Antioxidant activity of different species and varieties of turmeric (Curcuma spp): Isolation of active compounds

There are >80 species of turmeric (Curcuma spp.) and some species have multiple varieties, for example, Curcuma longa (C. longa) has 70 varieties. They could be different in their chemical properties and biological activities. Therefore, we compared antioxidant activity, total phenolic and flavonoid content of different species and varieties of turmeric namely C. longa [variety: Ryudai gold (RD) and Okinawa ukon], C. xanthorrhiza, C. aromatica, C. amada, and C. zedoaria. The antioxidant activity was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, oxygen radical absorbance capacity (ORAC), reducing power and 2-deoxyribose (2-DR) oxidation assay. Our results suggested that RD contained significantly higher concentrations of total phenolic (157.4 mg gallic acid equivalent/g extract) and flavonoids (1089.5 mg rutin equivalent/g extract). RD also showed significantly higher DPPH radical-scavenging activity (IC₅₀: 26.4 μg/mL), ORAC (14,090 μmol Trolox equivalent/g extract), reducing power absorbance (0.33) and hydroxyl radical scavenging activity (IC₅₀: 7.4 μg/mL). Therefore, RD was chosen for the isolation of antioxidant compounds using silica gel column, Toyopearl HW-40F column, and high-performance liquid chromatography. Structural identification of the compounds was conducted using ¹H NMR, ¹³C NMR, and liquid chromatography-tandem mass spectrometry. The purified antioxidant compounds were bisabolone-9-one (1), 4-methyllene-5-hydroxybisabola-2,10-diene-9-one (2), turmeronol B (3), 5-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-1-hepten-3-one (4), 3-hydroxy-1,7-bis(4-hydroxyphenyl)-6-hepten-1,5-dione (5), cyclobisdemethoxycurcumin (6), bisdemethoxycurcumin (7), demethoxycurcumin (8) and curcumin (9). The IC₅₀ for DPPH radical-scavenging activity were 474, 621, 234, 29, 39, 257, 198, 47 and 18 μM and hydroxyl radical-scavenging activity were 25.1, 24.4, 20.2, 2.1, 5.1, 17.2, 7.2, 3.3 and 1.5 μM for compound 1, 2, 3, 4, 5, 6, 7, 8 and 9, respectively. Our findings suggested that the RD variety of C. longa, developed by the University of the Ryukyus, Okinawa, Japan, is a promising source of natural antioxidants.

Differential expression of CURS gene during various growth stages, climatic condition and soil nutrients in turmeric (Curcuma longa): Towards site specific cultivation for high curcumin yield

Curcuma longa L., accumulates substantial amount of curcumin and essential oil. Little is known about the differential expression of curcumin synthase (CURS) gene and consequent curcumin content variations at different agroclimatic zones. The present study aimed to evaluate the effect of climate, soil and harvesting phase on expression of CURS gene for curcumin yield in two high yielding turmeric cultivars. Expression of CURS gene at different experimental zones as well as at different harvesting phase was studied through transcriptional analysis by qRT-PCR. Curcumin varied from 1.5 to 5% and 1.4-5% in Surama and Roma respectively. The expression of CURS also varied from 0.402 to 5.584 fold in Surama and 0.856-5.217 fold in Roma. Difference in curcumin content at a particular zone varied among different harvesting period from 3.95 to 4.31% in Surama and 3.57-3.83% in Roma. Expression of CURS gene was also effected by harvesting time of the rhizome which varied from 7.389 to 16.882 fold in Surama and 4.41-8.342 fold in Roma. The CURS gene expression was found regardless of variations in curcumin content at different experimental zones. This may be due to the effects of soil and environmental variables. Expression was positively correlated with curcumin content with different harvesting time at a particular zone. This find indicates effect of soil and environment on molecular and biochemical dynamics of curcumin biosynthesis and could be useful in genetic improvement of turmeric.

Protocols for In Vitro Propagation, Conservation, Synthetic Seed Production, Microrhizome Production, and Molecular Profiling in Turmeric (Curcuma longa L.)

