A deep learning LSTM-based approach for forecasting annual pollen curves: Olea and Urticaceae pollen types as a case study.

Airborne pollen can trigger allergic rhinitis and other respiratory diseases in the synthesised population, which makes it one of the most relevant biological contaminants. Therefore, implementing accurate forecast systems is a priority for public health. The current forecast models are generally useful, but they falter when long time series of data are managed. The emergence of new computational techniques such as the LSTM algorithms could constitute a significant improvement for the pollen risk assessment. In this study, several LSTM variants were applied to forecast monthly pollen integrals in Málaga (southern Spain) using meteorological variables as predictors. Olea and Urticaceae pollen types were modelled as proxies of different annual pollen curves, using data from the period 1992-2022. The aims of this study were to determine the LSTM variants with the highest accuracy when forecasting monthly pollen integrals as well as to compare their performance with the traditional pollen forecast methods. The results showed that the CNN-LSTM were the most accurate when forecasting the monthly pollen integrals for both pollen types. Moreover, the traditional forecast methods were outperformed by all the LSTM variants. These findings highlight the importance of implementing LSTM models in pollen forecasting for public health and research applications.

Target-Guided Isolation and Purification of Antioxidants from Urtica laetevirens Maxim. by HSCCC Combined with Online DPPH-HPLC Analysis.

Urtica laetevirens Maxim. is used extensively in traditional Chinese medicine (TCM) for its potent antioxidative properties. In this study, three antioxidants were purified from U. laetevirens. using HSCCC guided by online DPPH-HPLC analysis. Firstly, the online DPPH-HPLC analysis was performed to profile out the antioxidant active molecules in U. laetevirens. The ultrasonic-assisted extraction conditions were optimized by response surface methodology and the results showed the targeted antioxidant active molecules could be well enriched under the optimized extraction conditions. Then, the antioxidant active molecules were separated by high-speed countercurrent chromatography ethyl acetate/n-butanol/water (2:3:5, v/v/v) as the solvent system. Finally, the three targets including 16.8 mg of Isovitexin, 9.8 mg of Isoorientin, and 26.7 mg of Apigenin-6,8-di-C-ß-d-glucopyranoside were obtained from 100 mg of sample. Their structures were identified by 1H NMR spectroscopy.

Bioactive Molecules from Myrianthus arboreus, Acer rubrum, and Picea mariana Forest Resources.

Forest trees are the world's most important renewable natural resources in terms of their dominance among other biomasses and the diversity of molecules that they produce. Forest tree extractives include terpenes and polyphenols, widely recognized for their biological activity. These molecules are found in forest by-products, such as bark, buds, leaves, and knots, commonly ignored in forestry decisions. The present literature review focuses on in vitro experimental bioactivity from the phytochemicals of Myrianthus arboreus, Acer rubrum, and Picea mariana forest resources and by-products with potential for further nutraceutical, cosmeceutical, and pharmaceutical development. Although these forest extracts function as antioxidants in vitro and may act on signaling pathways involved in diabetes, psoriasis, inflammation, and skin aging, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods. Traditional forest management systems focused on wood must evolve towards a holistic approach, allowing the use of these extractives for developing new value-added products.

Recovery of Polyphenolic Compounds and Vitamins from the Stinging Nettle Leaves: Thermal and Behavior and Biological Activity of Obtained Extracts.

Stinging nettle (SN) is an extraordinary plant from the Urticaceae botanical family. It is well-known and widely used in food and folk medicine to treat different disorders and diseases. This article aimed to study the chemical composition of SN leaves extracts, i.e., polyphenolic compounds and vitamins B and C, because many studies ascribed high biological potency to these compounds and their significance in the human diet. Besides the chemical profile, the thermal properties of the extracts were studied. The results confirmed presence of many polyphenolic compounds and vitamins B and C. It also showed that the chemical profile closely correlated with the applied extraction technique. The thermal analysis showed that analyzed samples were thermally stable up to about 160 °C. Thermal degradation of samples UAE, MAE, and MAC took place in four steps, and sample SE in three steps. Altogether, results confirmed the presence of health-beneficial compounds in stinging nettle leaves and indicated the possible application of its extract in pharmaceutical and food industries as both a medicinal and food additive.

