Journal of Natural Medicines

In Ayurvedic medicine, Salacia reticulata is known to be useful against various metabolic diseases, including diabetes and obesity. In this study, we attempted to clarify the antiobesity mechanism and the safety of S. reticulata in vivo and in vitro. We gave ordinary MF feed, alone or mixed with S. reticulata (0.3 or 1.0%), to Tsumura Suzuki obesity diabetes (TSOD) mice (spontaneous obese type II diabetes model mice) and Tsumura Suzuki non-obese (TSNO) mice (the corresponding reference animals), ad libitum for 2 months. As compared with the TSNO control mice, the TSOD control mice became obese due to fat accumulation and developed various signs of metabolic diseases. The TSOD mouse group receiving S. reticulata showed the following effects: suppression of body weight increase and fat accumulation, alleviation of abnormal lipid metabolism and abnormal glucose tolerance, and suppression of intrahepatic fat accumulation. Also, S. reticulata prevented the mesenteric adipocyte hypertrophy recognized in TSOD mice. In the TSNO controls, the feed containing 1.0% S. reticulata exerted a suppressing effect on body weight increase and fat accumulation, but the feed containing 0.3% S. reticulata did not show any effect at all. In an in vitro experiment using mouse-derived adipocyte precursor 3T3-L1 cells, S. reticulata significantly suppressed fat accumulation in the differentiation induction phase and maturation phase. This suggested that the metabolic disease-preventing effects of S. reticulata, including the antiobesity effect, may involve suppression of differentiation and accumulation in the adipocytes.

Diaportholides A (1) and B (2), two polyketides with ɑ-pyrone moieties, were isolated from the cultures of an endophytic Diaporthe sp. ECN371 isolated from Orixa japonica, together with four known polyketides, phomopsolide B (3), phomopsolidones A (4) and B (5), and 5-[(1R)-1-hydroxyethyl]-γ-oxo-2-furanbutanoic acid (6). The structures of 1 and 2 were determined by extensive analysis of NMR and MS spectroscopic data. Furthermore, the structure of 2 was confirmed by analyzing the single-crystal X-ray diffraction data. The luciferase reporter gene assay revealed that among all isolated compounds (1–6), 3, a known ɑ-pyrone derivative, exhibited agonistic activity against the peroxisome proliferator-activated receptor ɑ, which is an important regulator of lipid metabolism in humans.

Six phenolic compounds were isolated from the flowers of Trachelospermum asiaticum var. intermedium (Apocynaceae). These structures were determined on the basis of spectral data.

A new crinine-type alkaloid crijaponine A (1), a new galanthamine-type alkaloid crijaponine B (2), and 11 known alkaloids—ungeremine (3), lycorine (4), 2-O-acetyllycorine (5), 1, 2-O-diacetyllycorine (6), (−)-crinine (7), 11-hydroxyvittatine (8), hamayne (9), (+)-epibuphanisine (10), crinamine (11), yemenine A (12), and epinorgalanthamine (13)—were isolated from the rhizome and fruits of Crinum asiaticum var. japonicum. The structural elucidation of the isolated compounds was performed by spectroscopic methods including 2D NMR. The isolated compounds were evaluated for cytotoxicity against HeLa and HL-60 cells lines and were tested for acetylcholinesterase inhibition activity.

