Effect of Different Sowing Dates on Disease Initiation and Development of Roselle (<i>Hibiscus sabdariffa</i>L.) Leaf Spot Disease Caused by <i>Coniella musaiensis</i>Var. <i>hibisci</i>in Makurdi, Central Nigeria

The experiment was conducted mainly to investigate the effect of change in sowing dates on disease severity of Roselle (Hibiscus sabdariffa L) leaf spot caused by Coniella musaiensis Var hibisci, plant height, number of branches, number of fruits and calyx yield of Roselle (H. sabdariffa L). Five dates were selected with an interval of fourteen days (14) between the dates for two years (2003 and 2004) to determine the most appropriate time to sow the crop using two Roselle accessions;green (Acc1) and red (Acc3).The first date was determined by the establishment of the rains in the season. It was observed that change in sowing dates had significant (p = 0.05) effect on disease severity but not on plant height, number of branches, number of fruits and calyx yield. Plants sown on July 18/27 had lowest disease indices;and are thus the best and therefore recommended for cropping of Roselle.

Effect of Organic and Chemical Fertilization on the Growth and Yield of Roselle Plants Hibiscus sabdariffa L.

This study was carried out during the growing season 2012-2013 at the fields of Agricultural Research Services in Sulaymaniyah Govemorate, to study the effect of chicken manure, sheep manure and chemical fertilizer NPK on growth, sepals, seeds yield and some chemical constituents of Roselle plants grown under Sulaymaniyah conditions. The experiment included several treatments as follows： sheep manure, 75% sheep ＋ 25% chicken, 50% sheep ＋ 50% chicken, 25% sheep ＋ 75% chicken, entire chicken manure, chemical fertilizer NPK and unfertilized control. The obtained results showed that all treatments of organic fertilization and NPK were significantly enhanced the vegetative growth parameters, sepals and concentration of anthocyanin of Roselle plants sepals. The treatment of （25% sheep ＋ 75% chicken） gave the best results： plant height （205.33 cm）, stem diameter （33.45 ram）, number of branches/plant （22.33）, total leaf area （3.29 m2）, root dry weight （56.81 g）, number of fruits/plant （110）, fresh weight of fruits （818.44 g） and dry weight of sepals （52.65 g）. But the highest concentration of anthocyanin was in the treatment of （75% sheep ＋ 25% chicken） （260.33 mg/100 g） and the lowest concentration of oxalic acid was found in the treatment of （50% sheep ＋ 50% chicken） （4.69 mg/100 g）. The results of this study showed that the use of （25% sheep ＋ 75% chicken） could enhance the vegetative growth and produce maximum yield of RoseUe calyx.

Tissue Culture and Rapid Propagation System of Roselle(Hibiscus sabdariffa L.)

[Objectives]This study was conducted to establish a tissue culture and rapid propagation system of roselle(Hibiscus sabdariffa L.)[Methods]A tissue culture and rapid propagation experiment was carried out with roselle plants as materials to study the suitable explants,the best disinfection method,the best growth medium,the best rooting medium and the transplanting and domestication method of roselle.[Results]The lateral buds of roselle were the best explants.Sterilizing with 0.1%mercuric chloride for 7 min showed a contamination rate of 5%and achieved a survival rate of 90%.With MS as the basic medium,adding 1.0 mg/L 6-BA and 0.5 mg/L IBA could obtain the best effect of bud induction.The medium with the highest proliferation rate was MS+6-BA 0.5 mg/L+BA 0.1 mg/L.On the basis of 1/2MS,adding 0.5 mg/L NAA+0.5 mg/L IBA could make adventitious buds root fastest and most,and greatly improve the propagation coefficient.And 1∶1 perlite rock:peat soil was the best transplanting substrate,with which the transplanting survival rate reached 95%.[Conclusions]This study provides technical reference for rapid cultivation and large-scale planting of roselle.

