Four new sesquiterpene lactones(SLs)(1–4),along with a biosynthetically related SL(5),have been isolated from the leaves of Magnolia grandiflora.Magrandate A(1)is notable as the first C18 homogemarane type SL,featuri...Four new sesquiterpene lactones(SLs)(1–4),along with a biosynthetically related SL(5),have been isolated from the leaves of Magnolia grandiflora.Magrandate A(1)is notable as the first C18 homogemarane type SL,featuring a unique 1,7-dioxaspiro[4.4]nonan-6-one core.Compounds 2 and 3,representing the first instances of chlorine-substituted gemarane-type SL analogs in natural products,were also identified.The structures of these isolates were elucidated through a combination of spectroscopic data analysis,electronic circular dichroism calculations,and X-ray single-crystal diffraction analysis.All isolates demonstrated anti-inflammatory activity in lipopolysaccharide-stimulated RAW264.7 cells.Notably,3–5 showed a significant inhibitory effect on nitric oxide production,with IC50 values ranging from 0.79 to 4.73μmol·L^(−1).Additionally,4 and 5 exhibited moderate cytotoxic activities against three cancer cell lines,with IC50 values between 3.09 and 11.23μmol·L^(−1).展开更多
The chemical composition and antioxidant activity of Magnolia grandiflora L.seed essential oil were examined.By combining gas chromatography and mass spectrometry （GC-MS）,16 types of compounds were identified,includ...The chemical composition and antioxidant activity of Magnolia grandiflora L.seed essential oil were examined.By combining gas chromatography and mass spectrometry （GC-MS）,16 types of compounds were identified,including 40.91% oxygen-containing terpene derivatives,19.51% terpenes,13.97% esters,13.05% nitrogenous compounds,and 3.64% acids.Its capability of removing hydroxyl free radical was lower than that of V c,but it was closer to V c with increasing concentration.In cell experiment,all essential oil concentration （6.9,13.8,27.7,55.5,111.0,and 222.0 g/mL） groups increased cell proliferation by 26% or more （26.0%,38.8%,44.8%,40.2%,35.8%,and 30.4%,respectively）.In rat experiment,the SD rats group showed an at least 38% rise （38.62%,61.68%,and 62.86%,respectively） in glutathione-peroxisome （GSH-Px）activity,which is more than 24% reduction （29.56%,24.30%,and 36.93%） in malondialdehyde （MDA） content,and no significant difference in SOD activity was found.The results show that the essential oil had strong antioxidant activity,without dose effect within the concentration range.展开更多
Background:The ability to produce seeds when pollinators or potential mates are scarce is one of the principal advantages of self-pollination in flowering plants.However,the role of pollinators mediating self-pollinat...Background:The ability to produce seeds when pollinators or potential mates are scarce is one of the principal advantages of self-pollination in flowering plants.However,the role of pollinators mediating self-pollination to ensure seed set when pollen or potential mates are limited has received less attention.This study examined the reproductive consequences and involvement of pollinators in assuring seed set in an isolated tree of Magnolia grandiflora,a predominantly outcrossing species.Methods:We tested various aspects of reproduction such as flower density,floral rewards,stigma receptivity,pollinator abundance and behaviour,fruit set and seed set,in two successive reproductive years(2015-2016).Results:Flowers of M.grandiflora