Nerine Bowdenii Research Articles

Isolation of Amaryllidaceae alkaloids from Nerine bowdenii W. Watson and their biological activities

Twenty-two isoquinoline alkaloids (1–22) were isolated from fresh bulbs of Nerine bowdenii (Amaryllidaceae) by standard chromatographic methods.

792. NERINE BOWDENII SUBSP. WELLSII

SummaryA subspecific name for the very hardy northern Drakensberg form of Nerine bowdenii Watson from South Africa is validated as N. bowdenii Watson subsp. wellsii C.A. Norris ex G.D. Duncan. A description and details of its history, taxonomy, distribution and cultivation requirements are given, accompanied by a watercolour painting, habitat photographs and distribution map.

Isolation and Cholinesterase Activity of Amaryllidaceae Alkaloids from Nerine bowdenii

Amaryllidaceae species are known as ornamental plants. Some contain galanthamine, an acetylcholinesterase inhibitor. The chemical composition of the alkaloid extract of bulbs of Nerine bowdenii Watson has been analyzed by means of GC/MS. Twenty-two compounds were detected and nineteen of them identified, one of which was belladine. The alkaloid extract showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 = 87.9 +/- 3.5 microg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 = 14.8 +/- 1.1 microg/mL). Belladine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 781 +/- 12.5 microM and 284.8 +/-4.2 microM, respectively.

Isolation of acetylcholinesterase inhibitory alkaloids from Nerine bowdenii

Alzheimer's disease (AD) is associated with a steady loss of attention and memory, which has been correlated with the impairment of brain cholinergic neurotransmission, particularly a deficit of cholinergic neurons in the nucleus basalis of Meynert. Therefore, one of the methods that has proven successful in the treatment of AD is the use of inhibitors of acetylcholinesterase (AchE) to supplement the acetylcholine level. Herein we describe the isolation of several AchE-inhibiting alkaloids from the bulbs of Nerine bowdenii, an Amaryllidaceae species. For the first time 11-O-acetylambelline and filofiline, previously reported from Brunsvigia josephinea and Nerine filifolia, respectively, were isolated.

네리네(Nerine bowdenii)의 기내 인편배양시 자구형성에 미치는 생장조절제와 Sucrose 농도의 영향

The twin-scale segments of nerine (Nerine bowdenii) were cultured to investigate the influence of NAA, BA and sucrose concentrations on in vitro bulblet formation. The formation of bulblets from twin-scale segments showed a good response both the percentage of bulblet formation and the number of bulblets per explant on MS medium supplemented with 1mg/L NAA and 2 mg/L BA. Formation of bulblet showed the highest efficiency on medium containing 30g/L, and the formation of bulblets was strongly inhibited on medium containing over 90g/L. When the twin-scale segments formed bulblets were subcultured three times to the same medium by 60 day subculture interval, the number of bulblets per explant was 6.5, 7.3 and 8.2 in order of first, second and third. The bulblets over 3mm in diameter were hypertrophied and rooted after transferring to the hormone-free MS medium. The plantlets over 50mm in height were successfully acclimatized in the soil mixed with the same volume of vermiculite and perlite, and the survival rate was over 95％.

Isolation of the Acetylcholinesterase Inhibitor Ungeremine from Nerine bowdenii by Preparative HPLC Coupled On-Line to a Flow Assay System

In an attempt to isolate the active compound while detecting acetylcholinesterase inhibitory activity, we applied a fluorometric flow assay system to an on-line coupled preparative HPLC. The MeOH extract of Nerine bowdenii showed a strong inhibitory peak in the on-line assay, and the active compound was isolated by CPC and HPLC. It was identified as ungeremine by analysis of its (1)H-NMR, 2D-NMR, and NOESY spectra. The assignment of the active N. bowdenii constituent was also confirmed by co-TLC, co-HPLC, and co-(1)H-NMR experiments using an authentic sample of synthetic ungeremine. The IC(50) value of ungeremine was 0.35 microM, showing stronger activity than galanthamine (2.2 microM).

Determining acetylcholinesterase inhibitory activity in plant extracts using a fluorimetric flow assay.

