N-alkylamides from Litsea cubeba (Lour.) Pers. with potential anti-inflammatory activity

Six amides, including a new N-alkylamide (1), four known N-alkylamides (2-5) and one nicotinamide (6) were isolated from Litsea cubeba (Lour.) Pers., which is a pioneer herb traditionally utilized in medicine. Their structures were elucidated on the basis of 1D and 2D NMR experiments and by comparison of their spectroscopic and physical data with the literature values. Cubebamide (1) is a new cinnamoyltyraminealkylamide and possessed obvious anti-inflammatory activity against NO production with IC50 values of 18.45 μM. Further in-depth pharmacophore-based virtual screening and molecular docking were carried out to reveal the binding mode of the active compound inside the 5-LOX enzyme. The results indicate that L. cubeba, and the isolated amides might be useful in the development of lead compounds for the prevention of inflammatory diseases.

Non-Volatile Component and Antioxidant Activity: A Comparative Analysis between Litsea cubeba Branches and Leaves

Litsea cubeba, which is found widely distributed across the Asian region, functions as both an economic tree and a medicinal plant with a rich historical background. Previous investigations into its chemical composition and biological activity have predominantly centered on volatile components, leaving the study of non-volatile components relatively unexplored. In this study, we employed UPLC-HRMS technology to analyze the non-volatile components of L. cubeba branches and leaves, which successfully resulted in identifying 72 constituents. Comparative analysis between branches and leaves unveiled alkaloids, organic acids, and flavonoids as the major components. However, noteworthy differences in the distribution of these components between branches and leaves were observed, with only eight shared constituents, indicating substantial chemical variations in different parts of L. cubeba. Particularly, 24 compounds were identified for the first time from this plant. The assessment of antioxidant activity using four methods (ABTS, DPPH, FRAP, and CUPRAC) demonstrated remarkable antioxidant capabilities in both branches and leaves, with slightly higher efficacy observed in branches. This suggests that L. cubeba may act as a potential natural antioxidant with applications in health and therapeutic interventions. In conclusion, the chemical composition and antioxidant activity of L. cubeba provides a scientific foundation for its development and utilization in medicine and health products, offering promising avenues for the rational exploitation of L. cubeba resources in the future.

Antifungal activity and mechanism of Litsea cubeba (Lour.) Persoon essential oil against the waxberry spoilage fungi Penicillium oxalicum and its potential application

Litsea cubeba essential oil (LCEO) is a broad-spectrum bacteriostatic substance produced from the fruit of the Litsea tree that has been used for the treatment of various diseases in China for thousands of years. Here, the antifungal activities of LCEO against 10 different fungi (Naganishia diffluens, Fusarium sacchari, Cladosporium tenuissimum, Fusarium proliferatum, Fusarium verticillioides, Fusarium subglutinans, Mucor racemosus, Penicillium oxalicum, Penicillium chrysogenum, and Aspergillus niger) that cause rot to waxberries were assessed. The chemical components of LCEO and its modes of action against P. oxalicum were investigated. Citral (32.62 %) was characterized as the main component of LCEO by gas chromatography-mass spectrometry. LCEO exhibited excellent antifungal activities against all 10 fungi. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration of LCEO against P. oxalicum were 2.24 and 4.48 g/L, respectively. Furthermore, LCEO (MIC) compromised membrane permeability and integrity, caused leakage of the cell components, and increased production of malondialdehyde and reactive oxygen species. Scanning electron microscopy and transmission electron microscopy indicated that the morphology and ultrastructure of the LCEO-treated hyphal cell membrane and organelles were severely damaged. Meanwhile, LCEO increased the shelf life of waxberries from 1-2 to 5-6 d. LCEO is a potential ecologically friendly alternative to commercial fungicides to inhibit postharvest fungal contamination of waxberries during shipment and storage.

Two rare flavonoid glycosides from Litsea glutinosa (Lour.) C. B. Rob.: experimental and computational approaches endorse antidiabetic potentiality

BACKGROUND

Litsea glutinosa (Lour.) C. B. Rob. belongs to the Litsea genus and is categorized under the family of Lauraceae. The study aimed to investigate the phytoconstituents and pharmacological properties of methanol extract of leaves of Litsea glutinosa, focusing on antidiabetic activity via in vivo and in silico techniques.

METHODS

Extensive chromatographic and spectroscopic techniques were applied to isolate and characterize the constituents from the L. glutinosa plant species. The antidiabetic activity was studied in streptozotocin-induced diabetes mice, and the computational study of the isolated compounds was carried out by utilizing AutoDock Vina programs. In addition, the pharmacokinetic properties in terms of absorption, distribution, metabolism and excretion (ADME) and toxicological profiles of the isolated compounds were examined via in silico techniques.

RESULTS

In the present study, two flavonoid glycosides 4΄-O-methyl (2 ̋,4 ̋-di-E-p-coumaroyl) afzelin (1) and quercetin 3-O-(2 ̋,4 ̋-di-E-p-coumaroyl)-α-L-rhamnopyranoside (2) were isolated from the leaves of L. glutinosa and characterized by 1H and 13C NMR, COSY, HSQC, HMBC, and mass spectral data. Although compounds 1 and 2 have been reported twice from Machilis litseifolia and Lindera akoensis, and Machilis litseifolia and Mammea longifolia, respectively, this is the first report of this isolation from a Litsea species. Administering the methanolic extract of L. glutinosa at doses of 300 and 500 mg/kg/day to mice with diabetes induced by streptozotocin led to a significant decrease in fasting blood glucose levels (p < 0.05) starting from the 7th day of treatment. Besides, the computational study and PASS analysis endorsed the current in vivo findings that the both isolated compounds exerted higher binding affinities to human pancreatic α-amylase and aldose reductase than the conventional drugs. The in silico ADMET analysis revealed that the both isolated compounds have a favorable pharmacokinetic and safety profile suitable for human consumption.

CONCLUSION

According to the current outcomes obtained from in vivo and in silico techniques, the leaf extract of L. glutinosa could be a natural remedy for treating diabetes, and the isolated phytoconstituents could be applied against various illnesses, mainly hyperglycemia. However, more investigations are required for extensive phytochemical isolation and pharmacological activities of these phytoconstituents against broader targets with exact mechanisms of action.

Essential oils composition of Litsea glauca and Litsea fulva and their anticholinesterase inhibitory activity

This study was designed to examine the essential oils compositions of Litsea glauca Siebold and Litsea fulva Fern.-Vill. growing in Malaysia. The essential oils were achieved by hydrodistillation and fully characterized by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The study identified 17 and 19 components from the leaf oils from L. glauca (80.7%) and L. fulva (81.5%), respectively. The major components of L. glauca oil were β-selinene (30.8%), β-calacorene (11.3%), tridecanal (7.6%), isophytol (4.8%) and β-eudesmol (4.5%); whereas in L. fulva oil gave β-caryophyllene (27.8%), caryophyllene oxide (12.8%), α-cadinol (6.3%), (E)-nerolidol (5.7%), β-selinene (5.5%) and tridecanal (5.0%). Anticholinesterase activity was evaluated using Ellman method. The essential oils showed moderate inhibitory activity on acetylcholinesterase and butyrylcholinesterase assays. Our findings demonstrate that the essential oil could be very useful for the characterization, pharmaceutical, and therapeutic applications of the essential oil from the genus Litsea.

