Shuang-Gang Ma

Lycojaponicumins A-C, three alkaloids with an unprecedented skeleton from Lycopodium japonicum.

Lycojaponicumins A-C (1-3), three trace alkaloids isolated from Lycopodium japonicum, represent a unique heterocyclic skeleton formed by the new linkage C4-C9. Notably, lycojaponicumins A and B (1 and 2) are the first examples of natural products possessing a 5/5/5/5/6 pentacyclic ring system with a 1-aza-7-oxabicyclo[2.2.1]heptane moiety. These structures were elucidated by spectroscopic methods and X-ray diffraction analysis. A plausible biogenetic pathway was proposed.

Indole alkaloids and quassinoids from the stems of Brucea mollis.

Seven new indole alkaloids, bruceollines H-N (1-7), three new quassinoids, yadanziolides T-V (10-12), and four known analogues, bruceolline E (8), bruceolline F (9), bruceine D (13), and yadanziolide B (14), were isolated from an ethanol extract of the stems of Brucea mollis. The absolute configurations of compounds 2 and 5 were determined by comparison of their experimental and calculated ECD spectra. The absolute configuration of the known compound 9 was determined by using Mo2(OAc)4-induced CD analysis for the first time. Compounds 10, 13, and 14 exhibited cytotoxic activities with IC50 values of 3.00-5.81 μM.

Rearranged Prenylated C6―C3 Compounds and a Highly Oxygenated seco-Prezizaane-Type Sesquiterpene from the Stem Bark of Illicium oligandrum

Three new rearranged prenylated C(6)-C(3) compounds, named illioliganones A, B, and C (1-3), and a new highly oxygenated seco-prezizaane-type sesquiterpene, oligandriortholactone (7), together with three known prenylated C(6)-C(3) compounds (4-6) and a known sesquiterpene lactone (8), have been isolated from the stem bark of Illicium oligandrum. The structures of 1-3 and 7 were elucidated by spectroscopic methods including 1D and 2D NMR, HRMS, and CD experiments. The absolute configuration of the 11,12-diol moiety in 2 and 3 was determined on the basis of observing the induced circular dichroism after addition of Mo(2)(OAc)(4) in DMSO solution. The anti-inflammatory and cytotoxic activities of 1-8 were evaluated.

Identification of new trace triterpenoid saponins from the roots of Panax notoginseng by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

Triterpenoid saponins are the major bioactive constituents of Panax notoginseng. In the study reported here, the fragmentation behavior of triterpenoid saponins from P. notoginseng was investigated by electrospray ionization tandem mass spectrometry (ESI-MS(n))and high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/ESI-MS(n)). Analyses revealed that product ions from glycosidic and cross-ring cleavages can give a wealth of structural information regarding the nature of the aglycone, sugar types, the sequence and linkage information of sugar units. It is noted that different glycosylation positions remarkably influenced the fragmentation behaviors, which could assist in the differentiation of saponin analogues. To rationalize this characteristic, the collision energy required for various glycosidic cleavages was investigated. According to the summarized fragmentation rules, identification of triterpenoid saponins from the roots of P. notoginseng could be fulfilled, even when reference standards were unavailable. Furthermore, minor and trace constituents were enriched and detected by eliminating the major constituents in one of the saponin fractions. As a result, a total of 151 saponins, including 56 new trace ones, were identified or tentatively characterized from saponin fractions based on their retention times, HPLC/HRMS, HPLC/ESI-MS(n) fragmentation behaviors and comparison with literature data.

