Portulaca oleraceaL Research Articles

Effect of portulaca (Portulaca oleracea L.) extract on the quality and physicochemical attributes of vacuum-packed seasoned steaks during chilled storage.

Vacuum packaging has the ability to reduce oxidative deterioration and microbial-induced spoilage of meat. However, in an oxygen-free environment, it can lead to the development of an unappealing purplish-red color and a decrease in the water-holding capacity of meat, thereby impacting the overall meat quality. Portulaca oleracea L. (POL) is a homology of medicine and food known for its exceptional antioxidant and antimicrobial properties. The aim of our present study was to investigate the antioxidant and antimicrobial ability of n-butanol phase extract of POL and the effect of POL extract incorporation on the quality (water-holding capacity, shear force, color, and texture) and physicochemical (pH, total volatile base nitrogen, and total viable counts) attributes of vacuum-packed seasoned steaks at 4 °C over a 15-day period. Results showed that the POL extract had excellent antioxidant and antimicrobial capacity. Furthermore, the addition of POL extract significantly inhibited protein oxidation and microbial growth of steaks (P < 0.05), and improved the water-holding capacity, color properties, and tenderness (P < 0.05). Moreover, there were no significant differences (P > 0.05) in the color, water-holding capacity, or tenderness between the 0.5and 1 g kg-1 POL extract treatment groups compared to the sodium nitrite control group. These results indicate that POL extract had the potential to replace sodium nitrite due to its ability to hinder protein oxidation and microbial growth of vacuum-packed seasoned steaks, while enhancing the color, water-holding capacity, and tenderness of seasoned steaks. © 2024 Society of Chemical Industry.

Two novel ketone alkaloids from Portulaca oleraceaL. and their anti-inflammatory activities

Eleven compounds were obtained from Portulaca oleracea L., including two novel ketone alkaloids, (1, 2), 4-hydroxy-3-methoxybenzamide (3) (isolated for the first time), β-adenosine (4), oleracrylimide A and B (5, 6), oleracein H, C, D, Q and A (7–11). The two novel ketone alkaloids were identified as 5-acetyl-5-methylcyclopent-2-ene-1-carboxamide (1), named oleraciamide H, and (2 R,3S,4R,5R)-5-((R)-1,2-dihydroxyethyl)-3,4-dihydroxytetrahydrofuran-2-yl glycinate (2), named oleracone Q by spectroscopic methods, including 1D, 2D NMR and compound fingerprints. Additionally, their anti-inflammatory activities were tested via RAW 264.7 cells induced by LPS and found that they could significantly inhibit the release of IL-1β and TNF-α.

Portulaca oleracea L. Polysaccharide Inhibits Porcine Rotavirus In Vitro.

Diarrhea is one of the most common causes of death in young piglets. Porcine rotavirus (PoRV) belongs to the genus Rotavirus within the family Reoviridae, and is considered to be the primary pathogen causing diarrhea in piglets. Portulaca oleracea L. (POL) has been reported to alleviate diarrhea and viral infections. However, the antiviral effect of Portulaca oleracea L. polysaccharide (POL-P), an active component of POL, on PoRV infection remains unclear. This study demonstrated that the safe concentration range of POL-P in IPEC-J2 cells is 0-400 μg/mL. POL-P (400 μg/mL) effectively inhibits PoRV infection in IPEC-J2 cells, reducing the expression of rotavirus VP6 protein, mRNA and virus titer. Furthermore, on the basis of viral life cycle analysis, we showed that POL-P can decrease the expression of PoRV VP6 protein, mRNA, and virus titer during the internalization and replication stages of PoRV. POL-P exerts antiviral effects by increasing IFN-α expression and decreasing the expression levels of TNF-α, IL-6, and IL-10 inflammatory factors. Overall, our study found that POL-P is a promising candidate for anti-PoRV drugs.

