Repair of UVB-Damaged Skin by the Antioxidant Sulphated Flavone Glycoside Thalassiolin B Isolated from the Marine Plant Thalassia testudinum Banks ex König

Daily topical application of the aqueous ethanolic extract of the marine sea grass, Thalassia testudinum, on mice skin exposed to UVB radiation resulted in a dose-dependent recovery of the skin macroscopic alterations over a 6-day period. Maximal effect (90%) occurred at a dose of 240 μg/cm², with no additional effects at higher doses. Bioassay-guided fractionation of the plant extract resulted in the isolation of thalassiolin B (1). Topical application of 1 (240 μg/cm²) markedly reduces skin UVB-induced damage. In addition, thalassiolin B scavenged 2,2-diphenyl-2-picrylhydrazyl radical with an EC₅₀ = 100 μg/ml. These results suggest that thalassiolin B is responsible for the skin-regenerating effects of the crude extract of T. testudinum. Erik L. Regalado and María Rodríguez have contributed equally to this work and should be considered as first authors.     

Enhanced plumbagin production from in vitro cultures of <Emphasis Type="Italic">Drosera burmanii</Emphasis> using elicitation

Methyl jasmonate, 50 μM, 0.5 mg yeast extract/l and 100 mg chitosan/l stimulated plumbagin production in Drosera burmanii whole plant cultures after 6 days of elicitation. Yeast extract (0.5 mg/l) was the most efficient enhancing plumbagin production in roots of D. burmanii to 8.8 ± 0.5 mg/g dry wt that was 3.5-fold higher than control plants.     

Insecticide-tolerant and plant growth promoting <Emphasis Type="Italic">Bradyrhizobium</Emphasis> sp. (<Emphasis Type="Italic">vigna</Emphasis>) improves the growth and yield of greengram [<Emphasis Type="Italic">Vigna radiata</Emphasis> (L.) Wilczek] in insecticide-stressed soils

This study was designed to identify rhizobial strains specific to greengram expressing higher tolerance against insecticides, fipronil and pyriproxyfen, and synthesizing plant growth regulators even amid insecticide-stress. Of the 50 bradyrhizobial isolates, the Bradyrhizobium sp. strain MRM6 showed tolerance up to 1,600 μg mL⁻¹ against each of fipronil and pyriproxyfen. The tolerant Bradyrhizobium sp. (vigna) produced plant growth promoting substances in substantial amounts, both in the presence and absence of insecticides. The strain MRM6 was further used to investigate its impact on greengram grown in soils treated with 200 (the recommended dose), 400 and 600 μg kg⁻¹ soil of fipronil and 1,300 (the recommended dose), 2,600 and 3,900 μg kg⁻¹ soil of pyriproxyfen. Fipronil at 600 μg kg⁻¹ soils and pyriproxyfen at 3,900 μg kg⁻¹ soils had greatest toxic effects and decreased plant biomass, symbiotic efficiency, nutrient uptake and seed yield of greengram plants. The Bradyrhizobium sp. (vigna) inoculant when used with fipronil and pyriproxyfen significantly increased the measured parameters compared to the plants grown in soils treated solely with the same concentration of each insecticide. This study inferred that the Bradyrhizobium sp. (vigna) strain MRM6 may be exploited as bio-inoculant to increase the productivity of greengram exposed to insecticide-stressed soils.     

Elicitation of guggulsterone production in cell cultures of <Emphasis Type="Italic">Commiphora wightii</Emphasis> by plant gums

Plant gum as an elicitor for guggulsterone production in cell cultures of Commiphora wightii is reported for the first time. Guggulsterone production increased 2.4 fold in the cell cultures by gum Arabic (100 mg l⁻¹), while mesquite gum elicited 2 fold. The cells treated with gum Arabic at 7th and 9th day accumulated enhanced guggulsterones within 24 h, which increased further up to 48 h and then declined. The cells treated at 9th day accumulated higher amount (218 μg l⁻¹) of guggulsterones after 48 h of elicitation as compared to cells treated at 7th day (164 μg l⁻¹). The optimized elicitation conditions were used in vessels of varying capacity where maximum yield of 285 μg l⁻¹ of guggulsterones was recorded in 3 l shake flasks. These experiments enabled highest guggulsterones yield in a short duration of 11 days in cell cultures of C. wightii.     

