A new hexenol glycoside from leaves ofSmallanthus sonchifolius

Metabolomic and Gene Expression Studies Reveal the Diversity, Distribution and Spatial Regulation of the Specialized Metabolism of Yacón (Smallanthus sonchifolius, Asteraceae)

Smallanthus sonchifolius, also known as yacón, is an Andean crop species commercialized for its nutraceutical and medicinal properties. The tuberous roots of yacón accumulate a diverse array of probiotic and bioactive metabolites including fructooligosaccharides and caffeic acid esters. However, the metabolic diversity of yacón remains unexplored, including the site of biosynthesis and accumulation of key metabolite classes. We report herein a multidisciplinary approach involving metabolomics, gene expression and scanning electron microscopy, to provide a comprehensive analysis of the diversity, distribution and spatial regulation of the specialized metabolism in yacón. Our results demonstrate that different metabolic fingerprints and gene expression patterns characterize specific tissues, organs and cultivars of yacón. Manual inspection of mass spectrometry data and molecular networking allowed the tentative identification of 71 metabolites, including undescribed structural analogues of known bioactive compounds. Imaging by scanning electron microscopy revealed the presence of a new type of glandular trichome in yacón bracts, with a distinctive metabolite profile. Furthermore, the high concentration of sesquiterpene lactones in capitate glandular trichomes and the restricted presence of certain flavonoids and caffeic acid esters in underground organs and internal tissues suggests that these metabolites could be involved in protective and ecological functions. This study demonstrates that individual organs and tissues make specific contributions to the highly diverse and specialized metabolome of yacón, which is proving to be a reservoir of previously undescribed molecules of potential significance in human health.

Two new 3-hexenol glycosides from the calyces of Physalis alkekengi var. franchetii

Two new hexenol glycosides, (Z)-hex-3-en-1-ol O-β-d-xylcopyranosyl-(1-6)-β -d-glucopyranosyl-(1-2)-β-d-glucopyranoside (1) and (E)-hex-3-en-1-ol O-β-d-xylcopyranosyl-(1-6)-β-d-glucopyranosyl-(1-2)-β-d-glucopyranoside (2), were isolated from the 50% ethanol elution of macroporous resin of Physalis alkekengi var. franchetii. Their structures were established by detailed spectroscopic analysis, including extensive 2D-NMR data. This is the first time to report the (Z) and (E) 3-hexenol glycosides from Physalis alkekengi var. franchetii.

New ent-kaurane diterpenoid dimer from Pulicaria inuloides

A new naturally occurring ent-kaurane diterpenoid dimer, 15β, 15'β-oxybis (ent-kaur-16-en-19-oic acid) (1) along with six known compounds, 15β-hydroxy-ent-kaur-16-en-19-oic acid (2), 15β-hydroxy-ent-kaur-16-en-19-oate-β-d-glucopyranoside (3), 6-hydroxykaempferol-3, 7-dimethyl ether (4), quercetagetin 3, 7, 3'-trimethyl ether (5), β-sitosterol (6) and β-sitosterol glucoside (daucosterol) (7) were isolated from the aerial parts of Pulicaria inuloides DC. Compounds 2-5 were isolated for the first time from genus Pulicaria. The structures of compounds 1-7 were established on the basis of extensive 1D and 2D NMR spectroscopic techniques in combination with ESI-MS. The antimicrobial activity of the isolated compounds was evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. Sulphorhodamine B cytotoxic assay against HepG2 (liver cancer) cell line and ABTS antioxidant assay were carried out.