Turmeric is a rhizomatous herbaceous perennial but cultivated as annual, belonging to the family Zingiberaceae. It is a native of India and South East Asia. The tuberous rhizomes or underground stems of turmeric are used from antiquity as condiments, a dye and as an aromatic stimulant in several medicines. Turmeric is an important crop in India and it is used as a spice, food preservative, coloring agent, cosmetic as well as for its medicinal properties. Propagation is done vegetatively with rhizome bits as seed materials. It is plagued by rhizome rot diseases most of which are mainly spread through infected seed rhizomes. Micropropagation will help in production of disease-free seed. Sexual reproduction is rare in turmeric, making recombinant breeding very difficult. In vitro technology can thus become the preferred choice and it can be utilized for multiplication, conservation of genetic resources, generating variability, gene transfer, molecular tagging, and their utility in crop improvement.

In vitro growth of Curcuma longa L. in response to five mineral elements and plant density in fed-batch culture systems

Plant density was varied with P, Ca, Mg, and KNO₃ in a multifactor experiment to improve Curcuma longa L. micropropagation, biomass and microrhizome development in fed-batch liquid culture. The experiment had two paired D-optimal designs, testing sucrose fed-batch and nutrient sucrose fed-batch techniques. When sucrose became depleted, volume was restored to 5% m/v sucrose in 200 ml of modified liquid MS medium by adding sucrose solutions. Similarly, nutrient sucrose fed-batch was restored to set points with double concentration of treatments’ macronutrient and MS micronutrient solutions, along with sucrose solutions. Changes in the amounts of water and sucrose supplementations were driven by the interaction of P and KNO₃ concentrations. Increasing P from 1.25 to 6.25 mM increased both multiplication and biomass. The multiplication ratio was greatest in the nutrient sucrose fed-batch technique with the highest level of P, 6 buds/vessel, and the lowest level of Ca and KNO₃. The highest density (18 buds/vessel) produced the highest fresh biomass at the highest concentrations of KNO₃ and P with nutrient sucrose fed-batch, and moderate Ca and Mg concentrations. However, maximal rhizome dry biomass required highest P, sucrose fed-batch, and a moderate plant density. Different media formulations and fed-batch techniques were identified to maximize the propagation and storage organ responses. A single experimental design was used to optimize these dual purposes.

Factors affecting the accumulation of curcumin in microrhizomes of Curcuma aromatica Salisb

Curcuminoids, and mainly curcumin, are potential therapeutic agents for the prevention of various diseases; however, little is known about the factors that influence their accumulation in Curcuma species. In this study, the effects of factors such as sucrose concentration, different ratios of 6-benzylaminopurine (6-BA) and α-naphthalene acetic acid (NAA), and light quality on the accumulation of curcumin and other curcuminoids in Curcuma aromatica were investigated. Microrhizomes grown on media containing 3% sucrose produced more curcumin and other curcuminoids than those grown on higher concentrations. Moreover, when compared to other ratios of 6-BA and NAA, microrhizomes induced on 3% sucrose media supplemented with 3.0 mg/L 6-BA and 0.5 mg/L NAA produced more curcumin and other curcuminoids; however, the amount was less than in microrhizomes grown on 3% sucrose alone. We determined that a 5% sucrose medium supplemented with 3.0 mg/L of 6-BA and 0.5 mg/L of NAA enhanced the levels of curcumin and curcuminoids and that exposure to red light further increased production.

[Breeding of new Curcuma wenyujin variety "Wenyujin No. 1"]

In order to breed and spread a new cultivar of Curcuma wenyujin, the C. wenyujin germplasm resources were investigated in authentic regions. Better varieties were chosen by comparing the yield, economic characters and quality differences between different cultivars. The results showed that the character of new selected cultivar was stable, the yield of zedoary, turmeric and curcuma was reached 313.7, 177.9, 91.2 kg per 667 m2, respectively, it increased 11.6%, 10.2%, 14.2% comparing with farmer varieties. The volatile oil contents in zedoary and turmeric was 4.0%, 3.0%, respectively. The target ingredients (germacrone) content was stable. It is demonstrated that the new cultivar "Wenyujin No. 1" has value for extension at authentic regions.

[Dynamic accumulation regulation of curcumin, demethoxycurcumin and bisdemethoxyeurcumin in three strains of curcuma longae rhizome]

The paper is aimed to study the dynamic accumulation regulation of curcumin (Cur), demethoxycurcumin (DMC) and bisdemethoxyeurcumin (BDMC) in three strains of Curcuma longa, and provide scientific references for formalized cultivation, timely harvesting, quality control and breeding cultivation of C. longa. The accumulation regulation of the three curcumin derivatives was basically the same in rhizome of three strains. The relative contents decreased along with plant development growing, while the accumulation per hectare increased with plant development growing. The accumulation of curcuminoids per hectare could be taken as the assessment standard for the best harvest time of C. longa. A3 was the best strain in terms of Cur and BDMC content.

