Phenolic and Terpenoid Constituents from the Sri Lankan Medicinal Plant Osbeckia aspera.

Abstract

A crude aqueous acetone extract of Osbeckia aspera. Blume (Melastomataceae), a plant from Sri Lanka used traditionally to treat liver disease, was fractionated by column and preparative paper chromatography, and the fractions were analyzed by high-performance liquid chromatography (HPLC) using diode array and mass spectrometric detection. Phenolic acids (gallic, protocatechuic, and ellagic acid), flavonol glycosides [quercetin 3-O.-β-galactopyranoside, quercetin 3-O.-β-glucopyranoside, kaempferol 3-O.-β-glucopyranoside, and kaempferol 3-O.-(6″-O.-p.-coumaroyl-β-glucopyranoside) (tiliroside)] and flavonol aglycones (quercetin and kaempferol) were identified by comparison of their retention times, UV and MS spectra with those of authentic standards. Five compounds from a methanol extract were identified by NMR spectroscopy as the flavonol glycosides, quercetin 3-O.-(3″-O.-acetyl-β-galactopyranoside) and kaempferol 3-O.-[2″,6″-di-O.-(E.,E.)-p.-coumaroyl-β-glucopyranoside], and the norsesquiterpenoids 6,9-dihydroxy-4,7-megastig-madien-3-one, 9-hydroxy-4,7-megastigmadien-3-one and 9-hydroxy-4-megastigmen-3-one. A crude water extract, 50% acetone extract and fractions from this extract, a 100% methanol extract, and three of the phenolic acids in the fractions were tested for in vitro. hepatoprotective activity against bromobenzene and 2,6-dimethyl-N.-acetyl p.-quinoneimine toxicity to HepG2 liver-derived cells. The crude water extract showed protective activity against both liver toxins, whereas the fractions and compounds were more protective against 2,6-dimethyl-N.-acetyl p.-quinoneimine than bromobenzene. Of the three phenolic acids present in the extracts that were tested, gallic and protocatechuic acids were more active at protecting the liver cells from the two toxic compounds than ellagic acid.     

Biotransformation of oleanolic acid by Alternaria longipes and Penicillium adametzi

Microbial transformation of oleanolic acid (1) was carried out. Six transformed products (2–7) from 1 by Alternaria longipes and three transformed products (8–10) from 1 by Penicillium adametzi were isolated. Their structures were elucidated as 2α,3α,19α-trihydroxy-ursolic acid-28-O-β-d-glucopyranoside (2), 2α,3β,19α-trihydroxy-ursolic acid-28-O-β-d-glucopyranoside (3), oleanolic acid 28-O-β-d-glucopyranosyl ester (4), oleanolic acid-3-O-β-d-glucopyranoside (5), 3-O-(β-d-glucopyranosyl)-oleanolic acid-28-O-β-d-glucopyranoside (6), 2α,3β,19a-trihydroxy-oleanolic acid-28-O-β-d-glucopyranoside (7), 21β-hydroxyl oleanolic acid-28-O-β-d-glucopyranoside (8), 21β-hydroxyl oleanolic acid (9), and 7α,21β-dihydroxyl oleanolic acid (10) based on the extensive NMR studies. Among them, 10 was a new compound and compounds 5 and 8–10 had stronger cytotoxic activities against Hela cell lines than the substrate. At the same time, it was reported for the first time in this paper that the skeletons of compounds 2 and 3 were changed from oleanane to uranane and seven glycosidation products were obtained by biotransformation.     