The potential of traditionally used medicinal plants for the synthesis of selenium nanoparticles.

Selenium nanoparticles (SeNPs) have the potential to be used in many applications. In recent years green synthesis using plant extracts has gained popularity, due to the use of non-toxic solvents. In this work, the application of plantain (Plantago lanceolata L.), yarrow (Achilea millefolium L.) and nettle (Urtica dioica L.) in the synthesis of SeNPs is presented. The obtained nanoparticles were characterized in terms of size and antioxidant activity. A strong correlation between the dimensions of synthesized nanoparticles and their ability to scavenge hydroxyl radicals was established.

Three first records of stick insects attacking plants (Inseect: Phasmida) in Tibet / Três primeiros registros de insetos-pau atacando plantas (Inseect: Phasmida) no Tibet

Except for a few stick insects that are economically valuable, most species be considered to be forest pests, so it is extremely important to obtain plant host-use information of more stick insects. In this paper, the plant hosts of three species of stick insects were recorded for the first time. We also discovered these stick insects can feed upon the flowers or leaves of plants. Lopaphus unidentatus (Chen & He, 1995) (Phasmida: Lonchodidae) attacked Hypericum choisianum Wall. ex N. Robson, 1973 (Hypericaceae), Leurophasma dolichocercum Bi, 1995 (Phasmida: Aschiphasmatidae) attacked Antenoron filiforme (Thunb.) Roberty & Vautier, 1964 (Polygonaceae) and Megalophasma granulatum Bi, 1995 (Phasmida: Lonchodidae) attacked Debregeasia orientalis C. J. Chen, 1991 (Urticaceae). Finally, we were lucky enough to also obtain photographs of them mating and feeding.

Exceto por alguns insetos-pau que são economicamente valiosos, a maioria das espécies pode ser considerada praga florestal, por isso é extremamente importante obter informações sobre o uso de hospedeiros de plantas de mais insetos-pau. Neste artigo, as plantas hospedeiras de três espécies de bicho-pau foram registradas pela primeira vez. Também descobrimos que esses bichos-pau podem se alimentar de flores ou folhas de plantas. Lopaphus unidentatus (Chen & He, 1995) (Phasmida: Lonchodidae) atacou a parede de Hypericum choisianum. ex N. Robson, 1973 (Hypericaceae), Leurophasma dolichocercum Bi, 1995 (Phasmida: Aschiphasmatidae) atacou Antenoron filiforme (Thunb.) Roberty & Vautier, 1964 (Polygonaceae) e Megalophasma granulatum Bi, 1995 (Phasmida: Lonchodidae orientaled) atacou Chen, 1991 (Urticaceae). Finalmente, tivemos a sorte de também obter fotos deles se acasalando e se alimentando.

Ethnomedicinal Uses, Geographical Distribution, Botanical Description, Phytochemistry, Pharmacology, and Quality Control of Laportea bulbifera (Sieb. et Zucc.) Wedd.: A Review.

Laportea bulbifera (Sieb. et Zucc.) Wedd. (L. bulbifera) is a significant plant in the Laportea genus. Traditionally, it has been used in ethnomedicine for treating various conditions such as rheumatic arthralgia, fractures, falling injuries, nephritis dropsy, limb numbness, pruritus, fatigue-induced internal imbalances, and irregular menstruation. Modern pharmacological studies have confirmed its therapeutic potential, including anti-inflammatory, immunosuppressive, analgesic, and anti-rheumatoid arthritis properties. To gather comprehensive information on L. bulbifera, a thorough literature search was conducted using databases like Web of Science, PubMed, ProQuest, and CNKI. This review aims to provide a comprehensive understanding of L. bulbifera, covering various aspects such as ethnomedicinal uses, geographical distribution, botanical description, phytochemistry, pharmacology, and quality control. The goal is to establish a solid foundation and propose new research avenues for exploring and developing potential applications of L. bulbifera. So far, a total of one hundred and eighty-nine compounds have been isolated and identified from L. bulbifera, including flavonoids, phenolics, nitrogen compounds, steroids, terpenoids, coumarins, phenylpropanoids, fatty acids and their derivatives, and other compounds. Notably, flavonoids and fatty acids have demonstrated remarkable antioxidant and anti-inflammatory properties. Additionally, these compounds show promising potential in activities such as analgesia, hypoglycemia, and hypolipidemia, as well as toxicity. Despite extensive fundamental studies on L. bulbifera, further research is still needed to enhance our understanding of its mechanism of action and improve quality control. This requires more comprehensive investigations to explore the specific material basis, uncover new mechanisms of action, and refine quality control methods related to L. bulbifera. By doing so, we could contribute to the further development and utilization of this plant.

