[A new cytotoxic alkaloid from roots of Alangium chinense].

We have carried out the chemical investigation on the roots of Alangium chinense. The chemical constituents from the roots of A.chinense were isolated and purified by various chromatographic techniques, such as silica gel, MCI-Gel resin, Sephadex LH-20 and high performance liquid chromatography. As a result, three alkaloids (1-3) were isolated from 90% EtOH extracts of the roots of this plant. Their structures were elucidated by physical-chemical properties and spectral data. Among them, compound 1 is a new compound, determined as 8-hydroxy-3-hydroxymethyl-6,9-dimethyl-7H-benzo[de]isoquinolin-7-one. Cytotoxicity of the compounds was evaluated by the MTT method. Compound 1 displayed cytotoxicity against NB4, A-549, SHSY5Y, PC-3 and MCF-7 cell lines with IC50 values of 4.2, 3.5, 5.7, 2.8 and 3.9 µmol•L⁻¹, respectively.

Biomimetic Synthesis of Macahydantoins A and B from Lepidium meyenii, and Structure Revision of Macahydantoin B as a Class of Thiohydantoin with a 4-Methyl-hexahydropyrrolo[1,2-c]imidazole Skeleton.

Phytochemical investigation on Lepidium meyenii led to the discovery of macahydantoin C (3), a new thiohydantoin with a 1,3-diazabicyclo[3.3.1]nonane core, the spectral properties of which indicate a potential structural misassignment of its previously reported analogue, macahydantoin B (2a). To probe this hypothesis, a concise, scalable, and biomimetic synthesis of the originally proposed 2a and its revised structure (2b) was efficiently accomplished using the modified Edman degradation as the key step from commercially available materials in 65% (three steps) and 52% (three steps) overall yields, respectively. These synthetic endeavors undoubtedly reassigned the structure of macahydantoin B as an unreported type of thiohydantoin featuring a 4-methyl-hexahydropyrrolo[1,2-c]imidazole scaffold.

(+)-Meyeniins A-C, Novel Hexahydroimidazo[1,5-c]thiazole Derivatives from the Tubers of Lepidium meyenii: Complete Structural Elucidation by Biomimetic Synthesis and Racemic Crystallization.

(+)-Meyeniins A-C (1-3), a novel class of sulfur-containing hexahydroimidazo[1,5-c]thiazole derivatives, were isolated from the tubers of Lepidium meyenii (maca) cultivated in Lijiang, Yunnan province, China. Guided by their biosynthetic hypothesis, a stereocontrolled biomimetic synthesis of meyeniins A-C and their individual enantiomers was efficiently accomplished by a combination of a condensation reaction and Edman degradation. The formation of high-quality crystals for X-ray crystallography occurred much more readily from a racemic mixture of (±)-meyeniin A than with the single enantiomer alone in this case. These extensive strategies, combined with circular dichroism (CD) spectra, allowed the complete structural assignments of (+)-meyeniins A-C. Among them, (+)-meyeniin A showed moderate selective cytotoxicities against the HL-60, A549 and MCF-7 human cell lines with IC50 values of 14.41, 32.22, and 33.14 µM, respectively. To some extent, these findings support traditional applications of maca as healthy nutritional supplements or functional foods for cancer prevention.

Three new biphenyls from the twigs of Garcinia tetralata and their anti-tobacco mosaic virus activity.

Phytochemical investigations on the ethanol extract of the twigs of Garcinia tetralata resulted in the isolation of three new biphenyls, tetralatabiphenyls A-C (1-3), along with three known biphenyl derivatives (4-6). Structural elucidations of 1-3 were performed by spectroscopic methods such as 1D and 2D NMR spectra, in addition to high-resolution mass spectra. Compounds 1-6 were also evaluated for their anti-tobacco mosaic virus (anti-TMV) activity. The results showed that compound 3 showed high anti-TMV activity with inhibition rate of 31.1%. Compounds 1, 2, and 4-6 also showed modest anti-TMV activities with inhibition rates in the range of 18.9-24.5%, respectively.

[A new isoindole alkaloid from leaves of Cassia siamea].

A new isoindole alkaloid (1), has been isolated from the leaves of Cassia siamea by using various chromatographic techniques. Compound 1 is a new compound, determined as 5-(hydroxymethyl)-2-methyl-6-prenylisoindolin-1-one, and it displayed cytotoxicity against NB4, A549, SHSY5Y, PC3 and MCF7 cell lines with IC50 values of 3.2,4.6,2.8,6.4, 2.5 µmol•L⁻¹, respectively.

[A new furan-2-carboxylic acid from stem bark of Cassia alata].

A new furan-2-carboxylic acid, 5-[3-(hydroxymethyl)-4,5-dimethoxyphenyl]-3-methylfuran-2-carboxylic acid(1),has been isolated from the bark of Cassia alata by using various chromatographic techniques. It displayed cytotoxicity against NB4, A549, SHSY5Y, PC3 and MCF7 cell lines with IC50 values of 2.5, 1.2, 2.2, 3.6 and 1.9 µmol•L⁻¹, respectively.

[A new sesquiterpene from seeds of Cassia occidentalis and its cytotoxicity].

For the purpose of finding new bioactive agents from ethnic medicines, the chemical study on Dai Medicine Cassia occidentalis was carried out. The chemical constituents from the seeds of C. occidentalis were isolated by column chromatographic methods on silica gel, MCI-Gel resin, Sephadex LH-20, and high performance liquid chromatography. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. The cytotoxicity of the compound for NB4, A549, SHSY5Y, PC3, and MCF7 cells line was also assayed by using the MTT method. Two sesquiterpenes (1 and 2) were isolated from this plant. Compound 1 is a new compound and named as methyl 6-(hydroxymethyl)-4-isopropyl-7-methoxynaphthalene-1-carboxylate. Compound 1 also displayed high cytotoxicity with the tested cancer cell-lines.

[A new nor-sesquiterpene from Cassia occidentalis and its bioactivity].

The phytochemistry investigation on the Cassia occidentalis, a Dai Medicine, was carried out. The C. occidentalis was extracted with ethanol and then partitioned with EtOAc. The EtOAc soluble materials were subjected repeatedly to column chromatography on silica gel and preparative RP-HPLC, leading to isolation of a nor-sesquiterpene, 3-isopropyl-1,6-dimethoxy-5-methyl-naphthalen-7-ol (1), and a sesquiterpene, 2,7-dihydroxy-4-isopropyl-6-methyl-naphthalene-1-carbaldehyde (2). Their structures were determined by means of spectroscopic studies. Compound 1 is a new compound. Compound 2 is also isolated from C. occidentalis for the first time. In addition, the cytotoxicity of compound 1 for NB4, A549, SHSY5Y, PC3, and MCF7 cells line was assayed by using the MTT method, and it displayed potential cytotoxicity for the tested cancer cell-line with IC50 valves of (1.8±0.2), (1.2±0.2), (0.9±0.1), (2.2±0.3), (2.6±0.3) µmol•L⁻¹, respectively.