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Two undescribed anthocyanins and two undescribed flavonols were isolated from the flowers of Primula ×polyantha Mill., along with five known anthocyanins and four known flavonols. The two undescribed anthocyanins and the two undescribed flavonols were determined to be hirsutidin 3-O-β-galactopyranoside-5-O-β-glucopyranoside, 7-O-methyl-petunidin 3-O-β-galactopyranoside-5-O-β-glucopyranoside, quercetin 3-O-β-[(6""-acetylglucopyranosyl)-(1 → 2)-β-glucopyranosyl-(1 → 6)-β-glucopyranoside], and kaempferol 3-O-β-[(6""-acetylglucopyranosyl)-(1 → 2)-β-glucopyranosyl-(1 → 6)-β-glucopyranoside] using chemical and spectroscopic methods. They were also found in the flowers of the Himalayan wild species, Primula primulina (Spreng.) H. Hara except for quercetin 3-O-β-[(6""-acetylglucopyranosyl)-(1 → 2)-β-glucopyranosyl-(1 → 6)-β-glucopyranoside]. The flower color variations of P. ×polyantha cultivars, reflected by the hue values (b*/a*) of the colors, were due to the glycosidic patterns in the anthocyanins and their concentrations in the petals. Moreover, in the P. ×polyantha cultivars with violet-blue flowers, both the intermolecular copigmentation occurs between hirsutidin 3-O-β-galactopyranoside-5-O-β-glucopyranoside and another flavonol, quercetin 3-O-β-glucopyranosyl-(1 → 2)-β-glucopyranosyl-(1 → 6)-β-glucopyranoside. Moreover, the flower color variation was affected by the pH value.

Supplemental material, Supplementary Material 1, for Flavonoids From the Flowers and Leaves of the Himalayan Megacodon stylophorus (Gentianaceae) by Tsukasa Iwashina, Rinchen Yangzom, Hari Prasad Devkota and Takayuki Mizuno in Natural Product Communications

A new species of Roscoea is described and illustrated. Roscoea megalantha Tosh.Yoshida & R.Yangzom occurs in the Eastern Zone of Bhutan and neighbouring Arunachal Pradesh in India. A distribution map and an IUCN conservation assessment are given. A key to the three species of Roscoea found in Bhutan is provided.

Aim We used published data of the floristic and elevational distribution of seed plants of Bhutan to test the contribution of climatic, topographical and biogeographical variables to shape elevational species richness and endemism patterns. Location Bhutan. Methods We compiled data of seed plant species distributions from the Flora of Bhutan and related them to energy, humidity, and topographically related variables and biogeographical distributions. We used multiple regression models to identify most predictive independent variables by multi-model-inference based on AICc. Results We find highest species richness at mid elevations (1500–2000 m), while endemic richness peaks markedly higher at 4500 m. Separated for life forms, the peak of richness shifts upward along the elevational gradient in the order of trees – shrubs – herbs – graminoids. Elevational richness peaks of temperate taxa were centred at high and of tropical taxa at low elevations. Temperature was identified as most influential for species richness patterns and showed a humped relationship to richness patterns. Main conclusions The humped patterns of species richness in Bhutan correspond to results from other studies in low latitude mountains, and the correlation of these patterns to energy driven variables, especially temperature, can be confirmed. The humped relationship of temperature (including water regimes driven by temperature) to richness indicates elevation zones of moderate temperatures with absence of temperature extremes as predicting species richness, and the high elevation peak of endemism may be related to mountain terrain configuration and climatic history. The different elevations of richness peaks of tropical and temperate taxa underlines the notion of a transition zone between temperate and tropical realms, thus the intermingling of different evolutionary histories. For further research, we require fine scale local data for detailed taxa distributions in order to infer issues from evolutionary processes in landscape development to identify target regions for conservation purposes.

Two flavonol glycosides were isolated from the yellow flowers of Bhutani Himalayan Meconopsis paniculata, together with other two minor flavonol glycosides. They were identified as 6-hydroxykaempferol 3-O-glucoside and 6-hydroxykaempferol 3-O-sophoroside by UV, LC-MS, acid hydrolysis and 1H and 13C NMR. Two minor flavonol glycosides were identified as kaempferol 3-O-glucoside and kaempferol 3-O-sophoroside. Although herbacetin (8-hydroxykaempferol) 3-O-glucoside has been reported from M. paniculata as a yellow pigment by Harborne (1969), 6-hydroxykaempferol 3-O-glucoside and 3-O-sophoroside were found in this survey. The latter flavonoid was reported in nature for the first time. On the other hand, four flavonol glycosides were isolated from the yellow flowers of M. integrifolia and characterized as quercetin 3-O-gentiobioside and three 3-O-(acetylgentiobiosides). Thus, it was proved that the yellow flower colour of two Meconopsis species, M. paniculata and M. integrifolia, are due to flavonol glycosides.