[Uptake and transport of Laportea bulbifera extract in Caco-2 cell model].

Laportea bulbifera extract is effective in resisting inflammation and shows a good therapeutic effect on rheumatoid arthritis in rats. However, the absorption characteristics of active components in L. bulbifera extract in Caco-2 cells are still unclear, which limits the in-depth development of L. bulbifera resources. The purpose of this study was to investigate the absorption and transport mechanism of the active components of L. bulbifera extract in the Caco-2 cell model and explore the effects of different factors(concentration, time, pH value, temperature, and efflux transporter inhibitor) on its uptake and transport. The results showed that L. bulbifera extract at the concentration of 2.0-8.0 mg·mL~(-1) showed no toxicity to Caco-2 cells. The uptake and transport of L. bulbifera extract in the Caco-2 cell model were concentration-dependent and time-dependent. The main absorption mechanism was passive diffusion, and acidic condition(pH 5.0-6.0) and 37 ℃ were more favorable for drug absorption. P_(app)>1.0×10~(-6 )cm·s~(-1) of each component indicated that L. bulbifera was a moderately absorbed drug. P-gp, MRP2, and BCRP were not involved in its uptake and transport.

Hydroethanolic Extract of Urtica dioica L. (Stinging Nettle) Leaves as Disaccharidase Inhibitor and Glucose Transport in Caco-2 Hinderer.

Herbal treatment for diabetes mellitus is widely used. The pharmacological activity is thought to be due to the phenolic compounds found in the plant leaves. The present study aims to investigate the phytochemical composition of Urtica dioica (UD) hydroethanolic extract and to screen its antidiabetic activity by disaccharidase hindering and glucose transport in Caco-2 cells. The results have shown that a total of 13 phenolic compounds in this work, viz. caffeic and coumaric acid esters (1, 2, 4-7, 10), ferulic derivative (3), and flavonoid glycosides (8, 9, 11-13), were identified using HPLC-DAD-ESI/MS2. The most abundant phenolic compounds were 8 (rutin) followed by 6 (caffeoylquinic acid III). Less predominant compounds were 4 (caffeoylquinic acid II) and 11 (kaempferol-O-rutinoside). The UD hydroethanolic extract showed 56%, 45%, and 28% (1.0 mg/mL) inhibition level for maltase, sucrase, and lactase, respectively. On the other hand, glucose transport was 1.48 times less at 1.0 mg/mL UD extract compared with the control containing no UD extract. The results confirmed that U. dioica is a potential antidiabetic herb having both anti-disaccharidase and glucose transport inhibitory properties, which explained the use of UD in traditional medicine.

[Potential pharmacodynamic substances of Laportea bulbifera in treatment of rheumatoid arthritis based on serum pharmacochemistry and pharmacology].

The present study investigated the pharmacodynamic material basis of Laportea bulbifera in the treatment of rheumatoid arthritis. Firstly, human rheumatoid arthritis fibroblast-like synoviocyte line MH7A was cultured in vitro and treated with tumor necrosis factor alpha(TNF-α, 50 ng·mL~(-1)). The proliferation and the levels of inflammatory cytokines such as prostaglandin E2(PGE2), interleukin-1ß(IL-1ß), and interleukin-6(IL-6) of the MH7A cells exposed to the serum containing L. bulbifera were determined to evaluate the anti-rheumatoid arthritis effects of the serum. Furthermore, the ultra-performance liquid chromatography tandem mass spectrometry fingerprints of the L. bulbifera crude extract, the drug-containing serum, and the drug-free serum were compared to identify the compounds newly generated in the serum after oral administration of the extract. According to the peak areas of common peaks and the results of anti-rheumatoid arthritis effect test, the active components were identified. The serum containing L. bulbifera significantly inhibited the proliferation of the MH7A cells activated by TNF-α and the expression of PGE2, IL-6, and IL-1ß. Thirty newly generated compounds were detected in the drug-containing serum. Among them, neochlorogenic acid, cryptochlorogenic acid, chlorogenic acid, rutin, isoquercitrin, luteoloside, kaempferol-3-O-rutinoside, and quercitrin were also present in the crude extract. Twelve characteristic peaks(3, 7, 8, 14, 18, 19, 21, 23, 24, m6, m7, and m15) were significantly correlated with the pharmaceutical effect. According to the correlations, neochlorogenic acid, cryptochlorogenic acid, and chlorogenic acid had great contributions to the anti-rheumatoid arthritis activity. This study preliminarily clarified the potential pharmacodynamic substances of L. bulbifera in the treatment of rheumatoid arthritis, which laid a theoretical and experimental foundation for further development and application of the medicinal plant.