Network pharmacology based research into the effect and potential mechanism of Portulaca oleracea L. polysaccharide against ulcerative colitis

BackgroundUlcerative colitis (UC) as a chronic inflammatory bowel disease (IBD) has received extensive concerns worldwide. As a traditional herbal medicine, Portulaca oleracea L. (POL) has a wide application in gastrointestinal diseases such as diarrhea and dysentery. This study aims to investigate the target and potential mechanisms of Portulaca oleracea L. polysaccharide (POL-P) in the treatment of UC. MethodThe active ingredients and relevant targets of POL-P were searched through the TCMSP and Swiss Target Prediction databases. UC related targets were collected through the GeneCards and DisGeNET databases. The intersection of POL-P targets with UC targets was done using Venny. Then, protein-protein interaction (PPI) network of the intersection targets was constructed through the STRING database and analyzed using Cytohubba to identify the key targets of POL-P in the treatment of UC. In addition, GO and KEGG enrichment analyses were performed on the key targets and the binding mode of POL-P to the key targets was further analyzed by molecular docking technology. Finally, the efficacy and target of POL-P were verified using animal experiments and immunohistochemical staining. ResultsA total of 316 targets were obtained based on POL-P monosaccharide structures, among which 28 were related to UC. Cytohubba analysis showed that VEGFA, EGFR, TLR4, IL-1β, STAT3, IL-2, PTGS2, FGF2, HGF, and MMP9 were the key targets for UC treatment and were mainly involved in multiple signaling pathways such as proliferation, inflammation, and immune response. Molecular docking results revealed that POL-P had a good binding potential to TLR4. In vivo validation results showed that POL-P significantly reduced the overexpression of TLR4 and its downstream key proteins (MyD88 and NF-κB) in intestinal mucosa of UC mice, which indicated that POL-P improved UC by mediating TLR4 related proteins. ConclusionPOL-P may be a potential therapeutic agent for UC and its mechanism is closely related to the regulation of TLR4 protein. This study will provide novel insights for the treatment of UC with POL-P.

Deciphering the Effective Constituents and Mechanisms of Portulaca oleracea L. for Treating NASH via Integrating Bioinformatics Analysis and Experimental Pharmacology.

Nonalcoholic steatohepatitis (NASH) is a highly prevalent metabolic disorder. Currently, there are no effective pharmacotherapeutic options for preventing and treating NASH. Portulaca oleracea L. (POL) is an edible herb that has been used for preventing and treating some metabolic disorders in China, but the bioactive constituents in POL and the related mechanisms for treating NASH are still unclear. Here, a comprehensive research strategy was used to identify the core genes and the key constituents in POL for treating NASH, via integrating bioinformatics analysis and experimental pharmacology both in vitro and in vivo. The phenotypes and mechanisms of POL were carefully investigated by performing a set of in vivo and in vitro experiments. Bioinformatics analysis suggested that prostaglandin-endoperoxide synthase 2 (PTGS2) was the core target and myricetin (Myr) was the key constituent in POL for treating NASH. In NASH mice model induced by methionine choline deficiency diet, POL significantly alleviated hepatic steatosis and liver injury. In free fatty acids-induced hepatocytes, POL and Myr significantly down-regulated the expression of PTGS2, decreased the number of lipid droplets, and regulated the mRNA expression of lipid synthesis and homeostasis genes, including FASN, CPT1a, SERBP1c, ACC1, and SCD1. In lipopolysaccharide-induced macrophages, POL and Myr significantly reduced the expression of PTGS2 and blocked the secretion of inflammatory mediators TNF-α, IL-6, and IL-1β. Further investigations demonstrate that Myr acts as both suppressor and inhibitor of PTGS2. Collectively, POL and its major component Myr can ameliorate NASH via down-regulating and inhibiting PTGS2, suggesting that POL and Myr can be developed as novel medicines for treating NASH.

Portulaca oleracea L. Extract Ameliorates Intestinal Inflammation by Regulating Endoplasmic Reticulum Stress and Autophagy.