A new triterpenoid saponin from the stem of Akebia trifoliata var. australis

A new triterpene glycoside mutongsaponin F (1), together with five known saponins and two known lipids, was isolated from the 70% ethanol extract of the stems of Akebia trifoliata (Thunb.) Koidz. var. australis (Diels) Rehd. Their structures were elucidated on the basis of the spectroscopic analysis and physicochemical properties as 3-β-[(β-d-glucopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 3)-O-]-α-l-arabinopyranosyl)oxy]-30-norolean-12-en-28-oic acid α-l-rhamnopyranosyl-(1 → 4)-O-β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranosyl ester (1), 3-β-[(β-d-glucopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 3)-O-]-α-l-arabinopyranosyl)oxy]-30-norolean-12-en-28-oic acid (2), leonticin E (3), collinsonidin (4), arjunolic acid 28-O-glucopyranoside (5), asiatic acid 28-O-glucopyranoside (6), soya-cerebroside I (7), and 1-O-α-l-galactosyl-(1 → 6)-O-β-d-galactosyl-3-O-hexadecanoyl-glycerol (8), respectively.     

A Novel 4′-O-Diglycoside of Decarboxyrosmarinic Acid from Blepharis ciliaris

Abstract

A novel natural phenolic 1 was isolated from the hydroalcoholic extract of the aerial parts of Blepharis ciliaris (L.) B.L. Burtt (Acanthaceae), in addition to apigenin 7-O-glucoside 2 and apigenin-7-O-(3″-acetyl-6″-E-p-coumaroyl glucoside) 3. The structure of 1 was established as 3′,4′-dihydroxy-β-phenyl ethyl caffeate-4′-β-O-D-galactopyranosyl-(1′″→4″)-α-O-L-rhamnopyranoside [= 9′-decarboxy rosmarinic acid-4′-O-(1→4)-galactosyl rhanmoside]. Structures were determined by conventional methods of analysis, as well as by different MS and NMR techniques.     

Four new oleanane type Saponins from Morina nepalensis var. alba

Four new oleanane type saponins, monepalosides G–J (1–4), were isolated from the water-soluble part of the whole plant of Morina nepalensis var. alba Hand-Mazz. On the basis of chemical and spectroscopic evidence, their structures were determined as 3-O-α-L-arabinopyranosyl-(1→3)-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside G, 1), 3-O-α-L-arabinopyranosyl-(1→3)-β-D-xylopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside H, 2), 3-O-α-L-arabinopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside I, 3), 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosy-(1→3)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside J, 4), respectively. Two-dimensional NMR spectra, including H–H COSY, HMQC, 2D HMQC–TOCSY, HMBC and ROESY were utilized in the structure elucidation and complete assignments of ¹H and ¹³C NMR spectra.     

Phytolacacinoside A,a new triterpenoid saponin from Phytolacca acinosa Roxb

Phytolacacinoside A (1), a novel triterpenoid saponin, together with the seven known compounds, was isolated from 75% ethanol extract of the root of Phytolacca acinosa Roxb (Phytolaccaceae). Their structures were elucidated on the basis of analysis of spectroscopic data and physicochemical properties as 3-O-β-[(β-d-glucopyranosyl-(1 → 4)-O-β-d-xylopyranosyl)]-11β-methoxy-jaligonic acid 30-methyl ester 28-O-β-d-glucopyranoside (1), 3-O-β-[(β-d-glucopyranosyl-(1 → 4)-O-β-d-xylopyranosyl)]-jaligonic acid 30-methyl ester 28-O-β-d-glucopyranoside (2, esculentoside G), 3-O-β-[(β-d-glucopyranosyl-(1 → 4)-O-β-d-xylopyranosyl)]-jaligonic acid 30-methyl ester (3, phytolaccoside E), 3-O-β-d-xylopyranosyl-jaligonic acid 30-methyl ester (4, phytolaccoside B), hypaphorine (5), palmitic acid monoglyceride (6), β-sitosterol (7), and daucosterol (8).     

