Identification and Molecular Characterization of the Alkaloid Biosynthesis Gene Family in Dendrobium catenatum

As one of the main active components of Dendrobium catenatum, alkaloids have high medicinal value. The physicochemicalproperties, conserved domains and motifs, phylogenetic analysis, and cis-acting elements of the genefamily members in the alkaloid biosynthesis pathway of D. catenatum were analyzed by bioinformatics, and theexpression of the genes in different years and tissues was analyzed by qRT-PCR. There are 16 gene families,including 25 genes, in the D. catenatum alkaloid biosynthesis pathway. The analysis of conserved domains andmotifs showed that the types, quantities, and orders of domains and motifs were similar among members ofthe same family, but there were significant differences among families. Phylogenetic analysis indicated that thegene family members showed some evolutionary conservation. Cis-acting element analysis revealed that therewere a large number of light-responsive elements and MYB (v-myb avian myeloblastosis viral oncogene homolog)-related elements in these genes. qRT-PCR showed that expressions of gene family members involved in alkaloidsynthesis were different in different years and tissues of D. catenatum. This study provides a theoretical basisfor further exploration of the regulatory mechanisms of these genes in the alkaloid biosynthesis of D. catenatum.

Comparison of Stomatal Characteristics between Dendrobium loddigesii and Dendrobium candidum

[Objective]This study was to reveal the physiological and ecological mechanism of growth and development of test-tube seedlings.[Methods]Leaf stomata of test-tube seedlings of D.loddigesii and D.candidum at different growth and development stages were observed under scanning electron microscope,and their fluorescence induction response curve was assayed by using modulate fluorometer.[Results] At each growth and development stage,D.loddigesii test-tube seedling has a higher leaf stomatal density over D.candidum,while a lower stomata opening rate.Along with the growth,the size of stomata of both D.loddigesii and D.candidum did not change obviously,but their stoma density increased by 83% and 17.6% respectively.Leaf stomata opening rate reached the highest at the age of 240-day-old.Under the conditions of three settled light intensities,stomatal opening degree of D.loddigesii was increased by the intensity of illumination,the maximum aperture occurred at the light intensity of 54 μmol/m2·s.Given the same culture condition,both the maximum electron transport rate（14 μmol/m2·s）and light saturation point（318 μmol/m2·s）of D.loddigesii test-tube seedling are lower than that of D.candidum（20 μmol/m2·s,483 μmol/m2·s）.Moreover,the potential photosynthetic capacity of D.loddigesii is relatively poor.[Conclusion]The photosynthetic rate varies among different species of Dendrobium,which could be attributed to their different stomatal characteristics.Usually,the light intensity of tissue culture chamber is set up as 27 μmol/（m2·s）,where both D.loddigesii and D.candidum do not acquire an optimal state for their leaf stomatal opening.Considering the characteristics to select suitable culture condition,the stomatal aperture and photosynthetic rate could be enhanced,which can promote the growth and development of test-tube seedlings.

Optimization of Culture Conditions for Chromium-enriched Protocorm of Dendrobium candidum

[Objective] To optimize the techniques for culturing Cr-enriched Dendrobi-um candidum protocorm. [Method] By adopting Plackett-Burman test, the effects of time, temperature, Cr-content in medium, NAA content, KT content and light intensi-ty on Cr-enriched protocorm were researched. Three factors of time, Cr-content in medium and light intensity had statistical y significant effects; then steepest ascent procedures were applied to define optimal response region of these three factors; fi-nal y the optimal factors were determined by RSM analysis. [Result] The results showed that the optimal conditions for Cr-enrichment were chromium concentration at 0.37 mg/L, culture time of 59 d and il umination intensity of 1 822.22 lx. The predicted value of Cr-content in protocorm was 5.08 mg/kg. [Conclusion] RSM can optimize the techniques for culturing Cr-enriched protocorm of Dendrobium can-didum, provide the optimum process parameters and lay the foundation for further research.

Artificial Pollination and Seed Germination of Dendrobium candidum Wall. ex Lindl.