LcMYB106 suppresses monoterpene biosynthesis by negatively regulating LcTPS32 expression in Litsea cubeba

Litsea cubeba, the core species of the Lauraceae family, is valuable for the production of essential oils due to its high concentration of monoterpenes (90%). The key monoterpene synthase and metabolic regulatory network of monoterpene biosynthesis have provided new insights for improving essential oil content. However, there are few studies on the regulation mechanism of monoterpenes in L. cubeba. In this study, we investigated LcTPS32, a member of the TPS-b subfamily, and identified its function as an enzyme for the synthesis of monoterpenes, including geraniol, α-pinene, β-pinene, β-myrcene, linalool and eucalyptol. The quantitative real-time PCR analysis showed that LcTPS32 was highly expressed in the fruits of L. cubeba and contributed to the characteristic flavor of its essential oil. Overexpression of LcTPS32 resulted in a significant increase in the production of monoterpenes in L. cubeba by activating both the MVA and MEP pathways. Additionally, the study revealed that LcMYB106 played a negative regulatory role in monoterpenes biosynthesis by directly binding to the promoter of LcTPS32. Our study indicates that LcMYB106 could serve as a crucial target for metabolic engineering endeavors, aiming at enhancing the monoterpene biosynthesis in L. cubeba.

Chemical Composition of Litsea pungens Essential Oil and Its Potential Antioxidant and Antimicrobial Activities

Litsea pungens is a plant with medicinal and edible properties, where the fruits are edible and the leaves have medicinal properties. However, there is limited research on the chemical and pharmacological activities of the plant. In this study, essential oils were extracted by steam distillation and their antioxidant and antibacterial activities were further evaluated. Gas chromatography-mass spectrometry (GC-MS) was used to identify the chemical components of L. pungens fresh fruit essential oil (FREO) and L. pungens fresh flower essential oil (FLEO), rapeseed oil (RO) and commercial Litsea oil (CEO). The results showed that 12 chemical components were identified in FREO. Twelve chemical components were identified from FLEO, four chemical components were identified from CEO, and thirteen chemical components were identified from RO. Except for RO, the other three oils were mainly composed of terpenes, among which limonene is the main chemical component. In terms of antioxidant activity, FREO, FLEO, CEO and RO have antioxidant capacity, mainly reflected in the scavenging DPPH free radicals and the iron ion chelating ability, and the antioxidant activity shows a certain dose effect, but the antioxidant activity of FLEO is the weakest among the four oils. Meanwhile, under the stress of hydrogen peroxide, CEO demonstrated a significant antioxidant protective effect on cells. It is worth mentioning that compared with the positive control, the FREO exhibited a better antibacterial rate. When the concentration of essential oil is 20 mg/mL, the bacteriostatic rate can reach 100%. Therefore, it could be a promising candidate among medicinal and edible plants.

Synergistic antibacterial mechanism of different essential oils and their effect on quality attributes of ready-to-eat pakchoi (Brassica campestris L. ssp. chinensis)

The mixture of garlic essential oil (GEO), ginger essential oil (GIEO) and litsea cubeba essential oil (LCEO) was prepared and its effect on the antibacterial activity of E. coli, S. aureus and P. aeruginosa, as well as properties of ready-to-eat pakchoi during storage were assessed. GEO, GIEO or LCEO treatment significantly enhanced the accumulation of reactive oxygen species (ROS) levels, resulting in disruption of the permeability of cell membrane, the leakage of cytoplasmic contents, and the alteration of the secondary structure of bacterial proteins. Meanwhile, GEO, GIEO or LCEO treatment repressed the key enzyme in tricarboxylic acid (TCA) and Hexose monophosphate pathway (HMP) cycle of E. coli, S. aureus and P. aeruginosa. Essential oil treatments (p < 0.05) could significantly prolong the shelf life of pakchoi, total bacterial count (TBC) values and chlorophyll content of GEO/GIEO/LCEO sample were 3.47 log cfu/g and 0.82 mg/g, respectively, after storage for 7 days. E. coli, S. aureus and P. aeruginosa counts in GEO/GIEO/LCEO samples decreased by 56.76 %, 70.10 %, 73.95 % compared to CK (no essential oil) samples. The comprehensive results from the sensory (flavor and color) and microbial analysis (especially TBC) showed that GEO/GIEO/LCEO could extend the shelf life of ready-to-eat pakchoi from 4 d to 7 d. As compared with GEO, GIEO or LCEO individually, the combination of GEO, GIEO and LCEO exhibited synergistic effect and more pronouncedly antibacterial activity to improve quality of ready-to-eat pakchoi.

Study on the pharmacokinetics, tissue distribution and excretion of laurolitsine from Litsea glutinosa in Sprague-Dawley rats

CONTEXT

Laurolitsine is an aporphine alkaloid and exhibits potent antihyperglycemic and antihyperlipidemic effects in ob/ob mice.

OBJECTIVE

To investigate the pharmacokinetics, tissue distribution and excretion of laurolitsine.

MATERIALS AND METHODS

A LC-MS/MS method was established and validated to determine laurolitsine concentrations in the biological matrix of rats (plasma, tissue homogenate, urine and faeces). 10 Sprague-Dawley (SD) rats were used for plasma exposure study: 5 rats were injected with 2.0 mg/kg of laurolitsine via the tail vein, and the other 5 rats were administered laurolitsine (10.0 mg/kg) by gavage. 25 SD rats used for tissue distribution study and 5 SD rats for urine and faeces excretion study: rats administered laurolitsine (10.0 mg/kg) by gavage. After administered, serial blood, tissue, urine and faeces were collected. Analytical quantification was performed by a previous LC-MS/MS method. The pharmacokinetics, bioavailability, tissue distribution and excretion of laurolitsine were described.

RESULTS

The pharmacokinetic parameters of oral and intravenous administration with T_max were 0.47 and 0.083 h, t_1/2 were 3.73 and 1.67 h, respectively. Oral bioavailability was as low as 18.17%. Laurolitsine was found at a high concentration in the gastrointestinal tract, liver, lungs and kidneys (26 015.33, 905.12, 442.32 and 214.99 ng/g at 0.5 h, respectively) and low excretion to parent laurolitsine in urine and faeces (0.03 and 1.20% in 36 h, respectively).

CONCLUSIONS

This study established a simple, rapid and accurate LC-MS/MS method to determine laurolitsine in different rat samples and successful application in a pharmacokinetic study.

Transcriptomic Analysis of Drug-Resistance Acinetobacter baumannii under the Stress Condition Caused by Litsea cubeba L. Essential Oil via RNA Sequencing

Litsea cubeba L. essential oil(LCEO) can affect the growth of drug-resistance bacteria. However, research on stress response of drug-resistant A. baumannii under sub-lethal LCEO concentrations had been limited so far. Therefore, transcriptomic analysisof A. baumannii under 1/2 minimum inhibitory concentration (MIC, 0.54 mg/mL) of LCEO was performed. Results of transcriptomic analysis showed that 320/352 genes were significantly up/down-regulated, respectively, in LCEO-treated A. baumannii. Both up and down-regulated genes were significantly enriched in three GO terms (oxidation-reduction process; oxidoreductase activity; oxidoreductase activity, acting on the CH-CH group of donors), which indicated that the redox state of A. baumannii was significantly affected by LCEO. LCEO may also inhibit aerobic respiration, synthesis of ketone bodies and the metabolism of some amino acids while, meanwhile, promoting fatty acid degradation of A. baumannii according to Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. The permeability and the stress of cell membrane of A. baumannii were significantly affected by LCEO. After crystal violet dyeing, the biofilm formation of A. baumannii was promoted/inhibited by extremely low/relatively high concentration of LCEO, respectively. LCEO and chloramphenicol have synergistic growth inhibitory effect against A. baumannii according to the Fractional Inhibitory Concentration Index (FICI) value = 0.375. Our results indicate that the growth of A. baumannii was inhibited by LCEO, and give insights into the stress response of A. baumannii under sub-lethal concentrations of LCEO. These results provided evidence that A. baumannii was inhibited by LCEO, and expanded knowledges of stress response of A. baumannii under sub-lethal concentration of LCEO.