ScopeTo investigate the role of endoplasmic reticulum stress (ERS)‐induced autophagy in inflammatory bowel disease (IBD) and the intervention mechanism of Portulaca oleracea L. (POL) extract, a medicinal herb with anti‐inflammatory, antioxidant, immune‐regulating, and antitumor properties, in vitro and in vivo.Methods and ResultsAn IL‐10‐deficient mouse model is used for in vivo experiments; a thapsigargin (Tg)‐stimulated ERS model of human colonic mucosal epithelial cells (HIECs) is used for in vitro experiments. The levels of ERS‐autophagy‐related proteins are examined by immunofluorescence and Western blot. Cellular ultrastructure is assessed with transmission electron microscopy.POL extract promotes a healing effect on colitis by regulating ERS‐autophagy through the protein kinase R‐like endoplasmic reticulum kinase (PERK)‐eukaryotic initiation factor 2α (eIF2α)/Beclin1‐microtubule‐associated protein light chain 3II (LC3II) pathway.ConclusionOverall, the results of this study further confirm the anti‐inflammatory mechanism and protective effect of POL extract and provide a new research avenue for the clinical treatment of IBD.

Improvement of a Traditional Orphan Food Crop, Portulaca oleracea L. (Purslane) Using Genomics for Sustainable Food Security and Climate-Resilient Agriculture

Purslane (Portulaca oleraceaL.) is a popular orphan crop used for its nutritional properties in various parts of the world. It is considered one of the richest terrestrial sources of omega-3 and omega-6-fatty acids (ω-3 and 6-FAs) suggesting its importance for human health. This ethnomedicinal plant is also an important part of traditional healing systems among the indigenous people. Many studies have indicated its tolerance against multiple stresses and found that it easily grows in a range of environmental gradients. It has also been considered one of the important biosaline crops for the future. Despite its huge nutritional, economic, and medicinal importance, it remains neglected to date. Most of the studies on purslane were focused on its ethnomedicinal, phytochemical, pharmacological, and stress-tolerance properties. Only a few studies have attempted genetic dissection of the traits governing these traits. Purslane being an important traditional food crop across the globe can be valorized for a sustainable food security in the future. Therefore, this review is an attempt to highlight the distribution, domestication, and cultivation of purslane and its importance as an important stress-tolerant food and a biosaline crop. Furthermore, identification of genes and their functions governing important traits and its potential for improvement using genomics tools for smart and biosaline agriculture has been discussed.

Critical Period for Weed Control in Grafted and Nongrafted Watermelon Grown in Plasticulture

AbstractField experiments determined the critical period for weed control (CPWC) in grafted and nongrafted watermelon [Citrullus lanatus(Thumb.) Matsum. &amp; Nakai] grown in plasticulture. Transplant types included ‘Exclamation’ seedless watermelon as the nongrafted control as well as Exclamation grafted onto two interspecific hybrid squash (ISH) rootstocks, ‘Carnivor’ and ‘Kazako’. To simulate weed emergence throughout the season, establishment treatments (EST) consisted of two seedlings each of common purslane (Portulaca oleraceaL.), large crabgrass [Digitaria sanguinalis(L.) Scop.], and yellow nutsedge (Cyperus esculentusL.) transplanted in a 15 by 15 cm square centered on watermelon plants at 0, 2, 3, 4, and 6 wk after watermelon transplanting (WATr) and remained until the final watermelon harvest at 11 WATr. To simulate weed control at different times in the season, removal treatments (REM) consisted of two seedlings of the same weed species transplanted in a 15 by 15 cm square centered on watermelon plants on the same day of watermelon transplanting and allowed to remain until 2, 3, 4, 6, and 11 WATr, at which time they were removed. Season-long weedy and weed-free controls were included for both EST and REM studies in both years. For all transplant types, aboveground biomass of weeds decreased as weed establishment was delayed and increased as weed removal was delayed. The predicted CPWC for nongrafted Exclamation and Carnivor required only a single weed removal between 2.3 and 2.5 WATr and 1.9 and 2.6 WATr, respectively, while predicted CPWC for Kazako rootstock occurred from 0.3 to 2.6 WATr. Our study results suggest that weed control for this mixed population of weeds would be similar between nongrafted Exclamation and Exclamation grafted onto Carnivor. But the observed CPWC of Exclamation grafted onto Kazako suggests that CPWC may vary with specific rootstock–scion combinations.