Stinging Nettle (Urtica dioica L.): Nutritional Composition, Bioactive Compounds, and Food Functional Properties.

Stinging nettle (Urtica dioica L., Urticaceae) is commonly found in Asia, Africa, and Europe and has a long history of being used as food and traditional medicine. Recently, this plant is gaining attention as a highly nutritious food, where fresh leaves are dried and used as powder or in other forms. Leaves are rich in many bioactive compounds. This review aims to cover the traditional uses in food and medicine, as well as its nutritional composition, including its bioactive chemical constituents and reported food functional activities. Various bioactive chemical constituents have been isolated from stinging nettle to date, such as flavonoids, phenolic acids, amino acid, carotenoids, and fatty acids. Stinging nettle extracts and its compounds, such as rutin, kaempferol, and vitamin A, are also used for their nutritional properties and as anti-inflammatory and antioxidant agents. Future studies should focus on the proper formulation and stability testing of the functional foods containing stinging nettle and their detailed activities in clinical studies.

Phytochemical, Chemotaxonomic and Bioinformatics Study on Laportea bulbifera (Urticaceae).

Phytochemical investigation of the aerial part of Laportea bulbifera (Siebold & Zucc.) Wedd. (L. bulbifera) showed the isolation of seventeen compounds, including five flavonoids (1-4 and 6), one terpenoid (5), five phenolic acids (7-11), one coumarin (12), two steroids (13-14), and three alkaloids (15-17). Structure elucidations of these compounds were performed on the basis of extensive NMR experiments and compared with the published data in the references. It is remarkable that compounds (3-5) were firstly isolated from the Urticaceae family, compounds (3-8, 11 and 15-17) were firstly obtained from genus Laportea. Furthermore, the result of the chemotaxonomic significance discussion showed that compounds (2-4) may can be served as compound fingerprints to distinguish between species of L. bulbifera and genus Urtica, and what' more, we proposed a bold conjecture that isoflavones can distinguish between species of L. bulbifera and genus Urtica. At the same time, the molecular docking method was used to evaluate the inhibitory effect of these compounds on human steroid 5α-reductase 2 (SRD5α2). The results showed that compounds (1-4 and 6) had better expected effects than the positive drug finasteride can by effectively binding to the active sites of SRD5α2. This study assisted in the future phytochemical and chemotaxonomic research on genus Laportea. Simultaneously, this research provided the theoretical evidence for the application of L. bulbifera in treating benign prostatic hyperplasia (BPH).

[Active constituents of Urtica fissa in inhibition of benign prostatic hyperplasia].

The present study investigated the material basis of Urtica fissa for the inhibition of benign prostatic hyperplasia(BPH). The active fractions were screened, and the extracts of dichloromethane and ethyl acetate exhibited significantly inhibitory activities against 5α-reductase in vitro and BPH in model rats. The chemical constituents in the active fractions were systematically investigated, and 28 compounds were obtained, which were identified as lobechine methyl ester(1), dibutyl-O-phthalate(2), 1-monolinolein(3), epipinoresinol(4), 5-hydroxy-3,4-dimethyl-5-pentanyl-2(5H)-furanone(5), E-7,9-diene-11-methenyl palmitic acid(6), evofolin B(7), ficusal(8), threo-2,3-bis-(4-hydroxy-3-methoxyphenyl)-3-ethoxypropan-1-ol(9), α-viniferin(10),(9R,7E)-9-hydroxy-5,7-mengatigmadien-4-one-9-O-ß-D-glucopyranoside(11), indole-3-carboxaldehyde(12), p-hydroxy ethyl cinnamate(13), benzyl alcohol-O-ß-D-glucoside(14), L-methionine(15), 4-methoxyaniline(16), 6-aminopurine(17), 8'-acetyl oilvil(18), 4-methoxyl-8'-acetyl oilvil(19), vanillic acid(20), ß-hydroxypropiovanillone(21), 7-hydroxy-6-methoxycoumarin(22), p-hydroxybenzaldehyde(23), pinoresinol(24), erythro-1,2-bis-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol(25), urticol(26), urticol-7-O-ß-D-glucopyranoside(27), and lobechine(28). Compounds 1-17 were isolated from U. fissa for the first time. Meanwhile, compound 1 was a new natural product. Compounds 10, 11, 19, 21, and 27 exhibited significant inhibitory effects on 5α-reductase.