Four new triterpenoid glycosides from the seed residue of Hippophae rhamnoides subsp. sinensis

Four new triterpenoid saponins (1–4) were isolated from the seed residue of Hippophae rhamnoides subsp. sinensis, named 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl-(1 → 3)]-[α-l-rhamnopyranosyl-(1 → 2)]-α-l-arabinopyranosyl-13-ene-19-one-28-oic acid 28-O-β-d-glucopyranosyl ester (1), 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl-(1 → 3)]-[α-l-rhamnopyranosyl-(1 → 2)]-α-l-arabinopyranosyl-13-ene-19-one-30-hydroxyolean-28-oic acid 28-O-β-d-glucopyranosyl ester (2), 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl-(1 → 3)]-[α-l-rhamnopyranosyl-(1 → 2)]-β-d-glucopyranosyl-13-ene-19-one-28-oic acid 28-O-β-d-glucopyranosyl ester (3), and 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl-(1 → 3)]-[α-l-rhamnopyranosyl-(1 → 2)]-β-d-glucopyranosyl-13-ene-19-one-30-hydroxyolean-28-oic acid 28-O-β-d-glucopyranosyl ester (4), and their structures were elucidated on the basis of spectroscopic and chemical methods.     

New phenolic glycosides from the seeds of Cucurbita moschata

Two new phenolic glycosides were isolated from the seeds of Cucurbita moschata. Their structures were elucidated as (2-hydroxy)phenylcarbinyl 5-O-benzoyl-β-d-apiofuranosyl(1 → 2)-β-d-glucopyranoside (1) and 4-β-d-(glucopyranosyl hydroxymethyl)phenyl 5-O-benzoyl-β-d-apiofuranosyl(1 → 2)-β-d-glucopyranoside (2) on the basis of spectroscopic analysis and chemical evidence.     

Aromatic glycosides from the flower buds of Lonicera japonica

Six new glycosides (1–6) have been isolated from the flower buds of Lonicera japonica. Their structures including the absolute configurations were determined by spectroscopic and chemical methods as ( ? )-2-hydroxy-5-methoxybenzoic acid 2-O-β-d-(6-O-benzoyl)-glucopyranoside (1), ( ? )-4-hydroxy-3,5-dimethoxybenzoic acid 4-O-β-d-(6-O-benzoyl)-glucopyranoside (2), ( ? )-(E)-3,5-dimethoxyphenylpropenoic acid 4-O-β-d-(6-O-benzoyl)-glucopyranoside (3), ( ? )-(7S,8R)-(4-hydroxyphenylglycerol 9-O-β-d-[6-O-(E)-4-hydroxy-3,5-dimethoxyphenylpropenoyl]-glucopyranoside (4), ( ? )-(7S,8R)-(4-hydroxy-3-methoxyphenylglycerol 9-O-β-d-[6-O-(E)-4-hydroxy-3,5-dimethoxyphenylpropenoyl]-glucopyranoside (5), and ( ? )-4-hydroxy-3-methoxyphenol β-d-{6-O-[4-O-(7S,8R)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (6), respectively.     

Two new phenolic glycosides from the rhizome of Gastrodia elata

Two new phenolic glycosides, named parishins F–G (1–2), together with known parishin E, were isolated from the rhizome of Gastrodia elata. The new structures were established as 1,3-di-[4-O-(β-d-glucopyranosyl) benzyl]-2-{4-O-[β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl] benzyl} citrate (1) and 2-[4-O-(β-d-glucopyranosyl)benzyl] citrate (2), by means of MS, 1D, and 2D NMR spectral analyses, as well as chemical methods.     

Three new dammarane-type triterpene saponins from the leaves of Panax ginseng C.A. Meyer

Three new dammarane-type triterpene ginsenosides, together with six known ginsenosides, were isolated from the leaves of Panax ginseng C.A. Meyer. The new saponins were named as ginsenoside Rh₁₁, ginsenoside Rh₁₂, and ginsenoside Rh₁₃. Their structures were elucidated as (20S)-3β,6α,12β,20-tetrahydroxydammara-25-ene-24-one 20-O-β-d-glucopyranoside (1), (20S)-3β,12β,20,24,25-pentahydroxydammarane 20-O-β-d-glucopyranoside (2), and (20S,23E)-3β,12β,20,25-tetrahydroxydammara-23-ene 20-O-β-d-glucopyranoside (3) on the basis of 1D and 2D NMR experiments and mass spectra. The known ginsenosides were identified as ginsenoside M_7cd, ginsenoside Rg₆, ginsenoside Rb₃, gypenoside XVII, gypenoside IX, and 20-(E)-ginsenoside F₄.     

