Flavonoids in translucent bracts of the Himalayan Rheum nobile (Polygonaceae) as ultraviolet shields

  title={Flavonoids in translucent bracts of the Himalayan Rheum nobile (Polygonaceae) as ultraviolet shields},
  author={Tsukasa Iwashina and Yuji Omori and Jun-ichi Kitajima and Shinobu Akiyama and Toshisada Suzuki and Hideaki Ohba},
  journal={Journal of Plant Research},
UV-absorbing substances were isolated from the translucent bracts of Rheum nobile, which grows in the alpine zone of the eastern Himalayas. Nine kinds of the UV-absorbing substances were found by high performance liquid chromatography (HPLC) and paper chromatography (PC) surveys. All of the five major compounds are flavonoids, and were identified as quercetin 3-O-glucoside, quercetin 3-O-galactoside, quercetin 3-O-rutinoside, quercetin 3-O-arabinoside and quercetin 3-O-[6″-(3-hydroxy-3… 

Ultraviolet-absorbing substances in the translucent bracts of Davidia involucrata (Davidiaceae).

Ultraviolet-absorbing substances in the bracts of Davidia involucrata, which is endemic to China, were surveyed. Two large translucent bracts of the species put on the inflorescence such as a parasol

An analysis of flavonoid compounds in leaves of Japonolirion (Petrosaviaceae)

Japonolirion, comprising Japonolirion osense Nakai, which occurs on serpentinite at two widely separated localities in Japan, has been considered as an isolated taxon, but more recently has been

Phenolic constituents from Rheum nobile and their antioxidant activity

Naphthalene glycosides, stilbene glyCosides, flavanols, especially anthraquinones are main chemical constituents of this plant.

Isolation and identification of sea buckthorn (Hippophae rhamnoides) phenolics with antioxidant activity and α-glucosidase inhibitory effect.

The results indicate that sea buckthorn leaf extracts could potentially be used for food additives and the development of useful natural compounds.

Flavonoids and their Qualitative Variation in Calystegia soldanella and Related Species (Convolvulaceae)

This survey elucidated the flavonoid composition of a seashore species Calystegia soldanella, which is distributed not only on the seashores, but also by the inland freshwater lake, Lake Biwa, and showed that the quercetin to kaempferol ratio of coastal populations was higher than that of lakeshore populations.

Tannins and Related Compounds. XLV. Rhubarb. (5). : Isolation and Characterization of Flavan-3-ol and Procyanidin Glucosides

A chemical examination of high-quality commercial rhubarb (Choukichio : ?? ?? ?? ) has led to the isolation and characterization of eight flavan-3-ol glucosides and three proanthocyanidin glucosides,

Flavonol glycosides from Dryas octopetala.

Six flavonol glycosides and ent-epicatechin were isolated from Dryas octopetala and their structures elucidated by chemical and spectroscopic methods. Two new flavonoids,

Tannins and related compounds. XLVIII. Rhubarb. (7). Isolation and characterization of new dimeric and trimeric procyanidins.

Together with the known flavan-3-ols and procyanidins, a new procyAnidin dimer and several new trimers have been isolated from high-quality rhubarb.

Ultraviolet‐B radiation absorbing capacity of leaf hairs

Pubescence layers with their native structure and orientation were isolated from the leaves of Olea europaea and Olea chrysophylla and were characterized as phenolics with considerable flavonoid contribution, suggesting that leaf hairs, besides other functions, may constitute a shield against UV-B radiation.

Pollen development of Rheum nobile Hook.f. & Thomson (Polygonaceae), with reference to its sterility induced by bract removal

It is suggested that the extreme difference of pollen stainability between two groups of R. nobile exposed to the surroundings may be related to the stage of microsporogenesis, which might play an important role in normal reproduction under low temperature at high altitudes.

Selective light transmittance of translucent bracts in the Himalayan giant glasshouse plant Rheum nobile Hook.f. & Thomson (Polygonaceae)

The role of the bracts of R. nobile is to protect the reproductive organs by absorbing UV radiation and to keep them warm by transmitting PA and IR radiation.

Optical and anatomical characteristics of bracts from the Chinese "glasshouse" plant, Rheum alexandrae Batalin (Polygonaceae), in Yunnan, China

  • H. Tsukaya
  • Biology, Medicine
    Journal of Plant Research
  • 2002
Absorption spectrum analyses of the half-translucent bracts showed that, despite their thinner structure, they absorbed ultraviolet (UV) radiation more efficiently than did the green rosette leaves.

Photosynthetic characteristics of a giant alpine plant, Rheum nobile Hook. f. et Thoms. and of some other alpine species measured at 4300 m, in the Eastern Himalaya, Nepal

Observations indicate that the gas-exchange characteristics of alpine forbs in the Eastern Himalaya are adapted to the local wet and humid monsoon conditions and thus photosynthetic rates attained during the monsoon period are similar to those of lowland plants.