Pharmacokinetic studies of soyalkaloid A from Portulaca oleracea L. using ultra high-performance liquid chromatography electrospray ionization quadrupole-time of flight mass spectrometry and its antioxidant activity.

Soyalkaloid A was isolated from Portulaca oleraceaL. for the first time in our laboratory and then a rapid and sensitive ultra-high-performance liquid chromatography electrospray ionization quadrupole-time of flight mass spectrometry (UHPLC-ESI-Q-TOF/MS) method with hesperidin as internal standard (IS) was developed and validated to investigate the pharmacokinetics of soyalkaloid A in rats after oral and intravenous administrations. The analysis was achieved on an Agilent Zorbax Eclipse Plus C18 Column (2.1 × 50 mm, 1.8 μm) by elution with acetonitrile and water (containing 0.1% formic acid), at a flow rate of 0.3 mL/min. The MS analysis was performed in the positive ion mode with monitored ion m/z 227.0814 [M + H]+ and 611.1971 [M + H]+ for soyalkaloid A and IS, respectively. The linear range was established over the concentration range 7.5-6000 ng/mL (r = 0.9951). The intra- and inter-assay accuracy and precision were between -4.86-4.49 and 1.93-9.66, respectively. The lower limits of detection and quantitation observed were 2.1 and 7.4 ng/mL, respectively. The rapid, sensitive and specific UHPLC-ESI-Q-TOF/MS method was successfully applied to a pharmacokinetic study of soyalkaloid A. Moreover, its antioxidant was studied via a 1,1-diphenyl-2-picryl-hydrazyl radical scavenging assay, the IC50 value being 20.73 ± 0.51μM.

Portulacaoleraceal extract alleviates trinitrobenzene sulfonic acid-induced colitis in rats.

Portulacaoleraceal (POL) has been widely used as an edible plant and a folk medicine in many countries, due to its several health benefits. This study examined the effects of POL on trinitrobenzene sulfonic acid (TNBS)-induced colitis via enema administration. Sixty male Sprague-Dawley rats were randomly divided into five groups: untreated, TNBS, TNBS + POL 10 g/kg, TNBS + POL 5 g/kg and TNBS + POL 2.5 g/kg groups. Rats were subjected to enema treatment once a day for 10 consecutive days with POL extract or distilled water after induction of TNBS. The changes of body weight, histological parameters, myeloperoxidase (MPO), superoxide dismutase (SOD), nitric oxide synthase activity (NOS), malondialdehyde (MDA) and nitric oxide (NO) levels in colon tissues were investigated. After POL extract treatment, body weights of rats significantly increased, macroscopic and microscopic damage scores reduced, MPO and NOS activity, as well as MDA and NO level significantly decreased, while SOD activity increased in a dose-dependent manner in the TNBS + POL groups compared with the TNBS group. Our results demonstrated that POL enema treatment attenuated pathologic changes of TNBS-induced colitis in rats through restoring colonic damage and reducing inflammatory response in the intestine. Thus, POL enema might be considered as a potential effective treatment for ulcerative colitis patients.

Synthesis and in vitro evaluation of homoisoflavonoids as potent inhibitors of nitric oxide production in RAW-264.7 cells

Syntheses of natural homoisoflavonoids, (±)-portulacanones A–C (4, 8 and 9), portulacanone D (6), isolated from Portulaca oleracea L. (POL) and their derivatives (3, 5 and 7) have been achieved for the first time along with the synthesis of known derivatives (1 and 2) and their in vitro inhibitory effect against NO production in LPS-induced RAW-264.7 macrophages was evaluated as an indicator of anti-inflammatory activity. All the compounds tested had a concentration-dependent inhibitory effect on NO production by RAW-264.7 macrophages without obvious cytotoxicity. Compounds 3 (97.2% at 10 μM; IC50 = 1.26 µM) followed by 6 (portulacanone D) (92.5% at 10 μM; IC50 = 2.09 µM), 1 (91.4% at 10 μM; IC50 = 1.75 µM) and 7 (83.0% at 10 μM; IC50 = 2.91 µM) were the most potent from the series. This finding was further correlated with the suppressed expression of iNOS induced by LPS. Our promising preliminary results may provide the basis for the assessment of compound 3 as a lead structure for a NO production-targeted anti-inflammatory drug development and also could support the usefulness of POL as a folklore medicinal plant in the treatment of inflammatory diseases.

