Salaprionol and Ponkoranol with Thiosugar Sulfonium Sulfate Structure from Salacia prinoides and a-Glucosidase Inhibitory Activity of Ponkoranol and Kotalanol Desulfate

Abstract

The methanolic extract from the roots and stems of Indian Salacia prinoides and its water-eluted fraction of Diaion HP-20 column were found to exhibit inhibitory activities against α-glucosidase. From the water-eluted fraction, two new unique constituents with thiosugar sulfonium sulfate, salaprinol (1) and ponkoranol (2), were isolated together with 10 known constituents including salacinol and kotalanol. The structures of 1 and 2 were elucidated on the basis of chemical and physicochemical evidence. Furthermore, ponkoranol (2) and kotalanol desulfate (14) were found to show potent inhibitory activities against αglucosidase.In the course of our studies on antidiabetogenic compounds from natural medicines, 1-5 we have isolated two potent α-glucosidase inhibitors, salacinol (3) and kotalanol (4), with unique thiosugar sulfonium sulfate inner salt structure from the roots, stems, and leaves of Salacia reticulata, 6-14 S. oblonga, 15 and S. chinensis [16][17][18][19][20] in Sri Lanka, India, and Thailand. As a continuation of our studies on Salacia species plant, 21 we have found that the methanolic extract from the roots and stems of Indian S. prinoides exhibited inhibitory activity against α-glucosidase. This plant is called as "Kushan" in Sanskrit and is widely distributed in India, Sri Lanka, and Southeast Asia countries. The roots and stems of this plant are extensively used for the treatment of diabetes and also used as an abortifacient in Indian traditional medicine. Through bioassay-guided separation using α-glucosidase inhibitory activities, we isolated two new constituents named salaprinol (1) and ponkoranol (2) together with 10 known constituents including salacinol and kotalanol. In this paper, we describe the isolation and structure elucidation of salaprinol (1) and ponkoranol (2), as well as the inhibitory activities of 2 and related compounds on α-glucosidase.

New Triterpene Constituents, Foliasalacins A₁&mdash;A₄, B₁&mdash;B₃, and C, from the Leaves of <i>Salacia chinensis</i>

“…As shown in Table 2, the Dd values of the 26-and 27-protons, the 26-and 31-protons, and the 27-and 31-protons in 1 were approximated to those of codisterol (12) and leucastrin (14), thus the configuration at the 24-position in 1 was elucidated to be S* orientation. On the basis of this evidence and comparison of the 1 H-and 13 C-NMR data of 1 with those of 9, foliasalacin A 1 (1) was characterized to be the 24-isomer of carnaubadiol (9 Fig. 1) indicated that 2 was the 20-isomer of 1.…”

“…The EI-MS of 7 exhibited a molecular ion peak at m/z 456, and the HR-EI-MS analysis revealed the molecular formula of 7 to be C 30 H 48 O 3 . The 1 H-(CDCl 3 ) and 13 C-NMR (Table 3) the stereostructure of the 20-position in 7 was clarified to be R* orientation. Finally, 7 was derived by oxidation of 5 with chromium trioxide (CrO 3 ) in pyridine, so that the stereostructure of foliasalacin B 3 (7) was clarified as shown.…”

“…The electron ionization (EI) MS of 1 exhibited a molecular ion peak at m/z 458, and the high resolution (HR) EI-MS analysis revealed the molecular formula of 1 to be C 31 H 54 O 2 . The 1 H-(CDCl 3 ) and 13 C-NMR (Table 1) ], together with ten methylenes, five methines, and six quaternary carbons. The spectral data of 1 were similar to those of a dammarane triterpene with an unusual and extra methyl group at the 24-position, carnaubadiol (9), 18) except for the signals due to the side chain part (C-23-27, 31).…”

“…Finally, the stereostructure of the 24-position in 1 was determined to be S* by the application of the reported NMR method. 20,21) Namely, the configuration at the 24-position in 1 was characterized by comparison of the Dd values of the side chain protons (H-26-27, H-26-31, and H-27-31) in the 1 H-NMR (CDCl 3 ) spectrum of 1 with those of known compounds, codisterol (12) [(24S)-methylcholesta-5,25-dien-3b-ol], epicodisterol (13) [(24R)-methylcholesta-5,25-dien-3b-ol], and leucastrin (14) [(3S,17S,20S,24S)-3,20-dihydroxy-24-methylprotost-25-ene]. As shown in Table 2, the Dd values of the 26-and 27-protons, the 26-and 31-protons, and the 27-and 31-protons in 1 were approximated to those of codisterol (12) and leucastrin (14), thus the configuration at the 24-position in 1 was elucidated to be S* orientation.…”

“…During the course of our characterization studies on bioactive constituents from Salacia species, [1][2][3][4][5][6][7][8][9][10][11][12][13] we have reported the isolation and absolute stereostructure elucidation of thirteen megastigmane glycosides, foliasalaciosides A 1 , A 2 , B 1 , B 2 , C, D, E 1 , E 2 , E 3 , F, G, H, and I, and seven new phenolic glycosides, foliachinenosides A 1 , A 2 , A 3 , B 1 , B 2 , C, and D, from the leaves of Salacia chinensis LINN. (Hippocrateaceae) together with twenty known constituents.…”