积雪草药理作用的研究

对伞形科植物积雪草的药理作用进行综述,为积雪草的研究提供基础资料,以便该资源在多领域得到充分利用。     

Genetic diversity and structure revealed by genomic microsatellite markers in Centella asiatica (L.) Urb., a plant with medicinal potential

Molecular Biology Reports - Around the world, medicinal plants are utilised for various purposes. Centella asiatica is one of the important medicinal plants widely used in many medicinal systems....     

In vitro keratinocyte antiproliferant effect of Centella asiatica extract and triterpenoid saponins.

Psoriasis is a hyperproliferative skin disorder estimated to be present in 1-3% of most populations. Conventional therapy using corticosteroids, Vitamin D analogs and cytotoxic agents eg psoralens is associated with low success rate and many side effects. Traditional plant remedies may provide leads for new treatments. A rapid-throughput, in vitro bioassay has been utilised to examine plants for inhibitory effects on the growth of SVK-14 keratinocytes. Centella asiatica, a reputed anti-psoriatic herb, has been compared against the psoralen-containing seeds of Psoralea corylifolia and the synthetic anti-psoriatic agent dithranol (anthralin). Aqueous extracts of Psoralea corylifolia and Centella asiatica inhibited keratinocyte replication with IC50 values of 18.4 +/- 0.6 microg/ml and 209.9 +/- 9.8 mg/ml respectively prior to treatment with polyvinylpolypyrrolidone (PVPP) and 36.3 +/- 3.3 mg/ml and 238.0 +/- 2.5 mg/ml respectively after PVPP treatment of the extracts. The effect produced by C. asiatica is thus unlikely to be due to phenolic compounds. It may, however, be due to its two constituent triterpenoid glycosides madecassoside and asiaticoside which had IC50 values of 8.6 +/- 0.6 microM respectively. These values were comparable to their concentrations in the crude extract and to the IC50 of dithranol (5.1 +/- 0.4 microM). These results suggest that the potential use of C. asiatica extracts as a topical anti-psoriatic agent is worthy of further investigation.     

Anti-herpes simplex virus activities of crude water extracts of Thai medicinal plants.

A number of Thai medicinal plants, recommended as remedies for herpesvirus infection and have been used in primary health care were investigated for their intracellular activities against herpes simplex viruses (HSV). Centella asiatica L., Maclura cochinchinensis Cornor, and Mangifera indica L. contained both anti-HSV-1 and -2 activities, as determined by plaque inhibition assay. An inhibition of the production of infectious HSV-2 virions from infected Vero cells could also be demonstrated. Combinations of each of these reconstituted extracts with 9-(2-hydroxyethoxymethyl) guanosine (acyclovir; ACV) resulted either in subadditive, additive, or synergistic interaction, against HSV-2, depending on the dose of ACV used; mixture of C. asiatica and M. indica exerted an additive effect in a similar assay. Furthermore, the inhibitory effects of these plant extracts were also substantiated by flow cytometric analysis of virus-specific antigens in the infected cells. The active constituent present in C. asiatica extract was determined to be asiaticoside while in M. indica was mangiferin. Thus, these data suggest therapeutic potential of these plant extracts.     

Triterpenoid saponin content and the expression level of some related genes in calli of Centella asiatica

Centella asiatica has been extensively studied but there has been no report to date that relates gene expression and centelloside production in non-differentiated tissues. We have determined the content of the four principal triterpenoid bioactive compounds of C. asiatica (asiaticoside, madecassoside, asiatic acid and madecassic acid) in calli grown in different media and checked the expression level of some of the genes in the centelloside biosynthetic pathway. The results when compared with data from in vitro plant cultures showed a significantly lower expression of the gene encoding beta-amyrin synthase in calli, which is consistent with the observed lower production of centellosides (less than 900 mug/g DW), while in the plants the production was around 1.5-2 mg/g DW. Moreover, we find an efficient housekeeping gene for this plant. The biosynthesis of phytosterols is also discussed.     