Air Flow-Assisted Ionization Imaging Mass Spectrometry Method for Easy Whole-Body Molecular Imaging under Ambient Conditions

Whole-body molecular imaging is able to directly map spatial distribution of molecules and monitor its biotransformation in intact biological tissue sections. Imaging mass spectrometry (IMS), a label-free molecular imaging method, can be used to image multiple molecules in a single measurement with high specificity. Herein, a novel easy-to-implement, whole-body IMS method was developed with air flow-assisted ionization in a desorption electrospray ionization mode. The developed IMS method can effectively image molecules in a large whole-body section in open air without sample pretreatment, such as chemical labeling, section division, or matrix deposition. Moreover, the signal levels were improved, and the spatial assignment errors were eliminated; thus, high-quality whole-body images were obtained. With this novel IMS method, in situ mapping analysis of molecules was performed in adult rat sections with picomolar sensitivity under ambient conditions, and the dynamic information of molecule distribution and its biotransformation was provided to uncover molecular events at the whole-animal level. A global view of the differential distribution of an anticancer agent and its metabolites was simultaneously acquired in whole-body rat and model mouse bearing neuroglioma along the administration time. The obtained drug distribution provided rich information for identifying the targeted organs and predicting possible tumor spectrum, pharmacological activity, and potential toxicity of drug candidates.

Neolignans and glycosides from the stem bark of Illicium difengpi.

Five new neolignans (1-4 and 9), two pairs of neolignan epimers (5-8), and two new aromatic glycosides (10 and 11) have been isolated from the stem bark of Illicium difengpi. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRESIMS, CD experiments, and chemical methods. The absolute configurations of the 3,4-diol moiety in 1 and 1,3-diol moiety in 2 were confirmed by Snatzkes method, observing the induced circular dichroism after addition of dimolybdenum tetraacetate in DMSO. Compounds 3, 4, and 11 exhibited moderate anti-inflammatory activities with IC(50) values ranging from 1.62 to 24.4 microM, while compound 3 displayed antioxidant activity with an IC(50) value of 42.3 microM.

New vernocuminosides from the stem barks of Vernonia cumingiana Benth.

Seven new stigmastane-type steroidal glycosides, vernocuminosides A-G (1-7), have been isolated from the stem barks of Vernonia cumingiana Benth. The structural elucidation and stereochemistry determination were achieved by spectroscopic and chemical methods including 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC, and NOE) experiments, especially the employment of Snatzkes method expressed by the induced circular dichroism spectra. Anti-inflammatory activities and cytotoxicities of compounds 1-7 were evaluated.

Cytotoxic oleanane triterpene saponins from Albizia chinensis.

Three new oleanane-type triterpene saponins, albizosides A-C (1-3), were isolated from the stem bark of Albizia chinensis. Their structures were established by 1D and 2D NMR experiments and chemical methods. Compounds 1-3 showed cytotoxic activity against a small panel of human tumor cell lines as well as hemolytic activity against rabbit erythrocytes.

Prenylated C6–C3 compounds with molecular diversity from the roots of Illicium oligandrum

Eleven prenylated C(6)-C(3) compounds, illioliganpyranone A (1), illioliganfunone A-D (2-5), and illioliganone D-I (6-11), together with five known prenylated C(6)-C(3) compounds (12-16), were isolated from roots of Illicium oligandrum. The structures of 1-11 were elucidated by spectroscopic methods including 1D and 2D NMR, HRESIMS, and CD experiments. Possible biosynthetic pathways to compounds 1-16 derived from a common precursor of 5-allylbenzene-1,2,4-triol were postulated. All compounds were evaluated for cytotoxic activities against five human cancer cell lines (HCT-8, Bel-7402, BGC-823, A549 and A2780). Compound 15 exhibited significant cytotoxicity against HCT-8, BGC-823, A549, and A2780 cell lines with IC(50) values of 0.30-2.57 μM. Compound 16 showed moderate selective cytotoxicity against sensitive A2780 cells with IC(50) value of 1.38 μM.

Bisindole Alkaloids with Neural Anti-inflammatory Activity from Gelsemium elegans

Three new trace bisindole alkaloids geleganimines A and B (1, 2) and geleganamide (3) were isolated from the aerial parts of Gelsemium elegans. Their structures were elucidated by spectroscopy, particularly from their carbon-proton coupling constants, and electronic circular dichroism. Compounds 1-3 are the first bisindole alkaloids discovered from the genus Gelsemium. Geleganimine B exhibited anti-inflammatory activity indirectly by suppressing lipopolysaccharide-induced pro-inflammatory factors in BV2 microglial cells with an IC50 value of 10.2 μM. These findings confirm the importance of bioactive trace components in medicinal plant research.