The artificial pollination and the seed germination on Dendrobium candidum were conducted. Results showed that the percentage of fruit-setting reaches the highest under cross pollination before 10 o＇ clock in the morning after blooming 2 d to 4 d. The optimal medium for seeds germination was MS＋ NAA 0.5 mg/L ＋ potato juice 10% ＋ active charcoal 0.5%, and cultured for 7 d in the dark then under light.

Functional analysis of flavanone 3-hydroxylase(F3H)from Dendrobium officinale,which confers abiotic stress tolerance

Flavonoids are important bioactive components in Dendrobium officinale,a medicinal orchid.They are involved in many biological activities,including protecting plants against biotic and abiotic stresses.Research on the key genes related to flavonoid biosynthesis in D.officinale is limited.In this study,one of the key flavonoid biosynthesis genes,flavanone 3-hydroxylase(F3H),was characterized from D.officinale.The open reading frame of DoF3H was 1134 bp long and it encoded a 377-amino acid protein.The DoF3H protein showed considerably high homology with F3H proteins from other plant species and shared a common evolutionary ancestor with other F3Hs.DoF3H transcripts were detected in different organs of adult plants and mainly accumulated in flowers,followed by roots,stems and leaves,a pattern that was similar to the content of flavonoids.Recombinant DoF3H protein,which was localized in the cytosol,could convert naringenin to dihydrokaempferol.The mRNA levels of DoF3H were significantly induced by salt and cold stresses.Furthermore,the heterologous expression of DoF3H in Escherichia coli conferred it higher tolerance to salt and cold stresses.These results provide insight into the molecular function of DoF3H in the biosynthesis of flavonoids,and provide a new application for improvement of abiotic tolerance in D.officinale.

Dendrobium species regulate energy homeostasis in neurodegenerative diseases: a review

Brain energy homeostasis is a vital physiological function in maintaining a balanced internal metabolic environment.The impairment of energy homeostasis is recognized as a key pathophysiological basis for brain metabolic disorders and related neurodegenerative diseases.Dendrobium species(‘Shihu’in Chinese)such as D.officinale,D.huoshanense,D.nobile,D.chrysanthum,D.loddigesii,D.moniliforme,D.gratiosissimum,D.candidum and D.caulis are widely used as traditional Chinese medicines/nutraceuticals to control and treat neurodegenerative disorders.These dietary herbs and their derived compounds possess a variety of biological properties,such as suppression of oxidative stress and neuroinflammation,regulation of energy homeostasis mainly through improving brain mitochondria function,insulin signaling and lipid metabolism.Furthermore,they reduce neurotoxicity,alleviate brain injury and neuropathy,and prevent neurodegenerative conditions including stroke,Alzheimer’s disease,Parkinson’s disease,and Huntington’s disease in humans and/or rodents.Moreover,the nutraceuticals from Dendrobium species promote gut health and aid digestion,which appear to be associated with beneficial effects on brain energy homeostasis.Based on the above-mentioned health benefits associated with Dendrobium species,this work reviews their nutraceutical role in neurodegenerative disorders and further suggests the need to elucidate mechanisms of the underlying molecular actions.

Effects of Dendrobium candidum polysaccharides on microRNA-125b and mitogen-activated protein kinase signaling pathways in diabetic cataract rats