The indiscriminate vector: Human distribution ofDlchondra micrantha (Convolvulaceae)

The complex movements of humans, the variety of organisms they purposefully and accidentally carry with them, and taxonomic confusion have partly obscured the transport of this cultivated ornamental and medicinal plant. Several lines of evidence indicate an American origin for this species. The data include: (1) greatest species richness in the Americas; (2) phylogenetic placement of D. micrantha with North American taxa D. recurvata and D. donelliana; (3) D. micrantha being the only species present in Cuba; (4) Chinese names and medicinal uses for the plants that suggest a recent adoption of D. micrantha, perhaps because of morphological similarity with Centella asiatica. Dichondra micrantha was present in several parts of Asia and the Americas by the 1800s. Most of these places were on sailing trade routes. Therefore, it appears that D. micrantha has been moved around the world by humans for 200–500 years. Humans continue spreading the species, and for the past few decades thousands of pounds of 2 × 1 mm seeds have been shipped around the world annually by American companies.     

Microsatellite markers isolated from the wild medicinal plant Centella asiatica (Apiaceae) from an enriched genomic library

? Premise of the study: Microsatellite markers for Centella asiatica, an important medicinal herb, were developed and characterized to promote genetic and molecular studies. ? Methods and Results: A GA/GT-enriched genomic library was constructed from an accession from Madagascar. Roughly 75% of the 768 clones of the enriched library contained microsatellites. Eighty sequences containing microsatellites were obtained from 96 positive clones. Specific primers were designed for 20 loci, and 17 of them displayed polymorphism when screened across 17 C. asiatica accessions, with an average of 4.3 alleles per locus. The observed and expected heterozygosity values averaged 0.114 and 0.379, respectively. ? Conclusions: This is the first report constructing an enriched genomic library and identifying microsatellite markers from C. asiatica. These 17 polymorphic microsatellite markers are a useful resource for this plant, applicable for diversity studies, pedigree analyses, and genetic mapping.     

The healing effects of Centella extract and asiaticoside on acetic acid induced gastric ulcers in rats

In this study, the healing effects of Centella asiatica water extract (CE) and asiaticoside (AC), an active constituent of CE, on acetic acid induced gastric ulcers (kissing ulcers) in rats were examined. CE was prepared from Centella asiatica dry plant and the concentration of AC in CE was quantitatively determined with the use of high performance liquid chromatography analysis. Different concentrations of CE and AC were orally administered to rats with kissing ulcers. They were found to reduce the size of the ulcers at day 3 and 7 in a dose-dependent manner, with a concomitant attenuation of myeloperoxidase activity at the ulcer tissues. Epithelial cell proliferation and angiogenesis were on the other hand promoted. The expression of basic fibroblast growth factor, an important angiogenic factor, was also upregulated in the ulcer tissues in rats treated with CE or AC. These results further suggest the potential use of Centella asiatica and its active ingredient as anti-gastric ulcers drugs.     

The effect of methyl jasmonate on triterpene and sterol metabolisms of Centella asiatica, Ruscus aculeatus and Galphimia glauca cultured plants

Considering that exogenously applied methyl jasmonate can enhance secondary metabolite production in a variety of plant species and that 2,3-oxidosqualene is a common precursor of triterpenes and sterols in plants, we have studied Centella asiatica and Galphimia glauca (both synthesizing triterpenoid secondary compounds) and Ruscus aculeatus (which synthesizes steroidal secondary compounds) for their growth rate and content of free sterols and respective secondary compounds, after culturing with or without 100 microM methyl jasmonate. Our results show that elicited plantlets of G. glauca and to a higher degree C. asiatica (up to 152-times more) increased their content of triterpenoids directly synthesized from 2,3-oxidosqualene (ursane saponins and nor-seco-friedelane galphimines, respectively) at the same time as growth decreased. In contrast, the free sterol content of C. asiatica decreased notably, and remained practically unaltered in G. glauca. However, in the case of R. aculeatus, which synthesizes steroidal saponins (mainly spirostane type) indirectly from 2,3-oxidosqualene after the latter is converted to the plant phytosterol-precursor cycloartenol, while the growth rate and free sterol content clearly decreased, the spirostane saponine content was virtually unchanged (aerial part) or somewhat lower (roots) in presence of the same elicitor concentration. Our results suggest that while methyl jasmonate may be used as an inducer of enzymes involved in the triterpenoid synthesis downstream from 2,3-oxidosqualene in both C. asiatica and G. glauca plantlets, in those of C. asiatica and R. aculeatus it inhibited the enzymes involved in sterol synthesis downstream from cycloartenol.     