An Overview on Total Valorization of Litsea cubeba as a New Woody Oil Plant Resource toward a Zero-Waste Biorefinery

With the increasing global demand for edible oils and the restriction of arable land minimum in China, woody oil plants have gradually become the optimal solution to cover the shortage of current edible oil supply and to further improve the self-sufficiency rate. However, due to the lack of knowledge and technique, problems like “how to make full use of these plant resources?” and “how to guide consumers with reasonable data?” limit the development of woody oilseed industry towards a sustainable circular economy. In this review, several emerging unique woody oil plants in China were introduced, among which Litsea cubeba as a new woody oil plant was highlighted as a reference case based on its current research progress. Unlike other woody oil plants, essential oil rather than oil from Litsea cubeba has always been the main product through the years due to its interesting biological activities. Most importantly, its major component, citral, could be the base for other synthesized perfume compounds with added value. Moreover, the sustainable biorefinery of large amounts of waste residual after Litsea cubeba essential oil processing is now technically feasible, which could inspire a total valorization pathway for other woody oil plants to make more competitive plant-based products with both economic, social, and ecological benefits.

Effects of Thai Local Ingredient Odorants, Litsea cubeba and Garlic Essential Oils, on Brainwaves and Moods

The functional food market is growing with a compound annual growth rate of 7.9%. Thai food recipes use several kinds of herbs. Lemongrass, garlic, and turmeric are ingredients used in Thai curry paste. Essential oils released in the preparation step create the flavor and fragrance of the famous tom yum and massaman dishes. While the biological activities of these ingredients have been investigated, including the antioxidant, anti-inflammatory, and antimicrobial activities, there is still a lack of understanding regarding the responses to the essential oils of these plants. To investigate the effects of essential oil inhalation on the brain and mood responses, electroencephalography was carried out during the non-task resting state, and self-assessment of the mood state was performed. The essential oils were prepared in several dilutions in the range of the supra-threshold level. The results show that Litsea cubeba oil inhalation showed a sedative effect, observed from alpha and beta wave power reductions. The frontal and temporal regions of the brain were involved in the wave alterations. Garlic oil increased the alpha wave power at lower concentrations; however, a sedative effect was also observed at higher concentrations. Lower dilution oil induced changes in the fast alpha activity in the frontal region. The alpha and beta wave powers were decreased with higher dilution oils, particularly in the temporal, parietal, and occipital regions. Both Litsea cubeba and turmeric oils resulted in better positive moods than garlic oil. Garlic oil caused more negative moods than the others. The psychophysiological activities and the related brain functions require further investigation. The knowledge obtained from this study may be used to design functional food products.

Litsea cubeba essential oil: chemical profile, antioxidant activity, cytotoxicity, effect against Fusarium verticillioides and fumonisins production

The purpose of this study was to determine the chemical profile of Litsea cubeba essential oil, carry out an in vitro evaluation of its antioxidant potential and its cytotoxicity, as well as its antifungal and antimicotoxigenic activities against Fusarium verticillioides. Most of the compounds observed in the EO were neral (32.75%) and geranial (37.67%). The radical scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid was 104.4 and 56.4 mmol Trolox mg^-1, respectively, indicating good antioxidant activity. The EO studied by us revealed cytotoxic effect against HT-29 and HeLa cancer cells. The Minimum Inhibitory and Minimum Fungicidal Concentrations against F. verticillioides were both 125 µg mL^-1. Morphological investigation, performed by fluorescence microscopy and scanning electron microscopy, showed that hyphae and microconidia structures underwent changes after treatment with the EO. Analyses performed with the EO strongly reduced the mycelial development of F. verticillioides and the synthesis of fumonisins B₁ and B₂ in dose-dependence effect compared (P < 0.01) with the fungal control (10⁵ conidia mL^-1) and positive control (fludioxonil + metalaxyl-M). Thus, the results obtained in vitro suggest that L. cubeba EO has excellent antioxidant, fungicidal, and antimycotoxigenic effects.

A natural compound (LCA) isolated from Litsea cubeba inhibits RANKL-induced osteoclast differentiation by suppressing Akt and MAPK pathways in mouse bone marrow macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Litsea cubeba (Lour.) Pers. has been traditionally used as a folk prescription for treating rheumatic diseases in China.

AIM OF THE STUDY

This study aimed to investigate the effects and underlying mechanism of LCA, a new type of dibenzyl butane lignin compound extracted from L. cubeba, on macrophage colony stimulating factor (M-CSF) plus receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation in mouse-derived bone marrow macrophages (BMMs).

MATERIAL AND METHODS

TRAP staining, TRAP enzyme activity assay and actin ring staining were applied to identify the effects of LCA on osteoclast differentiation. Protein expression of NFATc1, c-Fos and MMP-9, and phosphorylation of p65, Akt, JNK, ERK and p38 in RANKL-induced osteoclasts was determined using western blotting to investigate the underlying mechanism.

RESULTS

LCA significantly suppressed RANKL-induced osteoclast differentiation by inhibiting TRAP activity, decreasing the number of TRAP⁺ multinuclear osteoclasts and reducing the formation of F-actin ring without obvious cytotoxicity in BMMs. Moreover, LCA treatment strongly reduced protein expression of NFATc1, c-Fos and MMP-9, and attenuated the phosphorylation of p65, Akt, JNK, ERK and p38 in RANKL-stimulated BMMs.

CONCLUSIONS

LCA ameliorated RANKL-induced osteoclast differentiation via inhibition of Akt and MAPK signalings in BMMs, and may serve as a potential pro-drug for bone destruction prevention.

Caffeine-free hawk tea lowers cholesterol by reducing free cholesterol uptake and the production of very-low-density lipoprotein

Medicinal plants show important therapeutic value in chronic disease treatment. However, due to their diverse ingredients and complex biological effects, the molecular mechanisms of medicinal plants are yet to be explored. By means of several high-throughput platforms, here we show hawk tea extract (HTE) inhibits Niemann-Pick C1-like 1 (NPC1L1)-mediated free cholesterol uptake, thereby inducing the transcription of low-density lipoprotein receptor (LDLR) downstream of the sterol response element binding protein 2 (SREBP2) pathway. Meanwhile, HTE suppresses hepatocyte nuclear factor 4α (HNF4α)-mediated transcription of microsomal triglyceride transfer protein (MTP) and apolipoprotein B (APOB), thereby decreasing the production of very-low-density lipoprotein. The catechin EGCG ((-)-epigallocatechin gallate) and the flavonoids kaempferol and quercetin are identified as the bioactive components responsible for the effects on the NPC1L1-SREBP2-LDLR axis and HNF4α-MTP/APOB axis, respectively. Overall, hawk tea works as a previously unrecognized cholesterol-lowering agent in a multi-target and multi-component manner.

In vitro antimicrobial activity and phytochemical analysis of different solvent extracted samples from medicinally important Litsea glutinosa

The present research work investigate the antimicrobial activities of crude methanolic extracted samples from the leaves of Litsea glutinosa against different microorganisms through disc diffusion assay applied in two different concentrations of 1 and 2mg disc1. The tested microbial species included B. subtilis, E. coli, P. aeruginosa, K. pneumoniae and C. albicans. The crude methanolic extract was applied in two different concentrations of 1 and 2mg disc1. Analysis of the data revealed that crude methanolic extracted samples showed different ranges of antimicrobial activities against all the tested microbes at both concentrations. Maximum growth inhibition was measured against gram negative Pseudomonas aeruginosa followed by the fungal specie Candida albicans. In case of Petroleum extracted fractions maximum growth reduction was measured in Candida albicans at higher concentration. Similarly, growth inhibition was more in Pseudomonas aeruginosa at higher concentration of aqueous extracted samples. Different solvent extracted samples showed the presence of alkaloids, flavonoids, proteins, fats, oils, tannins, carbohydrates, sterols and saponins.

