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The peels of ripe fruit of 'Hass' and 'Hass' type (HT) avocado cultivars were evaluated for phytochemical composition and other attributes. Peels represented from 8.78 to 14.11% of fruit weight. Their color ranged from homogeneous black to black with very small greenish spots. The oil content in the peels was low. Twelve fatty acids were identified in peel oil and the ratio of unsaturated to saturated fatty acids suggested that peel oil might contribute to human health. The phytochemical composition varied significantly with cultivar. However, many HT peels were superior than 'Hass' peel in their content of α-tocopherol, β-sitosterol, perseitol, and cyanidin-3-glucoside, which was up to 211.67, 45.92, 337.17, and 519.27% higher in HT peels, respectively. The content of some phenolic compounds, especially procyanidin B2 and epicatechin, was significantly lower in 'Hass' than in many HT peels. Few HT peels showed a higher content of carotenoids and chlorophyll than 'Hass' peels. Lutein was the most abundant carotenoid. Chlorophyll a and b were also abundant in peels and low concentrations of chlorophyll derivatives were observed. Avocado peels are an important source of bioactive compounds, including some carotenoids, acids, sterols, and volemitol, which were observed for the first time.

Volemitol (d-glycero-d-manno-heptitol, α-sedoheptitol) is an unusual seven-carbon sugar alcohol that fulfills several important physiological functions in certain species of the genus Primula. Using the horticultural hybrid polyanthus (Primula × polyantha) as our model plant, we found that volemitol is the major nonstructural carbohydrate in leaves of all stages of development, with concentrations of up to 50 mg/g fresh weight in source leaves (about 25% of the dry weight), followed by sedoheptulose (d-altro-2-heptulose, 36 mg/g fresh weight), and sucrose (4 mg/g fresh weight). Volemitol was shown by the ethylenediaminetetraacetate-exudation technique to be a prominent phloem-mobile carbohydrate. It accounted for about 24% (mol/mol) of the phloem sap carbohydrates, surpassed only by sucrose (63%). Preliminary 14CO2 pulse-chase radiolabeling experiments showed that volemitol was a major photosynthetic product, preceded by the structurally related ketose sedoheptulose. Finally, we present evidence for a novel NADPH-dependent ketose reductase, tentatively called sedoheptulose reductase, in volemitol-containingPrimula species, and propose it as responsible for the biosynthesis of volemitol in planta. Using enzyme extracts from polyanthus leaves, we determined that sedoheptulose reductase has a pH optimum between 7.0 and 8.0, a very high substrate specificity, and displays saturable concentration dependence for both sedoheptulose (apparent Km = 21 mm) and NADPH (apparent Km = 0.4 mm). Our results suggest that volemitol is important in certainPrimula species as a photosynthetic product, phloem translocate, and storage carbohydrate.

1 H, 13 C, and 183 W NMR spectroscopic methods were used for the structural characterization of the tungstate and molybdate complexes of volemitol ( d - glycero - d - manno -hepitol) in aqueous solution. The major species (type E) are a pair of isomeric complexes formed at the arabino site in reversed orientation, i.e., HO-1,2,3,4 and HO-4,3,2,1. A single, minor complex is formed at the HO-3,4,5,6 altro site and is shown to be isostructural with the known single complexes of ribitol and d -altritol (type E′). The present NMR results support the hypothesis that complexes of type E′ are weaker than those of type E because they are destabilized by a steric strain due to the interaction of the side chain of the ligand with the site of chelation.

Aposymbiotic mycobionts of the ascomycetous lichens Cladonia caespiticia (1), Parmelia acetabulum (2), Physcia semipinnata (3) (all Lecanorales), Pertusaria pertusa (4) (Pertusariales), Xanthoria parietina (5) (Teloschistales), Chaenotheca chrysocephala (6), Coniocybe furfuracea (7) (both Caliciales), Baeomyces rufus (8) (Leotiales), Normandina pulchella (9) (incertae sedis), Gyalecta jenensis (10) (Gyalectales) and Thelotrema lepadinum (11) (Graphidales) were cultured in liquid media containing glucose and malt extract as carbon sources, and their polyol patterns investigated by gas liquid chromatography of their acetyl derivatives. The neutral fraction made up between 0·2 and 6·3% of the dry matter. Polyol contents were below 1% dry weight in all species except X. parietina and G. jenensis which yielded 2·6 and 1%, respectively of acyclic polyols. Mannitol and arabitol were found in all species, glycerol in mycobionts (1, 2, 6, 7, 8, 11), volemitol in mycobionts (1, 2, 7, 8) and erythritol in (1). None of the 11 ascomycetes contained the specific polyol which is presumably released by the compatible green algal photobiont in the symbiotic system.

The molecular structures of the title heptitols were determined by X-ray crystallography, using direct methods, and refined to final residual parameters of R = 0.037 and 0.039, respectively. Each compound adopts a bent conformation. For α-sedoheptitol ( 1 ), this is not the expected conformation (with O-6 in the extended planar position). Instead, 1 adopts a conformation with a 1,3- parallel interaction between O-4 and C-7.

The lichen Parmotrema cetratum contains traces of the unusual threitol and unexpected volemitol, along with galactose (2%). Present is a complex containing a lightly branched beta-glucan containing (1--3) and (1--4)-linkages in a 25:47 molar ratio chemically linked to a galactomannan with structural features common in other lichens. A glucogalactomannan with a small proportion of Glc rho side chains was also characterized.