In vitro induction of polyploidy in yacon (<Emphasis Type="Italic">Smallanthus sonchifolius</Emphasis>)

In vitro chromosome doubling was induced in octoploid (2n = 58) yacon using oryzalin and colchicine as mitotic spindle inhibitors. Nodal segments of in vitro cultured plants, 5–15 mm long, were exposed to 20, 25, or 30 μM oryzalin and 1, 3, or 5 mM colchicine for 24 or 48 h. The resulting ploidy level was determined by chromosome counting and flow cytometry. Out of 240 nodal segments, 3.33% hexadecaploid (2n = 116) plants were regenerated after the application of oryzalin. The greatest proportions of hexadecaploid plants (1.6%) were obtained after 48 h of 25 μM oryzalin treatment. With the colchicine treatment, only 0.42% hexadecaploid plants were detected and their survival rate was significantly lower in comparison with the oryzalin treatment. In hexadecaploid yacon, significantly higher levels of saccharides were detected (FOS 13.9 g/100 g FM, fructose 4.6 g/100 g FM and glucose 2.1 g/100 g FM) compared to the octoploid control (FOS 5.3 g/100 g FM, fructose 2.9 g/100 g FM and glucose 1.0 g/100 g FM). These results indicate that in vitro treatment of nodal segments with oryzalin solution could be an effective procedure for chromosome doubling and the polyploidy breeding can help to increase the FOS content in the tuberous roots.     

Physiological and antioxidant responses of <Emphasis Type="Italic">Mentha pulegium</Emphasis> (Pennyroyal) to salt stress

Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses. Physiological and biochemical parameters were assessed in the plant organs after 2 weeks of salt treatment with 25, 50, 75 and 100 mM NaCl. Results showed that, growth was reduced even by 25 mM, and salt effect was more pronounced in shoots (leaves and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K⁺ uptake, as well as an increase in Na⁺ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline conditions. Leaf and root guaiacol peroxidase activity showed an increase by different concentration of NaCl, but superoxide dismutase activity in the same organs showed a slight modification in NaCl-treated leaves and roots. Moreover, polyphenol contents and antioxidant activity were analysed in M. pulegium leaves and roots under salt constraint. The analysis showed an increase of total polyphenol content (2.41–8.17 mg gallic acid equivalent g⁻¹ dry weight) in leaves. However, methanol extract of leaves at 100 mM NaCl displayed the highest DPPH· scavenging ability with the lowest IC₅₀ value (0.27 μg ml⁻¹) in comparison with control which exhibited IC₅₀ equal to 0.79 μg ml⁻¹.     

Prevention of Selenite-Induced Cataractogenesis by an Ethanolic Extract of Cineraria maritima: An Experimental Evaluation of the Traditional Eye Medication

In the present study, the antioxidant potential of an ethanolic extract of Cineraria maritima and its efficacy in preventing selenite-induced cataractogenesis were assessed in vitro and in vivo. In the in vitro phase of the study, lenses dissected out from the eyes of Wistar rats were incubated for 24 h at 37°C in Dulbecco’s modified Eagle medium (DMEM) alone (group I), in DMEM containing 100 μM of selenite only (group II), or in DMEM containing 100 μM of selenite and 300 μg/ml C. maritima extract added at the same time (group III). Gross morphological examination of the lenses revealed dense opacification in group II, minimal opacification in group III, and no opacification in group I lenses. The mean activities of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase were significantly lower in group II than in group I or group III lenses, while malondialdehyde concentration was significantly higher in group II lenses than in group I and group III lenses. In the in vivo phase of the study, dense opacification of lenses was noted in all rat pups (100%) that had received a single subcutaneous injection of sodium selenite alone (19 μM/kg body weight) on postpartum day 10, whereas cataract formation occurred in only 33.3% of rat pups that had received selenite as well as an intraperitoneal injection of the extract of C. maritima (350 mg/kg body weight) for five consecutive days. These observations suggest that the ethanolic extract of C. maritima may prevent experimental selenite-induced cataractogenesis.     