Lignans from the Twigs of Litsea cubeba and Their Bioactivities

Litsea cubeba, an important medicinal plant, is widely used as a traditional Chinese medicine and spice. Using cytotoxicity-guided fractionation, nine new lignans 1–9 and ten known analogues 10–19 were obtained from the EtOH extract of the twigs of L. cubeba. Their structures were assigned by extensive 1D- and 2D-NMR experiments, and the absolute configurations were resolved by specific rotation and a combination of experimental and theoretically calculated electronic circular dichroism (ECD) spectra. In the cytotoxicity assay, 7′,9-epoxylignans with feruloyl or cinnamoyl groups (compounds 7–9, 13 and 14) were selectively cytotoxic against NCI-H1650 cell line, while the dibenzylbutyrolactone lignans 17–19 exerted cytotoxicities against HCT-116 and A2780 cell lines. The results highlighted the structure-activity relationship importance of a feruloyl or a cinnamoyl moiety at C-9′ or/and C-7 ketone in 7′,9-epoxylignans. Furthermore, compound 11 was moderate active toward protein tyrosine phosphatase 1B (PTP1B) with an IC₅₀ value of 13.5 μM, and compounds 4–6, 11 and 12 displayed inhibitory activity against LPS-induced NO production in RAW264.7 macrophages, with IC₅₀ values of 46.8, 50.1, 58.6, 47.5, and 66.5 μM, respectively.

Two new terpenoid ester glycosides from the twigs of Litsea cubeba

A new sesquiterpenoid ester glycoside (1) and a new monoterpenoid ester glycoside (2) have been isolated from an ethanol extract of the twigs of Litsea cubeba. Their structures were elucidated by extensive 1D- and 2D-NMR experiments, and the absolute configurations were determined by chemical methods, specific rotation, and a combination of experimental and theoretically calculated electronic circular dichroism spectra. Compound 1 exhibited selective cytotoxicity against A549 and HCT-8 cell lines with the IC₅₀ values of 8.9 and 9.6 μM, respectively.

Discrimination of Aroma Characteristics for Cubeb Berries by Sensomics Approach with Chemometrics

The dried cubeb berries are widely used as medicinal herb and spicy condiment with special flavor. However, there is a significant definition discrepancy for cubeb berries. In this study, an efficient analytical method to characterize and discriminate two popular cubeb fruits (Litsea cubeba and Piper cubeba) was established. The aroma profiles of cubeb berries were evaluated by different extraction methods including hydro-distillation, simultaneous distillation/extraction, and solid-phase micro-extraction followed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). In total, 90 volatile compounds were identified by HD, SDE, and SPME combined with GC-MS. Principal component analysis was further applied and discriminated ambiguous cubeb berries by their unique aromas: Litsea cubeba was characterized by higher level of d-limonene (“fruit, citrus”), citral (“fruit, lemon”) and dodecanoic acid; α-cubebene (“herb”) was identified as a marker compound for Piper cubeba with higher camphor (“camphoraceous”), and linalool (“flower”). Flavor fingerprint combined with PCA could be applied as a promising method for identification of cubeb fruits and quality control for food and medicinal industries.

Comparison of Aroma Character Impact Volatiles of Thummong Leaves ( Litsea petiolata Hook. f.), Mangdana Water Beetle ( Lethocerus indicus), and a Commercial Product as Flavoring Agents in Thai Traditional Cooking

Thummong ( Litsea petiolata Hook. f.) is a tree native to southern Thailand. The leaves of this tree are highly aromatic and used to flavor Thai dishes in place of the traditional water beetle Mangdana ( Lethocerus indicus) for religious and cultural reasons. Total and aroma-active volatiles from both flavoring materials were compared using gas chromatography-olfactory (GC-O) and gas chromatography-mass spectrometry (GC-MS). The volatiles from Thummong leaves and the Mangdana water beetle were collected and concentrated using headspace solid-phase microextraction. A total of 23 and 25 aroma-active volatiles were identified in Thummong leaves and Mangdana, respectively. The major aroma-active volatiles in Thummong leaves consisted of 7 aldehydes, 5 ketones, and 3 esters. In contrast, the aroma-active volatiles in the water beetle consisted of 11 aldehydes, 3 esters, and 2 ketones. Both had ( E)-2-nonenal as the most intense aroma-active volatile. The water beetle character impact volatile ( E)-2-hexenyl acetate was absent in the leaves, but its aroma character was mimicked by 11-dodecen-2-one in the leaves, which was absent in the beetle. In addition, a commercial Mangdana flavoring was examined using GC-O and GC-MS and found to contain only a single aroma-active volatile, hexyl acetate. All three flavoring sources exhibited similar aroma characteristics but were produced from profoundly different aroma-active volatiles.

A review on phytochemical and pharmacological properties of Litsea coreana

CONTEXT

Litsea coreana H. Lév. (Lauraceae) is used as an ethnic herb or beverage in China. Substantial studies indicate that it contains a variety of compounds and shows diverse bioactivities with no toxicity.

OBJECTIVE

This review analyzes and summarizes the ethnopharmacological applications, phytochemistry, and pharmacological activities and molecular mechanisms of L. coreana.

METHODS

Related literature (from 1998 to 2016) was obtained and compiled via searching databases including Scopus, Web of Science, Google Scholar, CNKI and PubMed. Keywords (Litsea coreana, hawk tea, eagle tea and laoying cha) were used to select the articles.

RESULTS

Studies indicate that L. coreana contains characteristic polysaccharides, polyphenols, essential oils, and numerious flavonoids, which exhibit remarkable bioactivities, such as hepatoprotection, hyperglycaemia, anti-inflammation, antioxidation and antibacterial, through multiple molecular mechanisms.

CONCLUSION

This paper provides a systematic review on the phytochemicals and pharmacological activities of L. coreana which should be useful for further study and application of this medicinal herb.

DPPH Radical Scavenging and Postprandial Hyperglycemia Inhibition Activities and Flavonoid Composition Analysis of Hawk Tea by UPLC-DAD and UPLC-Q/TOF MSE

Hawk tea (Litsea coreana Lévl. var. Lanuginosa (Migo) Yen C. Yang & P.H. Huang), a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT), primary leaf tea (PLT) and mature leaf tea (MLT). In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD) method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME) of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE), ethyl acetate fraction (EA), n-butanol fraction (n-BuOH), and water fraction (WF)) on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg) group and the high dose (1 g/kg) group with oral administration of the ME of PLT were significantly lower than the control group. What's more, the inhibitory effect of ME of PLT and its EA and n-BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS) was used to identify the flavonoids in Hawk PLT, and a total of 20 flavonoids were identified or tentatively identified by comparing their retention times and accurate mass measurements with reference compounds or literature data. The bioactive flavonoid composition and DPPH radical scavenging activities present in different Hawk tea raw materials are quite different due to the different ontogenesis of these raw materials. Further studies on PLT showed that the substances in PLT ME could reduce the level of mouse postprandial blood glucose through inhibiting the activity of α-glucosidase.

A new N-methoxyl-carbonyl benzylisoquinoline from Litsea cubeba

A new benzylisoquinoline alkaloid (•)-N-methoxycarbonyl-norjuziphine (1) was isolated from Litsea cubeba. Its structure was identified by extensively spectroscopic techniques and confirmed by the single-crystal X-ray diffraction analysis. Compound 1 showed cytotoxicity against HL-60 and MCF-7 cells, with IC₅₀ values of 18.1 and 15.0 μM, respectively, comparable to 3.1 and 17.5 μM of the cisplatin (positive control).