Influence of Polyphenolic Contents on the Antioxidant Properties of Hibiscus sabdariffa Extract (HSE), Aged Garlic Extract (AGE) and Garlic Tablet (GT) in Vitro

This study compared the antioxidant properties of Hibiscus sabdariffa extract (HSE), commercial aged garlic extract (AGE, Kyolic) and garlic tablet (GT). The results indicate that HSE, AGE and GT are effective antioxidant as xanthine/xanthine oxidase generated superoxide ions are significantly inhibited in the presence of 20% (v/v) diethyl ether extract of HSE, AGE and GT by 100%, 66.39% and 18.61% respectively, while uric acid production is not affected byAGEand GT. However, at 2.5% and 5.0% (v/v) reaction volumes,HSEsignificantly inhibits uric acid production by 9.5% and 33.0% respectively, and this suggests that components ofHSEinhibit xanthine oxidase activity while AGE and GT scavenge superoxide. In addition, it is also found that the three extracts scavenge ABTS radical cations in dose-dependent manner. In all cell free assays, HSE is found to be more effective as an antioxidant when compared with AGE and GT under the same experimental conditions. Chromatographic and colorimetric analyses suggest thatHSEhas numerous different types of phenolic compounds with higher amount of phenolic compounds (14.9 mg/g) when compared withAGE(2.8 mg/g) and GT (3.6 mg/g) catechin equivalent respectively. Therefore, the effectiveness of antioxidant activities of these three extracts may be related to their phenolic content.

Comparative Effect of Foliar Application of Cow Dung, Wood Ash and Benlate on the Disease Initiation and Development of Roselle (Hibiscus sabdariffa L.) Leaf Spot Disease Caused by Coniella musaiensis Var. Hibisci. in Makurdi, Central Nigeria

A study on the comparative effect of cow dung, wood ash and benlate for the control of leaf spot disease of Roselle (Hibiscus sabdariffa L.) was carried out following the preparation and foliar application of the materials on selected Roselle plants of the green and red accessions (Acc1 & Acc3) in the field. The cow dung was fermented for 14 days while sour milk was added to wood ash, dissolved and all filtered and labeled. The spraying commenced soon after the plants were thinned to one and was done weekly until after 50% of the plants had flowered. Results showed significant (p = 0.05) difference between benlate, the synthetic fungicide and the bio-fertilizers (cow dung and wood ash) for the two years of the study. Disease severity was significantly lower in the benlate than in the bio-fertilizers. There was no significant difference in yield between the treatments although higher yield was recorded in benlate. Though the bio-fertilizers could not suppress infection, they aided the growth of the plants by boosting luxuriant growth. The result showed that these bio-fertilizers cannot be used as substitute to the synthetic fungicide for the control of this leaf spot disease caused by Coniella musaiensis var. hibisci. However, since they give equally good yield the bio-fertilizers can still be used to minimize the reliance upon use of chemical fungicides.

Optimization of Ultrasonic-assisted Extraction of Polysaccharide from Hibiscus syriacus L.

The ultrasonic-assisted extraction of polysaccharides from Hibiscus syriacus L. at 180 W low power was optimized by the single factor tests and orthogonal test. Extraction temperature,ultrasonic treatment time,extraction times,and material-to-liquid ratio were considered as independent variables. The results suggested that the best extraction condition were determined as the extraction temperature at 80 ℃,the ultrasonic treatment time of 40 min,the material-to-liquid ratio at1∶ 20（ g/ml）,and the extraction times of 3. Under the optimal conditions,the extraction rate of polysaccharides from Hibiscus syriacus was 3. 114%.

玫瑰茄花青素提取条件优化研究

运用四因素二次回归正交旋转组合设计试验方案，研究了温度、时间、液料比、乙醇浓度对玫瑰茄千花萼花青素提取率的影响，确定了花青素的较优提取范围。通过贡献率法计算表明，在试验范围内各因子对花青素提取率作用的大小依次为提取温度〉液料比〉提取时间〉乙醇浓度。频率分析得到花青素提取率高于0．05％的优化条件：温度为70．27～74．06℃，时间为1．57～1．76h，液料比为24．12～26．18，乙醇浓度为39．84％～44．94％。

超声波辅助提取玫瑰茄花青素的工艺优化

研究玫瑰茄花青素超声波辅助提取最佳工艺条件,采用pH示差法对花青素含量进行测定。在单因素试验基础上通过正交试验确定最佳提取工艺条件为固液比1∶25(g/mL),提取温度50℃,提取时间20 min,超声波功率80 W。在此最佳工艺条件下,花青素得率为0.566%。与传统浸提方法相比,得率提高了14.3%,且缩短了提取时间。