Quality Characteristics and Antioxidant Activities of Morning Bread Containing Portulaca oleracea L.

The purpose of this study was to develop functional bread containing Portulaca oleracea L. (0%, 1%, 3% or 5%). The weight was higher in the bread with Portulaca oleracea L. (POL), compared with the control bread. The height and volume were lower in the bread containing POL. As the concentration of POL increased, the pH decreased and the acidity increased. The sugar concentration () and reducing sugar (%) decreased with increasing amounts of POL. On the hunter color system, L (lightness) and a (redness) values for the crumbs of breads with more POL were lower, but the b (yellowness) value was higher. Total phenolic compound contents increased with the addition of POL. Antioxidant activities such as DPPH and hydroxy radical scavenging activity for the breads with POL increased with increasing POL. The sensory test results showed that the over-all preference score for the breads containing POL were higher than those of the control.

Purslane Weed (Portulaca oleracea): A Prospective Plant Source of Nutrition, Omega-3 Fatty Acid, and Antioxidant Attributes

Purslane (Portulaca oleracea L.) is an important plant naturally found as a weed in field crops and lawns. Purslane is widely distributed around the globe and is popular as a potherb in many areas of Europe, Asia, and the Mediterranean region. This plant possesses mucilaginous substances which are of medicinal importance. It is a rich source of potassium (494 mg/100 g) followed by magnesium (68 mg/100 g) and calcium (65 mg/100 g) and possesses the potential to be used as vegetable source of omega-3 fatty acid. It is very good source of alpha-linolenic acid (ALA) and gamma-linolenic acid (LNA, 18 : 3 w3) (4 mg/g fresh weight) of any green leafy vegetable. It contained the highest amount (22.2 mg and 130 mg per 100 g of fresh and dry weight, resp.) of alpha-tocopherol and ascorbic acid (26.6 mg and 506 mg per 100 g of fresh and dry weight, resp.). The oxalate content of purslane leaves was reported as 671–869 mg/100 g fresh weight. The antioxidant content and nutritional value of purslane are important for human consumption. It revealed tremendous nutritional potential and has indicated the potential use of this herb for the future.

Screening of Purslane (Portulaca oleraceaL.) Accessions for High Salt Tolerance

Purslane (Portulaca oleracea L.) is an herbaceous leafy vegetable crop, comparatively more salt-tolerant than any other vegetables with high antioxidants, minerals, and vitamins. Salt-tolerant crop variety development is of importance due to inadequate cultivable land and escalating salinity together with population pressure. In this view a total of 25 purslane accessions were initially selected from 45 collected purslane accessions based on better growth performance and subjected to 5 different salinity levels, that is, 0.0, 10.0, 20.0, 30.0, and 40.0 dS m−1 NaCl. Plant height, number of leaves, number of flowers, and dry matter contents in salt treated purslane accessions were significantly reduced (P ≤ 0.05) and the enormity of reduction increased with increasing salinity stress. Based on dry matter yield reduction, among all 25 purslane accessions 2 accessions were graded as tolerant (Ac7 and Ac9), 6 accessions were moderately tolerant (Ac3, Ac5, Ac6, Ac10, Ac11, and Ac12), 5 accessions were moderately susceptible (Ac1, Ac2, Ac4, Ac8, and Ac13), and the remaining 12 accessions were susceptible to salinity stress and discarded from further study. The selected 13 purslane accessions could assist in the identification of superior genes for salt tolerance in purslane for improving its productivity and sustainable agricultural production.

