Antiproliferative piperidine alkaloids from giant taro (Alocasia macrorrhiza).

The rhizome of giant taro (Alocasia macrorrhiza (L.) Schott), which is a highly adaptable wild plant, is a traditional Chinese herbal medicine. In the current study, the antiproliferative constituents of giant taro were investigated and six new (1-6) and four known piperidine alkaloids (7-10) were isolated from its rhizomes. Their chemical structures and absolute configurations were elucidated using various spectroscopic methods and the Mosher ester method. The isolated alkaloids were screened for the antiproliferative activity through MTT assay. The results indicated that piperidine alkaloids exerted potential antiproliferative activity against HepG2, AGS and MCF-7 tumor cells. Further researches showed that compounds 3-5 dose-dependently decreased the colony formation rate and induced the apoptosis of AGS cells, while compound 4 induced AGS cell death via the proapoptotic pathway. This study demonstrates that the piperidine alkaloids isolated from giant taro exhibit significant antitumor activity, which provides phytochemical evidence for further development and utilization.

Antitumor quinazoline alkaloids from the seeds of Peganum harmala.

A phytochemical study on the methanol extracts from the seeds of Peganum harmala L. led to a new quizonaline alkaloid (S)-vasicinone-1-O-ß-d-glucopyranoside (1) and four known ones, (R)-vasicinone-1-O-ß-d-glucopyranoside (2), (S)-vasicinone (3), vasicine (4), and deoxyvasicinone (5). Their structures were elucidated by spectroscopic analysis including IR, HR-ESI-MS, 1D and 2D NMR, and specific rotation as well as by comparison of the data with those in the literature. All of the alkaloids were screened for antiproliferative activity against human gastric cancer cells MCG-803 with MTT method. Compounds 1 and 3 exhibited moderate inhibitory activity.

Acylphloroglucinol glycosides from the fruits of Pyracantha fortuneana.

Three new acylphloroglucinol glycosides, namely pyrafortunosides A (1), B (2) and C (3), together with three known glycosides (4-6), were isolated from the fruits of Pyracantha fortuneana (Maxim.) Li. Their structures were established to be 2,4,6-trihydroxy-acetophenone-6-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (1), 2,4,6-trihydroxy-benzophenone-6-O-alpha-L-rhamno-pyranosyl-(1-->6)-beta-D-glucopyranoside (2), 2,4,6-trihydroxy-benzophenone-6-O-beta-D-apiofuranosyl-(1-->6)-beta-D-gluco-pyranoside (3), garcimangosone D (4), 2,4,6-trihydroxy-acetophenone-6-O-beta-D-glucopyranoside (5), and 2,4,6-trihydroxy-acetophenone-4-O-beta-D-glucopyranoside (6) by spectral analysis. The three known glycosides (4-6) were obtained from this genus for the first time.

Andrographolide attenuates inflammation by inhibition of NF-kappa B activation through covalent modification of reduced cysteine 62 of p50.

NF-kappaB is a central transcriptional factor and a pleiotropic regulator of many genes involved in immunological responses. During the screening of a plant extract library of traditional Chinese herbal medicines, we found that NF-kappaB activity was potently inhibited by andrographolide (Andro), an abundant component of the plant Andrographis that has been commonly used as a folk remedy for alleviation of inflammatory disorders in Asia for millennia. Mechanistically, it formed a covalent adduct with reduced cysteine (62) of p50, thus blocking the binding of NF-kappaB oligonucleotide to nuclear proteins. Andro suppressed the activation of NF-kappaB in stimulated endothelial cells, which reduced the expression of cell adhesion molecule E-selectin and prevented E-selectin-mediated leukocyte adhesion under flow. It also abrogated the cytokine- and endotoxin-induced peritoneal deposition of neutrophils, attenuated septic shock, and prevented allergic lung inflammation in vivo. Notably, it had no suppressive effect on IkappaBalpha degradation, p50 and p65 nuclear translocation, or cell growth rates. Our results thus reveal a unique pharmacological mechanism of Andro's protective anti-inflammatory actions.

[Study on the active spirostanol saponins of Gualou xiebai baijiutang].

AIM: To study the basis of actions of Gualou xiebai baijiutang. METHODS: Guided by bioactivities, chemical and chromatographic ways were applied to isolate and purify the prescription. The chemical structures were identified by chemical and spectral ways. The activities on cardiovascular system of the pure compounds were measured. RESULTS: Seven steroidal compounds were isolated and identified from the active parts. CONCLUSION: Compounds 5 and 6 showed good anti-platelet aggregation activities induced by ADP and PAF. The IC50 of compound 5 and 6 induced by 2 mumol.L-1 ADP were 0.082 and 0.078 mmol.L-1, and the IC50 induced by 0.5 mumol.L-1 PAF were 0.182 and 0.151 mmol.L-1, respectively.

[Research on active constituents research of gualou xiebai baijiutang (III). The active flavanoids].

OBJECTIVE: To observe the substance basis of actions of Gualou xiebai baijiutang. METHOD: Guided by bioactivities, the prescription was isolated and purified by chemical and chromatographic methods, and the structures were identified by chemical and spectral methods. RESULT: 4 compounds were isolated from active parts. CONCLUSION: 3 compounds were isolated for the first time from Trichosanthes kirilowii and Allium macrostemon. Compound 1 had a good activity against platelet aggregation.

The active constituents from Gualou-xiebai-baijiu-tang part I: active saponins.

Two new steroidal saponins and a new triterpenoidal saponin, together with nine known steroidal saponins, were isolated from "Gualou-xiebai-baijiu-tang" consisting of Fructus trichosanthis and Bulbus allii macrostemi. The structures of the three new compounds were determined as 3-O-beta-D-galactopyranosyl-hederagenin 28-O-beta-D-xylopyranosyl (1-->6)-beta-D-galactopyranosyl ester (1), spirost 25(27)-ene-2beta,3beta-diol-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (2) and 26-O-beta-D-glucopyranosyl-22alpha-hydroxy-5beta-furost-25(27)-ene-1beta,3beta,6beta,26-tetraol-3-O-beta-D-galactopyranoside (3), respectively, by means of chemical evidences and spectral analysis.