Insecticidal activities of constituents of Litsea cubeba fruit extracts effective against the maize weevil (Coleoptera: Curculionidae)

In this study, we investigated the insecticidal activities, including contact toxicity, fumigant toxicity, and repellent activity, of Litsea cubeba fruit extracts against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The extracts, obtained by liquid-liquid extraction in n-hexane, ethyl acetate, chloroform, and water were analyzed by gas chromatography-mass spectrometry. Among the different extract types, chloroform extracts exhibited the strongest repellent, contact, and fumigant activities against S. zeamais. The main components of the chloroform extracts were identified as laurine (21.15%) and 2,6-diisopropyl aniline (16.14%), followed by chlorobutanol (10.54%), 3-O-methyl-N-acetyl-d-glucosamine (10.03%), and 6-methyl-5-hepten-2-one (8.33%). Among the identified components of the chloroform extracts, chlorobutanol showed the strongest fumigant toxicity (LD50 = 21.91 mg/liter), contact toxicity (LD50 = 54.25 µg/adult), and repellent activity against S. zeamais. These results indicate that L. cubeba fruit extracts possess natural insecticide-like activities against S. zeamais.

Bioactive Glycosides from the Twigs of Litsea cubeba

The air-dried twigs of Litsea cubeba, a traditional Chinese medicinal tree, afforded 10 new aromatic glycosides (1-10) and 26 known analogues. Their structures were assigned by extensive 1D and 2D NMR experiments, and the absolute configurations were resolved by chemical methods, electronic circular dichroism, specific rotation, and X-ray crystallographic analysis. Compound 4 is the first example of a naturally occurring homoneolignan glucoside. Compounds 4, 6-8, and the known neolignan glucosides (11, 12, and 14) at respective 10 μM concentrations were found to reduce acetaminophen-induced HepG2 cell injury with 30.5-46.0% inhibitions. Furthermore, compounds 12 and 15 demonstrated moderate inhibitory activities against HDAC1, with IC₅₀ values of 3.6 and 4.6 μM, respectively.

Flavonoids from Litsea japonica Inhibit AGEs Formation and Rat Lense Aldose Reductase In Vitro and Vessel Dilation in Zebrafish

In our ongoing efforts to identify effective naturally sourced agents for the treating of diabetic complications, two new (1 and 2) and 11 known phenolic compounds (3-13) were isolated from an 80 % ethanol extract of Litsea japonica leaves. The structures of the new compounds were established by spectroscopic and chemical studies. These isolates (1-13) were subjected to an in vitro bioassay evaluating their inhibitory activity on advanced glycation end products formation and rat lens aldose reductase activity. Of the compounds evaluated, the flavonoids (3, 4, 6-8, 11, and 12) markedly inhibited advanced glycation end products formation, with IC₅₀ values of 7.4-72.0 µM, compared with the positive control, aminoguanidine (IC₅₀ = 975.9 µM). In the rat lens aldose reductase assay, consistent with the inhibition of advanced glycation end products formation, the flavonoids (3, 4, 6-8, 11, and 12) exhibited considerable inhibition of rat lens aldose reductase activity, with IC₅₀ values of 1.1-12.5 µM. In addition, the effects of kaempferol (4) and tiliroside (7) on the dilation of hyaloid-retinal vessels induced by high glucose in larval zebrafish were investigated. Only kaempferol significantly reduced the diameters of high glucose-induced hyaloid-retinal vessels, by 52.2 % at 10 µM, compared with those in the high glucose-treated control group.

Anti-inflammatory constituents from the root of Litsea cubeba in LPS-induced RAW 264.7 macrophages

Context Litsea cubeba (Lour.) Pers. (Lauraceae) has long been used as a folk remedy in Traditional Chinese Medicine (TCM) for the treatment of rheumatic diseases. Previous studies from our laboratory indicated that L. cubeba extract showed anti-arthritic activity in rats. Objective To study L. cubeba chemically and biologically and to find the potential constituents responsible for its anti-arthritic effect. Materials and methods The compounds were isolated from the root of L. cubeba by column chromatography which eluted with PE:EtOAc gradient system, and the structures were elucidated by detailed spectroscopic data analysis; the anti-inflammatory activity of the isolated compounds was evaluated by lipopolysaccharide (LPS)-induced RAW 264.7 cells and the TNF-α and NO level were measured by ELISA (commercial kit); The iNOS and COX-2 mRNA expression were measured by RT-PCR and the phosphorylation of IκBα, IKKβ, P38 and Akt were determined by western blots. Results A novel 9-fluorenone, 1-ethoxy-3,7-dihydroxy-4,6-dimethoxy-9-fluorenone (1), together with 4 known compounds, namely pinoresinol (2), syringaresinol (3), 9,9'-O-di-(E)-feruloyl-meso-5,5'-dimethoxysecoisolariciresinol (4) and lyoniresinol (5) were isolated from the root of L. cubeba for the first time. The IC50 for NO inhibition on compounds 1 and 4 were 56.1 ± 1.2 and 32.8 ± 2.3 μM, respectively. The IC50 for TNF-α inhibition were 28.2 ± 0.9 and 15.0 ± 1.0 μM, respectively. Both 1 and 4 suppress mRNA expression of iNOS, COX-2 and protein phosphorylation of IκBα, IKKβ in LPS-induced RAW 264.7 cells. Discussion and conclusion Compounds 1 and 4 isolated from L. cubeba exhibited potent anti-inflammatory activity through the NF-κB signal pathway.

Ethnobotany, phytochemistry, and pharmacology of the genus Litsea: An update

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Litsea is one of the most diverse genera of evergreen trees or shrubs belong to Lauraceae, and comprises roughly 400 species of tree that are distributed abundantly throughout tropical and subtropical Asia, North and South America. Litsea species have been used globally in traditional medicine for the treatment of various diseases including influenza, stomach aches, diarrhea, diabetes, vomiting, bone pain, inflammation, illness related to the central nervous system and other ailments. The purpose of this review is to provide updated, comprehensive and categorized information on the ethnobotany, phytochemistry and pharmacological research of Litsea species in order to explore their therapeutic potential and evaluate future research opportunities.

MATERIALS AND METHODS

All the available information on Litsea species was actualised by systematically searching the scientific literatures including Chinese, Korean, Japanese, Indian, and South American herbal classics, library catalogs and scientific databases (PubMed, SciFinder, Web of Science, Google Scholar, VIP and Wanfang). The Plant List, International Plant Name index and Scientific Database of China Plant Species were used to validate scientific names.

RESULTS

407 secondary metabolites have been reported from Litsea species. Litsea Species are sources of secondary metabolites with interesting chemical structures (alkaloids, lactones, sesquiterpenes, flavonoids, lignans, and essential oils) and significant bioactivities. Crude extracts, fractions and phytochemical constituents isolated from Litsea show a wide spectrum of in vitro and in vivo pharmacological activities including anticancer, anti-inflammatory, antimicrobial, antioxidant, antidiabetic, anti-HIV, insecticidal, etc.

CONCLUSIONS

From data collected in this review, the genus Litsea comprises a wide range of therapeutically promising and valuable plants, and has attracted much attention owing to its multiple functions. Many traditional uses of Litsea species have now been validated by modern pharmacology research. Deep and systematic phytochemical investigation of the genus Litsea and the pharmacological properties, especially its mechanism of action and toxicology, to illustrate its ethnomedicinal use, explore the therapeutic potential and support further health-care product development will undoubtedly be the focus of further research. Therefore, detailed and extensive studies and clinical evaluation of Litsea species should be carried out in future for the safety approval of therapeutic applications.

Essential Oil Compositions and Antimicrobial Activities of Various Parts of Litsea cubeba from Taiwan

The essential oils of leaves, fruits, flowers, stems and twigs of Litsea cubeba were extracted by hydrodistillation. A total of 53, 50, 76, 94 and 90 compounds were identified from the leaf, fruit, flower, stem and twig oils, respectively, and their yields were 13.9 ± 0.09, 4.0 ± 0.03, 10.4 ± 0.05, 0.09 ± 0.01 and 0.4 ± 0.02 mL/100 g of the oven-dried (o.d.) materials, respectively. The main component in the leaf, flower and twig oils was 1,8-cineole, whereas in the fruit oil it was citral, and in the stem oil limonene, citronellal, and citronellol. When tested for their antibacterial activities using the paper disc diffusion method, oils from all parts showed excellent activities, particularly the fruit oil. When the oils were infused onto filter paper and tested for their antimicrobial paper capability according to the JIS L 1902 method, the fruit oil exhibited excellent antimicrobial activities. Citral was deemed the main cause of the antimicrobial activity. With the multiplicity of contagious diseases and their prevalence in hospitals, these essential oils present a potentially good choice as antibacterial agents. We think that the essential oils of this species are capable of multipurpose applications.