The Involvement of AMPA Receptor in the Antidepressant-like Effects of the Portulaca Oleracea L. Extract in Mice

AbstractObjectives :The development of natural drugs with antidepressant effects is important and needed. This study was performed to investigate the antidepressant-like effects of the distilled water extract of Portulaca oleracea L. (POL) in a mouse model and to investigate the role of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) rec eptors in producing these antidepressant-like effects.Methods :The forced swim test (FST) and tail suspension test (TST) were used to investigate the behavioral anti-depressive-like effects of POL in mice. Additional behavioral experiments with 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3- dione, an AMPA receptor antagonist, were undertaken to determin e the involvement of the antidepressant-like properties of POL in AMPA receptor throughput.Results :Oral administration of the POL extract (100 mg/kg) 1 h prior to testing significantly reduced the immobility times in the FST and TST. The antidepressant-like effects of the POL ext ract were not increased in a dose-dependent manner. Pre-treatment with NBQX significantly attenuated the reduction in immobility time induced by the POL extract in the FST.Conclusions :The distilled water extract of POL has antidepressant-like effe cts, which may be related to AMPA receptor. Pre-treatment with NBQX significantly attenuates the reduction in immobility time induced by the POL extract in the FST.Key Words:Antidepressant, Portulaca oleracea L. (POL), Forced swim test ( FST), Tail suspension test (TST), Depression, α-amino- 3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA).

The effect of different host plants on the reproduction and longevity ofNysius natalensis

AbstractNysius natalensisEvans (Hemiptera:Orsillidae) is a pest of sunflower inSouthAfrica. Adults invade sunflower fields from their weedy hosts which occur inside crop fields and on surrounding headlands. The host plant suitability for survival and reproduction as well as the effect of within‐generation host switching was studied on different wild host plants and sunflower. Life history parameters used to assess host plant suitability were F1adult survival, pre‐oviposition period, fecundity, and longevity. Nymphs and adults were provided with stems and seeds of five host plants, viz.,Amaranthus hybridusL. (Amaranthaceae),Portulaca oleraceaL. (Portulacaceae),Chenopodium albumL. (Chenopodiaceae),Conyza albidaSpreng. (Asteraceae), and sunflower,Helianthus annuusL. (Asteraceae). Nymphs were reared on crushed seed of the five plant species. After completion of the nymphal stage, emerging adults of each host plant group were provided with seed of a different host plant species for food. Adults did not survive long on stems only and very few eggs were laid. Seeds of the host plant species were shown to be an essential source of nutrients forN.natalensisreproduction, whereas the vegetative plant parts were unsuitable. Nymphal food and host‐plant switching between the nymphal and adult stages significantly affected the pre‐oviposition period. Nymphal and adult food source also affected female longevity. The number of eggs laid was not influenced by nymphal food, but was influenced by adult food and the switch between nymphal and adult food. The comparative attractiveness of sunflower and wild host plants for oviposition was also investigated and showed that females preferred to lay eggs on wild host plants, compared with sunflower. These results may explain whyN. natalensiswill lay their eggs on sunflower after weeds in the vicinity are controlled, or senesce toward the end of the growing season.

