Naphthalene glycosides in the Thai medicinal plant Diospyros mollis

Abstract

This study evaluated methanol extracts from the leaves and branches of the Thai medicinal plant Diospyros mollis (Ebenaceae). Seven triterpenes and 22 aromatic compounds, including five new compounds, were isolated, and their structures were determined. The new compounds had the following structures: diospyrol glycoside (makluoside A, 1), 8,8'-di-O-6-β-D-apiofuranosyl-β-D-glucopyranosyl-6,6'-dimethyl-2,3'-binaphthalene-1-ol-1',4'- dione (makluoside B, 2), and 3-methyl-1,8- naphthalenediol glycosides (makluosides C-E, 3-5). Makluoside B is the first example of a naphthoquinone glycoside that has both a 3-methyl-1,8-naphthalenediol unit and a 5-hydroxy-7-methyl-1,4-naphthoquinone unit. The hyaluronidase inhibitory activity of the isolates was evaluated, revealing that one of the triterpene derivatives possessed moderate inhibitory activity.

Seasonal Changes in the Metabolic Profiles and Biological Activity in Leaves of Diospyros digyna and D. rekoi “Zapote” Trees

“…In this context, the detection of the trigonelline–nicotinic acid combination, only detected in D. rekoi LEs was also interesting, considering that trigonelline, a pyridine alkaloid derived from nicotinic acid [49], has been reported to have a potent anti-diabetic effect, similar to naphthoquinones [50,51]. Approximately 100 trigonelline-forming plant species have been identified, including D. mollis [49,52].…”

Ebenamariosides A–D: Triterpene Glucosides and Megastigmanes from the Leaves of <i>Diospyros maritima</i>

“…The leaves of D. maritima extracted with MeOH and the MeOH extracts were separated by solvent partition according to the polarity of the constituents. The relatively polar 1-BuOH-soluble fraction was separated by various kinds of chromatography to afford four new triterpene saponins (1)(2)(3)(4) and two new megastigmanes (5,6), together with two known flavonol glycosides (7,8). The structures of new triterpene derivatives were elucidated using one-and two-dimensional spectroscopies.…”

“…1) In summer, it bears green sap fruits of 2 to 3 cm in diameter, which then turn to a dark orange colour in autumn. It is known that the fruits contain a toxic naphthoquinone derivative, plumbagin, and their constituents have been extensively investigated by Higa et al [2][3][4] Recently, from the leaves and branches of a related Thai medicinal plant, D. mollis, the isolation of naphthoquinone glycosides was reported. 5) In our continuing work on Okinawan resource plants, the constituents of the leaves of D. maritima were investigated to give eight ent-kaurane-type diterpenoid glycosides, called diosmariosides A-H. 6) Further extensive work resulted in the isolation of four new triterpene saponins, named ebenamariosides A-D (1-4) and two megastigmanes (5,6), along with two known flavonol glycosides, kaempferol 3-O-β-D-(2″,6″-di-O-α-L-rhamonopyranosyl) glucopyranoside (7) 7) and 3-O-β-D-(2″,6″-di-α-L-rhamonopyranosyl) galactopyranoside (8) 8) (Fig.…”

Eight <i>ent</i>-Kaurane Diterpenoid Glycosides Named Diosmariosides A–H from the Leaves of <i>Diospyros maritima</i> and Their Cytotoxic Activity

“…Eight new compounds (1)(2)(3)(4)(5)(6)(7)(8) and two known ones (9 and 10) were isolated from the MeOH extract of leaves of D. maritima, using various kinds of chromatographic techniques. The structures of the new compounds were elucidated by intensive one-and two-dimensional NMR spectroscopic analyses and chemical conversion.…”