Growth retardants stimulate guggulsterone production in the presence of fungal elicitor in fed-batch cultures of <Emphasis Type="Italic">Commiphora wightii</Emphasis>

Guggulsterone, a hypolipidemic natural agent, is produced in resin canals of the plant Commiphora wightii. In this study, the stimulatory effects of growth retardants [ALAR (N,N-dimethylaminosuccinamic acid) and CCC (chlormequat chloride)] and fungal elicitor on guggulsterone accumulation in cell cultures of C. wightii are reported. CCC at 1 mg l⁻¹ enhanced guggulsterone content (~123 μg l⁻¹) when added on the fifth day after inoculation, while ALAR at 2.5 mg l⁻¹ increased guggulsterone content (~116 μg l⁻¹) when added on the tenth day. In a two-stage fed-batch process, combined treatment with fungal elicitor and growth retardant caused a significant increase (~353 μg l⁻¹) in guggulsterone content in cell cultures after 17 days of growth. This represents an approximately fivefold increase over the guggulsterone contents in initial cultures of this plant.     

Toxicity of Diazinon 60 EC for embryos and larvae of tench, <Emphasis Type="Italic">Tinca tinca</Emphasis> (L.)

The effects of Diazinon 60 EC (organophosphate insecticide, active substance diazinon) on mortality, growth rate, early ontogenetic rate, and occurrence of malformations was studied in embryos and larvae of tench, Tinca tinca (L.). The exposure of fish to 0, 10, 100, 1,000, and 3,000 μg dm⁻³ of Diazinon 60 EC was initiated 24 h after fertilization of eggs and concluded 32 days later. At the highest concentration tested (3,000 μg dm⁻³), total mortality was observed within the first 15 days of exposure. A concentration of 1,000 μg dm⁻³ caused high incidence of malformations, decrease in growth rate and ontogenetic development slowed down. A concentration of 100 μg dm⁻³ mildly decreased growth rate, but at 10 μg dm⁻³ no changes compared to the control were observed. Thus, Diazion 60 EC at the concentration of 10 μg dm⁻³ is not dangerous for the embryos and larvae of tench.     

Synergistic effect of green tea extract and probiotics on the pathogenic bacteria, <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and <Emphasis Type="Italic">Streptococcus pyogenes</Emphasis>

The aim of this study was to assess the effect of a commercial green tea extract (TEAVIGO™) on the microbial growth of three probiotic strains (Lactobacillus and Bifidobacterium), as well as three pathogenic bacteria. MIC and co-culture studies were performed. The MICs of the green tea extract against Staphylococcus aureus and Streptococcus pyogenes (100 μg ml⁻¹) were considerably lower than those against the probiotic strains tested (>800 μg ml⁻¹) and Escherichia coli (800 μg ml⁻¹). In co-culture studies, a synergistic effect of the probiotic strains and the green tea extract was observed against both Staph. aureus and Strep. pyogenes. Green tea extract in combination with probiotics significantly reduced the viable count of both pathogens at 4 h and by 24 h had completely abolished the recovery of viable Staph. aureus and Strep. pyogenes. These reductions were more significant than the reductions induced by probiotics or green tea extracts used separately. These results demonstrate the potential for combined therapy using the green tea extract plus probiotics on microbial infections caused by Staph. aureus and Strep. pyogenes. As probiotics and the green tea extract are derived from natural products, treatment with these agents may represent important adjuncts to, or alternatives to, conventional antibiotic therapy.     

