中国猕猴桃科新异名

作者在编写《Flora of China》猕猴桃科Actinidiaceae时, 对一些分类群的处理做了变动, 提出了一些异名, 本文对异名进行了必要的解释。     

Relationships between inhibitory activity against a cancer cell line panel, profiles of plants collected, and compound classes isolated in an anticancer drug discovery project

In an attempt to determine the relationships between the plant profiles (country of collection, taxonomy, plant part) and the compound classes isolated with cytotoxic activity against a panel of human tumor cell lines, the data compiled from a 15-year anticancer drug-discovery project were subjected to an analysis of variance (ANOVA). The results indicate significant trends in cytotoxic activity relative to collection location, taxonomy, plant part, and compound classes isolated. Plant collections were made in tropical forests in six countries, with collections from Ecuador resulting in higher activity than those from Indonesia and Peru. Interestingly, collections from Florida were not statistically different than those from the countries with higher biodiversity. One hundred and forty-five families were represented in the collections, with the Clusiaceae, Elaeocarpaceae, Meliaceae, and Rubiaceae having low ED50 (half maximal effective dose) values. Especially active genera included Aglaia, Casearia, Exostema, Mallotus, and Trichosanthes. Roots and below-ground plant materials were significantly more active than above-ground materials. Cucurbitacins, flavaglines, anthraquinones, fatty acids, tropane alkaloids, lignans, and sesquiterpenoids were significantly more active than xanthones and oligorhamnosides. The results from this study should serve as a guide for future plant collection endeavors for anticancer drug discovery.     

Koenoline,a further cytotoxic carbazole alkaloid from Murraya koenigii

Koenoline, a carbazole alkaloid, has been isolated from the root bark of Murraya koenigii for the first time as a natural product. Its structure was established as 1-methoxy-3-hydroxymethylcarbazole by analysis of spectroscopic data and was confirmed by partial synthesis from murrayanine isolated from M. siamensis roots. Koenoline exhibited cytotoxic activity against the KB cell-culture test system.     

Cytotoxic and NF-κB and mitochondrial transmembrane potential inhibitory pentacyclic triterpenoids from Syzygium corticosum and their semi-synthetic derivatives

Syzygium is a large genus of flowering plants, with several species, including the clove tree, used as important resources in the food and pharmaceutical industries. In our continuing search for anticancer agents from higher plants, a chloroform extract of the leaves and twigs of Syzygium corticosum collected in Vietnam was found to be active toward the HT-29 human colon cancer cell line. Separation of this extract guided by HT-29 cells and nuclear factor-kappa B (NF-κB) inhibition yielded 19 known natural products, including seven triterpenoids, three ellagic acid derivatives, two methylated flavonoids, a cyclohexanone, four megastigmanes, a small lactone, and an aromatic aldehyde. The full stereochemistry of (+)-fouquierol (2) was defined for the first time. Biological investigations showed that (+)-ursolic acid (1) is the major cytotoxic component of S. corticosum, which exhibited also potent activities in the NF-κB and mitochondrial transmembrane potential (MTP) inhibition assays conducted, with IC₅₀ values of 31?nM and 3.5?µM, respectively. Several analogues of (+)-ursolic acid (1) were synthesized, and a preliminary structure-activity relationship (SAR) study indicated that the C-3 hydroxy and C-28 carboxylic acid groups and 19,20-dimethyl substitution are all essential in the mediation of the bioactivities observed for this triterpenoid.     

Antimalarial constituents from Nauclea orientalis (L.) L

Bioassay-guided fractionation of the antimalarial-active CHCl3 extract of the dried stem of Nauclea orientalis (L.) L. (Rubiaceae) has resulted in the isolation of two novel tetrahydro-beta-carboline monoterpene alkaloid glucosides, naucleaorine (= (16alpha,17beta)-3,14:15,20-tetradehydro-16-ethenyl-17-(beta-D-glucopyranosyloxy)-19alpha-methoxyoxayohimban-21-one; 1) and epimethoxynaucleaorine (2), as well as the known compounds, strictosidine lactam (= (15beta,16alpha,17beta)-19,20-didehydro-16-ethenyl-17-(beta-D-glucopyranosyloxy)oxayohimban-21-one; 3), 3,4,5-trimethoxyphenol (4), 3alpha-hydroxyurs-12-en-28-oic acid methyl ester (5), 3alpha,23-dihydroxyurs-12-en-28-oic acid (6), 3alpha,19alpha,23-trihydroxyurs-12-en-28-oic acid methyl ester (7), and oleanolic acid (8). Compounds 1, 2, 6, and 8 showed moderate in vitro activities against Plasmodium falciparum. Their structures and configurations were elucidated by spectroscopic methods including 1D- and 2D-NMR analyses.     

Investigation of Vietnamese plants for potential anticancer agents

Higher plants continue to afford humankind with many new drugs, for a variety of disease types. In this review, recent phytochemical and biological progress is presented for part of a collaborative multi-institutional project directed towards the discovery of new antitumor agents. The specific focus is on bioactive natural products isolated and characterized structurally from tropical plants collected in Vietnam. The plant collection, identification, and processing steps are described, and the natural products isolated from these species are summarized with their biological activities.     

Bioactivity-guided isolation of cytotoxic constituents of Brucea javanica collected in Vietnam

Five new triterpenoids (1–5), together with two known quassinoids, bruceantin (6) and bruceine A (7), and a known flavonolignan, (?)-hydnocarpin (8), were isolated from the chloroform-soluble subfraction of a methanol extract of the combined twigs, leaves, and inflorescence of Brucea javanica collected in Vietnam. The structures of the new compounds 1–5 were established on the basis of spectroscopic methods. All isolates were evaluated for cytotoxicity against a small panel of human cancer cell lines. Quassinoids 6 and 7 were found to be highly active against these cell lines. (?)-Hydnocarpin (8) showed a potentiating effect when combined with both 6 and 7, during cytotoxicity testing using the MCF-7 human breast cancer cell line.     

Sweetening agents of plant origin*

The most important sweet substance known is sucrose, which is obtained commercially from sugar cane and sugar beet. Because the intake of sucrose has been associated with a number of adverse effects on health, an intensive search has been undertaken to find alternative substances to satisfy the human craving for a sweet taste. Many other plant‐derived compounds are sweet, ranging in structural complexity from sugars and polyhydric alcohols through diterpene and triterpene glycosides to proteins; some of these compounds are intensely sweet, being hundreds or even thousand times sweeter than sucrose, and offer potential for commercial use in dietetic and diabetic foodstuffs. The present review examines the role of ethnobotany in the discovery of sweet‐tasting plants, the chemical isolation and elucidation of the sweet compounds, and some safety and sensory evaluation aspects of these compounds. A discussion on the future prospects of discovering and developing new plant‐derived sweeteners concludes the review.     

Chemical constituents from Xylosma longifolia and their anti-tubercular activity

Two new glucosides, 3-methoxy-4-hydroxyphenylpropane-7,8-(6′-benzoyl-2′,1′-O-β-glucopyranosyl)-7,8,9-trio (1), and 2-hydroxyphenyl-4-caffeoyl-β-d-glucoside (2), together with seven known compounds were isolated from the stem bark of Xylosma longifolia (Flacourtiaceae). The structures of the isolates were established on the basis of their spectral data, including mass spectrometry and 2D-NMR. The compound 8-hydroxy-6-methoxy-pentylisocoumarin (3) exhibited an MIC value of 40.5 μg/mL against M. tuberculosis.