[GC-MS analysis of essential oil from Curcuma aromatica rhizome of different growth periods]

OBJECTIVE

To analyze the essential oil from the rhizome of Curcuma aromatica of different growth periods, and to provide the scientific reference for reasonable cultivation and quality control of this plant.

METHODS

The essential oil was extracted by hydrodistillation and analyzed with GC-MS. The relative contents were determined with area normalization method.

RESULTS

The main volatile constituents in the rhizome of Curcuma aromatica were basically the same. Among these volatile constituents, curdione was the major. The relative content of curdione was 16.35% in the rhizome of wild plant in Hengxian county, and 15.81% in the rhizome of one-year-old plant in Mingyang farm, Nanning city. The relative content of eucalyptol in the 2-year-old cultivated rhizome in Hengxian county was 15.40%, and 14.59% in the rhizome of wild plant in Hengxian county. beta-Elemene, beta-caryophyllene,eugenol and germacrone were also the main constituents in the rhizome essential oil.

CONCLUSION

Volatile constituents in the rhizome of Curcuma aromatica are similar to each other,but the relative content of each component is different. This result can provide the scientific foundation for the cultivation of Curcuma aromatica.

Micropropagation of a Thai medicinal plant for women's health, Curcuma comosa Roxb., via shoot and microrhizome inductions

We studied the effects of explant types, plant growth regulators, and sucrose concentrations on shoot and microrhizome inductions of Curcuma comosa Roxb., an important Thai medicinal plant for women's health. Explant types significantly affected shoot induction of the plant. The maximum shoot multiplication rate of 11.82 ± 1.03 shoots/responding explant was obtained when culturing terminal bud explants on semi-solid Murashige and Skoog (MS) medium supplemented with 18.16 μM thidiazuron for 8 weeks. Subsequently, they were transferred to a semi-solid MS medium without plant growth regulators for 4 weeks. The regenerated shoots produced roots spontaneously. Rooted plantlets were successfully transferred to the soil. Microrhizome induction was significantly influenced by sucrose concentrations, but not by 6-benzyladenine (BA). Liquid MS medium with a combination of 17.76 μM BA and 50 g L(-1) sucrose was optimal for microrhizome induction of C. comosa. After 12 weeks of culture, the microrhizome induction rate was 3.36 ± 0.44 microrhizomes/responding explant. Starch accumulation in microrhizomes increased with higher sugar concentration and with longer duration of culture. The microrhizomes were allowed to germinate under greenhouse conditions and further developed into normal plants. The protocols established will be used for the production of uniform plantlets suitable for field plantation for the herbal industry.

[Fingerprints of Curcuma wenyujin by RP-HPLC]

OBJECTIVE

To establish a mutual mode fingerprint of Curcuma wenyujin for quality control of C. wenyujin.

METHODS

Waters Symmetry C18 column was used; the mobile phase was methanol-water in a linear gradient elution with the flow rate of 1.0 mL/ min, the temperature of column was 30 degrees C; the detection wavelength was set at 215 nm. 10 batches of C. wenyujin from different places and different time were determined, 3 batches of C. phaeocaulis and 3 batches of C. kwangsiensis were determined in the same chromatographic conditions.

RESULTS

11 mutual peaks in the fingerprint of the 10 groups of C. wenyujin, and the S peak among them represented germacrone.

CONCLUSION

Curcuma wenyujin's fingerprints have strong feature and specificity, which can be combined with assaying in the quality control of C. wenyujin.

Short-term incorporation of organic manures and biofertilizers influences biochemical and microbial characteristics of soils under an annual crop [Turmeric (Curcuma longa L.)]

The study was conducted to determine whether short-term incorporation of organic manures and biofertilizers influence biochemical and microbial variables reflecting soil quality. For the study, soils were collected from a field experiment conducted on turmeric (Curcuma longa L.) involving organic nutrient management (ONM), chemical nutrient management (CNM) and integrated nutrient management (INM). The findings revealed that application of organic manures and biofertilizers (ONM and INM) positively influenced microbial biomass C, N mineralization, soil respiration and enzymes activities. Contrarily, greater metabolic quotient levels in CNM indicated a stressed soil microbial community. Principal component analysis indicated the strong relationship between microbial activity and the availability of labile and easily mineralizable organic matter. The findings imply that even short-term incorporation of organic manures and biofertilizers promoted soil microbial and enzyme activities and these parameters are sensitive enough to detect changes in soil quality due to short-term incorporation of biological fertilizers.