Chemical constituents from the roots and stems of Litsea cubeba

A new monoterpene and a new lignan, named litsecols A and B (1 and 2), respectively, together with nine known compounds (3-11), were isolated in a continuous investigation on the roots and stems of Litsea cubeba. Their structures were elucidated on the basis of extensive spectroscopic data analysis, and the absolute configuration of 1 was resolved by X-ray diffraction analysis. Compounds 2-5 and 7-9 showed significant inhibitory activity against nitric oxide (NO) production in lipopolysaccharide (LPS)-induced murine microglial (Bv-2) cell line. Compounds 10 and 11 exhibited significant neuroprotective effect against hydrogen peroxide-induced oxidative damage in rat adrenal pheochromocytoma (PC12) cell line.

Anti-Osteoarthritic Effects of the Litsea japonica Fruit in a Rat Model of Osteoarthritis Induced by Monosodium Iodoacetate

Osteoarthritis (OA) is a degenerative chronic disease that affects various tissues surrounding the joints, such as the subchondral bone and articular cartilage. The onset of OA is associated with uncontrolled catabolic and anabolic remodeling processes of the joints, including the cartilage and subchondral bone, to adapt to local biological and biochemical signals. In this study, we determined whether 70% ethanolic (EtOH) extract of Litsea japonica fruit (LJFE) had beneficial effects on the articular cartilage, including structural changes in the tibial subchondral bone, matrix degradation, and inflammatory responses, in OA by using a rat model of monosodium iodoacetate-induced OA. Our results showed that administration of LJFE increased the bone volume and cross-section thickness, but the mean number of objects per slice in this group was lower than that in the OA control (OAC) group. In addition, the LJFE decreased the expression of inflammatory cytokines. Compared to the OAC group, the group treated with high doses of LJFE (100 and 200 mg/kg) showed a more than 80% inhibition of the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases. Our results suggest that LJFE can be used as a potential anti-osteoarthritic agent.

Chemotype of Litsea cubeba Essential Oil and Its Bioactivity

The essential oils from different parts of Litsea cubeba, collected from the highlands of Sarawak, were isolated and their chemical compositions analyzed. This study demonstrated significant variations in the chemical compositions and the chemical profiles of the volatiles and could provide valuable supplementary information on the geographical variations of the species. The fruit essential oil was dominated by citronellal, d-limonene and citronellol, while the leaf oil was high in eucalyptol and a-terpineol. High concentrations of citronellal and citronellol in both the root and bark oils were identified. In the stem, the oil was dominated by eucalyptol, d-limonene and α-terpineol. The activity of the oils against brine shrimp larvae, bacteria, yeast and fungi was determined. The oils were toxic against brine shrimp larvae with LC50 values ranging from 25.1 - 30.9 μL/mL. The oils also demonstrated a wide spectrum of inhibition against microorganisms with inhibition zones between 19.5 - 46.7 mm against Gram-positive bacteria and 10.5 - 90.0 mm against yeast and fungi. However, the oils were not active against Gram-negative bacteria.

The genus Litsea in traditional Chinese medicine: an ethnomedical, phytochemical and pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Litsea, mainly distributed in the tropical and subtropical regions, has been used in traditional and indigenous Chinese medicines for the treatment of diarrhea, stomachache, dyspepsia, gastroenteritis, diabetes, edema, cold, arthritis, asthma, pain, traumatic injury, etc. for a long history. The present review aims to provide a comprehensive summary on the ethnomedical uses, phytochemistry, and pharmacology of the Litsea species used in traditional Chinese medicine (TCM). Based on these data, evidences supporting their ethnopharmacological effectiveness are illustrated, and opportunities for the future research and development as well as the therapeutic potential of this genus are analyzed to highlight the gaps in our knowledge that deserves further investigation.

MATERIAL AND METHODS

Information on the Litsea species was collected via electronic search (using Pubmed, SciFinder, Google Scholar, Web of Science and CNKI) and a library search for articles published in peer-reviewed journals. Furthermore, information was also obtained from some local books on ethnopharmacology.

RESULTS

Twenty plants of the genus Litsea are found to be important traditional medicines in China, and have a long medicinal application for diarrhea, stomachache, dyspepsia, gastroenteritis, diabetes, edema, cold, arthritis, asthma, pain, traumatic injury, etc. Over 200 ingredients have been identified from these 20 Litsea species used in TCM, and flavonoids, terpenoids and alkaloids are considered as the characteristic and bioactive constituents. The crude extracts and the isolated metabolites of these medicinal plants have exhibited some in vitro and in vivo pharmacological effects, including antimicrobial, hepatoprotection, anti-inflammatory, antiasthmatic, immunomodulation, anti-diabetic, anticholelithogenic, as well as function on central nervous system, etc.

CONCLUSIONS

The extensive literature survey reveals Litsea species to be a group of important medicinal plants used for the ethnomedical treatment of gastrointestinal diseases, diabetes, inflammatory disorders, and microbial infection in TCM. Pharmacological investigations have supported the use of some Litsea species in the traditional medicines. In addition, further researches targeting individual ingredients responsible for the pharmacological effects, as well as their mechanisms of action are necessary. The outcome of these studies will further support the therapeutic potential of the genus Litsea, and provide convincing evidences to its future clinical applications in modern medicine.

Naturally produced citral can significantly inhibit normal physiology and induce cytotoxicity on Magnaporthe grisea

Given the importance of finding alternatives to synthetic fungicides, the antifungal effects of natural product citral on six plant pathogenic fungi (Magnaporthe grisea, Gibberella zeae, Fusarium oxysporum, Valsa mali, Botrytis cinerea, and Rhizoctonia solani) were determined. Mycelial growth rate results showed that citral possessed high antifungal activities on those test fungi with EC50 values ranging from 39.52 to 193.00 µg/mL, which had the highest inhibition rates against M. grisea. Further action mechanism of citral on M. grisea was carried out. Citral treatment was found to alter the morphology of M. grisea hyphae by causing a loss of cytoplasm and distortion of mycelia. Moreover, citral was able to induce an increase in chitinase activity in M. grisea, indicating disruption of the cell wall. These results indicate that citral may act by disrupting cell wall integrity and membrane permeability, thus resulting in physiology changes and causing cytotoxicity. Importantly, the inhibitory effect of citral on M. grisea appears to be associated with its effects on mycelia reducing sugar, soluble protein, chitinase activity, pyruvate content, and malondialdehyde content.

[Aporphine alkaloids from Litsea greenmaniana]

A new aporphine alkaloid (1), together with five known analogues (2-6), has been isolated from the branch of Litsea greenmaniana by using various chromatographic techniques. Their structures were identified by spectroscopic data analysis ( MS, IR, 1D and 2D NMR) as 2,9-dihydroxy-1,10-dimethoxy-4,5-dihydro-7-oxoaporphine (1), laurotetanine (2), N-methyllaurotetanine (3), isodomesticine (4), isocorydine (5), and norisocorydine (6). Compound 1 was a new compound, and compounds 2-6 were obtained from this plant for the first time.