Cadmium-induced stress on the seed germination and seedling growth of <Emphasis Type="Italic">Brassica napus</Emphasis> L., and its alleviation through exogenous plant growth regulators

Because of its prolific growth, oilseed rape (Brassica napus L.) can be grown advantageously for phytoremediation of the lands contaminated by industrial wastes. Therefore, toxic effect of cadmium on the germination of oilseed rape, the capability of plants for cadmium phytoextraction, and the effect of exogenous application of plant growth regulators to mitigate phytotoxicity of cadmium were investigated. For the lab study of seedlings at early stage, seeds were grown on filter papers soaked in different solutions of Cd²⁺ (0, 10, 50, 100, 200 and 400 μM). In greenhouse study, seedlings were grown in soil for 8 weeks, transferred to hydroponic pots for another 6 weeks growth, and then treated with plant growth regulators and cadmium. Four plant growth regulators viz. jasmonic acid (12.5 μM), abscisic acid (10 μM), gibberellin (50 μM) and salicylic acid (50 μM); and three levels of Cd²⁺ (0, 50 and 100 μM) were applied. Data indicated that lower concentration of Cd²⁺ (10 μM) promoted the root growth, whereas the severe stresses (200 or 400 μM) had negative effect on the establishment of germinating seedlings. Plants treated with any of the tested plant growth regulators alleviated cadmium toxicity symptoms, which were reflected by more fresh weight, less malondialdehyde concentration in leaves and lower antioxidant enzyme activities. The application of abscisic acid to the plants cultivated in the medium containing 100 μM Cd²⁺ resulted in significantly lower plant internal cadmium accumulation. Huabing Meng and Shujin Hua contributed equally to this paper.     

Age-related protective effect of deprenyl on changes in the levels of diagnostic marker enzymes and antioxidant defense enzymes activities in cerebellar tissue in Wistar rats

Antioxidants are free radical scavengers and protect living organisms against oxidative damage to tissues. Experimental evidence implicates oxygen-derived free radicals as important causative agents of aging and the present study was designed to evaluate the age-related effects of deprenyl on the antioxidant defense in the cerebellum of male Wistar rats. Experimental rats of three age groups (6, 12, and 18 months old) were administered with liquid deprenyl (2 mg/kg body weight/day for a period of 15 days i.p) and levels of diagnostic marker enzymes (alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and creatine phosphokinase) in plasma, lipid peroxides, reduced glutathione and activities of glutathione-dependent antioxidant enzymes (glutathione peroxidase and glutathione-S-transferase) and antiperoxidative enzymes (catalase and superoxide dismutase) in the cerebellar tissue were determined. Intraperitonial administration of deprenyl (2 mg/kg body weight/day for a period of 15 days) significantly (p < 0.05) attenuated the age-related alterations noted in the levels of diagnostic marker enzymes plasma of experimental animals. Deprenyl also exerted an antioxidant effect against aging process by hindering lipid peroxidation to an extent. Moderate rise in the levels of reduced glutathione and activities of glutathione-dependent antioxidant enzymes and antiperoxidative enzymes was also observed. The results of the present investigation indicated that the protective potential of deprenyl was probably due to the increase of the activity of the free radical scavenging enzymes or to a counteraction of free radicals by its antioxidant nature or to a strengthening of neuronal membrane by its membrane-stabilizing action. Histopathological observations also confirmed the protective effect of deprenyl against the age-related aberrations in rat cerebellum. These data on the effect of deprenyl on parameters of normal aging provides new additional information concerning the anti-aging potential of deprenyl.     

Productivity of greengram in tebuconazole-stressed soil, by using a tolerant and plant growth-promoting Bradyrhizobium sp. MRM6 strain