[Study on geo-herbalism of Curcuma wenyujin based on ecological factors]

OBJECTIVE

To reveal the effects of ecological factors on geo-herbalism,by researching the correlation between yields or qualities of Curcuma wenyujin and ecological factors.

METHODS

All measured dates were divided into three components, meteorological factors, soil conditions, the yields and qualities of geo-herbals, and analyzed through canonical correlation using SPSS software.

RESULTS

The results showed that there were two canonical correlation models to explain correlation between meteorological factors and yields or qualities of medicinal materials, as well as soil conditions and yields or qualities, and both of canonical correlations reached the significant or extremely significant level. The analysis indicated that main ecological factors affecting the yields or qualities of medicinal materials were average temperature from May to June,the days of high temperature (over 35 degrees C) and average rainfall from August to October, annual average rainfall, altitude, available potassium content in soil.

CONCLUSIONS

This study has tentatively made clear which ecological factors to affect the yields and qualities of Curcuma wenyujin; and provided some basis for revealing geo-herbalism of Curcuma wenyujin.

Assimilation and translocation of nitrogen and carbon in Curcuma alismatifolia Gagnep

Curcuma or Siam tulip (Curcuma alismatifolia Gagnep.) is an ornamental flowering plant with two underground storage organs, rhizomes and storage roots. Characteristics of N and C assimilation and transport in curcuma were investigated. The plants were treated with (15)NH(4) (+) + (15)NO(3) (-) and (13)CO(2) at 10, 13 or 21 weeks after planting. Plants were sampled at several stages up to 32 weeks. The C stored in old storage roots was used rapidly during the first 10 weeks; after which N stored in old rhizomes and old storage roots were used. The daily gain in C depending on photosynthesis was remarkably high between 10 and 21 weeks. However, the daily gain in N was relatively constant throughout the growth period. The (15)N absorbed at 10 weeks was initially accumulated in leaves and roots, but some was transported to flowering organs at 13 weeks. At harvest, 41% of (15)N was recovered in new rhizomes and 17% in new storage roots. After (13)CO(2) exposure at 10 and 13 weeks, the distribution of (13)C among organs was relatively constant in subsequent stages. When given (13)CO(2) at 21 weeks, a large amount of labelled C was recovered in new storage roots and new rhizomes at harvest. Both new rhizomes and new storage roots stored N and C, however, rhizomes played a more important role in supplying N, while storage roots provided C.

[Analysis on adaptive area of Curcuma wenyujin based on GIS]

OBJECTIVE

This stdudy was to determine the suitable area for Curcuma wenyujin in Wenzhou, and expand its growing region, based the growth characteristic of Curcuma wenyujin.

METHODS

The 13 main factors including climate, soil and other environmental conditions were selected. The best genuine production area was regarded as the goal area in similar calculation. The grid data was calculated from the station and sampling sites by Inverse Distance Interpolation on GIS. After normolizing to the grid data, the dimension effect was removed. on this basis, calculating the absolute distance of every cell to the the goal cell. Wenzhou region was divided into best suitable area, suitable area, second suitable area and unsuitable area by clustering analyzing.

RESULT

Most of area in Wenzhou are suit for Curcuma wenyujin, best suitable area, suitable area, second suitable area and unsuitable area reach 98% area of Wenzhou.

CONCLUSION

This result give important reference value of Curcuma wenyujin breeding in Wenzhou.

[Study on genetic diversity of Curcuma wenyujin from various habitats by SRAP]

OBJECTIVE

The DNA fingerprints of Curcuma wenyujin from various habitats were generated by using SRAP markers to find the feasibility in analyzing their relationship.

METHODS

The DNA polymorphism of Curcuma wenyujin from various habitats were detected by SRAP molecular markers.

RESULTS

We had screened five pairs of primer combinations, and built the DNA fingerprints of Curcuma wenyujin from various habitats. The phylogenetic clustering results revealed that the genetic difference in Curcuma wenyujin from various habitats were little.

CONCLUSION

SRAP markers may offer some evidence for protecting and exploiting of Curcuma wenyuji.

[Effect of different seminal rhizomes on yield and quality of Curcuma longa]

OBJECTIVE

To study the effect of different seminal rhizomes on the growth, quality and quantity of Curcuma longa root.