Background:Diabetic cataract is a common complication and a lens disorder in diabetes.Moreover,Dendrobium officinale polysaccharide(DOP)is found to alleviate diabetes complications.Consequently,microRNA-125b and mitogen-activated protein kinase signaling pathways play significant roles in diabetes.However,the mechanism and the effect of DOP on diabetic cataract remains unknown.Methods:Wistar male rats were randomly assigned to the control,model,and DOP groups.Diabetes was induced with streptozotocin.Furthermore,DOP was orally given for 12 weeks.The Lens Opacities Classification System III was used to evaluate lens opacity by slit-lamp microscope.The lens was then harvested for testing the mRNA expression of microRNA-125b,ERK1,ERK2,Raf and Ras using reverse transcription-polymerase chain reaction.The protein expression of ERK1,ERK2,Raf,and Ras was detected using the Western blot analysis.The targets of microRNA-125b were predicted in miRWalk 2.0.These targets were obtained from the Kyoto Encyclopedia of Genes and Genomes pathway.Results:The lens opacities of the rats in the control group were almost at C0N0.Moreover,the majority of the lens opacities in the model group were C3 to C4 and N1 to N2,and were mostly at C1 to C2 and N0 to N1 in the DOP group.The difference was statistically significant(P<0.05).Furthermore,the microRNA-125b expression in the model group is significantly higher compared with the control group.Conversely,the microRNA-125b expression in the DOP group is significantly decreased(all P<0.05).The mRNA expression of ERK1,ERK2,Raf,and Ras in the model groups were upregulated compared with those of the control group.However,the ERK1 and Raf mRNA expressions of the DOP group were lower compared with the model group(all P<0.05).The protein expression of ERK1,Raf,and Ras in the model group was significantly increased compared with those of the control group.The protein expression of ERK1,Raf,and Ras in the DOP group was significantly lower compared with the model group(all P<0.05).Moreover,3,378 genes of the microRNA-125b target were gained from the miRWalk.After Kyoto Encyclopedia of Genes and Genomes pathways analysis in Gene Set Enrichment Analysis,246 items were gained including Ras(rno04014)and mitogen-activated protein kinase(rno04010)signaling pathways.A positive correlation exists between microRNA-125b and mRNA expression of ERK1,ERK2,Raf and Ras(r=0.940,0.841,0.666,and 0.768;all P<0.05).Conclusion:DOP can alleviate the severity of the opacity of the lens in diabetic cataract rats via microRNA-125b and mitogen-activated protein kinase signaling pathways.Thus,microRNA-125b has something to do with the mitogen-activated protein kinase signaling pathway.

Metabolic and transcriptomic analyses elucidate a novel insight into the network for biosynthesis of carbohydrate and secondary metabolites in the stems of a medicinal orchid Dendrobium nobile

Dendrobium nobile is an important medicinal and nutraceutical herb.Although the ingredients of D.nobile have been identified as polysaccharides,alkaloids,amino acids,flavonoids and bibenzyls,our understanding of the metabolic pathways that regulate the synthesis of these compounds is limited.Here,we used transcriptomic and metabolic analyses to elucidate the genes and metabolites involved in the biosynthesis of carbohydrate and several secondary metabolites in the stems of D.nobile.A total of 1005 metabolites and 31,745 genes were detected in the stems of D.nobile.The majority of these metabolites and genes were involved in the metabolism of carbohydrates(fructose,mannose,glucose,xylulose and starch),while some were involved in the metabolism of secondary metabolites(alkaloids,β-tyrosine,ferulic acid,4-hydroxybenzoate and chrysin).Our predicted regulatory network indicated that five genes(AROG,PYK,DXS,ACEE and HMGCR) might play vital roles in the transition from carbohydrate to alkaloid synthesis.Correlation analysis identified that six genes(ALDO,PMM,BGLX,EGLC,XYLB and GLGA) were involved in carbohydrate metabolism,and two genes(ADT and CYP73A) were involved in secondary metabolite biosynthesis.Our analyses also indicated that phosphoenol-pyruvate(PEP) was a crucial bridge that connected carbohydrate to alkaloid biosynthesis.The regulatory network between carbohydrate and secondary metabolite biosynthesis established will provide important insights into the regulation of metabolites and biological systems in Dendrobium species.

Pollination Biology of the Endangered Herbal Medicines Dendrobium chrysotoxum(Orchidaceae)

Pollination biology studies of the endangered herbal medicines Dendrobium chrysotoxum were conducted in natural pollination conditions using flower observation,pollinator observation and artificial pollination experiments.Populations of D.chrysotoxum with fragrance and nectar were pollinated by Ctenoplectra davidi Valhalla(Hymenoptera:Apidae)species.The floral structure of D.chrysotoxum adapted precisely to its pollinators.Flowers had a low capsule setting(0.17%)under natural conditions.However,compared to open pollination,artificial pollination experiments showed a significant increase in capsule setting,and D.chrysotoxum was cross-compatible and self-compatible,but there was pollinator limitation also.This study will provide important information for the preservation of this endangered species.

