Medicinal Flowers. XII.1) New Spirostane-Type Steroid Saponins with Antidiabetogenic Activity from Borassus flabellifer

Abstract

The Palmae plant, Borassus flabellifer L. (palmyra palm in English), is widely distributed and cultivated in tropical Asian countries such as Thailand, Bangladesh, India, Myanmar, Sri Lanka, Malaysia, etc. The fruit pulp of B. flabellifer has been used in traditional dishes and the sap, which was trapped from the flower part, has been used as a sweetener for diabetic patients. In the previous studies, several steroidal saponins, 2-4) a polysaccharide, 5) and a triterpene 6) constituents were isolated from the fruit pulp, seeds, and young shoot of B. flabellifer. However, the chemical and pharmacologic studies for the flower parts of this medicinal food were left uncharacterized. In the course of our characterization studies on Thai medicinal foods, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] we found that the methanolic extract from the male flowers of B. flabellifer was found to inhibit the increase of serum glucose levels in sucrose-loaded rats. From the methanolic extract, six new spirostane-type steroid saponins, borassosides A-F (1-6), were isolated together with 20 known steroidal glycosides (7-25 and b-sitosterol 3-O-b-D-glucopyranoside) and three known steroids (26, 27, and b-sitosterol). This paper deals with the structure elucidation of borassosides A-F (1-6) from the male flowers of B. flabellifer as well as the inhibitory effects of the methanolic extract and a principal constituent, dioscin (13), on the increase of serum glucose levels in sucrose-loaded rats.Extraction and Isolation The male and female flowers of B. flabellifer (collected in Thailand) were extracted with methanol to give methanolic extracts (12.2% from the male flowers; 11.3% from the female flowers). As shown in Table 1, the methanolic extract from the male flowers of B. flabellifer was found to inhibit the increase of serum glucose levels in sucrose-loaded rats at a dose of 250 mg/kg, p.o. However, Yamashina-ku, Kyoto 607-8412, Japan: and b Pharmaceutical Research and Technology Institute, Kinki University; 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502, Japan. Received October 18, 2006; accepted November 27, 2006; published online November 30, 2006 The methanolic extract from the male flowers of Borassus flabellifer was found to inhibit the increase of serum glucose levels in sucrose-loaded rats at a dose of 250 mg/kg, p.o. From the methanolic extract, six new spirostane-type steroid saponins, borassosides A-F (1-6), were isolated together with 23 known constituents. The structures of borassosides (1-6) were elucidated on the basis of chemical and physicochemical evidences. In addition, the principal steroid saponin, dioscin (13), inhibited the increase of serum glucose levels in sucroseloaded rats at a dose of 50 mg/kg, p.o.

Medicinal Flowers. XXVI. Structures of Acylated Oleanane-Type Triterpene Oligoglycosides, Yuchasaponins A, B, C, and D, from the Flower Buds of <i>Camellia oleifera</i>&mdash;Gastroprotective, Aldose Reductase Inhibitory, and Radical Scavenging Effects&mdash;

“…10,11) Furthermore, those oligoglycosides were found to exhibit antiallergic, 6) antidiabetic, 7) antiobesitic, 5,8) gastroprotective, 7,10,11) and platelet aggregation 10,11) activities. In the course of our characterization studies on Camellia speicies [12][13][14][15] and medicinal flowers, [16][17][18][19][20][21] we found that the methanolic (MeOH) extract and its 1-butanol (1-BuOH)-soluble fraction from the flower buds of C. oleifera showed gastroprotective effects on ethanol-or indomethacin-induced gastric mucosal lesions in rats. The 1-BuOH-and ethyl acetate (EtOAc)-soluble fractions exhibited inhibitory activities on rat lens aldose reductase and scavenging effects on 1,1-diphenylpicryl-2-hydrazyl (DPPH) radical and superoxide.…”

Medicinal Flowers. XXX. Eight New Glycosides, Everlastosides F-M, from the Flowers of Helichrysum arenarium

“…3,11,12,17,18) The 1 H-and 13 C-NMR (CD 3 OD, Table 1) spectra of 1, which were assigned by various NMR experiments, 21) showed signals assignable to two The connectivities of glycopyranosyl parts were determined by a heteronuclear multiple-bond correlations (HMBC) experiment on 1. Namely, long-range correlations were observed between the terminal-Glc-1-proton (1Љ-H) and the inner-Glc-6-carbon (d C 69.5, 6Ј-C) and between the innerGlc-1-proton (1Ј-H) and the angeloyl ester carbonyl carbon (d C 167.7, 1-C) (Fig.…”

“…The H 2 Oeluted fraction was subjected to HPLC analysis under the following conditions: HPLC column, Kaseisorb LC NH 2 -60-5, 250ϫ4.6 mm i.d. (Tokyo Kasei Co., Ltd., Tokyo, Japan); detection, optical rotation [Shodex OR-2 (Showa Denko Co., Ltd., Tokyo, Japan); mobile phase, CH 3 …”

“…During the course of our studies on medicinal flowers, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] we found that the methanolic extract of the flowers of Helichrysum arenarium L. MOENCH (Asteraceae, Everlasting in English) was found to inhibit on tumor necrosis factor-a (TNF-a)-induced cytotoxicity in L929 cells. 17) From the methanolic extract, nine glycosides, arenariumosides I-IV 17) and everlastosides A-E, 18) were isolated together with 46 known compounds.…”

Induction of apoptosis byDioscorea nipponicaMakino extracts in human SH-SY5Y neuroblastoma cells via mitochondria-mediated pathway

“…Dioscorea plants are important agricultural crops in tropical regions, grown for their large tubers in parts of Africa, Asia, and Oceania (Oke 1972). The rhizome of Dioscorea nipponica Makino has high saponin content and use in folk medicine as treatment for coronary heart disease, asthma, rheumatoid arthritis, and hyperlipidemia, as well as a source of hormonal sterol synthesis precursors (Yoshikawa et al 2007). Recently, studies revealed that Dioscorea plant extracts exert antiobesity effects (Kwon et al 2003;Xiao et al 2010).…”