possess a suite of traits facilitating pollinator-mediated self-pollination(PMS),although the chances of autonomous self-pollination are reduced due to herkogamy,spatial separation of anther and stigma.The mean pollen production/flower was 5,152,289±285,094 with a pollen-to-ovule ratio of 39430±164.We found a significant positive correlation between number of visits and seed production for bees(r=0.5099,p=0.0007)and beetles(r=0.7159,p=0.00001),indicating these are effective at PMS.There was a significant negative correlation for thrips(r=-0.3206,p=0.044)and no correlation for flies or spiders.The percent fruit set was 100%and the seed set per ovule ranged between 19 and 20%.Conclusions:PMS will guarantee reproductive assurance and mitigate the effect of reduced mates or pollen limitation which is expected to increase the fecundity and establishment of individual trees in geographically isolated locations.展开更多
为了提高聚丙烯酰胺凝胶电泳（PAGE）的银染效果和条带回收的效率,以广玉兰DNA为材料进行ISSR-PCR分析,比较了两种银染（常规银染法和快速银染法）和条带回收法（乙醇糖原法和改进的煮沸法）.结果显示：两种银染方法效果一致,但常规银...为了提高聚丙烯酰胺凝胶电泳（PAGE）的银染效果和条带回收的效率,以广玉兰DNA为材料进行ISSR-PCR分析,比较了两种银染（常规银染法和快速银染法）和条带回收法（乙醇糖原法和改进的煮沸法）.结果显示：两种银染方法效果一致,但常规银染要用2-3 h,而快速银染仅用30 m in,是常规银染的1/6-1/4;改良的煮沸法回收条带比乙醇糖原法更简便、更快捷.因此,快速银染和改良的煮沸法条带回收法可以应用在以后的研究中.展开更多
结合树干解析取样,借助光学显微镜和扫描电镜,分别从宏观角度和微观角度研究了广玉兰木材的解剖构造;利用木材万能力学试验机,参照现行国家标准对广玉兰木材的力学性质进行了测定和分析。结果表明:广玉兰木材属于散孔材,管孔为圆形、椭...结合树干解析取样,借助光学显微镜和扫描电镜,分别从宏观角度和微观角度研究了广玉兰木材的解剖构造;利用木材万能力学试验机,参照现行国家标准对广玉兰木材的力学性质进行了测定和分析。结果表明:广玉兰木材属于散孔材,管孔为圆形、椭圆形,多数为复管孔;轴向薄壁组织量较多,为傍管类的环管束状,且多数为全部包围;木射线纺锤形,多为同型多列,偶有异形射线。广玉兰木材基本密度随着树干高度的增加整体上呈下降趋势,最大基本密度值出现在胸径处,为0.47 g/cm3。广玉兰木材端面硬度、径面硬度、弦面硬度、顺纹抗压强度、顺纹抗拉强度、抗弯强度和抗弯弹性模量分别为4.87 k N、3.84 k N、4.26 k N、35.02 MPa、114.97 MPa、83.30 MPa和10 500 MPa,为高档用材。展开更多
基金supported by the National Natural Science Foundation of China(Nos.82060631 and 32270413)the Science and Technology Department of Guizhou Province[Nos.QKH JC(2020)1Z076 and QKH JC(2020)1Y400],the Cultivation Project of National Natural Science Foundation of Guizhou Medical University(No.2023-106)+2 种基金the Outstanding Young Scientific and Technological Talents in Guizhou Province[No.QKH PTRC(2021)5633],High-level Innovative Talents in Guizhou Province(Thousand Levels of Talent for YUAN Chunmao in 2018)“Light of the West”Talent Cultivation Program of Chinese Academy of Sciences for YUAN Chunmao[RZ(2020)82],Guizhou Science and Technology Innovation Talent Team(No.QKHPTRCCXTD[2022]007)the Natural Science Foundation of Guizhou Province[No.QKHZYD(2022)4015].
文摘Four new sesquiterpene lactones(SLs)(1–4),along with a biosynthetically related SL(5),have been isolated from the leaves of Magnolia grandiflora.Magrandate A(1)is notable as the first C18 homogemarane type SL,featuring a unique 1,7-dioxaspiro[4.4]nonan-6-one core.Compounds 2 and 3,representing the first instances of chlorine-substituted gemarane-type SL analogs in natural products,were also identified.The structures of these isolates were elucidated through a combination of spectroscopic data analysis,electronic circular dichroism calculations,and X-ray single-crystal diffraction analysis.All isolates demonstrated anti-inflammatory activity in lipopolysaccharide-stimulated RAW264.7 cells.Notably,3–5 showed a significant inhibitory effect on nitric oxide production,with IC50 values ranging from 0.79 to 4.73μmol·L^(−1).Additionally,4 and 5 exhibited moderate cytotoxic activities against three cancer cell lines,with IC50 values between 3.09 and 11.23μmol·L^(−1).
