Yacon has been considered to be a potent alternative food source for patients who require a dietary cure in regional area, while the leaf part has been provided and consumed as an herbal tea in local markets. We demonstrated here potent antioxidative effects of the tea leaves from yacon in different free radical assays, reducing power assay, and cellular superoxide anion radical generation assay. Results support yacon tea leaves may be a good source of natural antioxidants for preventing O2(-) radical-mediated disorders.

We extracted polysaccharides (PS) from Aphanothece sacrum using a hot alkaline solution which degraded other biopolymers such as proteins and nucleotides. The spectroscopy and elemental analyses indicated the PS contain carboxyls and sulfate groups. The degree of sulfation was estimated as about 10 mol %. 1H NMR studies demonstrated that the PS of A. sacrum had a dimethylated fucose unit. The combination of sulfate group and fucose in the prokaryotic PS was first evidenced by the direct spectroscopic studies. The PS showed efficient gelation behavior, binding to metal ions abundant in soil, and the swelling volume of the gel was approximately 250 times the dry volume. These results imply that PS of A. sacrum, which has been mass cultivated in Japan for a long time, may have potential as an environmentally benign water absorbent.

Four new resin glycosides having intramolecular cyclic ester structures (jalapins), named calysolins I-IV (1-4), were isolated from the methanol extract of leaves, stems, and roots of Calystegia soldanella , along with one known jalapin (5) derivative. The structures of 1-4 were determined on the basis of spectroscopic data and chemical evidence. They fall into two types, one having a 22-membered ring (1 and 4) and the other with a 27-membered ring (2 and 3). The sugar moieties of 1-4 were partially acylated by some organic acids. Compound 4 is the first example of a hexaglycoside of jalapin.

Four new resin glycosides, named calysolins XIV (1), XV (2), XVI (3), and XVII (4) were isolated from the leaves, stems, and roots of Calystegia soldanella ROEM. et SCHULT. (Convolvulaceae). Their structures were determined based on spectroscopic and chemical evidence, and consisted of two different types: those (1) with a macrolactone structure and those (2-4) with a non-macrolactone structure. Their sugar moieties were partially acylated by specific organic acids, including tiglic, 2S-methylbutyric, and 2S,3S-nilic acids. Additionally, evaluation of the antiviral activity of 1-4 revealed effects against the herpes simplex virus type 1.

Yacon (Smallanthus sonchifolius [Poepp. & Endl.] H. Robinson) plant cultivation has extended rapidly throughout Japan since 1985 because of its utility as a tuberous root crop. In this study, strains with high yields of both above‐ground and underground parts were identified to investigate the use of above‐ground parts for animal feed silage. In addition, we measured the anti‐oxidative activity of the silage as a functional characteristic. Data from 5 years of the cultivation of 17 yacon strains suggest that the most suitable strain for planting in the Aso region of Japan is SY217, which has a high yield of both above‐ground parts and tuberous roots. The root tuber parts of yacon are used almost entirely as food; actually, most foliage parts are hardly used, except for some above‐ground parts, which are used as tea. The fermentation qualities of the silage using all above‐ground parts and harvest residue tuberous roots (harvest residues) are high and their dry matter digestibility, investigated using pigs, is 66.7%. Fresh above‐ground parts had very strong anti‐oxidative activity as compared with butylated hydroxyanisole and α‐tocopherol. In addition, that activity is retained during ensiling for 4 weeks. These results suggest that the entire yacon plant can be used effectively as a feedstuff resource with the added bonus of anti‐oxidant activity.

Calysolins V-IX, Resin Glycosides from Calystegia soldanella and Their Antiviral Activity Toward Herpes. -(ONO*, M.; TAKIGAWA, A.; KANEMARU, Y.; KAWAKAMI, G.; KABATA, K.; OKAWA, M.; KINJO, J.; YOKOMIZO, K.; YOSHIMITSU, H.; NOHARA, T.; Chem. Pharm. Bull. 62 (2014) 1, 97-105, http://dx.doi.org/10.1248/cpb.c13-00610 ; Sch. Agric., Kyushu Tokai Univ., Aso, Kumamoto 869-14, Japan; Eng.) -H. Toeppel 23-210

We investigated the content of phenolic compounds and antioxidant capacity of two batches of non-heated and heated leaves of the yacon cultivar “Andes no yuki”, grown in Japan. Lyophilized yacon leaves heated at 160°C for 20 min and 100°C for 60 min had a 1.96 to 9.69-times higher total phenolic content than that of the non-heated leaves. Heated leaves exhibited a 1.98 to 4.07-times higher antioxidant capacity than that of the non-heated leaves in three different free radical scavenging assays. Heated leaves were more efficient at attenuating the superoxide anion radical production in human granulocytic cells than the non-heated leaves. High-performance liquid chromatography analysis revealed that, in the heated leaves, the caffeic acid content was 2.13 to 3.64-times higher and the chlorogenic acid content was slightly lower than those in the non-heated leaves. Hence, heat processing may affect the active constituent contents in yacon leaves, potentiating its antioxidant capacity. Abbreviations: ABTS+: 2,2′-azinobis(2-ethylbenzothiazoline-6-sulfonic acid) cation; DPPH: 1,1-diphenyl-2-picrylhydrazyl, HPLC: high-performance liquid chromatography; NBT: nitroblue tetrazolium; O2−: superoxide anion; PMA: phorbol 12-myristate 13-acetate; PMS: phenazine methosulfate; TEAC: Trolox equivalent antioxidant capacity

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