超声波辅助提取玫瑰茄多糖工艺研究

通过超声波辅助提取,对玫瑰茄多糖的提取工艺进行优化。在单因素试验基础上,选择超声波功率、提取温度、提取时间和固液比为考察因素,以玫瑰茄多糖提取率为评价指标,采用正交试验考察各个因素及其交互作用对玫瑰茄多糖提取率的影响。最佳提取工艺为:超声波功率为270 W,提取温度60℃,提取时间30 min,固液比1∶20(g/mL),提取2次,最佳提取条件下玫瑰茄多糖提取率为60.35%。

响应面法优化玫瑰茄粗多糖提取工艺及其抗氧化活性的研究

利用响应面法优化玫瑰茄粗多糖的提取工艺条件,测定粗多糖的抗氧化活性。按照Box-Behnken中心组合试验设计原理,以玫瑰茄粗多糖的得率为响应值,在单因素试验的基础上,进行响应面分析试验,考察料液比、提取时间和提取温度对得率的影响。玫瑰茄粗多糖最佳提取工艺条件为:料液比1∶26(g/mL)、提取时间3.1 h、提取温度90℃,在该最优条件下所得玫瑰茄粗多糖的得率为14.41%,与预测值接近;玫瑰茄粗多糖对DPPH、羟基、超氧阴离子自由基具有一定的清除作用。研究结果为玫瑰茄粗多糖的研究、开发和利用提供了理论基础。

大孔树脂吸附法提取玫瑰茄红色素

对使用大孔树脂吸附提取玫瑰茄红色素的条件和方法进行研究。通过7种树脂对玫瑰茄红色素的吸附及不同洗脱剂的解吸比较表明:HPD-100树脂对该色素有较好的吸附性能,用90%的乙醇洗脱,使用20次后其吸附性能无明显减弱,可循环使用。

紫荆花红色素开发利用的研究

首次报道紫荆花红色素的提取纯化方法及红色素的理化性质，并与玫瑰茄红色素作对比研究，证实同属于花青甙类化合物．又经急性毒性试验证明其毒性极低，故紫荆花天然红色素具有开发利用的价值。

Box-Behnken响应面法优化超声波-微波协同提取玫瑰茄多糖工艺

在单因素试验基础上,以玫瑰茄为原料,液料比、提取时间和微波功率为自变量,玫瑰茄多糖得率为因变量,采用Box-Behnken响应面法优化超声波-微波协同提取玫瑰茄多糖工艺,并和水浴浸提、微波提取、超声波提取进行比较。结果表明:超声波-微波协同提取玫瑰茄多糖最佳工艺条件为:液料比(mL∶g)20∶1,提取时间15min,微波功率150W,超声波功率240W。最佳提取条件下,玫瑰茄多糖提取率为3.51%。超声波-微波协同提取玫瑰茄多糖工艺可行,操作简单。与其他提取法相比,不仅缩短了提取时间,而且提高玫瑰茄多糖的提取率。

玫瑰茄总黄酮超声波-微波协同提取及抗氧化活性

采用Box-Behnken响应面试验设计法对玫瑰茄总黄酮超声波-微波协同提取工艺进行优化,研究了乙醇浓度、液固比、提取时间、微波功率、提取次数5个单因素对总黄酮提取量的影响,建立了乙醇浓度、液固比和微波功率的三因素回归模型,并研究其抗氧化活性。结果表明,提取的最佳工艺参数为乙醇浓度40%、液固比50∶1(mL/g)、微波功率250 W、提取时间20 min、超声波功率50 W,在此条件下提取2次,总黄酮提取量为40.2 mg/g。同时以维生素C作对照,研究了玫瑰茄总黄酮粗提物和纯化物的体外抗氧化活性。结果表明,玫瑰茄总黄酮粗提物和纯化物都具有较强的抗氧化活性,能够有效清除O2^-·自由基和DPPH自由基,清除能力与浓度呈较明显的量效关系,但抗氧化能力较维生素C弱。

响应面法优化玫瑰茄花青素提取工艺及稳定性研究

使用响应面法分析超声功率、乙醇浓度、料液比、提取时间对玫瑰茄花青素超声提取的影响,并对提取的花青素稳定性进行研究。以玫瑰茄花青素得率为响应值,通过响应面试验优化花青素超声提取条件。结果表明:对玫瑰茄花青素得率的影响从大到小依次为:超声功率、乙醇浓度、料液比、提取时间。最佳的提取方案为提取时间27 min、超声功率138 W、乙醇浓度68%、料液比1∶34(g/mL),优化试验花青素得率为(3.93±0.04)mg/g。稀释倍数越大、热处理温度越高花青素稳定性越差,玫瑰茄花青素在90℃、120 min条件下保留率减少量最大为42.05%。在pH3~7范围内,随着pH值增大花青素稳定性降低。