Summary Volemitol, sucrose and starch are the principal photosynthetic products of the leafy liverwort Plagiochila asplenioides (L.) Dum. var. major Nees. but the quantitatively most abundant carbohydrates, fructans, do not rapidly incorporate 14C from 14CO2. The limited amount of starch present turns over rapidly but sucrose and especially volemitol do so very slowly and much 14C incorporated during a short pulse remains in these compounds after prolonged periods in the dark (up to 4 months). The liverwort grows under these conditions and 14C incorporated during the pulse passes into insoluble polymers. Loss of chlorophyll is also slow and tissue is photosynthetically viable after such long periods in the dark. Exogenous glucose, fructose and sucrose are absorbed and metabolized in the dark similarly to CO2 in the light except that there is enhanced incorporation into fructans. Exogenous mannitol is absorbed but poorly metabolized. Results are discussed in relation to polyol- and fructan-containing angiosperms and algae, and from both biochemical and ecological viewpoints.

Volemitol in Lophoeolea bidentata and Plagioehila spinulosa, volemitol and sedoheptulose in Bazzania trierenata and Lepidozia reptans, and mannitol in Barbilophozia floerkei and Seapania undulata are photosynthetic products in addition to sucrose and fructans. Polyols are not primary assimilatory products in Mylia taylori, Nardia sealaris, Saeeogyna vitieulosa or Porella platyphylla. It is concluded that neither Mylia nor Saeeogyna is closely related to the Plagiochilaceae/Lophocoleaceae complex and that chemotaxonomic investigation would aid the classification of the Jungermanniaceae s.l.

Summary Pelvetia canaliculata (L.) Dcne. et Thur. (Fucales; Phaeophyceae) is the only brown algal species hitherto known to contain two polyols (alditols), mannitol and volemitol. Biosynthesis of mannitol in this species follows the well-documented sequence via reduction of fructose-6-phosphate by a NADH-linked dehydrogenase. In addition, a NADH-linked enzyme which converts sedoheptulose-7-phosphate with high specifity has been found. A biosynthetic pathway for the formation of volemitol in Pelvetia is proposed: sedoheptulose-7-phosphate → volemitol-1-phosphate → volemitol.

Summary The soluble carbohydrates of both Plagiochila asplenioides var. asplenioides and var. major consist of volemitol and a volemitol derivative, sucrose and a series of sucrosyl-fructans and mannitol. Glucose, fructose and trehalose are present in trace amounts. Quantitatively, volemitol is the single most abundant compound but this is exceeded by total fructan. Starch is only a minor component and the neutral insoluble fraction consists of galactose, arabinose (major components), glucose, xylose and mannose (intermediate quantities) and fucose and rhamnose (minor components). Only starch and sucrose are depleted when tissue is kept in the dark overnight. Results are discussed in relation to the soluble composition of bryophytes in general.

Summary The distribution of the heptitol volemitol within the genus Primula has been investigated. About 90 species representing 23 sections of the genus have been included. Volemitol is not a common constituent of all Primula species, but is restricted to a few sections as far as examined, e.g. to all sections of the subgenus Primula . Species which have volemitol contain this compound in all parts of the plant. Highest concentrations are found in the leaves. Volemitol is strongly 14 C-labelled during photosynthetic 14 C0 2 -assimilation. The results are discussed with respect to the chemotaxonomic significance of the pattern of distribution of volemitol and of hamamelitol.

The distribution of C6- and C7-alditols among species of the genus Pelvetia has been investigated. The noticeable occurrence of volemitol is restricted to Pelvetia canaliculata (L.) Dcne & Thur. This species is thus the only marine algae investigated in detail containing a heptitol as accumulation product. The physiological and taxonomic implications of volemitol in Pelvetia canaliculata are discussed.

Because D-e~~t~l~O-D-g~~~C~O-OCtitOl is closely related to D-gijxero-D-mzmooctulose and both have been found in the avocado3, and because that octulose has been found also in Sedum3, a special search was made for the octitol in Sedum. To this end, 37.5 kg of S. speciabile Bor. was processed as described in the Experimental section, and &rally fractionated on a column of Dowex 5OW-X8 (Bat+) ion-exchange

An aqueous extract of 20 kg of the dried roots of Primula officinalis Jacq. has been deproteinized, deionized, fermented with bakers' yeast, and fractionated by chromatography on cellulose columns, Dowex 50W-X8 (Ba2+) resin columns, and sheets of filter paper. The following higher-carbon sugars were isolated: D-altro-heptulose (sedoheptulose), D-manno-heptulose, D-allo-heptulose, D-altro-3-heptulose, D-glycero-D-manno-heptose, D-glycero-D-gluco-heptose, D-glycero-D-manno-octulose, D-glycero-L-galacto-octulose, D-erythro-L-gluco-nonulose, and D-erythro-L-galacto-nonulose. Two higher-carbon polyhydric alcohols —volemitol (D-glycero-D-manno-heptitol) and β-sedoheptitol (D-glycero-D-gluco-heptitol)—were also isolated, as well as glycerol, erythritol, xylitol, myo-inositol, D-xylose, and primeverose. Of all these substances, only volemitol had previously been isolated from P. officinalis, although primeverose was known to occur there as a constituent of the glycosides primeverin and primulaverin. In addition, primeverose has been reduced to primeveritol (6-O-β-D-xylopyranosyl-D-glucitol), which was characterized further as the crystalline octaacetate; and the crystalline D-glycero-β-D-gluco-heptose has been converted into the new, crystalline D-glycero-β-D-gluco-heptose hexaacetate.

Four Trentepohlia species and the related Cephaleuros virescens (Chroolepidaceae, Trentepohliales, Chlorophyceae) photosynthesize and accumulate mannitol, arabinitol, erythritol and glycerol, while Trentepohlia spp. additionally synthesize a second pentitol, ribitol (adonitol). T. umbrina also contains small amounts of a heptitol, volemitol.