Effects of 3, 4-divanillyltetrahydrofuran from Urtica fissa on sexual dysfunction in diabetic mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Urtica fissa E. Pritz. are important herbs and have been traditionally used as ethnic medicine to treat rheumatism, inflammation, diabetes, and benign prostatic hyperplasia by the Han, Uighur, and other minorities in China, and also as an aphrodisiac in Uighur medicine. AIMS OF THE STUDY: To determine the effect and potential mechanism of 3, 4-divanillyltetrahydrofuran (DVTF), one of the main active components isolated from U. fissa on hypogonadism in diabetic mice. MATERIALS AND METHODS: The active compound DVTF was extracted and separated from the roots of U. fissa and identified using mass spectrometry and nuclear magnetic resonance spectroscopy. A mouse model of diabetes was established using high fat and sugar diet combined with streptozotocin. In the treatment groups, mice were received different doses of DVTF for 4 weeks. Fasting blood glucose levels, physiological and biochemical indices, and the mating behavior of DM mice were analyzed. Changes in testicular morphology were assessed using light microscopy and transmission electron microscopy. The expression of testosterone synthesis-related signaling proteins was detected using western blotting. Molecular docking was used to determine the binding ability of DVTF to Nur77. RESULTS: In diabetic mice, body weight and fasting blood glucose levels decreased. Mating behavior, including mount latency, mount number, and intromission number, was improved following DVTF treatment. Plasma total testosterone, free testosterone, and insulin resistance were positively associated with the recovery of testicular pathological structures in diabetic mice. DVTF treatment increased the expression of Nur77, StAR, and P450scc in the testes of diabetic mice. DVTF and Nur77 formed chemical bonds at five sites. CONCLUSION: As one of the main active components of U. fissa, DVTF exert potential therapeutic effects on testicular injury and hypogonadism caused by diabetes through activating the expression of Nur77 and testosterone synthesis related proteins. Our result will provide new insight for the clinical application of Urtica fissa E. Pritz., especially DVTF, as a potential drug candidate in the treatment of hypogonadism in diabetes.

Imaging Flow Cytometry as a Quick and Effective Identification Technique of Pollen Grains from Betulaceae, Oleaceae, Urticaceae and Asteraceae.

Despite the continuous and intensive development of laboratory techniques, a light microscope is still the most common tool used in pollen grains differentiation. However, microscopy is time-consuming and needs well-educated and experienced researchers. Other currently used techniques can be categorised as images and non-images analysis, but each has certain limitations. We propose a new approach to differentiate pollen grains using the Imaging Flow Cytometry (IFC) technique. It allows for high-throughput fluorescence data recording, which, in contrast to the standard FC, also enables real-time control of the results thanks to the possibility of digital image recording of cells flowing through the measuring capillary. The developed method allows us to determine the characteristics of the pollen grains population based on the obtained fluorescence data, using various combinations of parameters available in the IDEAS software, which can be analysed on different fluorescence channels. On this basis, we distinguished pollen grains both between and within different genera belonging to the Betulaceae, Oleaceae, Urticaceae and Asteraceae families. Thereby, we prove that the proposed methodology is sufficient for accurate, fast, and cost-effective identification and potentially can be used in the routine analysis of allergenic pollen grains.

Three new p-coumaroylated sesquiterpenoids from Pilea cavaleriei.