METHOD

Single factor randomized block design was applied, plant samples were collected and investigated periodically, and dry weight, production and the main active ingredient content were measured.

RESULT

The difference seminal rhizomes affected the growth, quality and quantity of C. longa root.

CONCLUSION

The bigger and stronger rhizomes should be chosen as seeds.

[Analysis of growth dynamics of Curcuma wenyujin]

OBJECTIVE

To study the accumulation of matter and dynamic of chemical compositions in rhizoma of Curcuma wenyujin for its cultivation.

METHODS

The weight of various parts and chemical composition content of rhizoma were determined at regular time.

RESULTS

The growth of Curcuma wenyujin could be divided into the seedling period, the rhizoma growing period and dry matter accumulating period. In seedling period, the aerial parts were the center of organism, the matter accumulated mainly in leaves; In rhizoma growing period, the organic center were gradually transformed from the aerial parts to the underground parts. The tendency of total chemical composition quantity in rhizome presented rises at first but gradually dropped at last.

CONCLUSIONS

The growth of Curcuma wenyujin has two organic centers, the seedling period and the rhizoma vegetal and weighted period. The total chemical composition quantity in Curcuma wenyujin rhizome reaches the maximum value from the last third part of October to mid-November.

Modules of co-regulated metabolites in turmeric (Curcuma longa) rhizome suggest the existence of biosynthetic modules in plant specialized metabolism

Turmeric is an excellent example of a plant that produces large numbers of metabolites from diverse metabolic pathways or networks. It is hypothesized that these metabolic pathways or networks contain biosynthetic modules, which lead to the formation of metabolite modules-groups of metabolites whose production is co-regulated and biosynthetically linked. To test whether such co-regulated metabolite modules do exist in this plant, metabolic profiling analysis was performed on turmeric rhizome samples that were collected from 16 different growth and development treatments, which had significant impacts on the levels of 249 volatile and non-volatile metabolites that were detected. Importantly, one of the many co-regulated metabolite modules that were indeed readily detected in this analysis contained the three major curcuminoids, whereas many other structurally related diarylheptanoids belonged to separate metabolite modules, as did groups of terpenoids. The existence of these co-regulated metabolite modules supported the hypothesis that the 3-methoxyl groups on the aromatic rings of the curcuminoids are formed before the formation of the heptanoid backbone during the biosynthesis of curcumin and also suggested the involvement of multiple polyketide synthases with different substrate selectivities in the formation of the array of diarylheptanoids detected in turmeric. Similar conclusions about terpenoid biosynthesis could also be made. Thus, discovery and analysis of metabolite modules can be a powerful predictive tool in efforts to understand metabolism in plants.

Extraction, processing, and storage effects on curcuminoids and oleoresin yields from Curcuma longa L. grown in Jamaica

Aromatic diarylheptanoid compounds from Curcuma longa Linn grown in Jamaica were quantified by UV-vis spectrophotometry and high-performance liquid chromatographic (HPLC) analyses. The oleoresin yields from ethanolic extracts were quantified and evaluated with regard to the effects of the type of postharvesting process and the type of extraction method conducted on the plant material. Fresh samples that were hot solvent extracted provided the highest oleoresin yields of 15.7% +/- 0.4 ( n = 3), and the lowest oleoresin yields of 7.8% +/- 0.2 ( n = 3) were from the dried milled samples that were cold solvent extracted. Data from the ASTA spectrophotometer assay confirmed that dried samples contained the highest curcuminoid content of 55.5% +/- 2.2 ( n = 6) at the fifth month of storage, and the fresh samples showed a curcuminoid content of 47.1% +/- 6.4 ( n = 6) at the third month of storage. A modified HPLC analysis was used to quantify curcumin content. Data from the HPLC analysis confirmed that the dried treated, hot extracted, room temperature stored samples had the highest curcumin content of 24.3%. A novel high-performance thin layer chromatography (HPTLC) method provided a chemical fingerprint of the C. longa with the use of a commercial curcumin standard.

[Study on growth and dry substance accumulation of Curcuma longa]

OBJECTIVE

To explore the growth characteristics of Curcuma longa, and provide basis for standardized cultivation.

METHOD

Plant samples were collected and investigated periodically.