Study on Mechanism of Dendrobium officinale Kimura et Migo in Preventing and Treating Exercise-induced Muscle Damage(EIMD)in Rats

[Objectives]This study was conducted to observe the mechanism of Dendrobium officinale Kimura et Migo on gastrocnemius muscle in rats with exercise-induced muscle damage(EIMD).[Methods]The micro-injury model of skeletal muscle was established by treadmill training.Forty two SD rats were randomly divided into a control group,1,12 and 24 h exercise groups,D.officinale 2 ml+1 h exercise group,D.officinale 2 ml+12 h exercise group,and D.officinale 2 ml+24 h exercise group,with 6 rats in each group.Various D.officinale groups were given the drug once in the morning and once in the evening at a dose of 2 ml/time,a week in advance.Except for the quiet group,the samples were collected from the 1,12 and 24 h exercise groups after anesthesia following 1,12 and 24 h of exercise for the last time,respectively,and the D.officinale 2 ml+1 h exercise group,D.officinale 2 ml+12 h exercise group and D.officinale 2 ml+24 h exercise group were also sampled after anesthesia following 1,12 and 24 h of exercise for the last time,respectively.The contents of ATP,CK-MM and CK in rat serum were determined by enzyme-linked immunosorbent assay(ELISA).The histopathological changes of gastrocnemius muscle were observed by HE staining.PCR and Western-blot detection were carried out to analyze the effects of D.officinale on IGF-1 mRNA and protein expression in gastrocnemius muscle.[Results]Compared with the quiet group,the ATP contents in the serum of rats in the 1,12 and 24 h exercise groups significantly decreased(P<0.01),while the CK and CK-MM contents significantly increased(P<0.01).The expression of IGF-1 mRNA and protein in the gastrocnemius muscle tissue significantly increased(P<0.01).Compared with the 1 h exercise group,the ATP content and IGF-1 protein expression in the gastrocnemius muscle tissue of the D.officinale liquid+1 h exercise group significantly increased(P<0.05),while the CK and CK-MM contents significantly decreased(P<0.01).Compared with the 12 h exercise group,the D.officinale liquid+12 h exercise group showed a significant increase in ATP content(P<0.01),significant increases in IGF-1 mRNA and protein expression in the gastrocnemius muscle tissue(P<0.01),and significant decreases in CK and CK-MM contents(P<0.01).Compared with the 24 h exercise group,the ATP content and IGF-1 mRNA and protein expression in the gastrocnemius muscle tissue of the D.officinale liquid+24 h exercise group significantly increased(P<0.01),while the CK and CK-MM contents significantly decreased(P<0.01).From the pathological tissue morphology of the gastrocnemius muscle in rats with EIMD treated with D.officinale,it could be concluded that the gastrocnemius muscle of each exercise group was significantly damaged,and the damage was significantly alleviated after administration of D.officinale liquid.[Conclusions]The effects and mechanism of D.officinale on prevention and treatment of EIMD in rats might be related to the promotion of IGF-1 mRNA and protein expression in injured tissues by reducing ATP energy consumption,CK-MM and CK activity.

芽孢杆菌发酵法提取铁皮石斛多糖、多肽及其抗氧化活性分析

目的研究一种有效的铁皮石斛多糖、多肽提取方法,并分析其基本性质及体外抗氧化活性。方法以铁皮石斛为研究对象,采用芽孢杆菌发酵法对铁皮石斛进行提取,用蒽酮-硫酸法和双缩脲法分别测定铁皮石斛提取液的多糖和多肽含量,以传统热水浸提法和超声波辅助提取法为对照,通过提取液对自由基清除能力、螯合金属离子能力、抑制亚油酸自氧化能力指标,评价芽孢杆菌发酵提取液的抗氧化活性。结果芽孢杆菌发酵提取法工艺参数为:投料比例4%(g/mL)、发酵pH 6、发酵温度33.5℃、发酵时间46 h,此时多糖提取率为37.21%,多肽含量高达4.43 mg/kg,分子量主要分布在2000 Da以下,占84.95%。提取液对羟基自由基(hydroxyl radical,·OH)、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-trinitrophenylhydrazine,DPPH)自由基和2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)(2,2’-diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid,ABTS)阳离子自由基有较强的清除能力,Fe2+螯合能力67%、亚油酸自氧化抑制率53%。结论芽孢杆菌发酵法提取的铁皮石斛提取液,多糖、多肽含量高,具有较好的抗氧化性,为铁皮石斛在食品领域的开发利用提供了一定的理论指导和实验数据参考。