English

Portulaca oleracea&nbsp;L.&nbsp;(POL)&nbsp;has been used as one of the traditional oriental medicines to treat&nbsp;bacteria, virus, antherasis, caducity, diabetes and for enhancing immunity.&nbsp;This study aims at revealing effects of POL&nbsp;on alloxan-induced diabetic rats and its mechanisms.&nbsp;According to thin layer chromatography assay, the main compounds of&nbsp;POL&nbsp;included&nbsp;organic acid,flavonoids,&nbsp;alkaloids,&nbsp;terpene ansteroid,&nbsp;hydroxybenzene, saponin and polysaccharide. The rats were divided into four groups: normal control (NC), diabetes control (DC), diabetes +&nbsp;POL&nbsp;high dose&nbsp;(400 mg/kg), diabetes&nbsp;+&nbsp;POLlow dose (200 mg/kg). The diabetic rats were administrated with&nbsp;POL or dH2Odaily for 28 days. The&nbsp;POL&nbsp;treatment resulted in significant decreases of fasting blood glucose,&nbsp;total cholesterol and triglycerides.&nbsp;POL&nbsp;also showed a tendency of improvement body weight gain on diabetic rats.&nbsp;Furthermore, the DC group had low serum insulin level comparing with that of NC&nbsp;group, at the same time,the insulin levels were dose-dependently raised in the&nbsp;POL-treated groups than that of DC&nbsp;group. According to single cell gel electrophoresis and LD50&nbsp;analysis, POL was proved to be nontoxic to the animals. The results indicate that POL would alleviate the blood glucose and lipid rising associated&nbsp;with diabetes, and improve the abnormal glucose metabolism and increase insulin secretion&nbsp;byrestoring the impaired pancrease &beta; cells in alloxan-induced diabetic rats, which suggest&nbsp;that POL&nbsp;has the hypoglycemic potential and could be useful on the diabetes therapy. &nbsp; Key words:&nbsp;Portulaca oleracea L.,&nbsp;diabetes, hypoglycemia, hypolipidemia, insulin.

Modified Rancimat Method for Evaluation of Antioxidative Effect against Skin Lipids

Skin is a highly complicated tissue which possesses the largest surface area in the body and serves as the protective layer for internal organs. It is designed to give both physical and biochemical protection, and is equipped with a large number of defense mechanisms. 1 However, skin is very susceptible to oxidative reaction, because there are rich contents of lipids, proteins and DNA in the skin cell, all of which are very sensitive to the oxidation process. 2 Lipid peroxidation could be induced from excessive exposure to UV light, and has been considered as a major factor for skin aging processes. 3 In particular, squalene, main component of skin surface polyunsaturated lipids, is easily peroxidized. 4 The initial product of peroxidized squalene, squalene-monohydroperoxide (Sq-OOH), is produced at the human skin by natural exposure to sun light. Recently, the damages of hairless mice skin by the topical application of Sq-OOH 5 have been reported. Repeated application of Sq-OOH to the hairless mice induced clear skin wrinkles. Thus, in order to prevent or retard skin aging process, prevention of skin lipid peroxidation by natural or chemical antioxidants is desirable. To identify efficient antioxidants in cosmetic applications, a convenient assay method suitable for the estimation of skin lipid peroxidation is necessary. Rancimat 6 is a convenient method which can evaluate the lipid peroxidation by observing the change of electrical conductivity due to the formation of volatile dicarboxylic acids. It has been used in food industry to determine the peroxidation of unsaturated fatty acid components. However, the rancimat method is not suited for skin research, because the composition of oils used as a lipid source in this method is very different from that of skin lipid. 6c In this report, we demonstrate that modified rancimat method is a powerful tool for screening natural antioxidants for skin lipid peroxidation. We changed composition of lipid source to what is very close to skin lipid. At first, we tested antioxidative activities of several natural extracts by using general rancimat method. As shown in Table 1, extracts from Korean medicinal plants presented different induction time on retarding the peroxidation of corn oil. Their activities were compared with BHT as a positive control. Among the three natural extracts, Scutellaria baicalensis Georgi (SBG) extract was found to have the most powerful antioxidative activity. Portulaca oleracea L. (POL) extracts appeared to be the compound with the next activity and Rheum coreanum Nakai (RCN) extract was less active than other extracts. The order of activity is BHT > SBG > POL > RCN. However, ranges of Pf values of tested natural product are too small (from 1.2 to 1.6). Thus, sensitivity is not enough for primary screening of antioxidative activity. To establish the modified rancimat system suitable for skin lipid peroxidation studies, we prepared the artificial skin lipid and used it instead of corn oil. The prepared artificial skin lipid 7 was consisted of pork lard (33%), stearic acid (24%), lanolin (22%), squalene (12%) and cholesterol (4%). This composition is similar to that of human skin. According to the Table 2, the results of new rancimat method were different from previous general rancimat data. Surprisingly, SBG extract shows the strongest antioxidative activity among the tested samples. Induction period of SBG was 11.4 times longer than that of control with this new method. The sensitivity for evaluation of antioxidative activity was dramatically increased due to the wide ranges of Pf value (from 2.2 to 11.4). It is interesting to observe that the order of activity between RCN and ROL was reversed. In contrast to previous rancimat data, RCN is more active than POL. These interesting and meaningful differences between general rancimat and modified method may be due to changing of lipid composition which is suited to skin research. In search of new antioxidant applicable to prevent skin lipid peroxidation, we selected meso-dihydroguaiaretic acid (MDGA) 8 as a candidate. MDGA, a naturally occurring polyphenol,