Antibacterial activity and kinetics of Litsea cubeba oil on Escherichia coli

Litsea cubeba oil is extracted from the fresh fruits of Litsea cubeba by distillation. In this study, its chemical constituents, antibacterial activity, kinetics and effects against Escherichia coli were studied. Its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 0.125% (v/v) by toxic food method. Moreover, the antibacterial kinetic curves indicated 0.0625% (v/v) of litsea cubeba oil was able to prolong the growth lag phase of E. coli cells to approximate 12 hours while 0.125% (v/v) of litsea cubeba oil was able to kill the cells completely. Furthermore, transmission electron microscope (TEM) observation showed most E. coli cells treated with 0.125% (v/v) of litsea cubeba oil were killed or destroyed severely within 2 hours. The litsea cubeba oil might penetrate and destroy the outer and inner membrane of E. coli cells. Thus many holes and gaps were observed on the damaged cells, which led to their death eventually. The antibacterial effects of litsea cubeba oil mainly attributed to the presence of aldehydes, which accounted for approximately 70% in its whole components analyzed by GC/MS. Based on the antimicrobial properties, litsea cubeba oil would have a broad application in the antimicrobial industry.

[Alkaloids from roots and stems of Litsea cubeba]

A phytochemical investigation on the roots and stems of Litsea cubeba led to the isolation of seven isoquinolone alkaloids. By spectroscopic analysis and comparison of their 1H and 13C-NMR data with those in literatures, these alkaloids were identified as (+)-norboldine (1), (+)-boldine (2), (+)-reticuline (3), (+)-laurotetanine (4), (+)-isoboldine (5), (+)-N-methyl-laurotetanine (6), and berberine (7), respectively. Among them, 7 was isolated from the genus for the first time. The evaluation of these compounds showed weak anti-inflammatory activity against NO production in RAW 267.4 and BV-2 cells.

Fumigant, contact, and repellent activities of essential oils against the darkling beetle, Alphitobius diaperinus

The fumigant, contact, and repellent activities of four essential oils extracted from Citrus limonum (Sapindales: Rutaceae), Litsea cubeba (Laurales: Lauraceae), Cinnamomum cassia, and Allium sativum L. (Asparagales: Alliaceae) against 6th instars and adults of the darkling beetle, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), one of the main pests of materials and products of Juncus effuses L. (Poales: Juncaceae) during the storage period, were assayed, and chemical ingredients were analyzed with gas chromatography-mass spectrometry in this study. While the major ingredients found in C. limonum and C. cassia were limonene and (E)-cinnamaldehyde, the main constituents of L. cubea were D-limonene, (E)-3,7-dimethyl-,2,6-octadienal, (Z)-3,7-dimethyl,2 ,6-octadienal, and diallyl disulphide (18.20%), while the main constituents of and A. sativum were di-2-propenyl trisulfide and di-2-propenyl tetrasulfide. The fumigation activities of A. sativum and C. limonum on A. diaperinus adults were better than those of the other two essential oilss. The toxicities of A. sativum and C. limonum were almost equitoxic at 96 hr after treatment. Essential oils from Allium sativum and L. cubeba also showed good contact activities from 24 hr to 48 hr, and toxicities were almost equitoxic 48 hr posttreatment. The repellent activities of A. sativum and L. cubeba oils on 6th instars were also observed, showing repellence indexes of 90.4% and 88.9% at 12 hr after treatment, respectively. The effects of A. sativum on AChE activity of 6th instars of A. diaperinus were strongest compared to the other essential oils, followed by C. limonum, L. cubeba, and C. cassia. These results suggest that the essential oils of C. limonum and A. sativum could serve as effective control agents of A. diaperinus.

A new diterpene from Litsea cubeba fruits: structure elucidation and capability to induce apoptosis in HeLa cells

A new diterpene, identified as (+)-6-(4-hydroxy-4-methyl-2-pentenoyl)-4,6-dimethyl-5-(3-methyl-2-butenyl)-1,3-cyclohexadienecarbaldehyde (1, cubelin), was isolated from a methanol extract of Litsea cubeba fruits by normal phase column chromatography and purified by preparative HPLC. The structure elucidation was conducted by spectroscopic methods (UV, IR, ESI-TOF-MS, 1-D and 2-D NMR). Cubelin exhibited activity against HeLa cell viability and proliferation. The cells also exhibited changes in nuclear morphology which are hallmarks of apoptotic cell death. The presence of cleaved caspase-3/-7, caspase-8 and caspase-9 in the cubelin treated population indicated the potential of the compound to induce apoptosis in HeLa cells via both intrinsic and extrinsic pathways.

[Total flavonoids of litsea coreana decreases the cytotoxicity of oxaliplatin in TM3 Leydig cells via enhancing the function of gap junction]

OBJECTIVE

To investigate the effects of total flavonoids of Litsea Coreana (TFLC) on the gap junction (GJ) intercellular communication in TM3 testicular Leydig cells and whether TFLC can reduce the cytotoxicity of oxaliplatin (OHP) in vitro.

METHODS

We detected the effect of TFLC on the dye spread of the in vitro cultured TM3 cells by parachute assay, observed changes in the expression of connexin 43 (Cx43) total protein in the TFLC-treated TM3 cells by Western blot, and determined the effects of TFLC on the expression of Cx43 on the membrane of the TM3 cells by immunofluorescence assay and on the cytotoxicity of OHP by MTT assay.

RESULTS

TFLC obviously enhanced the GJ function with the increasing of the TFLC concentration in the TM3 cells. Western blot and immunofluorescence assay confirmed that TFLC significantly enhanced the expression of Cx43 total protein and Cx43 expression on the membrane of the TM3 cells. MTT assay showed that at a high cell density (confluent with GJ formation), 20 microg/ml TFLC enhanced the GJ function of the TM3 cells and reduced the cytotoxicity of OHP (P < 0.05), while at a low density (preconfluent with no GJ formation), TFLC exhibited no effect on the cytotoxicity of OHP (P > 0.05).

CONCLUSION

TFLC increases the Cx43 expression and GJ function in normal TM3 Leydig cells, and the enhancement of GJ function reduces the cytotoxicity of OHP.

[A phytochemical and pharmacological advance on medicinal plant Litsea cubeba (Lauraceae)]

Litsea cubeba is one of aromatic medicinal plant belonging to family Lauraceae. The roots, stems and fruits of L. cubeba have been widely applied as folk medicines in some districts in China for relieving rheumatism and cold, regulating Qi (meridian) to alleviate pain. Previous studies revealed that this species contains major alkaloids, in specific aporphines, and minor flavonoids, lignans as well. Related pharmacological investigations demonstrated its activities and clinical applications on cardiovascular diseases, anti-cancer, against rheumatoid arthritis, relieving asthma and anti-allergic effects, as anti-oxidants, and so on. As an effort for further exploration of this bioactive ingredients and potential drug development, this paper summarizes most phytochemical and pharmacological results. Further, future prospects are also included.

Hydrothermal liquefaction of Litsea cubeba seed to produce bio-oils

Hydrothermal liquefaction (HTL) of Litsea cubeba seed was conducted over different temperature (250-350°C), time (30-120 min), reactor loading (0.5-4.5 g) and Na2CO3 loading (0-10 wt.%). Temperature was the most influential factor affecting the yields of product fractions. The highest bio-oil yield of 56.9 wt.% was achieved at 290°C, 60 min, and reactor loading of 2.5 g. The presence of Na2CO3 favored the conversion of the feedstock but suppressed the production of bio-oil. The higher heating values of the bio-oil were estimated at around 40.8 MJ/kg. The bio-oil, which mainly consisted of toluene, 1-methyl-2-(1-methylethyl)-benzene, fatty acids, fatty acid amides, and fatty acid esters, had a smaller total acid number than that of the oil obtained from the direct extraction of the starting material. It also contained nitrogen that was far below the bio-oil produced from the HTL of microalgae, making it more suitable for the subsequent refining.