响应面法优化玫瑰茄中花青素的超声波提取工艺

[目的]为分离纯化玫瑰茄花青素提供参考。[方法]以冰醋酸为溶剂,采用超声波法提取玫瑰茄中的花青素,以提取率为评价指标,在单因素试验的基础上采用响应面法对提取工艺进行优化。[结果]玫瑰茄提取液在522 nm左右出现特征吸收峰,说明该提取液具有花青素的特征,属于花青素类物质。各因素对玫瑰茄花青素提取率的影响依次为:液料比>冰醋酸浓度>超声功率>超声时间。最佳提取工艺为:冰醋酸浓度9%,液料比22,超声时间28.5 min,超声功率490W。[结论]该研究确定了超声波提取玫瑰茄中花青素的最佳工艺条件。

玫瑰茄浸提工艺条件的研究

通过单因素试验,设计了3因素3水平的正交试验。研究了浸提温度、浸提时间和料液比对玫瑰茄花萼可溶性固形物、总酸和单体花青素提取效率的影响,确定了最佳的浸提条件为:浸提温度为75℃,浸提时间为50min,花萼与水的质量比为1∶25。

玫瑰茄水提物抗贫血作用的研究

初步探究玫瑰茄水提物的抗贫血作用机制。建立IDA大鼠模型,随机分成4组,对IDA大鼠灌胃低、中、高剂量的玫瑰茄水提物。30d后,解剖大鼠,取十二指肠和肝脏。利用Q-PCR和Westernblot技术分别检测试验大鼠十二指肠中二价金属转运体(DMT-1)、膜铁转运蛋白(FPN-1)、膜铁转运辅助蛋白(Hp)及其mRNA的表达量,肝脏铁调素(Hepcidin)及其mRNA的表达水平。结果表明,与低铁对照组比较,玫瑰茄水提物低、中剂量组对DMT-1、FPN-1、Hp表达量的下调幅度不超过9%,mRNA的表达水平则超过50%,低、中剂量均对Hp mRNA无显著性差异;高剂量组对DMT-1、FPN-1、Hp及其mRNA表达量的下调程度不一。低剂量组Hepcidin-25的表达量是低铁对照组的1.61倍;高剂量组的表达量则下调了65.79%;各剂量组均抑制了相关mRNA的表达。因此,玫瑰茄水提物通过提供有效成分促进机体铁的吸收,从而影响IDA大鼠的DMT-1、FPN-1、Hp、Hepcidin-25及其mRNA的表达,维持机体铁稳态。

玫瑰茄花色素的提取工艺研究

通过单因素和正交实验对玫瑰茄花色素提取工艺条件进行了比较筛选和优化。结果表明:玫瑰茄花色素提取的适宜溶剂为乙醇,适宜的酸碱度为p H 2.0;影响提取效果因素依次是提取时间、乙醇浓度、温度、料液比;最佳提取工艺条件为粉碎粒度40目、乙醇浓度70%(V∶V)、提取温度40℃、提取时间1.5 h、最佳料液比1∶20,在此优化条件下,玫瑰茄花色素的提取率可达0.485%。

紫苏油凝胶的制备及贮藏特性研究

紫苏油凝胶在贮藏过程中质构品质下降且易氧化,该研究通过单因素试验筛选得到紫苏油凝胶制备的最佳工艺,而后通过添加玫瑰茄提取物(复合型抗氧化剂)和Ve(单一型抗氧化剂)进行对比贮藏,利用主成分分析(PCA)综合评价抗氧化剂对紫苏油凝胶质构特性和氧化特性方面的影响。结果表明:紫苏油凝胶制备的最佳工艺为凝胶剂添加比例β-谷甾醇:大豆磷脂为7∶3(g∶g),凝胶剂添加量14%,加热温度85℃,加热时间45 min;基于主成分综合评价结果表明:若进行短期贮藏(2周以内),空白组得分最高,为3.805;若较长时期贮藏(超过3周),0.3%玫瑰茄组得分最高,为1.118。