铁皮石斛苗床下立体栽培羊肚菌技术及其对土壤理化性质的影响

探讨四川省攀枝花市秋末冬初设施塑料大棚中羊肚菌(Morchella spp.)-铁皮石斛(Dendrobium officinale Kimura et Migo)立体栽培的可行性,测定在羊肚菌生长过程中的菌丝生长期(M1)、子实体生长期(M2)和采收期(M3)表层土壤的pH、全氮、铵态氮、速效磷、有效钾、有机质、电导率(Electric conductivity,EC)和固体溶解性物质总量(Total dissolved solids,TDS)等。结果表明,与对照组相比,在羊肚菌生长的过程中,试验组不同时期表层土壤的pH和有效钾含量均下降,而速效磷、全氮、铵态氮、EC、TDS和有机质的含量均显著增高,且产量达(1950±180)kg/hm^(2)。

杉上斛多糖对特应性皮炎小鼠的干预效果及肠道菌群的影响研究

目的探究杉上斛多糖对特应性皮炎(AD)小鼠的干预效果以及对肠道菌群的影响作用。方法将小鼠随机分为对照组(3只)、AD组(4只)和AD+杉上斛多糖组(4只),比较3组小鼠临床表现(搔抓次数、皮损评分、耳廓肿胀度),HE染色观察皮肤组织病理损伤。酶联免疫吸附测定(ELISA)法检测3组小鼠外周血和皮损部位免疫球蛋白E(IgE)、白细胞介素-4(IL-4)和干扰素-γ(IFN-γ)水平;定量聚合酶链反应(qPCR)检测3组小鼠IL-4和IFN-γmRNA水平。收集3组小鼠粪便进行16SrRNA测序分析。结果与对照组比较,AD组小鼠出现红斑、水肿、表皮剥脱和鳞屑等病理表现,皮损评分显著升高;皮损部位角化过度伴角化不全,棘层肥厚,表皮层、真皮层可见明显的炎性细胞浸润,毛细血管扩张;血清及皮损部位的炎性因子表达水平显著升高;肠道菌群中拟杆菌属、葡萄球菌丰度增加,Muri菌、拟普雷沃氏菌属、毛螺菌科-NK4A136组丰度减少。使用杉上斛多糖干预后,AD小鼠的病理情况、皮损评分、皮损部位严重程度、炎性因子表达及差异菌群丰度均有改善。结论杉上斛多糖通过调节肠道菌群平衡,减轻炎性反应以发挥药理作用,可有效缓解AD的皮损状况。

PEG6000模拟干旱胁迫对铁皮石斛幼苗生理和叶绿素荧光特性的影响

【目的】研究聚乙二醇6000(PEG 6000)模拟干旱对铁皮石斛Dendrobium candidum生理和叶绿素荧光特性的影响,为铁皮石斛的品种选育、产业化栽培和近野生栽培等提供参考。【方法】以铁皮石斛‘晶品1号’D.candidum‘Jingpin No.1’幼苗为实验材料,通过不同质量分数PEG 6000(5%、10%、20%、30%)模拟干旱胁迫处理铁皮石斛幼苗,观察铁皮石斛幼苗茎段和叶片细胞结构,并检测铁皮石斛叶片过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)质量摩尔浓度、可溶性糖质量分数、可溶性蛋白质量分数、叶绿素质量分数及叶绿素荧光参数的动态变化。【结果】①高质量分数PEG 6000(20%-30%)处理后铁皮石斛茎段和叶片细胞内叶绿素质量分数减少。②PEG 6000模拟干旱胁迫处理对铁皮石斛幼苗可溶性糖和可溶性蛋白、MDA、POD和CAT有显著影响(P<0.05)。可溶性糖质量分数随着PEG 6000质量分数的增加和处理时间的延长均呈上升趋势,到第12天时达最高值;可溶性蛋白则呈下降趋势;MDA质量摩尔浓度、POD活性和CAT活性随着PEG 6000质量分数的增加呈先上升后下降的趋势,在PEG 6000为20%时达到峰值。③PEG 6000模拟干旱处理对铁皮石斛幼苗最大光化学效率(F_(v)/F_(m))、光合效率(α)、电子传递速度(ETR)、光化学猝灭系数(q_(P))和非化学猝灭系数(qNP)等叶绿素荧光参数有显著的影响(P<0.05)。随着PEG 6000胁迫处理时间的延长和PEG 6000质量分数的增加,α、ETR、F_(v)/F_(m)和q_(P)均呈显著下降趋势(P<0.05);而qNP则呈先上升后下降的趋势。【结论】20%PEG 6000处理12 d可用作铁皮石斛抗干旱品种的筛选,铁皮石斛幼苗可通过增加可溶性糖质量分数,减少可溶性蛋白质量分数,提高POD和CAT活性等防御酶活性抵抗和适应一定程度的干旱胁迫;铁皮石斛幼苗的最大光能转换效率降低,光合系统Ⅱ(PSⅡ)受到胁迫损伤,严重影响铁皮石斛幼苗的光合作用。同时,铁皮石斛幼苗通过启动qNP途径来消耗PSⅡ反应中心吸收的过剩光能,维持正常的光合作用。因此,可溶性糖和可溶性蛋白、POD和CAT以及叶绿体荧光参数均可作为铁皮石斛耐干旱的指标。