In this study, a total of 50 rhizobial isolates were recovered from the root nodules of greengram plants. Of the 50 isolates, 9 bradyrhizobial strains namely, MRM1, MRM2, MRM3, MRM4, MRM5, MRM6, MRM7, MRM8, and MRM9, exhibiting a higher tolerance levels of 600, 800, 1,200, 1,000, 1,000, 1,600, 1,400, 1,400, and 1,000 μg ml⁻¹, respectively, to triazole fungicide tebuconazole (chromatographically pure) were selected and tested for plant growth-promoting activities. Generally, the rhizobial strain with maximum fungicide-tolerance ability produced higher amounts of plant growth-promoting substances. Among the nine bacterial strains, Bradyrhizobium strain MRM6 was preferably selected due to its ability to tolerate tebuconazole maximally (up to 1,600 μg ml⁻¹) on minimal salt agar medium. In addition, the strain MRM6 grew well in minimal salts medium supplemented with 100 (recommended), 200 (two times of the recommended), and 300 μg tebuconazole l⁻¹ (three times of the recommended rate) and synthesized highest amounts of plant growth-promoting substances like indole acetic acid, siderophores, exopolysaccharides, hydrogen cyanate, and ammonia, both in the absence and presence of 100, 200, and 300 μg l⁻¹ of tebuconazole. Following these properties, the strain MRM6 was used as inoculant and the inoculated greengram plants was raised in soils treated separately with recommended, two and three times the recommended dose of tebuconazole. Generally, tebuconazole at recommended and the higher rates decreased biomass, nodulation, nutrient-uptake, and grain yield of uninoculated greengram plants. Interestingly, Bradyrhizobium sp. (vigna) strain MRM6 when used with any concentration of tebuconazole, significantly increased the measured phyto-chemical-parameters of greengram plants when compared with those grown in soils treated exclusively (without inoculant) with tebuconazole. This study inferred that the strain MRM6 of Bradyrhizobium sp. (vigna) was compatible with tebuconazole and may be co-inoculated with this fungicide for enhancing the production of legumes especially greengram in soils poisoned with fungicides.     

Improved clonal propagation of <Emphasis Type="Italic">Spilanthes</Emphasis><Emphasis Type="Italic">acmella</Emphasis> Murr. for production of scopoletin

A reproducible protocol for clonal propagation of Spilanthes acmella has been established. Routinely, the cultures were established in spring (January–April) season because of the highest aseptic culture establishment and high frequency shoot proliferation. Incorporation of 5 μM N⁶-benzyladenine (BA) to Murashige and Skoog (MS) basal medium showed 100% bud-break and promoted multiple shoot proliferation in cultures. Interestingly, a higher concentration of BA (7–15 μM) promoted stunted shoots with pale leaves while a lower concentration (1–3 μM) resulted in shoots with long internodes and excessive adventitious root proliferation from all over their surface. For recurrent shoot multiplication, single node segments from in vitro-developed shoots were excised and cultured on MS + BA (5 μM) medium where 20.3-fold shoot multiplication was achieved every 5 weeks. Finally, these shoots were successfully rooted on half-strength MS medium (major salts reduced to half-strength) with 50 g l⁻¹ sucrose, with a frequency of 100%. Transplantation survival of micropropagated plants was 88.9%. Additionally, accumulation of scopoletin, a phytoalexin, was revealed for the first time in the uninfected leaves of Spilanthes. Further, the quantitative estimation by HPLC with a fluorescence detector showed that the amounts of scopoletin content (0.10 μg g⁻¹ DW) in the leaves of micropropagated plants are comparable to those of field-grown mother plants. The study thus signifies the effectiveness of in vitro methodology for true-to-type plant regeneration of Spilanthes and their later utility for biosynthesis and constant production of scopoletin throughout the year.     

Protective Effect of <Emphasis Type="Italic">Nigella sativa</Emphasis> Extract and Thymoquinone on Serum/Glucose Deprivation-Induced PC12 Cells Death

The serum/glucose deprivation (SGD)-induced cell death in cultured PC12 cells represents a useful in vitro model for the study of brain ischemia and neurodegenerative disorders. Nigella sativa L. (family Ranunculaceae) and its active component thymoquinone (TQ) has been known as a source of antioxidants. In the present study, the protective effects of N. sativa and TQ on cell viability and reactive oxygen species (ROS) production in cultured PC12 cells were investigated under SGD conditions. PC12 cells were cultured in DMEM medium containing 10% (v/v) fetal bovine serum, 100 units/ml penicillin, and 100 μg/ml streptomycin. Cells were seeded overnight and then deprived of serum/glucose for 6 and 18 h. Cells were pretreated with different concentrations of N. sativa extract (15.62–250 μg/ml) and TQ (1.17–150 μM) for 2 h. Cell viability was quantitated by MTT assay. Intracellular ROS production was measured by flow cytometry using 2′,7′-dichlorofluorescin diacetate (DCF-DA) as a probe. SGD induced significant cells toxicity after 6, 18, or 24 h (P < 0.001). Pretreatment with N. sativa (15.62–250 μg/ml) and TQ (1.17–37.5 μM) reduced SGD-induced cytotoxicity in PC12 cells after 6 and 18 h. A significant increase in intracellular ROS production was seen following SGD (P < 0.001). N. sativa (250 μg/ml, P < 0.01) and TQ (2.34, 4.68, 9.37 μM, P < 0.01) pretreatment reversed the increased ROS production following ischemic insult. The experimental results suggest that N. sativa extract and TQ protects the PC12 cells against SGD-induced cytotoxicity via antioxidant mechanisms. Our findings might raise the possibility of potential therapeutic application of N. sativa extract and TQ for managing cerebral ischemic and neurodegenerative disorders.     