Five flavonols, four flavones and one C-glycosylflavone were isolated from the leaves of Cathcartia villosa which is growing in the Himalayan Mountains. They were characterized as quercetin 3-O-vicianoside (1), quercetin 7,4′-di-O-glucoside (3), quercetin 3-O-rutinoside (4), quercetin 3-O-glucoside (5), quercetin 3-O-arabinosylarabinosylglucoside (6) (flavonols), luteolin (7), luteolin 7-O-glucoside (8), apigenin (9), chrysoeriol (10) (flavones), and vicenin-2 (11) (C-glycosylflavone) by UV, LC-MS, acid hydrolysis, NMR and/or HPLC and TLC comparisons with authentic samples. On the other hand, two flavonols 1 and kaempferol 3-O-vicianoside (2) were isolated and identified from the flowers of the species. Flavonoids were reported from the genus Cathcartia in this survey for the first time. Their chemical characters were chemotaxonomically compared with those of related Papaveraceous genera, Meconopsis and Papaver.

Five flavonol O-glycosides and 4 C-glycosylflavones were isolated from the flowers of the Himalayan Megacodon stylophorus (Gentianaceae). They were characterized as quercetin 3- O-glucoside (1), quercetin 3- O-rutinoside (2), kaempferol 3- O-glucoside (3), isorhamnetin 3- O-glucoside (4) and kaempferol 3,7-di- O-glucoside (5) (flavonols), and isovitexin (6), isoorientin (7), isovitexin X″- O-arabinoside (8) and isovitexin 4′- O-glucoside (9) ( C-glycosylflavones) by ultraviolet, liquid chromatography-mass spectrometry, acid hydrolysis, nuclear magnetic resonance, and/or high-performance liquid chromatography and thin-layer chromatography comparisons with authentic samples. On the other hand, 5 C-glycosylflavones were isolated from the leaves and identified as 6, 7, 9, vitexin (10), and orientin (11). Although many C-glycosylflavones and xanthones have been reported from Gentianaceae species, flavonols are minor occurrence in the family. Flavonoids were reported from the Megacodon species for the first time.

Blue flowers of six Bhutani Meconopsis species, M. bhutanica, M. bella, M. horridula, M. simplicifolia, M. primulina and M. polygonoides, were surveyed for anthocyanins and other flavonoids. Four anthocyanins were isolated and identified as cyanidin 3-O-sambubioside-7-O-glucoside (1), cyanidin 3-O-[xylosyl-(1 → 2)-(6″-malonylglucoside)]-7-O-glucoside (2), cyanidin 3-O-sambubioside (4) and cyanidin 3-O-[xylosyl-(1 → 2)-(6″-malonylglucoside)] (5). On the other hand, 12 flavonols were isolated from their Meconopsis species with various combination and characterized as kaempferol 3-O-glycosides (8–12), kaempferol 3,7-O-glycosides (13–16), quercetin 3-O-glycosides (17 and 18) and isorhamnetin 3-O-glycoside (19). Of six Meconopsis species which were surveyed in this experiment, anthocyanin and flavonol composition of five species except for M. horridula was clarified for the first time. Their Meconopsis species showed the different flavonoid profiles, respectively, and flavonoid diversity within the glycosylation level of Meconopsis flowers were indicated.

Three anthocyanins were isolated from the red flowers of Meconopsis wallichi in Bhutan. They were characterized as cyanidin 3- O-glucoside, cyanidin 3- O-sambubioside and cyanidin 3- O-(succinylsambubioside) by UV-VIS, LC-MS, acid hydrolysis, alkaline saponification, and HPLC comparisons with authentic samples. The latter anthocyanin was reported in nature for the first time. However, flavonoids except for anthocyanins were not found in the flowers, showing that the red color is due to three cyanidin glycosides alone, without copigments and metals. Although the anthocyanins were reported from the blue flowers of three Meconopsis species, those of red flower Meconopsis species were characterized for the first time.