A fluorometric assay for acetylcholinesterase inhibitory activity was developed in a flow system using the fluorogenic substrate 7-acetoxy-1-methyl quinolinium iodide which is hydrolysed to the highly fluorescent 7-hydroxy-1-methyl quinolinium iodide. The detection limit of galanthamine is 0.5 microM, which is about 20 times more sensitive than in the colorimetric flow assay. In the presence of 30% methanol or of 5% acetonitrile, about 70% of the enzyme activity could still be detected. Various plant extracts have been screened using the described system including bulbs of Galanthus nivalis, Eucharis amazonica (E. x grandiflora), Crinum powelli and Nerine bowdenii (all members of the Amaryllidaceae), which showed strong AchE inhibitory activity.

Qualitative determination of false-positive effects in the acetylcholinesterase assay using thin layer chromatography.

A method has been developed to determine the false-positive effects on acetylcholinesterase inhibition in the TLC assay based on Ellman's method. Various aldehydes and amines have been tested in order to determine whether the observed inhibition is due to a true enzyme inhibition or due to the inhibition of the reaction between thiocholine and 5,5'-dithiobis-(2-nitrobenzoic acid). 4-Dimethylaminobenzaldehyde, 3-ethoxy-4-hydroxybenzaldehyde, diethylamine, triethylamine, triethanolamine and tyramine showed real enzyme inhibition, although their activity was about 10(3) times lower than that shown by galanthamine. Heptanal, decanal, cinnamaldehyde, anisaldehyde, benzaldehyde, hexylamine and tryptamine appeared to show a non-specific chemical inhibition. By checking this chemical inhibition on the TLC assay, the true enzyme inhibition could be distinguished from the false-positive chemical inhibition observed in the toluene extract of Nerine bowdenii in the course of isolation of active compounds.

BULB PRODUCTION OF NERINE BOWDENII AND YEAR ROUND STORAGE

Traditionally Nerine bowdenii is grown in glasshouses in a one year cycle. The period that the crop is growing in the glasshouse is 8-9 months and after harvesting of the flowers, the bulbs are stored at 2-5°C for 3-4 months. A shorter storage period will lead to problems with dormancy while a storage period longer than 5 months will lead to inflorescence-abortion. Apparently the optimal culture cycle is one year, and consequently bulbs have to be planted each year in the same period. In theory, Nerine bowdenii bulbs can be planted throughout the year which leads to a year round supply of flowers. When however, flowering is planned from February until June, abortion of the inflorescence is likely to occur due to the climatic conditions during winter or, to the hot growing conditions of the bulbs after flowering in the previous years. It was found that flower production in the period from February to June is possible when bulb production and flower production are separated: outdoor bulb production with an extended storage period of the bulbs (at lower temperatures) is combined with flower production in the glasshouse. Bulbs grown outdoors could be stored for 13 months. Storage at 0-l°C gave much better flowering percentage than at 2-5°C. In addition, 1-2 months at 13°C before cool storage is necessary to prevent rotting, without affecting abortion of the inflorescence.

Changes in Carbohydrate Composition of the Different Bulb Components of Nerine bowdenii W. Watson (Amaryllidaceae)

Flowering-size Nerine bowdenii bulbs were sampled from a commercial planting at 2-week intervals from 13 Aug. 1991 to 14 June 1992. They were dissected, the dry weight of foliage and leaf bases was recorded, and carbohydrate analysis was performed on the foliage leaves, leaf bases, and roots. Starch was the dominant storage carbohydrate, and leaf bases were the principal bulb structures where it was stored. Changes in starch content closely followed dry weight changes in the bulb. When exposed to low temperatures, starch was converted to sugars. Except for these high levels in the leaf bases, sugars, expressed both as concentration and total content, were low in bulb components, indicating continued export and conversion to starch. Low sugar levels during the period that florets in the current season's inflorescence develop to stage Late G (gynoecium elongated, carpels fused) is implicated in the abortion of the inflorescence.