Comparison of metabolite levels in callus of <Emphasis Type="Italic">Tecoma stans</Emphasis> (L.) Juss. ex Kunth. cultured in photoperiod and darkness

Tecoma stans is a tropical plant from the Americas. Antioxidant activity and both phenolic compound and flavonoid total content were determined for callus tissue of T. stans cultured in either a set photoperiod or in darkness. Callus lines from three explant types (hypocotyls, stem, and leaf) were established on B5 culture medium supplemented with 0.5 μM 2,4-D and 5.0 μM kinetin. While leaf-derived callus grew slower under a 16-h photoperiod (specific growth rate, μ = 0.179 d⁻¹, t _D = 3.9 d) than in darkness (μ = 0.236 d⁻¹, t _D = 2.9 d), it accumulated the highest amount (p < 0.05) of both phenolics (86.6 ± 0.01 mg gallic acid equivalents/g) and flavonoids (339.6 ± 0.06 mg catechin equivalents/g). Similarly, antioxidant activity was significantly higher (p < 0.05) when callus was cultured in period light than when grown in extended darkness. Antioxidant activity measured with a 2,20-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS)-based assay was 350.5 ± 15.8 mmol Trolox/g extract for callus cultured under a defined photoperiod compared to 129.1 ± 7.5 mmol Trolox/g extract from callus cultured in darkness. Content of phenolic compounds and flavonoids was in agreement with a better antioxidant power (EC₅₀ = 450 μg extract/mg 1,1-diphenyl-2-picrylhydrazyl) and antiradical efficiency. Results of the present study show that calli of T. stans are a source of compounds with antioxidant activity that is favored by culture under a set photoperiod.     

Effects of Exogenous Selenium on Nicotine-Induced Oxidative Stress in Rats

The effect of two different doses of selenium [1 and 50 μg selenium/100 g body weight (wt)] on nicotine-induced oxidative damage in liver was investigated in experimental rats. Male albino rats were maintained for 60 days as follows: (1) control group (normal diet), (2) nicotine group (0.6 mg/kg body wt)/day, (3) high-dose selenium (50 μg/100 g body wt)/day, (4) high-dose selenium (50 μg/100 g body wt) + nicotine (0.6 mg/kg body wt)/day, (5) low-dose selenium (1 μg/100 g body wt)/day, and (6) low-dose selenium (1 μg/100 g body wt) + nicotine (0.6 mg/kg body wt)/day. Nicotine administration caused a decrease in the activity of antioxidant enzymes, an increase in the concentration of lipid peroxidation products and protein carbonyls and an increase in the activity of nitric oxide synthase compared to the control group. Coadministration of nicotine and selenium reduced the concentration of lipid peroxidation products and increased the activity of antioxidant enzymes compared to the nicotine group. Selenium also enhanced the metabolism of nicotine. The antioxidant effect was more significant in the group administered a low dose of selenium.     

Production of psoralen by in vitro regenerated plants from callus cultures of <Emphasis Type="Italic">Psoralea corylifolia</Emphasis> L.