Artemisinin, a Constituent of Annual Wormwood (Artemisia annua), is a Selective Phytotoxin

Artemisinin (qinghaosu), a sesquiterpenoid lactone peroxide constituent of annual wormwood (Artemisia annuaL. # ARTAN) that is used as an antimalarial drug, was tested for phytotoxic properties. It inhibited germination of lettuce (Lactuca sativaL.) and annual wormwood, and growth of roots and shoots of lettuce, redroot pigweed (Amaranthus retroflexusL. # AMARE), pitted morningglory (Ipomoea lacunosaL. # IPOLA), annual wormwood, and common purslane (Portulaca oleraceaL. # POROL) was inhibited at 33 μM. No effects of 33 μM artemisinin were detected on growth of velvetleaf (Abutilon theophrastiMedik. # ABUTH) and grain sorghum [Sorghum bicolor(L.) Moench.]. Chlorophyll content was not affected in lettuce, and chlorosis was not observed in any species tested. The probable biosynthetic precursors of artemisinin, arteannuin B and qinghao acid, had no effect on growth or chlorophyll content of lettuce; however, they inhibited lettuce seed germination. Artemisinin and cinmethylin {exo-1-methyl-4-(1-methylethyl)-2-[(2-methylphenyl)methoxy]-7-oxabicyclo [2.2.1] heptane} were equally effective in reducing growth of lettuce; however, cinmethylin had no effect on germination. Respiration of lettuce roots or cotyledons was not inhibited by artemisinin. Artemisinin only marginally increased the mitotic index of lettuce root tips at 33 μM. At the ultrastructural level, however, chromosomes were less condensed during mitosis in artemisinin-treated than control meristematic cells. The growth-inhibiting ability of artemisinin could not be reduced by feeding the plants with hydrolyzed protein or treatment with putrescine. Artemisinin is a selective phytotoxin that reduces growth by a mechanism other than mitotic disruption or inhibition of protein synthesis.

Weed Seed Population Dynamics During Six Years of Weed Management Systems in Crop Rotations on Irrigated Soil

The influence of two weed management systems was determined on weed seed and seedling populations and on yields of cantaloupe (Cucumis meloL. var.reticulatusNaudin ‘Perlita′), bell pepper (Capsicum annuumL. var.grossum‘Grande Rio 66′), cotton (Gossypium hirsutumL. ‘CP 3374′), onion (Allium cepaL. ‘1015Y′), and cabbage (Brassica oleracea, var.capitataL. 'Sanibel′) sequentially grown in two 3-yr cycles. Palmer amaranth (Amaranthus palmeriS. Wats. # AMAPA) did not exist initially, but hurricane-introduced seed populations increased to 1.1 billion/ha as seed populations of common purslane (Portulaca oleraceaL. # POROL) decreased from 786 million/ha to 124 million/ha in the 6-yr period, without weeding or herbicide. Use of herbicides and handweeding reduced Palmer amaranth seed populations 98%, but 18 million/ha still remained after 6 yr. The use of herbicides and Palmer amaranth interference decreased the seed populations of common purslane by 84%, but handweeding was inefficient. Yields of all but the first crop of cantalouple were almost totally eliminated by season-long interference of Palmer amaranth. Savings with the utilization of herbicides rather than handweeding ranged from $62/ha for cotton to $4703/ha for bell pepper.