Triterpenoids and their glycosides from the bark of Schefflera octophylla.

A new triterpene and its glycosides were isolated from the bark of Schefflera octophylla together with asiatic acid and asiaticoside. Based on spectroscopic data, especially 2DNMR, and chemical transformations the structures of the new compounds were determined as 3 alpha-hydroxy-urs-12-ene-23,28-dioic acid and 3 alpha-hydroxy-urs-12-ene-23,28-dioic acid 28-O-[alpha-L-rhamnopyranosyl (1----4)-O-beta-D-glucopyranosyl (1----6)]-beta-D-glucopyranoside. For the first time asiaticoside was isolated from a plant other than Centella asiatica.     

积雪草活性成分的分析方法及药理作用研究进展

就近年来国内外对积雪草的化学成分、提取纯化、分析检测方法和药理活性的研究进展作了综述,为积雪草的进一步开发利用提供科学依据。     

Inhibitory effect of asiatic acid on acetylcholinesterase, excitatory post synaptic potential and locomotor activity

The asiatic acid, a triterpenoids isolated from Centella asiatica was used to delineate its inhibitory effect on acetylcholinesterase (AChE) properties, excitatory post synaptic potential (EPSP) and locomotor activity. This study is consistent with asiatic acid having an effect on AChE, a selective GABA(B) receptor agonist and no sedative effect on locomotor.     

Somatic embryogenesis in Centella asiatica L. an important medicinal and neutraceutical plant of India

Leaf segments excised from Centella asiatica, a medicinal and neutraceutical plant, produced abundant somaticembryoswhen cultured onMS mediumwith 9.29 Mkinetin in combination with 2.26 M2,4-D. Granular, white,shiny clusters of callus developed after 1 week of culture, and then formed heart and cotyledonary stage embryoson the same medium after 4 weeks. Somatic embryos matured and germinated in the presence of MS mediumcontaining 2.32 M kinetin with (2.89M) GA3. Plantlets were successfully transferred to pots containing amixture of soil and vermiculite (1:1).     

林缘和荒草坡不同草本层盖度小生境中积雪草的等级可塑性

为研究克隆植物在不同生境中对小生境的利用能力和对不同尺度异质性生境的等级可塑性及其格局差异,比较了林缘和荒草坡不同草本层盖度小生境中积雪草(Centella asiatica)分株种群、克隆片段和叶水平的形态和生理特征。在分株种群水平,林缘和荒草坡积雪草被测的分株种群特征差异均不显著,不同草本层盖度小生境间积雪草根冠比差异显著,即在盖度小的小生境中其根冠比显著大于盖度大的小生境。在克隆片段水平,林缘和荒草坡生境显著影响积雪草的根干重、花果干重、一级匍匐茎节间长和总匍匐茎节间长,而不同草本层盖度小生境则显著影响花果干重、根冠比、一级匍匐茎数、二级匍匐茎节间长和总匍匐茎节间长。荒草坡积雪草拥有更大的根干重和花果干重,但一级匍匐茎节间长和总匍匐茎节间长较短。草本层盖度小的小生境中积雪草的根冠比和一级匍匐茎数显著高于盖度大的小生境,而花果干重、二级匍匐茎节间长和总匍匐茎节间长则相反。在叶水平,荒草坡和草本层盖度大的小生境中,积雪草的叶片长、叶片宽和叶面积都较大,而草本层盖度大的小生境中积雪草叶柄长和比叶柄长都显著大于盖度小的小生境;林缘和荒草坡生境与不同草本层盖度小生境对4个叶绿素指标影响均不显著,林缘和荒草坡生境与不同草本层盖度小生境的交互作用对所有测量特征均无显著影响。上述结果表明,积雪草对不同生境和有草本层盖度差异的小生境的反应存在等级可塑性,但是二者的等级差异格局不同;等级反应格局的差异反映出积雪草对不同生境条件有不同的生态适应对策,且对生境小尺度异质性的可塑性强于对大尺度异质性的可塑性。     

