The antioxidant, anti-inflammatory, and cytotoxic activities of water and ethanol extracts of 14 Chinese medicinal plants were investigated and also their total phenolics and flavonoid contents measured. The antioxidant activity was evaluated in a biological assay using Saccharomyces cerevisiae, whereas the radical scavenging activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Total phenolics and flavonoid contents were estimated by Folin-Ciocalteu and aluminum chloride methods, respectively. The anti-inflammatory activities of the plant extracts were determined by measuring the inhibition of production of nitric oxide (NO) and TNF-α in LPS and IFN-γ activated RAW 264.7 macrophages. Their cytotoxic activities against macrophages were determined by Alamar Blue assay. Four plants, namely, Scutellaria baicalensis, Taxillus chinensis, Rheum officinale, and Sophora japonica, showed significant antioxidant activity in both yeast model and also free radical scavenging methods. The ethanol extract of S. japonica showed highest levels of phenolics and flavonoids (91.33 GAE mg/g and 151.86 QE mg/g, respectively). A positive linear correlation between antioxidant activity and the total phenolics and flavonoid contents indicates that these compounds are likely to be the main antioxidants contributing to the observed activities. Five plant extracts (S. baicalensis, T. chinensis, S. japonica, Mahonia fortunei, and Sophora flavescens) exhibited significant anti-inflammatory activity by in vitro inhibition of the production of NO and TNF-α with low IC 50 values. These findings suggest that some of the medicinal herbs studied in this paper are good sources of antioxidants.

Antioxidant and anti-inflammatory activities of selected medicinal plants containing phenolic and flavonoid compounds.

Chaetominine, a cytotoxic alkaloid produced by endophytic Chaetomium sp. IFB-E015.

Two antibacterial and xanthine oxidase inhibitory cerebrosides, one of which is chemically new, were characterized from the chloroform-methanol (1∶1) extract of Fusarium sp. IFB-121, an endophytic fungus in Quercus variabilis. By means of chemical and spectral methods [IR, electrospray ionization MS (ESI-MS), tandem ESI-MS, 1H and 13C NMR, distortionless enhancement by polarization transfer, COSY, heteronuclear multiple-quantum coherence, heteronuclear multiple-bond correlation, and 2-D nuclear Overhauser effect correlation spectroscopy], the structure of the new metabolite named fusaruside was established as (2S,2′R,3R,3′E,4E,8E,10E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8,10-sphingatrienine, and the structure of the other was identified as (2S,2′R,3R,3′E,4E,8E)-1-O-β-d-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine. Both new and known cerebrosides, although inactive to Trichophyton rubrum and Candida albicans, showed strong antibacterial activities against Bacillus subtilis, Escherichia coli, and Pseudomonas fluorescens, with their minimum inhibitory concentrations being 3.9, 3.9, and 1.9 μg/mL, and 7.8, 3.9, and 7.8 μg/mL, respectively. Furthermore, both metabolites were inhibitory to xanthine oxidase, with the IC50 value of fusaruside being 43.8±3.6 μM and the known cerebroside being 55.5±1.8 μM.

Antibacterial and xanthine oxidase inhibitory cerebrosides from Fusarium sp. IFB-121, and endophytic fungus in Quercus variabilis

Asperamides A (1) and B (2), a sphingolipid and their corresponding glycosphingolipid possessing a hitherto unreported 9-methyl-C-20-sphingosine moiety, were characterized from the culture extract of Aspergillus niger EN-13, an endophytic fungus isolated from marine brown alga Colpomenia sinuosa. The structures were elucidated by spectroscopic and chemical methods as (2S,2'R,3R,3'E,4E,8E)-N-(2'-hydroxy-3'-hexadecenoyl)-9-methyl-4,8-icosadien-1,3-diol (1) and 1-O-beta-D-glucopyranosyl-(2S,2'R,3R,3'E,4E,8E)-N-(2'-hydroxy-3'-hexadecenoyl)-9-methyl-4,8-icosadien-1,3-diol (2). In the antifungal assay, asperamide A (1) displayed moderate activity against Candida albicans.

New sphingolipids with a previously unreported 9-methyl-C20-sphingosine moiety from a marine algous endophytic fungus Aspergillus niger EN-13.

Cordyceps militaris (bei-chong-chaw, northern worm grass) is a precious and edible entomopathogenic fungus, which is widely used in traditional Chinese medicine (TCM) as a general booster for the nervous system, metabolism, and immunity. Saccharides, nucleosides, mannitol, and sterols were isolated from this fungus. The biological activity of C. militaris was attributed to the saccharide and nucleoside contents. In this study, the aqueous methanolic fraction of C. militaris fruiting bodies exhibited a significant anti-inflammatory activity. Bioactivity-guided fractionation of the active fraction led to the isolation of eight compounds, including one new and two known cerebrosides (ceramide derivatives), two nucleosides, and three sterols. Cordycerebroside A (1), the new cerebroside, along with soyacerebroside I (2) and glucocerebroside (3) inhibited the accumulation of pro-inflammatory iNOS protein and reduced the expression of COX-2 protein in LPS-stimulated RAW264.7 macrophages. This is the first study on the isolation of cerebrosides with anti-inflammatory activity from this TCM.

Anti-inflammatory Cerebrosides from Cultivated Cordyceps militaris

Pinelloside, an antimicrobial cerebroside from Pinellia ternata.

An antimicrobial cerebroside, pinelloside, was isolated from the air-dried tubers of Pinellia ternata (Thunb.) Breit. Its structure was determined as 1-O-beta-D-glucopyranosyl-(2S,3R,4E,11E)-2-(2'R-hydroxyhexadecenoylamino)-4,11-octadecadiene-1,3-diol by chemical transformation and extensive spectroscopic analyses (IR, MS, 1H and 13C NMR, DEPT as well as 2D NMR techniques HMBC, HMQC, 1H-1H COSY and NOESY). The antimicrobial assay showed that this compound was inhibitory to the growth of Bacillus subtilis, Staphylococcus aureus, Aspergillus niger and Candida albicans, with minimum inhibitory concentrations (MICs) of 20, 50, 30 and 10 microg/ml, respectively. The MICs of penicillin G against bacteria B. subtilis, S. aureus, E. coli, P. fluorescens and H. pylori were 0.80, 0.34, 0.56, 1.34 and 0.92, and those of ketoconazole against fungi A. niger, C. albicans and T. rubrum 0.90, 0.65 and 1.0 microg/ml, respectively.

G. Y. Cui

Papers

Pinelloside, an antimicrobial cerebroside from Pinellia ternata.

Pinelloside, an Antimicrobial Cerebroside from Pinellia ternata.