Total synthesis of 3,7-dimethyl-7-hydroxy-2-octen-1,6-olide and 3,7-dimethyl-2,6-octadien-1,6-olide

3,7-Dimethyl-7-hydroxy-2-octen-1,6-olide and 3,7-dimethyl-2,6-octadien-1,6-olide, the natural bioactive compounds isolated from the fruit of Litsea cubeba and the liverwort Plagiochila rutilans, were totally synthesized using easily available cis-geraniol as raw material in short, convenient, and low-cost, five-step reactions including three steps of oxidation, cyclization, and dehydration, with an overall yield of 47.5% and 37.3%.

[Chemical constituents from Litsea greenmaniana]

A new compound (1), together with ten known compounds (2-11), have been isolated from the branch of Litsea greenmaniana by using various chromatographic techniques. Their structures were identified by spectroscopic data analysis as N-trans-3, 4-methylenecinnamoyl-3-methoxytyramine (1), N-trans-feruloyltyramine (2), N-cis-feruloyltyramine (3), (+)-sesamin (4), (+)-pinoresinol(5), cinnamophilin (6), dihydrodehydrodiconiferyl alcohol (7), benzoic acid (8), 4-hydroxy ethylbenzoate (9), p-hydroxybenzaldehyde(10), and 4-hydroxy-3-methoxy-benzyl alcohol (11). Compound 1 was a new compound, and compounds 2-11 were obtained from this plant for the first time.

Two new dihydrostilbenoid glycosides isolated from the leaves of Litsea coreana and their anti-inflammatory activity

Two new dihydrostilbenoid glycosides, named 5-(2-phenylethyl)-3-hydroxyphenol-1-O-beta-D-glucopyranoside (1) and 6-(2-phenylethyl)-2,4-dihydroxy benzoic acid-2-O-beta-D-glucopyranoside (2), together with two known compounds, were isolated from the leaves of Litsea coreana Levl.. Their structures were established on the basis of NMR spectroscopic, MS and chemical data. Biological tests revealed that 1-3 exhibited moderate anti-inflammatory activity through an inhibitory effect on TNF-alpha, IL-1 production from RAW264.7 cell line activated with lipopolysaccharides (LPS).

Mosquito (Diptera: Culicidae) repellency field tests of essential oils from plants traditionally used in Laos

Essential oils of Hyptis suaveolens (Lamiaceae), Croton roxburghii (Euphorbiaceae), and Litsea cubeba (Lauraceae) were tested in the field near Vientiane city, Lao PDR, on humans for repellent activity against mosquitoes. Landing mosquitoes were collected and later identified. The most abundant mosquitoes captured belonged to the genera Armigeres, Culex, and Aedes. All the plant oils tested at concentrations of 1.7 microg/cm(2), 3.3 microg/cm(2), and 6.3 microg/cm(2) were significantly more mosquito repellent than the negative control. Croton oil was significantly repellent against mosquitoes of the three genera at the highest (6.3 microg/cm(2)) concentration tested. Litsea oil was significantly repellent against Armigeres at all (1.7 microg/cm(2), 3.3 microg/cm(2), and 6.3 microg/cm(2)) concentrations tested. Hyptis oil was significantly repellent against Armigeres at 3.3 microg/cm(2) and 6.3 microg/cm(2) and against Culex at 1.7 microg/cm(2) and 6.3 microg/cm(2). The oils were analyzed for chemical content of volatiles, mainly terpenes. Main constituents were beta-pinene, sabinene, and 1,8-cineol from oils of the green parts of H. suaveolens; alpha-pinene, beta-pinene, and alpha-phellandrene from fresh bark of C. roxburghii; and alpha-pinene, beta-phellandrene, sabinene, and 1,8-cineol from fresh fruits of L. cubeba.

Vapor of volatile oils from Litsea cubeba seed induces apoptosis and causes cell cycle arrest in lung cancer cells

Non-small cell lung carcinoma (NSCLC) is a major killer in cancer related human death. Its therapeutic intervention requires superior efficient molecule(s) as it often becomes resistant to present chemotherapy options. Here we report that vapor of volatile oil compounds obtained from Litsea cubeba seeds killed human NSCLC cells, A549, through the induction of apoptosis and cell cycle arrest. Vapor generated from the combined oils (VCO) deactivated Akt, a key player in cancer cell survival and proliferation. Interestingly VCO dephosphorylated Akt at both Ser(473) and Thr(308); through the suppression of mTOR and pPDK1 respectively. As a consequence of this, diminished phosphorylation of Bad occurred along with the decreased Bcl-xL expression. This subsequently enhanced Bax levels permitting the release of mitochondrial cytochrome c into the cytosol which concomitantly activated caspase 9 and caspase 3 resulting apoptotic cell death. Impairment of Akt activation by VCO also deactivated Mdm2 that effected overexpression of p53 which in turn upregulated p21 expression. This causes enhanced p21 binding to cyclin D1 that halted G1 to S phase progression. Taken together, VCO produces two prong effects on lung cancer cells, it induces apoptosis and blocked cancer cell proliferation, both occurred due to the deactivation of Akt. In addition, it has another crucial advantage: VCO could be directly delivered to lung cancer tissue through inhalation.

Chemical composition of essential oils of Litsea cubeba harvested from its distribution areas in China

Litsea cubeba (Lour.) Pers. is a promising industrial crop with fruits rich in essential oils. The chemical composition of essential oils of L. cubeba (EOLC) were determined for fruits harvested from eight regions in China. The overall essential oil content, obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), ranged from 3.04% to 4.56%. In total, 59 compounds were identified, the dominant components being monoterpenes (94.4-98.4%), represented mainly by neral and geranial (78.7-87.4%). D-Limonene was unexpectedly a lesser constituent (0.7-5.3%) in fruits, which differed from previous reports (6.0-14.6%). Several components were only detected in certain regions and compounds such as o-cymene and eremophilene have never before been reported in EOLC. These results demonstrate significant regional variation in the chemical composition of EOLC. This investigation provides important information with regard to the bioactivity, breeding work and industrial applications of L. cubeba.

Composition and antimicrobial activity of the leaf and twig oils of Litsea acutivena from Taiwan

The chemical composition, and antimicrobial and anti-wood-decay fungal activities of the essential oils isolated from the leaves and twigs of Litsea acutivena of Taiwan were investigated. The essential oils from the fresh leaves and twigs were isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Ninety-five and fifty-two compounds were identified in the leaf and twig oils, respectively. The main components of the leaf oil were gamma-patchoulene (11.0%), delta-cadinene (6.3%), trans-muurola-3,5-diene (5.9%), and beta-selinene (5.3%), whereas the main components of the twig oil were tau-cadinol (13.1%), beta-selinene (9.6%), trans-beta-ocimene (6.2%) and alpha-cadinol (7.7%). Bioactivity studies demonstrated that twig oil had excellent antimicrobial and anti-wood-decay fungal activities, superior to those of the leaf oil. For the antimicrobial and anti-wood-decay fungal activities of the twig oil, the active compounds were determined to be tau-cadinol and alpha-cadinol.

Novel cytotoxic chalcones from Litsea rubescens and Litsea pedunculata

Two novel flavonoids with chalcone skeleton, together with seven known flavonoids, were isolated from the stem barks of Litsea rubescens and Litsea pedunculata. The structures of the new compounds were elucidated on the basis of spectral methods including IR, UV, 1D and 2D NMR. The new chalcones were found to contain the rare epoxy or ethylidenedioxy group. This is the first report on the presence of chalcone in the plant genus Litsea. The cytotoxic potential of two new chalcones was evaluated in vitro against three human tumor cell lines. Both new chalcones displayed potent cytotoxic activities against myeloid leukaemia (HL-60) and epidermoid carcinoma (A431) cell lines and more active than cisplatin (DDP). Interestingly, compound 1 exhibited cytotoxic activity against HL-60 with IC(50) value 2.1-fold more sensitive to DDP.