New phenolic glycosides from Pilea cavaleriei

Five new phenolic glycosides, 2-hydroxy-(2′E)-prenyl benzoate-2,4′-di-O-β-d-glucopyranoside (1), 2-hydroxy-(2′E)-prenyl benzoate-2-O-α-l-arabinopyranosyl-(1 → 6)-β-d-glucopyranoside (2), 4-methylphenol-1-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (3), 4-methylphenol-1-O-α-l-arabinopyranosyl-(1 → 6)-β-d-glucopyranoside (4), and 3,5-dimethoxyphenol-1-O-β-d-apiofuranosyl-(1 → 2)-β-d-glucopyranoside (5), together with six known glycosides (6–11), were isolated from the n-BuOH fraction of the EtOH extract of Pilea cavaleriei Levl subsp. cavaleriei. Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR spectroscopy as well as HR-ESI-MS, and chemical evidences. All these compounds were isolated from the genus Pilea for the first time.     

Three new triterpenoid saponins from the seeds of Aesculus turbinata

Three new triterpenoid saponins, named isoescins VIIa (1), VIa (2), and VIIIa (3), were isolated from the seeds of Aesculus turbinata and identified by spectroscopic analysis and chemical hydrolysis. Their structures were established as 21β-O-tigloyl-28-O-acetylprotoaescigenin 3β-O-[β-d-galactopyranosyl(1 → 2)][β-d-glucopyranosyl(1 → 4)]-β-d-glucopyranosiduronic acid (Isoescin VIIa, 1), 21β-O-(2-methylbutyryl)-28-O-acetylprotoaescigenin 3β-O-[β-d-glucopyranosyl(1 → 2)] [β-d-glucopyranosyl(1 → 4)]-β-d-glucopyranosiduronic acid (Isoescin VIa, 2), and 21β-O-angeloyl-28-O-acetylbarringtogenol C 3β-O-[β-d-glucopyranosyl(1 → 2)] [β-d-glucopyranosyl(1 → 4)]-β-d-glucopyranosiduronic acid (Isoescin VIIIa, 3).     

Furostanol oligoglycosides from Asparagus cochinchinensis

Three new furostanol oligoglycosides, named aspacochioside A (1), B (2) and C (3), together with the known compound 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-(25S)-5β-spirostane-3β-ol were isolated from the roots of Asparagus cochinchinensis. Their structures were elucidated by spectroscopic techniques (IR, HR-ESIMS, ESIMS/MS, 1D and 2D NMR) and chemical methods as 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-(25S)-5β-furostane-3β,22α,26-triol (1), 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-22α-methoxy-(25S)-5β-furostane-3β,26-diol (2), and 3-O-[{α-l-rhamnopyranosyl-(1→4)}{β-d-glucopyranosyl}]-26-O-[β-d-glucopyranosyl]-(25S)-5β-furost-20(22)-en-3β,26-diol (3).     

Water-soluble constituents from the leaves of Ilex oblonga

Four new water-soluble constituents, oblongaroside A (1), oblongar ester A (2), oblongaroside B (3), and oblongaroside C (4), were isolated along with four known compounds: 4-O-β-d-glucopyranosyl-3-hydroxybenzalcohol (5), 7-methoxyl-4-O-β-d-glucopyranosyl-3-hydroxybenzalcohol (6), 4-O-β-d-glucopyranosyl-3-hydroxybenzoic acid (7), and 3,4-dihydroxybenzoic acid (8) from the leaves of Ilex oblonga. Identification of their structures was achieved by 1D and 2D NMR experiments, including ¹H–¹H COSY, NOESY, HMQC, and HMBC methods and FAB mass spectral data.     

