against T. flavus after 7 days of treatment. The essential oil components were then identified by gas chromatography-mass spectrometry (GC-MS). The insecticidal activity of orange leaf oil, pomelo peel oil, and zanthoxylum oil could be attributed to their main constituents, such as methyl jasmonate (50.92%), D-limonene (76.96%), and linalool (52.32%), respectively. In the olfactory test, adult T. flavus were attracted by zanthoxylum oil and Chuan-shan pepper oil. We speculated that linalool might be the key signaling compound that attracts T. flavus. These results showed that orange leaf oil, zanthoxylum oil, and pomelo peel oil exhibited insecticidal activities under controlled conditions. They can be implemented as effective and low-toxicity botanical insecticides and synergistic agents against T. flavus.