Jun-Jiang Lv

Cytotoxic bisbenzylisoquinoline alkaloids from Stephania epigaea.

Six new bisbenzylisoquinoline alkaloids (1-6) and seven known compounds (8-14) were isolated from the tubers of Stephania epigaea, in addition to the major alkaloid, cepharanthine (7). The structures of 1-6 were elucidated by combined spectroscopic data analysis and chemical methods, with their configurations determined from their optical rotation values and confirmed using circular dichroism. Compounds 1-6 belong to the oxyacanthine type of bisbenzylisoquinoline alkaloids and have a rare methylenedioxy substituent. Compound 1, a dimer composed of benzylisoquinoline and seco-aristolactam units, represents a new type of bisbenzylisoquinoline alkaloid, while compounds 3-6 are bisbenzylisoquinoline N-oxides. These compounds were evaluated for their in vitro cytotoxicities against six human cancer cell lines (A-549, ECA109, HL-60, MCF-7, SMMC-7721, and SW480). Cepharanthine (7), the major component of S. epigaea, exhibited cytotoxicity against all of these cancer cell lines except ECA109, while its known analogue, 10, displayed cytotoxicity against all six cancer cell lines.

Anti-hepatitis B virus norbisabolane sesquiterpenoids from Phyllanthus acidus and the establishment of their absolute configurations using theoretical calculations.

Nineteen new highly oxygenated norbisabolane sesquiterpenoids, phyllanthacidoid acid methyl ester (1), and C-T (4-21), were isolated from Phyllanthus acidus Skeels, together with two known ones, phyllanthusols A (2) and B (3), whose sugar moiety was revised as glucosamine-N-acetate, rather than the previously assigned mannosamine-N-acetate. Compounds 2 and 3 were renamed respectively as phyllanthacidoids A (2) and B (3) to avoid confusion. All of the isolates except for 1 are glycosides, whose saccharide moieties possess a pentaoxy cyclohexane (scyllo quercitol) connecting with glucosamine-N-acetate or glucosyl moieties, which are first examples in natural products. Phyllanthacidoids N-R (15-19) with 8R configurations and/or 5,8-diketal skeleton, are unprecedented structures among norbisabolane sesquiterpenoids. Phyllanthacidoids S (20) and T (21) have the unusual tricyclo [3.1.1.1] oxygen bridge skeleton formed by a diketal system, of which the relative configurations of the aliphatic chain were assigned on the basis of heteronuclear coupling constants. The absolute configurations of compounds (1-21) were established by means of calculated electronic circular dichroism (ECD) and coupling constants. Compounds 1-5, 7-9, 10, and 14 displayed potential anti-hepatitis B virus (HBV) activities, with IC50 values of 0.8-36 μM against HBV surface antigen (HBsAg) and HBV excreted antigen (HBeAg), and the results indicated that the 5-ketal group and sugar moieties had contributions to the selectivity of HBsAg and HBeAg.

Triterpenoids with Promoting Effects on the Differentiation of PC12 Cells from the Steamed Roots of Panax notoginseng.

The roots of Panax notoginseng, an important Chinese medicinal plant, have been used traditionally in both the raw and processed forms, due to the different chemical constituents and bioactivities found. Thirty-eight dammarane-type triterpenoid saponins were isolated from the steam-processed roots of P. notoginseng, including 18 new substances, namely, notoginsenosides SP1-SP18 (1-18). The structures of 1-18 were determined on the basis of spectroscopic analysis and acidic hydrolysis. The absolute configuration of the hydroxy group at C-24 in 1-4, 19, and 20 was determined in each case by Mo2(AcO)4-induced circular dichroism. The new compounds were found to feature a diversity of highly oxygenated side chains, formed by hydrolysis of the C-20 sugar moiety followed by dehydration, dehydrogenation, epoxidation, hydroxylation, or methoxylation of the main saponins in the raw roots. The new saponins 1, 2, 6-8, 14, and 17 and the known compounds 20-27 showed promoting effects on the differentiation of PC12 cells, at a concentration of 10 μM.

Minor dehydrogenated and cleavaged dammarane-type saponins from the steamed roots of Panax notoginseng.

Nine new minor dehydrogenated and cleavaged dammarane-type triterpenoid saponins, namely notoginsenosides ST6-ST14 (1-9) were isolated from the steamed roots of Panax notoginseng, together with 14 known ones. Among them, 5-7 and 21-22 were protopanaxadiol type and the left 18 compounds, including 1-4, 8-20, and 23 were protopanaxatriol type saponins. Their structures were identified by extensive analysis of MS, 1D and 2D NMR spectra, and acidic hydrolysis. Resulted from the side chain cleavage, the new saponins 1 and 2 featured in a ketone group at C-25, and 3-5 had an aldehyde unit at C-23. The known saponins 12, 16 and 18 displayed the enhancing potential of neurite outgrowth of NGF-mediated PC12 cells at a concentration of 10 μM, while 20 exhibited acetyl cholinesterase inhibitory activity, with IC50 value of 13.97 μM.