RESULT

According to the growth of different parts and the characteristics of dry substance accumulation of C. longa, the development of C. longa could be divided into five stages: emergence of seedlings, seedling, leaf, root tuber expansion, and dry substance accumulation of root tuber. In terms of number, leaf of C. longa increases gradually from one at first to eight at the final stage. Leaf size increases at a very low speed at the stage of seedling. However, leaves expands their sizes at a much higher speed at the stage of leaf. The dry substance in different parts accumulates increasingly with the development of C. longa dry substance mainly accumulates in leaves at the stage of leaf, and in rhizome at the stage of root tuber expansion. At the final stage, it mainly accumulates in root tuber.

CONCLUSION

Cultivation technologies of C. longa and the relevant management methods could be established according to the growth of different parts of C. longa and the characteristics of dry substance accumulation in different stages.

[Study on effects of seed stock, cultivating density on the yields and volatile oil of Curcuma wenyujin]

OBJECTIVE

According to the study on effects of cultivating density and seed stock on the yield and volatile oil, to provide a scientific basis for standardized cultivating measures.

METHODS

The yield and the content of volatile oil at harvest were counted and analyzed the variance by SPSS.

RESULTS

The effect of cultivating density on the yields from 3 different medicinal parts of medical material was significant. The effect of seed stock on the yield of Rhizoma wenyujin concisa and Rhizoma wenyujin curcumae was significant, but to the yield of Radix wenyujin curcumae was very little. The mutual effect between cultivating density and seed stock was also very little.

CONCLUSION

The cultivating density play an important role in the yields of Curcuma wenyujin.

Accumulation of bioactive compounds during growth and development of mango ginger (Curcuma amada Roxb.) rhizomes

Accumulation of bioactive compounds and storage components during developmental stages of mango ginger ( Curcuma amada Roxb.) rhizome was investigated from 60 to 240 days, as a function of physiological maturity. Four distinct developmental phases were defined, namely, vegetative phase (up to 60 days from planting), initiation and development phase (60-150 days), maturation phase (150-180 days), and senescence phase (180 days). Difurocumenonol, a bioactive terpenoid compound and phenolics were identified as biomarkers, to determine the optimum physiological maturity to harvest mango ginger rhizome. Accumulation of phenolics was observed in newly initiated rhizomes (after 60 days from planting). The phenolic content was high in mango ginger pulp compared to its juice. Newly initiated rhizome contained no difurocumenonol, and it was observed after 120 days after planting. Peak accumulation of phenolics, difurocumenonol, and total protein were noticed in 180 day old rhizome. Accordingly, the abundance of these components on 180 days was set as an optimum maturity standard for harvest of mango ginger rhizome, compared with a conventional harvest period that ranges from 200 to 240 days.

[Study on growth characteristics of Curcuma wenyujin]

OBJECTIVE

To study on growth characteristics of Curcuma wenyujin, and provide theoretical basis for the development of high-quality and high-yield medical material.

METHOD

The morphological change of the plant was observed periodically, the content of volatile oil and dry matter in leaves, rhizome, root tuber was determine.

RESULT

The growth of C. wenyujin could be divided into 5 stages, i. e. seed germination, seedling, leaf growth, rhizome expansion, accumulation of dry matter, respectively. Before the stage of rhizome expansion, over 70% dry matter was accumulated in the aerial part of the plant, and during the stage of leaf growth, the maximum increase rate of dry matter in aerial part was 3.90 g/p/d. During the stage of rhizome expansion, the ratio of dry matter of rhizome increased quickly and reached above 33% , and the increase rate of dry matter of rhizome rise up to 3.83 g/p/d, in the end of the stage, the content of volatile oil in the rhizome also rose up to 1.20 mL x 100 g(-1).

CONCLUSION

During the whole growth stage, there are two growth centers, when the two curves of dry matter increase of aerial part and rhizome intersect, it is regarded as a signal that the growth transformed form the aerial part to rhizome. When the rate of dry matter from rhizome rise, the content of volatile oil in rhizome rises quickly with the increase of dry matter in rhizome. The optimal harvest time is in mid-December.

