Triterpene saponins from Craniotome furcata

Bioactive Secondary Metabolites from the Aerial Parts of Buddleja macrostachya

A new iridoid glycoside, buddlemacroside A (1) and 15 known compounds, including 6-α-L-(4″- O-trans-p-coumaroyl)rhamnopyranosylcatalpol (2), 6-α-L-(2″-caffeoyl)rhamnopyranosylcatalpol (3), salidroside (4), echipuroside A (5), darendoside A (6), decaffeoylacteoside (7), acteoside (8), martynoside (9), 8-hydroxylinalool 3- O-β-D-glucopyranoside (10), 9- O-α-L-rhamnopyranosyl-4-hydroxy-cinnamic acid (11), apigenin (12), acacetin-7- O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (13), mimengoside C (14), buddlejasaponin Ia (15), and buddejasaponin I (16) were isolated from a methanol extract of the aerial parts of Buddleja macrostachya Benth. Their chemical structures were elucidated by extensive spectroscopic analyses, including MS and NMR spectra as well as by comparison with the data reported in the literature. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test showed that compounds 3 and 7-9 possess significant scavenging capacity, with SC50 values ranging from 6.9-19.6 μM. Compound 8 was shown to have potent inhibitory effect against the release of malondialdehyde (MDA) - the major product of the cellular lipid peroxidation, with IC50 value of 2.3 μM. Compounds 12 and 16 significantly inhibited nitrite production in LPS-stimulated BV2 microglia, with IC50 values of 14.2 and 11.4 μM, respectively. Furthermore, compound 16 showed cytotoxicity toward three human cancer cell lines, including SK-LU-1, MCF7, HepG2, with IC50 values in the range of 6.5-8.0 μM.

Chemical study and medical application of saponins as anti-cancer agents

Saponins are a group of naturally occurring plant glycosides, characterized by their strong foam-forming properties in aqueous solution. The presence of saponins has been reported in more than 100 families of plants out of which at least 150 kinds of natural saponins have been found to possess significant anti-cancer properties. There are more than 11 distinguished classes of saponins including dammaranes, tirucallanes, lupanes, hopanes, oleananes, taraxasteranes, ursanes, cycloartanes, lanostanes, cucurbitanes and steroids. Due to the great variability of their structures, saponins always display anti-tumorigenic effects through varieties of antitumor pathways. In addition, there are a large amount of saponins that still either remain to be trapped or studied in details by the medicinal chemists. This article reviews many such structures and their related chemistry along with the recent advances in understanding mechanism of action and structure-function relationships of saponins at the molecular and cellular levels. These aglycones have been described and their classification and distribution have been listed in the review. Some special saponins with strong antitumor effects have also been exhibited. Ginsenosides, belonging to dammaranes, have been found beneficial targeted on inhibition of tumor angiogenesis by suppressing its inducer in the endothelial cells of blood vessels, and then on prevention of adhering, invasion, and metastasis of tumor cells. Dioscin, one of the steroidal saponins, and its aglycone diosgenin also have been extensively studied on its antitumor effect by cell cycle arrest and apoptosis. Other important molecules discussed include oleanane saponins such as avicins, platycodons, saikosaponins, and soysaponins along with tubeimosides.

Antimicrobial activity of the extracts of Craniotome furcata (Lamiaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Craniotome furcata (Link.) O. Kuntze (Lamiaceae) is used in the traditional medicine for the treatment of cuts and wounds indicating antimicrobial activity.

AIM OF THE STUDY

To validate the traditional medicinal claim, in vitro antimicrobial activity of the extracts was screened against eleven human pathogenic bacteria and fungi.

MATERIALS AND METHODS

The ethyl acetate (CE) and n-butanol (CB) extracts of the aerial parts of Craniotome furcata were tested against four Gram-positive bacteria, four Gram-negative bacteria and three fungi species. Antimicrobial activity was determined by the tube-dilution method.

RESULTS

The CE and CB extracts showed antimicrobial activity against all of the tested microorganisms, with minimum inhibitory concentration (MIC) values in the range of 0.41-4.58mg/ml.

CONCLUSIONS

The tested microbes Micrococcus flavus and Escherichia coli were highly susceptible to extract CE and antimicrobial activity of CB is comparable to that of extract CE against Escherichia coli and Staphylococcus faecalis while it is better than that of extract CE, against Klebsiella pneumoniae. Both the extracts were found less susceptible against tested fungi.

Chemical Composition of the Essential Oil of the Flowering Aerial Parts of Craniotome Furcata

The composition of the steam volatile constituents of the flowering aerial parts of Craniotome furcata (Link.) O. Kuntze was determined by GC, GC/MS and NMR. The oil was constituted mainly of sesquiterpene hydrocarbons (68%). The main constituents were germacrene D (49.2%), germacrene D-4-ol (8.8%), epi-α-cadinol (5.9%) and 10- epi-γ-eudesmol (4.2%). Germacrene-derivative constituents represented 61.5% of the total oil.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, lanostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleannes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins. The literature from January to December 2002 is reviewed and 221 references are used.

Effects of astragali radix on the growth of different cancer cell lines

AIM: To investigate the inhibitory effect of a Chinese herb medicine Astragali radix (AR) on growth of different cancer cell lines.

METHODS: To observe the in vitro effects of AR on tumor cell proliferation by trypan blue exclusion, MTS method and tritium thymidine incorporation assay. Apoptosis was detected by DNA ladder method.

RESULTS: The inhibition rates of AR on the cell respiration of AGS, KATOIII, HT29, MDA231, MEL7 and MEL14 were 68.25%, 62.36%, 22.8%, 27.69%, 2.85% and 5.14% respectively at the concentration of 100 ug/mL; it inhibited AGS DNA synthesis by 87.33% at the concentration of 50 ug/mL. The inhibitory effect on AGS was time-and dose-dependent. AR did not induce apoptosis in AGS cells.

CONCLUSION: AR specifically inhibits gastric cancer cells growth in vitro and the mechanism is mainly cytostatic but not cytotoxic or inducing apoptosis.