中药石斛研究的回顾与展望

中药石斛基原复杂,其主流品种有霍山石斛Dendrobium huoshanense C.Z.Tang et S.J.Cheng、铁皮石斛D.officinale Kimura et Migo、金钗石斛D.nobile Lindl.,《中华人民共和国药典》(以下简称《中国药典》)2005年版石斛项下增加了“及其近似种”的描述,难以确定具体物种,有必要对其进一步正本清源。对石斛属的起源进行本草考证,对霍山石斛、铁皮石斛、金钗石斛的本草起源进行梳理,为不同石斛属药材的应用提供参考。霍山石斛是最早作为中药石斛应用的品种,高效液相色谱法特征图谱等方法为《中国药典》2020年版收录霍山石斛提供了技术支撑;铁皮石斛应为石斛药材中应用时间最久、范围最广的品种,其主要为浙江、云南、贵州,以及广东、广西、福建、江西等地丹霞地貌上生长的种群,应高度重视并对其进行保护;D.nobile在历代文献中的中文名称混乱,应明确将其作为金钗石斛的拉丁学名。枫斗是我国名贵中药和传统保健品,起源于霍山石斛。古代名医对霍山石斛、铁皮石斛、金钗石斛、川石斛的用法各有特色,建议厘清品种来源、功效,加强现代研究,在修订《中国药典》时将其各自单列,充分发挥中药石斛的临床价值。

齿瓣石斛多糖对小鼠胃溃疡的防治作用及机制研究

目的:研究齿瓣石斛多糖对小鼠胃溃疡的防治作用并阐述其作用机制。方法:分别采用水浸法、乙醇法和消炎痛法进行造模。动物实验分3批次进行,每批次将96只昆明种雄性小鼠(体重18~22 g)随机分为正常组、模型组、阳性药(枸橼酸铋钾1560 mg/kg/d)组及齿瓣石斛多糖高剂量(600 mg/kg/d)组、中剂量(500 mg/kg/d)组、低剂量(400 mg/kg/d)组,每组各16只小鼠。各给药组连续灌胃给予相应剂量药物14天,正常组和模型组给予等体积蒸馏水,每天1次。除正常组外,各组小鼠于第14天给药30 min后进行造模,再将各组16只小鼠随机分为两小组,其中1个小组8只小鼠的胃组织固定后用于胃黏膜损伤程度观察和病理组织学观察,并计算溃疡指数及溃疡抑制率。另1个小组8只小鼠用于测定胃组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量。结果:三种方法中,与正常组比较,模型组小鼠胃溃疡指数极显著升高(P<0.001),胃组织中SOD活力极显著降低(P<0.01),MDA含量极显著升高(P<0.01),胃溃疡模型造模成功。与模型组比较,阳性药组和齿瓣石斛多糖高剂量组能极显著降低小鼠胃溃疡指数(P<0.001),显著升高小鼠胃组织中SOD活力(P<0.05)并显著降低MDA含量(P<0.05);病理切片观察结果显示,上述两组小鼠胃组织再生黏膜较厚,黏膜修复较完全,胃黏膜上皮细胞排列较整齐,溃疡程度较轻。结论:齿瓣石斛多糖对胃溃疡具有确切的防治效果,其作用机制与保护胃黏膜和抗氧化作用有关。