Carbohydrate metabolism in Dioscorea esculenta (Lour.) Burk. tubers and Curcuma longa L. rhizomes during two phases of dormancy

We have examined the changes in carbohydrate metabolism in food yam (Dioscorea esculenta (Lour.) Burk.) tubers and in an economically important spice cum medicinal plant turmeric (Curcuma longa L.) rhizomes under storage. Both specimens showed varied levels of dormancy and sprouting appeared at the end of dormant period. Harvested, fully matured tubers of yam and rhizomes of turmeric were stored in wooden boxes under the conditions of 28+/-2 degrees C temperature and 65-75% relative humidity (RH) in dark. The starch, sugars, enzymes of starch degradation, respiration, glycolysis, tricarboxylic acid (TCA) cycle and oxidative pentose phosphate pathway (PPP) were studied during 1-70 days after harvest (DAH). This investigation revealed that, the starch degradation and the enzymes involved, viz. alpha-amylases and starch phosphorylase showed a lower level of activity during early period of dormancy, while sugar content and enzymes of carbohydrate metabolism increased rapidly during sprouting. The isoenzymic profiles of alpha-amylases showed marked variations in these two phases. The key enzymes of glycolysis, TCA cycle and PPP, viz. aldolase, succinic dehydrogenase, malic dehydrogenase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were increased even before the visible appearance of sprouting and their activities were at their maximum during sprouting. Based of the observations the dormancy period may be distinctly divided into peak period of rest and presprouting period.

[Primary study on rapid propagation of Curcuma xanthorrhiza]

Using the rhizome of Curcuma xanthorrhiza Roxb. as explant to induce the adventitious bud, multiplication and radication. The results showed that the inducing and differentiating of bud was better on MS + 6-BA 1.0 mg/L + NAA 0.5 mg/L, the multiplication of bud was on MS+6-BA 1.2 mg/L + NAA 0.l mg/L and the redication was on 1/2 MS + NAA 0.5 mg/L.

Metabolic profiling of turmeric (Curcuma longa L.) plants derived from in vitro micropropagation and conventional greenhouse cultivation

Turmeric (Curcuma longa) was considered only a culinary spice in many parts of the world until the notable anti-inflammation curcuminoids were discovered from this herb. Because it is a sterile triploid and is propagated vegetatively by rhizome division, turmeric is susceptible to pathogens that accumulate and are transmitted from generation to generation, and amplification of particularly useful stocks is a slow process. An in vitro propagation method has been developed to alleviate these problems. Metabolic profiling, using GC-MS and LC-ESI-MS, was used to determine if chemical differences existed between greenhouse-grown and in vitro micropropagation derived plants. The major chemical constituent curcuminoids, a group of diarylheptanoid compounds, as well as major mono- and sesquiterpenoids were identified and quantified. Principal component analysis and hierarchical cluster analysis revealed chemical differences between lines (T3C turmeric vs Hawaiian red turmeric) and tissues (rhizome, root, leaf, and shoot). However, this analysis indicated that no significant differences existed between growth treatments (conventional greenhouse-grown vs in vitro propagation derived plants).

An efficient protocol for genetic transformation and shoot regeneration of turmeric (Curcuma longa L.) via particle bombardment

Turmeric (Curcuma longa L.) is an important spice crop plant that is sterile and cannot be improved by conventional breeding. An efficient method for stable transformation for turmeric, C. longa L., was developed using particle bombardment. Callus cultures initiated from shoots were bombarded with gold particles coated with plasmid pAHC25 containing the bar and gusA genes each driven by the maize ubiquitin promoter. Transformants were selected on medium containing glufosinate. Transgenic lines were established on selection medium from 50% of the bombarded calluses. Transgenic shoots regenerated from these were multiplied and stably transformed plantlets were produced. Polymerase chain reaction (PCR) and histochemical GUS assay confirmed the stable transformation. Transformed plantlets were resistant to glufosinate.

[Effects of seeding and sowing methods on the yields of root tubers of Curcuma longa]

OBJECTIVE

To provide a scientific basis for standardizing the cultivation method for Curcuma longa.

METHOD

Plant heights and seeding numbers were sampled periodically, the plot yields were counted a tharvested.

RESULT

The effects of seeding method on yields, plant height and number were significant. The effects of different sowing ways on the yields were very little.

CONCLUSION

The hole seeding method using mother tuber or blastostyle bearing three to four knots was shown to be the best may, worthy to be widely applied in production.

