Two new C27 steroidal glycosides, named taccaoside A (1) and B (2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O--D-...Two new C27 steroidal glycosides, named taccaoside A (1) and B (2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O--D-glucopyranosyl-(25R)-3?26-dihydroxy furost-5,20-diene -3-O-[?L-rhamnopyranosyl(12)]-[?L-rhamnopyranosyl(13)]--D-glucopyranoside (1) and 26-O--D-glucopyranosyl-(25R)-3?26-dihydroxy furost-5,20-diene-3-O-[?L-rhamnopyranosyl- (12)]-[?D-glucopyranosyl(13)--L-rhamnopyranosyl(13)]--D-glucopyranoside (2), res- pectively.展开更多
Two new steroidal bitter principles, taccolanolide O, P have been isolated from Tacca subflaellata and their structures were established by spectroscopic methods.
Tacca involucrata (Batflower or Polynesian arrowroot) tubers are a stable food in tropics where it occurs. In central Nigeria, it is processed locally after digging it from the ground by peeling with sharp sand, grati...Tacca involucrata (Batflower or Polynesian arrowroot) tubers are a stable food in tropics where it occurs. In central Nigeria, it is processed locally after digging it from the ground by peeling with sharp sand, grating and soaking in fresh water after which it is filtered and the filtrate is dried and is cooked with other ingredients. The marc, said to be bitter, is usually discarded by deep burial as it is considered poisonous to livestock and humans. All parts of the plant are used in folk medicine to treat various diseases. The aim of this work was to analyze quantitatively the phytochemical, elemental, vitamin and proximate composition of the marc of the tubers with a view of assessing its pharmacological and nutritional potentials. The marc was obtained from Jandeikyura Village in Wukari LGA of Taraba State, Nigeria, and was extracted with 80% methanol for 72 hr to give a yield of 10.1% w/w and was whitish in colour. Phytochemical analysis showed the presence of reducing sugars, tannins, flavonoids, steroids, glycosides and hydrogen cyanide at 195.65 ± 0.5, 3.44 ± 0.2, 1.29 ± 0.5, 0.83 ± 0.4, 1.36 ± 1.0 and 0.00985 ± 0.3 (mg/100g), respectively. The elemental analysis showed the presence of potassium, sodium, magnesium, selenium, manganese, vanadium and some heavy metals like lead, aluminium, arsenic and mercury at 36.45 ± 0.1, 44.04 ± 0.1, 1.52 ± 0.2, 0.80 ± 0.9, 0.52 ± 0.7, 0.27 ± 0.7, 0.07 ± 0.6, 0.008 ± 0.05, 0.085 ± 0.6 and 0.026 ± 0.6 (mg/100g), respectively. Vitamin analysis showed the presence of vitamins A, B1, B2, B3, C and E in various amount as 2.26 ± 0.8 μg, 0.83 ± 0.8 mg/100g, 0.58 ± 0.4 mg/100g, 0.33 ± 0.6 mg/100g, 9.80 ± 0.4 mg/100g and 6.86 ± 0.9 mg/100g, respectively. The proximate analysis showed the marc to contain moisture, ash, fats, fibre, crude protein and carbohydrate in the range of 10.83% ± 0.3%, 1.93% ± 0.6%, 1.06% ± 0.5%, 4.42% ± 0.4%, 6.12% ± 0.6% and 86.07% ± 0.3%, respectively. This shows that despite the presence of hydrogen cyanide and some heavy metals in traces amount which are considered poisonous to livestock and humans, the marc contains some elements, vitamins, phytochemical and nutrients which are pharmacologically and nutritionally important.展开更多
Most species in the genus Tacca （Dioscoreaceae） feature green to black purple, conspicuous inflorescence involucral bracts with variable shapes, motile filiform appendages （bracteoles）, and diverse types of inflor...Most species in the genus Tacca （Dioscoreaceae） feature green to black purple, conspicuous inflorescence involucral bracts with variable shapes, motile filiform appendages （bracteoles）, and diverse types of inflorescence morphology. To infer the evolution of these inflorescence traits, we reconstructed the molecular phylogeny of the genus, using DNA sequences from one nuclear, one mitochondrial, and three plastid loci （Internal Transcribed Spacer （ITS）, atpA, rbcL, trnL-F, and trnH-psbA）. Involucres and bracteoles characters were mapped onto the phylogeny to analyze the sequence of inflorescence trait evolution. In all analyses, species with showy involucres and bracteoles formed the most derived clade, while ancestral Tacca had small and plain involucres and short bracteoles, namely less conspicuous inflorescence structures. Two of the species with the most elaborate inflorescence morphologies （T. chantrieri in southeast China and T. integrifolia in Tibet）, are predominantly self-pollinated, indicating that these conspicuous floral displays have other functions rather than pollinator attraction. We hypothesize that the motile bracteoles and involucres may facilitate selfing; display photosynthesis in the dim understory, and protect flowers from herbivory.展开更多
Two pentacyclic steroidal bitter principles, taccalonolide E and F, have been isolated from Tacca Plantaginea. Their structures were elucidated by spectroscopic methods.