Psoralea corylifolia is an attractive, endangered annual producing various bioactive compounds of medical importance. This plant contributes to Indian pharmaceutical and cosmetic industries for the production of commercial medicines, Ayurvedic skin care ointments and soap. The influence of various plant growth regulators (PGRs) and additives on high-frequency rapid adventitious shoot regeneration from transverse thin cell layer (tTCL) hypocotyl explants of P. corylifolia was investigated. Organogenic callus was obtained in tTCL hypocotyl explants on Murashige and Skoog (1962) medium supplemented with 15 μM naphthaleneacetic acid (NAA) and 3 μM benzylaminopurine (BA). The highest adventitious shoot regeneration (107.5 shoots per explant) was achieved in culture when transferred to half-strength solid MS medium. The regenerated shoots were rooted and the plantlets successfully acclimatized in moistened (1/8-MS basal salt solution with 3 μM indole-3-butyric acid (IBA), 1 μM 2-isopentenyladenine (2iP) and 100 mg l⁻¹ Bavistin (BVN)); garden soil, farmyard soil and sand (2:1:1, v/v/v). The acclimatized plants produced flowers in the growth chamber. When planted in the field these plants set viable seed. The psoralen content in different tissues of ex vitro and naturally-grown plants was determined by high-performance liquid chromatography (HPLC). The highest psoralen content was recorded in seeds from naturally-grown (6.48 μg g⁻¹ DW) and ex vitro plants (6.46 μg g⁻¹ DW). This system can be used for rapid mass propagation of P. corylifolia, for conservation strategies, and to produce phytomedicines.     

Activity of 1-aminocyclopropane carboxylic acid synthase and growth of mustard (<Emphasis Type="Italic">Brassica juncea</Emphasis>) following defoliation

To examine the possible relationship between the activity of 1-aminocyclopropane carboxylic acid synthase (ACS; EC 4.4.1.14) and growth of mustard (Brassica juncea L.), ACS activity, ethylene and plant growth were studied in the presence of ACS activity modulators in no-defoliation and defoliated plants. Growth of plants was greatest when subjected to defoliation of 50% lower leaves in the plant axis compared to defoliation of 25% lower leaves or no-defoliation. The activity of ACS in no-defoliation and defoliated plants was correlative with growth of plants. ACS activity and ethylene evolution in no-defoliation plants treated with 10 μM indole-3-acetic acid (IAA) and defoliated plants treated with water were equal and resulted in maximum plant growth. On the contrary, the application of 10 μM IAA on defoliated plants resulted in the increase in ACS activity and ethylene evolution to an extent that inhibited the growth. The application of 100 μM IAA on no-defoliation and defoliated plants increased ACS activity and ethylene evolution maximally and proved inhibitory for the plant growth. The association of ACS activity, ethylene evolution and growth of plants was further substantiated with the use of 50 μM aminoethoxyvinyl glycine (AVG) applied alone or in combination with 10 or 100 μM IAA. The application of AVG resulted in the inhibition of ACS activity and the growth of no-defoliation or defoliated plants. The results indicate that there exists a correlation between ACS activity, ethylene and the growth of mustard plants.     

Content of the <Emphasis Type="Italic">Alternaria</Emphasis> mycotoxin tenuazonic acid in food commodities determined by a stable isotope dilution assay

The Alternaria mycotoxin tenuazonic acid (TA) was quantified in fruit juices (n = 50), cereals (n = 12) and spices (n = 38) using a recently developed stable isotope dilution assay (SIDA). [¹³ C₆,¹⁵ N]-TA was used as the internal standard. Method validation revealed low limits of detection (LODs) of 0.15 μg/kg (fruit juices), 1.0 μg/kg (cereals) and 17 μg/kg (spices). The respective limits of quantitation were about three times higher. Recovery was about 100% for all matrices. The precision (relative standard deviation of replicate analyses of naturally contaminated samples) was 4.2% (grape juice; 1.7 μg/kg), 3.5% (whole wheat flour; 36 μg/kg) and 0.9% (curry powder; 215 μg/kg). The median content of TA in the analyzed samples was 1.8 μg/kg (fruit juices), 16 μg/kg (cereals) and 500 μg/kg (spices). Positive samples amounted to 86% (fruit juices), 92% (cereals) and 87% (spices).