New cytotoxic lignan glycosides from Phyllanthus glaucus

During the process of exploring bioactive lead compounds from Phyllanthus species, two new glycosides including an arylnaphthalene lignan, diphyllin 4-O-α-l-arabinopyranosyl-(1 → 3)-α-l-arabinopyranoside (1), and a phenolic compound, 3,4,5-trimethoxybenzyl alcohol 7-O-α-l-arabinofuranosyl-(1 → 6)-β-d-glucopyranoside (2), were isolated from the methanol extract of the whole plants of Phyllanthus glaucus Wall. ex Müll. Arg. In addition, 31 known compounds, including 19 lignan derivatives (3–21), four phenylpropanoids (22–25), seven simple phenolics (26–32) and one monoterpenoid (33) were obtained. Their structures were determined on the basis of the HR-ESI-MS, 1D and 2D NMR spectroscopic analysis, and pre-column derivative/chiral HPLC analysis in case of 1 for the absolute configurations. All these compounds were obtained from P. glaucus for the first time. Moreover, the known lignan glycoside, phyllanthusmin C (5) showed in vitro cytotoxicities against HL-60, MCF-7 and SW480 cells with IC50 values of 9.2 ± 0.2, 19.2 ± 1.7 and 20.5 ± 0.9, respectively.

Stereochemistry of cleistanthane diterpenoid glucosides from Phyllanthus emblica

Time-dependent density functional theory (TDDFT) calculated electronic circular dichroism (ECD) and Mosher’s method were applied to establish the absolute configurations of six new highly oxygenated cleistanthane diterpenoid glucosides, phyllanembloids A–F (1–6), isolated from the roots of Phyllanthus emblica. Compounds 1–5 featured a carboxyl group at C-13 adjacent to the hydroxyl group at C-12, and are the first examples of cleistanthane diterpenoids with a salicylic acid fragment. The carboxyl group at C-13 can significantly affect the CD spectrum of cleistanthane diterpenoids, and make the excitations of phenylethylene dominate the Cotton effects (240 and 280 nm), rather than the benzene ring excitations dominating the Cotton effects at 220 and 240 nm as in the 13-methyl analogues. The characteristic Cotton effects of cleistanthane diterpenoids were summarized according to the experimental and calculated ECD curves, which can be applied as a common method to determine the absolute configurations of this type of diterpenoid.

New phenolic glycosides from Phyllanthus cochinchinensis

Chemical investigation of the whole plants of Phyllanthus cochinchinensis (Euphorbiaceae) led to the isolation of three new phenolic glycosides, phyllanthuosides A-C, together with 12 known compounds. Their structures were established on the basis of extensive spectroscopic analysis and chemical methods. Among them, phyllanthuosides A and B are two of the rare phenolic glycosides, featuring with a C6-C3-C6 skeleton. The absolute configurations of phyllanthuosides A and B were established by calculated electric circular dichroism (ECD) using time dependent density functional theory (TDDFT). The isolates were also tested for their cytotoxicity and antimicrobial activity.

Dammarane-type saponins from steamed leaves of Panax Notoginseng

Four new dammarane-type triterpenoid saponins, namely notoginsenosides SFt1-SFt4 (1–4) were isolated from the steamed leaves of Panax notoginseng (Burk.) F. H. Chen (Araliaceae), together with 17 known saponins. Their structures were established on the basis of detailed spectroscopic analyses and acidic hydrolysis. The known ginsenosides Rk2 and Rh3 were obtained from P. notoginseng for the first time. All of these new saponins showed no in vitro cytotoxicity against five human cancer cell lines (HL-60, SMMC-7712, A-549, MCF-7, and SW480).

Anti-viral and cytotoxic norbisabolane sesquiterpenoid glycosides from Phyllanthus emblica and their absolute configurations

In an effort to identify anti-viral and cytotoxic compounds from Phyllanthus spp., 14 highly oxygenated norbisabolane sesquiterpenoids, phyllaemblicins H1-H14, were isolated from the roots of Phyllanthus emblica Linn, along with phyllaemblicins B and C and glochicoccinoside D. Their structures were determined on the basis of detailed spectroscopic analysis and chemical methods. Determination of absolute configurations of these compounds was facilitated by theoretical calculations of electronic circular dichroism (ECD) spectra using time-dependent density functional theory (TDDFT) for the aglycone components, and pre-column derivative/chiral HPLC analysis for the monosaccharides. The known glochicoccinoside D displayed potent activity against influenza A virus strain H3N2 and hand, foot and mouth virus EV71, with IC50 values of 4.5±0.6 and 2.6±0.7 μg/ml, respectively. Phyllaemblicin H1 showed moderate cytotoxicity against human cancer cell lines A-549 and SMMC-7721, with IC50 values of 4.7±0.7 and 9.9±1.3 μM, respectively.

Phyllaciduloids A–D: Four new cleistanthane diterpenoids from Phyllanthus acidus (L.) Skeels

Four new cleistanthane diterpenoids, phyllaciduloids A-D (1-4), were isolated from the roots and stems of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Their structures were elucidated on the basis of extensive spectroscopic analysis. Phyllaciduloids B-D (2-4) present in their structures with ether bond between C-7 and C-16, which were rarely reported. All the isolates were evaluated for their cytotoxic activities against five human cancer cell lines.