文摘Two new C27 steroidal glycosides, named taccaoside A (1) and B (2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O--D-glucopyranosyl-(25R)-3?26-dihydroxy furost-5,20-diene -3-O-[?L-rhamnopyranosyl(12)]-[?L-rhamnopyranosyl(13)]--D-glucopyranoside (1) and 26-O--D-glucopyranosyl-(25R)-3?26-dihydroxy furost-5,20-diene-3-O-[?L-rhamnopyranosyl- (12)]-[?D-glucopyranosyl(13)--L-rhamnopyranosyl(13)]--D-glucopyranoside (2), res- pectively.
文摘Two new steroidal bitter principles, taccolanolide O, P have been isolated from Tacca subflaellata and their structures were established by spectroscopic methods.
文摘Tacca involucrata (Batflower or Polynesian arrowroot) tubers are a stable food in tropics where it occurs. In central Nigeria, it is processed locally after digging it from the ground by peeling with sharp sand, grating and soaking in fresh water after which it is filtered and the filtrate is dried and is cooked with other ingredients. The marc, said to be bitter, is usually discarded by deep burial as it is considered poisonous to livestock and humans. All parts of the plant are used in folk medicine to treat various diseases. The aim of this work was to analyze quantitatively the phytochemical, elemental, vitamin and proximate composition of the marc of the tubers with a view of assessing its pharmacological and nutritional potentials. The marc was obtained from Jandeikyura Village in Wukari LGA of Taraba State, Nigeria, and was extracted with 80% methanol for 72 hr to give a yield of 10.1% w/w and was whitish in colour. Phytochemical analysis showed the presence of reducing sugars, tannins, flavonoids, steroids, glycosides and hydrogen cyanide at 195.65 ± 0.5, 3.44 ± 0.2, 1.29 ± 0.5, 0.83 ± 0.4, 1.36 ± 1.0 and 0.00985 ± 0.3 (mg/100g), respectively. The elemental analysis showed the presence of potassium, sodium, magnesium, selenium, manganese, vanadium and some heavy metals like lead, aluminium, arsenic and mercury at 36.45 ± 0.1, 44.04 ± 0.1, 1.52 ± 0.2, 0.80 ± 0.9, 0.52 ± 0.7, 0.27 ± 0.7, 0.07 ± 0.6, 0.008 ± 0.05, 0.085 ± 0.6 and 0.026 ± 0.6 (mg/100g), respectively. Vitamin analysis showed the presence of vitamins A, B1, B2, B3, C and E in various amount as 2.26 ± 0.8 μg, 0.83 ± 0.8 mg/100g, 0.58 ± 0.4 mg/100g, 0.33 ± 0.6 mg/100g, 9.80 ± 0.4 mg/100g and 6.86 ± 0.9 mg/100g, respectively. The proximate analysis showed the marc to contain moisture, ash, fats, fibre, crude protein and carbohydrate in the range of 10.83% ± 0.3%, 1.93% ± 0.6%, 1.06% ± 0.5%, 4.42% ± 0.4%, 6.12% ± 0.6% and 86.07% ± 0.3%, respectively. This shows that despite the presence of hydrogen cyanide and some heavy metals in traces amount which are considered poisonous to livestock and humans, the marc contains some elements, vitamins, phytochemical and nutrients which are pharmacologically and nutritionally important.
基金funded by the Key Project of the Chinese Academy of Science (KSCX2-YW-Z-0904)National Natural Science Foundation of China (30670131)+1 种基金Yunnan Provincial Natural Science Foundation (2006C0055M)to Ling ZhangLaboratory equipment for phylogenetic analyses was provided by the State Key Basic Research and Development Plan of China (973, 2008GA001) to De-Zhu Li
文摘Most species in the genus Tacca （Dioscoreaceae） feature green to black purple, conspicuous inflorescence involucral bracts with variable shapes, motile filiform appendages （bracteoles）, and diverse types of inflorescence morphology. To infer the evolution of these inflorescence traits, we reconstructed the molecular phylogeny of the genus, using DNA sequences from one nuclear, one mitochondrial, and three plastid loci （Internal Transcribed Spacer （ITS）, atpA, rbcL, trnL-F, and trnH-psbA）. Involucres and bracteoles characters were mapped onto the phylogeny to analyze the sequence of inflorescence trait evolution. In all analyses, species with showy involucres and bracteoles formed the most derived clade, while ancestral Tacca had small and plain involucres and short bracteoles, namely less conspicuous inflorescence structures. Two of the species with the most elaborate inflorescence morphologies （T. chantrieri in southeast China and T. integrifolia in Tibet）, are predominantly self-pollinated, indicating that these conspicuous floral displays have other functions rather than pollinator attraction. We hypothesize that the motile bracteoles and involucres may facilitate selfing; display photosynthesis in the dim understory, and protect flowers from herbivory.
基金This research was supported by the National Natural Science Foundation of China.
文摘Two pentacyclic steroidal bitter principles, taccalonolide E and F, have been isolated from Tacca Plantaginea. Their structures were elucidated by spectroscopic methods.