Four p-coumaroylated sesquiterpenoids (1-4), including three new ones (1, 2, and 4), were isolated from the whole plants of Pilea cavaleriei. Their structures were established on the basis of comprehensive spectroscopic analysis and comparison with data reported in the literature. Compounds 1-4 were evaluated for their antimycobacterial activities, and 2 and 4 were active against Mycobacterium tuberculosis H37Rv with the MIC values of 19.6 ± 0.19 and 17.4 ± 0.12 µg/mL, respectively.

Myrianthus arboreus P. Beauv improves insulin sensitivity in high fat diet-induced obese mice by reducing inflammatory pathways activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Metabolic syndrome is currently recognized as the major cause of morbidity, with dramatic complications on life expectancy and health status. Myrianthus arboreus is a medicinal plant traditionally used in local communities as a safe remedy in treating diabetes and other metabolic diseases. AIM OF THE STUDY: This study aimed to investigate the impact of a methanol extract of Myrianthus arboreus leaf (MAL) in a mice model of metabolic syndrome induced by a high-fat diet (HFD) intake. MATERIALS AND METHODS: Male C57BL/6J mice were assigned to the following groups: control, obese control, and obese treated with MAL extract (10, 25, and 50 mg/kg) for 6 weeks. Control mice received a standard chow diet, while all obese mice were fed with HFD. Animal weight and food consumption were periodically measured. At the end of the treatment, fasting blood glucose and metabolic plasma analysis (insulin level, triglycerides, and total cholesterol (TC)) were performed. The HFD-induced inflammatory status and the expression of several obesity-related markers were evaluated in liver and fat using qPCR and Western blot analysis. In addition, the phytochemical composition of MAL was identified by GC-MS and HPLC-MS. RESULTS: MAL administration significantly reduced body weight gain, basal glycemia, and insulin resistance, and improved plasma lipid profile compared with HFD-fed mice. Similarly, this extract improved the HFD-associated inflammatory status in mice by gene expression modulation of different inflammatory markers involved in this experimentally induced metabolic condition. CONCLUSION: These results demonstrate the novel applicability of MAL, thus suggesting it as a promising therapeutic approach for the management of metabolic disorders.

Active constituents of Urtica fissa in inhibition of benign prostatic hyperplasia / 中国中药杂志

The present study investigated the material basis of Urtica fissa for the inhibition of benign prostatic hyperplasia(BPH). The active fractions were screened, and the extracts of dichloromethane and ethyl acetate exhibited significantly inhibitory activities against 5α-reductase in vitro and BPH in model rats. The chemical constituents in the active fractions were systematically investigated, and 28 compounds were obtained, which were identified as lobechine methyl ester(1), dibutyl-O-phthalate(2), 1-monolinolein(3), epipinoresinol(4), 5-hydroxy-3,4-dimethyl-5-pentanyl-2(5H)-furanone(5), E-7,9-diene-11-methenyl palmitic acid(6), evofolin B(7), ficusal(8), threo-2,3-bis-(4-hydroxy-3-methoxyphenyl)-3-ethoxypropan-1-ol(9), α-viniferin(10),(9R,7E)-9-hydroxy-5,7-mengatigmadien-4-one-9-O-β-D-glucopyranoside(11), indole-3-carboxaldehyde(12), p-hydroxy ethyl cinnamate(13), benzyl alcohol-O-β-D-glucoside(14), L-methionine(15), 4-methoxyaniline(16), 6-aminopurine(17), 8'-acetyl oilvil(18), 4-methoxyl-8'-acetyl oilvil(19), vanillic acid(20), β-hydroxypropiovanillone(21), 7-hydroxy-6-methoxycoumarin(22), p-hydroxybenzaldehyde(23), pinoresinol(24), erythro-1,2-bis-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol(25), urticol(26), urticol-7-O-β-D-glucopyranoside(27), and lobechine(28). Compounds 1-17 were isolated from U. fissa for the first time. Meanwhile, compound 1 was a new natural product. Compounds 10, 11, 19, 21, and 27 exhibited significant inhibitory effects on 5α-reductase.

[Lignans with inhibitory effect on 5α-reductase from Urtica cannabina].