基金Supported by the Foundation of National Agriculture Bureau of China for the Key Research Program (2004.NO.514)
文摘The chemical composition and antioxidant activity of Magnolia grandiflora L.seed essential oil were examined.By combining gas chromatography and mass spectrometry （GC-MS）,16 types of compounds were identified,including 40.91% oxygen-containing terpene derivatives,19.51% terpenes,13.97% esters,13.05% nitrogenous compounds,and 3.64% acids.Its capability of removing hydroxyl free radical was lower than that of V c,but it was closer to V c with increasing concentration.In cell experiment,all essential oil concentration （6.9,13.8,27.7,55.5,111.0,and 222.0 g/mL） groups increased cell proliferation by 26% or more （26.0%,38.8%,44.8%,40.2%,35.8%,and 30.4%,respectively）.In rat experiment,the SD rats group showed an at least 38% rise （38.62%,61.68%,and 62.86%,respectively） in glutathione-peroxisome （GSH-Px）activity,which is more than 24% reduction （29.56%,24.30%,and 36.93%） in malondialdehyde （MDA） content,and no significant difference in SOD activity was found.The results show that the essential oil had strong antioxidant activity,without dose effect within the concentration range.
基金One of the authors VPK is thankful to Department of Biotechnology(DBT),New Delhi,for financial assistance.
文摘Background:The ability to produce seeds when pollinators or potential mates are scarce is one of the principal advantages of self-pollination in flowering plants.However,the role of pollinators mediating self-pollination to ensure seed set when pollen or potential mates are limited has received less attention.This study examined the reproductive consequences and involvement of pollinators in assuring seed set in an isolated tree of Magnolia grandiflora,a predominantly outcrossing species.Methods:We tested various aspects of reproduction such as flower density,floral rewards,stigma receptivity,pollinator abundance and behaviour,fruit set and seed set,in two successive reproductive years(2015-2016).Results:Flowers of M.grandiflora possess a suite of traits facilitating pollinator-mediated self-pollination(PMS),although the chances of autonomous self-pollination are reduced due to herkogamy,spatial separation of anther and stigma.The mean pollen production/flower was 5,152,289±285,094 with a pollen-to-ovule ratio of 39430±164.We found a significant positive correlation between number of visits and seed production for bees(r=0.5099,p=0.0007)and beetles(r=0.7159,p=0.00001),indicating these are effective at PMS.There was a significant negative correlation for thrips(r=-0.3206,p=0.044)and no correlation for flies or spiders.The percent fruit set was 100%and the seed set per ovule ranged between 19 and 20%.Conclusions:PMS will guarantee reproductive assurance and mitigate the effect of reduced mates or pollen limitation which is expected to increase the fecundity and establishment of individual trees in geographically isolated locations.
文摘为了提高聚丙烯酰胺凝胶电泳（PAGE）的银染效果和条带回收的效率,以广玉兰DNA为材料进行ISSR-PCR分析,比较了两种银染（常规银染法和快速银染法）和条带回收法（乙醇糖原法和改进的煮沸法）.结果显示：两种银染方法效果一致,但常规银染要用2-3 h,而快速银染仅用30 m in,是常规银染的1/6-1/4;改良的煮沸法回收条带比乙醇糖原法更简便、更快捷.因此,快速银染和改良的煮沸法条带回收法可以应用在以后的研究中.
文摘结合树干解析取样,借助光学显微镜和扫描电镜,分别从宏观角度和微观角度研究了广玉兰木材的解剖构造;利用木材万能力学试验机,参照现行国家标准对广玉兰木材的力学性质进行了测定和分析。结果表明:广玉兰木材属于散孔材,管孔为圆形、椭圆形,多数为复管孔;轴向薄壁组织量较多,为傍管类的环管束状,且多数为全部包围;木射线纺锤形,多为同型多列,偶有异形射线。广玉兰木材基本密度随着树干高度的增加整体上呈下降趋势,最大基本密度值出现在胸径处,为0.47 g/cm3。广玉兰木材端面硬度、径面硬度、弦面硬度、顺纹抗压强度、顺纹抗拉强度、抗弯强度和抗弯弹性模量分别为4.87 k N、3.84 k N、4.26 k N、35.02 MPa、114.97 MPa、83.30 MPa和10 500 MPa,为高档用材。