The Effect of Irradiance, Defoliation, and Bulb Size on Flowering of Nerine bowdenii W. Watson (Amaryllidaceae)

Large Nerine bowdenii bulbs (>14 cm in circumference) were exposed to low ligbt intensities for different periods during two successive growing seasons. The flowering percentage and number of florets in the current season's inflorescence were recorded at anthesis. Small and large bulbs were subjected to continual defoliation starting at different times during the growing season. Bulbs were dissected at planting (26 Sept. 1992) and on 12 Jan. 1993 (nondefoliated control bulbs) to determine growth and developmental stage. At anthesis, inflorescences were harvested and the florets per inflorescence were counted. After anthesis in the fall, all bulbs were dissected and the following variables recorded: 1) percentage flowering, quiescence, or abortion of the current season's inflorescence; 2) developmental stage of quiescent inflorescences; 3) number of florets in the outermost inflorescence; 4) developmental stage of the innermost inflorescence; 5) number of leaves or leaf bases in each growth unit; 6) number of daughter bulbs; and 7) dry weight of new leaf bases. There were three reasons for nonflowering of the bulbs, viz., failure to initiate an inflorescence, inflorescences remaining quiescent, and inflorescence abortion. Individual florets that had not reached stage “Late G” (gynoecium elongated, carpels fused) at the start of rapid inflorescence elongation aborted. The more florets that aborted, the greater the probability that the entire inflorescence aborted. The inflorescence was more vulnerable to stress during the first half of the growing season due to its relatively weak position in the hierarchy of sinks within the bulb.

Comparative Growth and Development of Nerine bowdenii W. Watson: Bulbs in Situ versus Replanted

Flowering-size Nerine bowdenii bulbs were sampled from a commercial planting at 2-week intervals from 13 Aug. 1991 to 14 June 1992. They were dissected, and the following variables were recorded: 1) number and dry weight of fully sheathing leaf bases or leaves of each growth unit, 2) length and dry weight of foliage leaves, 3) fresh weight of outermost inflorescence, and 4) dry weight of daughter bulbs. Bulb organs that served as sinks and sources changed as the bulb progressed in its growth and developmental cycle. Before the new foliage provided photosynthates, growth depended on reserves deposited and stored in leaf bases during the preceding seasons. Reserves were used for the development of new leaves (foliage and bases), roots, and daughter bulb enlargement. Once the foliage became the photosynthate source, reserves were stored in old and new leaf bases. The inflorescence became the major sink when elongation of the scape initiated. Thereafter, daughter bulbs became the dominant sinks, receiving photosynthates from the senescence foliage and the reserves stored in leaf bases. The decrease in dry weight of the leaf bases was prominent in bulbs that remained in situ.

Periodicity of Inflorescence Initiation and Development in Nerine bowdenii W. Watson (Amaryllidaceae)

Nerine bowdenii bulbs were sampled from a commercial planting and dissected at 2-week intervals from 9 Oct. 1990 to 12 Nov. 1991. The following variables were recorded: number of florets per inflorescence, differentiation stage of the oldest floret, exterior dimensions of the inflorescence, and the number of leaf primordia between the two innermost inflorescences and between the innermost inflorescence and the vegetative apex. Scanning electron micrographs were made of the inflorescences at different stages of development. The development of the inflorescences of the growth units appeared to be synchronized. When the florets of the outermost inflorescence reached stage Late G (gynoecium elongated, carpels fused), the spathe started to elongate. When florets in the second inflorescence reached stage Mid G (three carpels elongated, not fused), the innermost inflorescence was initiated. Inflorescence development passed through three phases: 1) a floret initiation phase of ≈1 year, when nine to ten florets were initiated, 2) a differentiation phase, also ≈1 year long, when individual florets developed up to stage Late G, and 3) an inflorescence enlargement phase, which lasted ≈4 months and culminated in anthesis. Leaf primordia were initiated at the same rate as florets (one per month) and the vegetative phase for a growth unit was completed within 1 year.