正交试验优化铁皮石斛传统种苗繁育技术

为了提高铁皮石斛传统育苗腋芽萌发成苗率,指导铁皮石斛传统育苗技术在生产上的推广应用,开展影响腋芽萌发成苗率因子[繁育模式(A)、激素处理(B)、育苗基质(C)、品系(D)]的四因素五水平正交试验研究。结果显示:影响传统育苗腋芽萌发成苗率因素主次顺序为D>A>B>C,4个因素的最优水平分别是A_(2)(整条平铺并覆盖基质1 cm左右)、B_(2)(NAA 0.5 mg/L+6-BA 0.5 mg/L)、C_(1)(苔鲜)、D_(4)(紫精灵),试验筛选出传统育苗因素最优组合A_(2)B_(2)C_(1)D_(4),其萌发成苗率可达81%,较自然腋芽萌发成苗率(10%~20%)大大提高。

全自动固相萃取结合气相色谱-串联质谱法快速测定石斛中62种常用农药残留

建立全自动QuEChERS方法结合气相色谱-串联质谱技术检测石斛中62种常用农药残留的分析方法。样品经全自动QuEChERS样品制备系统涡旋、振动和离心处理,HP-5MS色谱柱分离,选择分时间段的多反应监测模式进行数据采集及定性定量分析,内标法定量。62种农药在5~500ng·mL^(-1)范围内线性关系良好,相关系数(r^(2))大于0.99;3个加标水平下(0.01mg·kg^(-1)、0.05mg·kg^(-1)和0.1mg·kg^(-1)),平均回收率为65.6%~109.3%,相对标准偏差(RSD)为2.4%~15.1%;定量限均低至0.01mg·kg^(-1)。该方法简便、快速、灵敏、准确性高,适用于石斛中62种常用农药残留的快速检测。

粒径对铁皮石斛粉多糖释放及其粉体特性影响

为明确粒径对铁皮石斛(D. officinale)粉中多糖溶出率及其粉体特性的影响,采用中药粉碎机结合球磨仪制备了8种不同粒径的铁皮石斛粉体,研究各粉体样本的粒径分布、比表面积、多糖溶出率、粉体流动性、水合特性、表面微观结构及色差变化。结果表明,[20,200)目粉体中多糖溶出率随粒径减小总体呈上升趋势,但≥200目时溶出率逐渐下降;粉体流动性参数(休止角、滑动角和Carr’s指数)与粒径呈负相关,即粒径越小流动性越差,尤其是[200,250)目较[150,200)目粉体的流动性明显变差;水合特性(WHC、WSC和WSI)随粒径变小先升后降,拐点同样出现在200目前后;色差分析表明,粉体色度参数(L*、a*、b*和ΔE值)也是在[150,200)目与[200,250)目的变化幅度最大。上述结果主要与[200,250)目粉体的比表面积较[150,200)目显著增加(68.1%)有关。综上,[150,200)目(d50=95.6μm)的铁皮石斛粉兼具较好的粉体特性和多糖释放率,同时保证了粉体细度。本研究结果为铁皮石斛的粉体化高效加工及高值化利用提供了理论参考。

黄精铁皮石斛口服液中多糖含量测定研究

目的:建立黄精铁皮石斛口服液多糖含量的检测方法。方法:采用紫外—可见分光光度法,测定黄精铁皮石斛口服液中的多糖含量,并对其检测方法进行方法学研究。结果:多糖含量在0.0166 mg/mL至0.1660 mg/mL之间呈现较好的线性关系,中间精密度测试结果为稳定,重复性试验结果RSD<1%,平均加样回收率可达96.86%,稳定性试验结果表明试验在1 h内呈现稳定状态。结论:研究建立的方法简便、灵敏、可靠,能够有效检测黄精铁皮石斛口服液的产品质量。