Comparison of yield, composition, and antioxidant activity of turmeric (Curcuma longa L.) extracts obtained using various techniques

Turmeric extracts were obtained from two lots of raw material (M and S) using various techniques: hydrodistillation, low pressure solvent extraction, Soxhlet, and supercritical extraction using carbon dioxide and cosolvents. The solvents and cosolvents tested were ethanol, isopropyl alcohol, and their mixture in equal proportions. The composition of the extracts was determined by gas chromatography-flame ionization detection (GC-FID) and UV. The largest yield (27%, weight) was obtained in the Soxhlet extraction (turmeric (S), ethanol = 1:100); the lowest yield was detected in the hydrodistillation process (2.1%). For the supercritical extraction, the best cosolvent was a mixture of ethanol and isopropyl alcohol. Sixty percent of the light fraction of the extracts consisted of ar-turmerone, (Z)-gamma-atlantone, and (E)-gamma-atlantone, except for the Soxhlet extracts (1:100, ethanol), for which only ar-turmeronol and (Z)-alpha-atlantone were detected. The maximum amount of curcuminoids (8.43%) was obtained using Soxhlet extraction (ethanol/isopropyl alcohol). The Soxhlet and low pressure extract exhibited the strongest antioxidant activities.

High-frequency shoot multiplication in Curcuma longa L using thidiazuron

The effects of plant growth regulators, explant types, and culture regimens were investigated on in vitro shoot proliferation from terminal bud explants of Curcuma longa. Each bud was longitudinally divided into four equal pieces, each 1 cm in length, and used as explants. These were then cultured on MS medium supplemented with 18.17 microM thidiazuron for 4 weeks prior to transfer to MS medium without growth regulator for 8 weeks. Under these conditions, a shoot induction rate of 18.22+/-0.62 shoots/explant was obtained after 12 weeks of cultures. Spontaneous rooting was achieved. The regenerated plants were transferred to soil under greenhouse conditions and subsequently grown successfully in the field.

[A study on soil suitability for growth of rhizome of Curcuma longa L]

OBJECTIVE

To seek for the type of soil that influences favorably the yield and quality of Curcuma longa.

METHOD

Field contrast control experiment, correlation analysis, path analysis and cluster analysis were used.

RESULT

The rhizome yield and quality of Curcuma longa. varied greatly with the types of soil texture. There are clear correlations among the soil factors, as well as between the soil factors and the rhizome yield and quality of the plant. A regression equation of the rhizome yield and soil factors has been built up.

CONCLUSION

The soil suitable for growing Curcuma longa. can be classified into three types according to the results of correlation analysis and cluster analysis.

[A study on fresh rhizome simulation model and its application to comprehensive agronomic measures for good quality and high yield of Curcuma longa L]

OBJECTIVE

To work out standardized cultivating measures for Curcuma longa according to the analysis of fresh rhizome simulation model.

METHOD

Second order orthogonal rotative regression design.

RESULT

The fresh rhizome simulation model was built up, and 5 main measures that affect fresh rhizome yield were analyzed by the mathematical model of five unknowns second order orthogonal rotative regression. Sowing time, plant population and potassium play an important role in raising the fresh rhizome yield. Sowing time is clearly interrelated with plant population, and plant population is clearly interrelated with the fertilizer used Sufficient N and K are necessary for raising the yield. There is a clear interrelation among the fertilizer factors.

CONCLUSION

Optimal farming measures: sowing time March 1-17, and plant population-110,000 to 115,000 mother rhizomes per hm2. The optimal fertilizer requirements have also been formulated.

[Effect of growth period, storage time and varieties on the contents of main active constituents of Curcuma longa L. in rhizome]

OBJECTIVE

To provide criteria for selection, storage and cultivation of the rhizome of Curcuma longa.

METHOD

Field observation and sample analysis on the rhizome.

RESULT

The contents of curcuminoids and essential oils in mother and daughter rhizome went up with the progress of plant development. The contents of curcuminoids reached the maximum in early September and early October. The contents of essential oils in mother rhizome reached the maximum in early September. The contents of curcuminoids and essential oils in the rhizome varied with the species and went down with the increase of storage years.

CONCLUSION

The rhizome should be collected when leaves of the plant have just withered. The suitable storage time is three years.

[Effects of cultivating measures on rhizome yield and some main active constituents of Curcuma longa L]

OBJECTIVE

To substantiate the effects of cultivating measures on the rhizome yield and main active constituents of Curcuma longa.

METHOD

Randomized block design was applied to the study of the sowing time and plant density, and orthogonal experiment L9 (3(4)) was conducted to determine the quantity of fertilizer.

RESULT

The effects of cultivating measures on the rhizome yield and some main active constituents of Curcuma longa were noticeable. The rhizome yield went up, and the contents of curcuminoids and essential oils went down with the increase of fertilizer application.

CONCLUSION

The main cultivating measures for high-yield and good-quality of rhizome: rational sowing time-late March, plant population-12 checkrows per m2, 1 mother rhizome per checkrow. The suitable fertilizer requirements have also been formulated.