Monocotyledonous Plants as Hosts for Agrobacterium

Fifteen species from nine monocotyledonous families were inoculated with strains of Agrobacterium tumefaciens, A. rhizogenes, and A. rubi. Tumor production was observed in seven of these species: Arthropodium cirratum (New Zealand rock lily), Cordyline australis (New Zealand cabbage tree), Dioscorea bulbifera (yam), Monstera deliciosa (fruit salad plant), Nerine bowdenii, Polygonatum x hybridum (Solomon's seal), and Zantedeschia aethiopica (arum lily). The use of appropriate controls for Agrobacterium inoculations and the detection of opines in extracts from most of these tumors confirmed that they had resulted from Agrobacterium-mediated gene transfer. Chlorophyll retention around tumors during senescence in some of the plant species was attributed to the expression of the T-DNA isopentyl-transferase gene. We conclude that more monocotyledons are hosts for Agrobacterium transformation than previously thought. Important factors for the induction of tumors included the choice of Agrobacterium strain, the growth phase of the plant, and the organ being inoculated.

Ultrastructural Study of Cytoplasmic Inclusions in Plants Infected with Potyviruses

AbstractThe ultrastructure of cell inclusions of different ornamental plants infected with several filamentous viruses of the potyviruses was studied at the transmission electron microscope. The plants examined were: Crocus sativus, Hyacinthus sp., Gladiolus sp., rhizomatous Iris, Muscari sp., Nerine bowdenii and Sparaxis sp. Differences in morphology of cylindrical inclusions have been used to separte the potyviruses in several subdivisions.

Extending Vaselife and Improving Quality of Nerine Cut Flowers with Preservatives

Abstract The addition of chemicals, particularly sucrose and silver, to flower holding solutions prolongs the vaselife of many cut flowers. These preservatives have their greatest effect when used either continuously at lower 2% to 5% concentrations (holding solutions) (3), or at 10% to 20% concentrations for a short period immediately after harvest (pulse solutions). The optimal sucrose concentration for pulsing varies with species; 20% for gladiolus (4), 10% for bird of paradise (2), and 5% for leucospermum (1). Nerines are a cut flower crop of increasing importance in New Zealand, but little information exists on postharvest handling requirements. We evaluated the effects of floral preservatives on vaselife, flower development, and changes in fresh weight of Nerine bowdenii, W. Wats ‘Pink Triumph’ and ‘Bowdenii 63’.

Adventitious plantlet regeneration from floral stem explants of Nerine bowdenii W. Watts.

Explants (1.5 mm thick) from the floral stems of cv. Favoriet were cultured on a basal medium (containing Murashige and Skoog micro-elements, half-strength macro-elements and 4% sucrose) with 1 mg/litre BA and 0.5 mg/litre NAA, at 18 degrees C in continuous darkness. Bulblet regeneration was strongly influenced by the age (length) of the original floral stem, optimal regeneration occurring with immature stems 2.5 to 10 cm in length. To obtain plantlets the regenerated bulblets were subcultured on a cytokinin-free medium (with macroelements increased to full strength) at 25 degrees in continuous light. Plantlets were easily transplanted into soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Nerine latent virus: some properties and serological detectability in Nerine bowdenii

Nerine latent virus (NeLV), first found inNerine bowdenii, may occur also in the otherNerine species investigated so far:N. sarniensis, N. flexuosa ‘Alba’, andN. ‘Mansellii’.

Narcissus mosaic virus found in Nerine bowdenii. Identification aided by anomalies in SDS PAGE.

Narcissus mosaic virus was isolated from naturally infected Nerine bowdenii cv. ‘Rose Queen’; hitherto it has been found only in narcissus. It was identified by the morphology of its particles, its serological specificity, symptoms in various plant species and by the specific anomalous behavior of its coat protein in sodium dodecyl sulfate (SDS) PAGE. N. bowdenii cv. ‘Rose Queen’ also contained another virus with particles about 660 nm long, but this has so far not been identified.

Biosynthesis in the Amaryllidaceae. Incorporation of 3-C14-Tyrosine and Phenylalanine in Nerine Bowdenii W. Wats.

<b>Biosynthesis in the Amaryllidaceae. Incorporation of 3-C¹⁴-Tyrosine and Phenylalanine in</b> <i>Nerine Bowdenii</i> <b>W. Wats.</b>