The lignans in Urtica cannabina were isolated by preparative HPLC, silica, and ODS column chromatographies, and identified by NMR and HR-MS. The inhibitory activities on 5α-reductase were evaluated in vitro. As a result, ten secolignans,(2R,4S)-2,4-bis(3-methoxyl-4-hydroxyphenyl)-3-butoxypropanol(1), 3,4-trans-3-hydroxymethyl-4-[bis(3,4-dimethoxyphenyl)methyl] butyrolactone(2), 3,4-trans-3-hydroxymethyl-4-[(3,4-dimethoxyphenyl)(3-methoxyl-4-hydroxyphenyl)methyl] butyrolactone(3), 3,4-trans-3-hydroxymethyl-4-[bis(3-methoxyl-4-hydroxyphenyl)methyl] butyrolactone(trans urticol, 4), 3,4-trans-3-hydroxymethyl-4-[bis(3,4-dimethoxyphenyl)methyl] butyrolactone-3-O-ß-D-glucopyranoside(5), 3,4-trans-3-hydroxymethyl-4-[(3,4-dimethoxyphenyl)(3-methoxyl-4-hydroxyphenyl)methyl]butyrolactone-3-O-ß-D-glucopyranoside(6), 3,4-trans-3-hydroxymethyl-4-[bis(3-methoxyl-4-hydroxyphenyl)methyl]butyrolactone-3-O-ß-D-glucopyranoside(trans-urticol-7-O-ß-D-glucopyranoside, 7), cycloolivil-4-O-ß-D-glucopyranoside(8), isolariciresinol-4'-O-ß-D-glucopyranoside(9), and olivil-4'-O-ß-D-glucopyranoside(10), together with a polyphenol [α-viniferin(11)], were isolated from U. cannabina for the first time. Compound 1 was a new lignan. Compound 7 was potent in inhibiting 5α-reductase.

Distribution, Ecology, Chemistry and Toxicology of Plant Stinging Hairs.

Plant stinging hairs have fascinated humans for time immemorial. True stinging hairs are highly specialized plant structures that are able to inject a physiologically active liquid into the skin and can be differentiated from irritant hairs (causing mechanical damage only). Stinging hairs can be classified into two basic types: Urtica-type stinging hairs with the classical "hypodermic syringe" mechanism expelling only liquid, and Tragia-type stinging hairs expelling a liquid together with a sharp crystal. In total, there are some 650 plant species with stinging hairs across five remotely related plant families (i.e., belonging to different plant orders). The family Urticaceae (order Rosales) includes a total of ca. 150 stinging representatives, amongst them the well-known stinging nettles (genus Urtica). There are also some 200 stinging species in Loasaceae (order Cornales), ca. 250 stinging species in Euphorbiaceae (order Malphigiales), a handful of species in Namaceae (order Boraginales), and one in Caricaceae (order Brassicales). Stinging hairs are commonly found on most aerial parts of the plants, especially the stem and leaves, but sometimes also on flowers and fruits. The ecological role of stinging hairs in plants seems to be essentially defense against mammalian herbivores, while they appear to be essentially inefficient against invertebrate pests. Stinging plants are therefore frequent pasture weeds across different taxa and geographical zones. Stinging hairs are usually combined with additional chemical and/or mechanical defenses in plants and are not a standalone mechanism. The physiological effects of stinging hairs on humans vary widely between stinging plants and range from a slight itch, skin rash (urticaria), and oedema to sharp pain and even serious neurological disorders such as neuropathy. Numerous studies have attempted to elucidate the chemical basis of the physiological effects. Since the middle of the 20th century, neurotransmitters (acetylcholine, histamine, serotonin) have been repeatedly detected in stinging hairs of Urticaceae, but recent analyses of Loasaceae stinging hair fluids revealed high variability in their composition and content of neurotransmitters. These substances can explain some of the physiological effects of stinging hairs, but fail to completely explain neuropathic effects, pointing to some yet unidentified neurotoxin. Inorganic ions (e.g., potassium) are detected in stinging hairs and could have synergistic effects. Very recently, ultrastable miniproteins dubbed "gympietides" have been reported from two species of Dendrocnide, arguably the most violently stinging plant. Gympietides are shown to be highly neurotoxic, providing a convincing explanation for Dendrocnide toxicity. For the roughly 648 remaining stinging plant species, similarly convincing data on toxicity are still lacking.