Structures of Novel Norstilbene Dimer, Longusone A, and Three New Stilbene Dimers, Longusols A, B, and C, with Antiallergic and Radical Scavenging Activities from Egyptian Natural Medicine Cyperus longus

Abstract

The methanolic extract of the whole plant of Cyperus longus originating in Egypt was found to show antiallergic effect on ear passive cutaneous anaphylaxis reactions in mice. By bioassay-guided separation, 11 stilbenes and stilbene dimers including a novel norstilbene dimer, longusone A, and three new stilbene dimers, longusols A, B, and C, were isolated. Their structures were elucidated on the basis of chemical and physicochemical evidence. Among the isolates, longusol B (IC(50)=96 µM), luteolin (3.0 µM), resveratrol (17 µM), piceatannol (24 µM), and cassigarols E (84 µM) and G (84 µM) were found to inhibit the release of β-hexosaminidase, as a marker of antigen-induced degranulations, in rat basophilic leukemia (RBL-2H3) cells. In addition, the methanolic extract and the constituents showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (SC(50)=22 µg/ml and 2.8-29 µM, respectively).

Inhibitors ofα-glucosidase andα-amylase fromCyperus rotundus

“…In this study, this compound showed strong inhibitory effects against a-glucosidase and a-amylase. Previous studies have indicated that the addition of a hydroxyl group increases the biological activities of stilbene (Lam et al, 2008;Morikawa et al, 2010;Richard et al, 2011). Consistent with these reports, our results indicated that the inhibitory effects of scirpusin B (4) against a-glucosidase were stronger than those of the less hydroxylated derivative, scirpusin A.…”

“…The stilbene cassigarol E (2) has been shown to exhibit antioxidant, antiallergic and antitumor activities (Morikawa et al, 2010;Wada et al, 2009;Xiang et al, 2005). In this study, this compound showed strong inhibitory effects against a-glucosidase and a-amylase.…”

“…In our search for antidiabetic agents of natural origins, a methanol extract of C. rotundus rhizomes was found to show significant inhibitory activity against a-glucosidase and a-amylase. Phytochemical investigation of the methanol extract of C. rotundus rhizomes led to the isolation of a new flavan-3-ol (1) and three stilbene dimers, cassigarol E (2), scirpusin A (3) and scirpusin B (4) (Morikawa et al, 2010) (Figure 1). These compounds showed strong a-glucosidase and a-amylase inhibitory effects as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity.…”

Hydroxystilbenes Are Monomers in Palm Fruit Endocarp Lignins

“…1C)] and oligomeric structures. Indeed, such compounds, 165 often optically active, are known from various plant extractives (Baba et al, 1994;Iliya et al, 166 2002;Li et al, 2005;Xiang et al, 2005;Morikawa et al, 2010;Quideau et al, 2011). Moreover, 167 piceatannol can also cross-couple with monolignols (and oligolignols) in a variety of ways, two 168 of which are shown in Fig.…”

Degranulation Inhibitors from Medicinal Plants in Antigen-Stimulated Rat Basophilic Leukemia (RBL-2H3) Cells

“…5) In the course of our search for bioactive constituents from medicinal plants, we have isolated various degranulation inhibitors from medicinal plants using rat basophilic leukemia (RBL-2H3) cells. For example, flavonoids from various medicinal plants including the aerial parts of Cissus sicyoides [6][7][8] ; stilbenes, stilbene dimers, and phenanthrenes from the rhizomes of Rheum undulatum, the tuber of Gymnadenia conopsea, and the whole plant of Cyperus longus [9][10][11] ; diarylheptanoids including curcuminoides from the barks of Myrica rubra and Acer nikoense and the rhizomes of Curcuma zedoaria and C. comosa [12][13][14][15] ; 3-phenyl-isocoumarins from the processed leaves of Hydrangea macrophylla var. thunbergii 16,17) ; phenylpropanoids from the rhizomes of Alpinia galanga 18) ; β-carboline-type alkaloids from the roots of Stellaria dichotoma 19) ; sesquiterpenes from the rhizomes of Hedychium coronarium and the fruits of Alpinia oxyphylla 20,21) ; meroterpenes from the seeds of Psoralea corylifolia 22) ; and acylated oleanane-type triterpene saponin from Camellia sinensis and C. assamica [23][24][25] were reported.…”