Effect of Centella asiatica Linn on physical and chemical factors induced gastric ulceration and secretion in rats

Centella asiatica is commonly mentioned as a Rasayana in Ayurveda, an ancient system of Indian medicine for various ailments including abdominal disorders. Rasayanas have been advocated for use in rejuvenation therapy. The present study was conducted to evaluate the possible anti-ulcerogenic activity of fresh juice of C. asiatica (CAJ) against ethanol-, aspirin-, cold-restraint stress- and pyloric ligation induced gastric ulcers in rats. The drug given orally in doses of 200 and 600 mg/kg twice daily for five days, showed significant protection against all the above experimental ulcer models and the results were comparable with those elicited by sucralfate (SF, 250 mg/kg, p.o., BD x 5 days). CAJ showed little or no effect on offensive acid-pepsin secretion. However, at 600 mg/kg CAJ significantly increased gastric juice mucin secretion and increased the mucosal cell glycoproteins signifying increase in cellular mucus. It also decreased cell shedding indicating fortification of mucosal barrier. Thus, the ulcer protective effect of CAJ may be due to strengthening of the mucosal defensive factors.     

Nitric oxide-related toxicity in cultured astrocytes: effect of Bacopa monniera

There is growing evidence that high concentrations of nitric oxide (NO), generated by activated astrocytes, might be involved in a variety of neurodegenerative diseases, such as Alzheimer's disease, ischemia and epilepsy. It has recently been suggested that glial cells may produce NO under superoxide radical stimulation by enzyme-independent mechanism. This suggests that also natural antioxidants may have therapeutical relevance in neurodegenerative diseases. Studies of Bhattacharya et al. have evidenced that Bacopa monniera (BM) (family Scrophulariaceae), an Ayurvedic medicinal plant clinically used for memory enhancing, epilepsy, insomnia and as a mild sedative, is able to reduce the memory-dysfunction in rat models of Alzheimer's disease, but the molecular mechanisms of this action are yet to be determined. In the present study, we examined the effect of a methanolic extract of BM on toxicity induced by the nitric oxide donor, S-nitroso-N-acetyl-penicillamine (SNAP), in culture of purified rat astrocytes. Our results indicate that, after 18 h of treatment, SNAP induced an increase in the production of reactive species, but did not induce the rupture of cellular membrane. Conversely, this NO donor induced a fragmentation of genomic DNA compared to control astrocytes. The extract of BM inhibited the formation of reactive species and DNA damage in a dose dependent manner. This data supports the traditional use of BM and indicates that this medicinal plant has a therapeutic potential in treatment or prevention of neurological diseases.     

Antimutagenicity of secondary metabolites from higher plants.

Higher plants contain both mutagens and antimutagens and are susceptible to mutagenesis but screening programs for detection of antimutagenesis rarely employ higher plant systems. Short-term bacterial and mammalian tissue culture systems are the norm. Using modified screening tests for detecting antimutagenic agents, higher plants have been shown to contain a variety of structurally novel antimutagenic agents. Systematic bioassay-directed methodology resulted in the isolation in pure form and biological and chemical characterization of the responsible individual active components from various plants. The methodology in use is illustrated by the isolation of cinnamic acid, cinnamyl cinnamate and cinnamyl ricinoleate as the active constituents of the classic medicinal plant product, Styrax asiatica. The methods which may be used to reveal structure-activity relationships and to explore putative molecular modes of action are illustrated with excerpts from the same study.