Triterpenoid saponins from the rhizome of Polygonatum sibiricum

Three new triterpenoid saponins, polygonoides C (1), D (2), and E (3), were obtained from the ethanolic extract of the rhizome of Polygonatum sibiricum Redoute. On the basis of NMR and ESI-MS spectra, and chemical evidence, the structures of the three new compounds were elucidated as 3-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl-3β,7β,22β-trihydroxy-oleanolic acid (1), 3-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl-3β,7β,22β-trihydroxy-oleanolic acid methyl ester (2), and 3-O-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-(1 → 4)-[α-L-rhamno-pyranosyl-(1 → 2)]-β-D-glucopyranosyl-3β,21β-dihydroxy-oleanolic acid 28-O-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranoside (3).     

New sesquiterpenoid glycoside and phenylpropanoid glycosides from the tuber of Ophiopogon japonicus

A new sesquiterpenoid glycoside, cryptomeridiol 11-O-β-d-xylopyranosyl-(1→6)-β-d- glucopyranoside (1), two new phenylpropanoid glycosides, 3,4-dihydroxy-allylbenzene 3-O-β-d-glucopyranosyl-4-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (2), and 3,4,5-trihydroxy-allylbenzene 3-O-β-d-glucopyranosyl-4-O-β-d-glucopyranoside (3), along with four known phenylpropanoid glycosides (4–7), were isolated from the tuber of Ophiopogon japonicus. Compounds 4–7 were obtained from the genus Ophiopogon for the first time. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR and HR-ESI-MS.     

Two new steroidal saponins from Tribulus terrestris

Two new steroidal saponins and two known flavonoid glycosides were isolated from the fruits of Tribulus terrestris. Their structures were assigned by spectroscopic analysis and chemical reaction as 26-O-β-d-glucopyranosyl-(25R)-5α-furostan-12-one-3β,22α,26-triol-3-O-β-d-glucopyranosyl (1 → 2)-β-d-glucopyranosyl(1 → 4)-β-d-galactopyranoside (1), 26-O-β-d-glucopyranosyl-(25S)-5α-furostan-22-methoxy-2α,3β,26-triol-3-O-β-d-glucopyranosyl(1 → 2)-β-d-glucopyranosyl(1 → 4)-β-d-galactopyranoside (2), kaempferol-3-gentiobioside (3), and isorhamnetin-3-gentiobioside (4).     

Cytotoxic triterpenoid saponins from Vaccaria segetalis

By the guidance of bioassay, one new cytotoxic triterpenoid saponin, 3-O-[β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl] quillaic acid 28-O-β-d-glucopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-[β-d-fucopyranosyl-(1 → 4)]-β-d-fucopyranoside (1), and five known cytotoxic triterpenoid saponins, vaccaroside E (2), vaccaroside G (3), vaccaroside B (4), segetoside H (5) and segetoside I (6), were isolated from Vaccaria segetalis. Their structures were established on the basis of ESI-MS, IR, extensive NMR (¹H NMR, ¹³C NMR, TOCSY, ¹H–¹H COSY, DEPT, HMQC, HMBC and ROESY) analyses, chemical degradation, and by comparing with previously reported data. Compounds 1–6 showed moderate cytotoxic activities against LNcap, P-388 and A-549 cell lines with IC₅₀ values in the range 0.1–12.9 μM.     

Aromatic glycosides from the whole plants of Iris japonica

Phytochemical investigation on the whole plants of Iris japonica led to the isolation of four new aromatic glycosides. Their structures including the absolute configurations were determined by spectroscopic and chemical methods as (?)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7R,8S)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (1), (?)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7S,8R)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (2), (?)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7R,8R)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (3), (?)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7S,8S)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (4), respectively.