Two new isoflavone glycosides, tectorigenin 7-O-β-d-glucopyranoside-4′-O-[β-d-glucopyranosyl-(1″″ → 6′′′)-β-d-glucopyranoside] (1) and iristectorigenin B 4′-O-[β-d-glucopyranosyl-(1′′′ → 6″)-β-d-glucopyranoside] (2), together with 11 known compounds, including six isoflavones, tectorigenin 7-O-β-d-glucopyranoside-4′-O-β-d-glucopyranoside (3), tectorigenin 4′-O-[β-d-glucopyranosyl-(1′′′ → 6″)-β-d-glucopyranoside] (4), tectorigenin 7-O-β-d-glucopyranoside (5), genistein 7-O-β-d-glucopyranoside (6), tectorigenin 4′-O-β-d-glucopyranoside (7), and tectorigenin (8); two phenolic acid glycosides, vanillic acid 4-O-β-d-glucopyranoside (9) and glucosyringic acid (10); a phenylpropanoid glycoside, E-coniferin (11); an auronol derivative, maesopsin 6-O-β-d-glucopyranoside (12); and a pyrrole derivative, 4-(2-formyl-5-hydroxymethylpyrrol-1-yl) butyric acid (13), were isolated from fresh Iris spuria (Calizona) rhizomes. The structures of these compounds were established on the basis of spectroscopic and chemical evidence. Inhibitory effects on the activation of Epstein–Barr virus early antigen were examined for compounds 1–8 and 12.

Three new prenylated xanthones, garcinexanthones G−I (1–3), together with fifteen known ones (4–18) were identified from the leaves of Garcinia lancilimba. Their structures were determined by extensive spectroscopic analyses. Most of the compounds exhibited inhibitory effects against HL-60 (human leukemia), A549 (human lung cancer), and MCF-7 (human breast cancer) cell lines. Among them, compounds 7, 17, and 13 exhibited the most pronounced growth inhibitory activity against HL-60, A549, and MCF-7 cell lines with GI50 values of 1.68, 4.88, and 6.28 μM, respectively.

Six new naphthoquinones, euchronin A–F (1–6) and nine known naphthoquinones (7–15), were isolated from the roots of Arnebia euchroma (Royle) Johnst. The structures of the new compounds were confirmed by extensive spectroscopic analyses, including UV, IR, HR-ESI–MS, 1D and 2D NMR. In the present study, we estimated the anti-proliferative activities of these compounds with HaCaT cells. The results indicated that compounds 2 and 4 showed strong anti-proliferative activities at 25 μM, with relative viability at 38.83% and 68.44%, respectively.

Previously, phytochemical investigation of the roots of Asclepias tuberosa (Asclepiadaceae) led to the isolation of some 8,12;8,20-diepoxy-8,14-secopregnane tri-, tetra-, and penta-glycosides. An additional eight new minor 8,12;8,20-diepoxy-8,14-secopregnane glycosides were afforded in the recent investigation of this plant. These glycosides consisted of six or seven 2,6-dideoxy-hexopyranoses together with the aglycone, tuberogenin. The structures of each of these compounds were established using NMR, mass spectroscopic analysis and chemical evidence. As 8,12;8,20-diepoxy-8,14-secopregnane-type glycosides were observed only in A. tuberosa, these compounds were considered to be characteristic phytochemicals of this plant.

Febrifugine and isofebrifugine alkaloid mixtures extracted from the leaves and buds of Hydrangea macrophylla var. Otaksa, collected during different months, in Japan, were quantified using high-performance liquid chromatography. Leaves collected during the flowering season, namely from June to August, contained 0.16–0.31 mg/g of the alkaloid mixture, whereas those collected from September to December had less than 0.03 mg/g of the mixture. However, extracts of buds harvested from October to February contained a consistently larger amount (more than 0.49 mg/g) of the alkaloids. Hot-water extracts from the leaves and buds collected during different seasons were evaluated for antimalarial activity against Plasmodium yoelii 17XL in mice. The extract of leaves collected in August demonstrated high antimalarial activity, and all mice that received the extract survived the infection. In contrast, the extract of leaves collected in December showed little activity. The extract of buds collected in December cleared parasites, but with subsequent mortality to mouse. The present results show that the amount of antimalarial agent—febrifugine and isofebrifugine mixture—in H. macrophylla var. Otaksa is both part- and season-dependent, suggesting that the choice of plant parts and their harvesting season are important factors worth considering in the pharmacological use of medicinal plants.