Antiatherogenic and radioprotective role of folic acid in whole body γ-irradiated mice

Free radical mediated oxidative damage is one of the prime factors for atherogenic changes in humans. We have shown that the folic acid administration reduced the risk of the atherogenic factors induced by γ -radiation. Folic acid administration prevented the radiation induced increase in the plasma lipoprotein lipase activity and also prevented the radiation-induced increase in the hepatic cholesterol and triglycerides levels. These results indicate the role of folic acid as an antiatherogenic agent. Further, we also report the radioprotective property of folic acid as demonstrated by reduction in the radiation induced membrane damage as measured by lipid peroxidation products and DNA damage, which was measured by alkaline comet assay.     

DNA damage induced by novel demethylcantharidin-integrated platinum anticancer complexes

Oxaliplatin is a third generation platinum (Pt) drug with a diaminocyclohexane (DACH) entity, which has recently obtained worldwide approval for the clinical treatment of colon cancer, and apparently operates by a different mechanism of action to the classical cisplatin or carboplatin. Introducing a novel dual mechanism of action is one approach in designing a new platinum-based anticancer agent, whereby an appropriate ligand, such as demethylcantharidin (DMC), is released from the parent compound to exert a cytotoxic effect, in addition to that of the DNA-alkylating function of the platinum moiety. To investigate the likelihood of a novel dual mechanism of anticancer action, demethylcantharidin-integrated Pt complexes: Pt(R,R-DACH)(DMC) with the same Pt-DACH moiety as oxaliplatin, and Pt(NH(3))(2)(DMC) akin to carboplatin; were studied for their ability to induce DNA damage in HCT116 colorectal cancer cells by an alkaline comet assay. The results showed that the DMC ligand released from the novel complexes caused additional DNA lesions when compared with oxaliplatin and carboplatin. The comet assay also revealed that the DNA-damaging behavior of cisplatin is characteristically different; and this study is the first to demonstrate the ability of DMC to induce DNA lesions, thus providing sufficient evidence to explain the superior antiproliferative effect of the novel DMC-integrated complexes.     

Induction of oxidative DNA damage in human foreskin fibroblast Hs68 cells by oxidized β-carotene and lycopene

Two recent clinical trials suggest that β-carotene may be harmful to smokers. In this study we examined the hypothesis that β-carotene may become toxic when degradation occurs. β-Carotene (BC) and lycopene (LP) with or without prior heat treatment (60°C for 1h in open air) were incubated at 20 and 40 μM with calf thymus DNA or human fibroblasts Hs68 cells. The heat treatment resulted in ca. 80% and 35% bleaching of BC and LP, respectively. When Hs68 cells were incubated with the oxidized β-carotene (OBC) or oxidized lycopene (OLP) at 37°C for 20h, cell viability was significantly and dose-dependently decreased whereas cell viability was not affected by BC or LP. Cell death, which was already evident at 4h after incubation with OBC or OLP, was possibly attributable to apoptosis, as shown by the increased histone-associated DNA fragmentation. However, cell lysis, measured as release of lactate dehydrogenase, also occurred at 4h after incubation with OBC and OLP, although the extent was relatively small and was greater for OLP than for OBC. When calf thymus DNA was incubated with OBC or OLP at 37°C for 20h, the 8-hydroxy-2-deoxyguanosine (8-OH-dG) level was significantly and dose-dependently increased by OLP whereas the increase by OBC was only significant at 40 μM. When Hs68 cells were incubated with OBC and OLP for 20h, both compounds increased the 8-OH-dG level, but the effect was only significant for 40 μM OLP. Comet (single-cell gel electrophoresis) assay of DNA damage in Hs68 cells was determined at 2h after incubation with OBC or OLP because of its high sensitivity. Both OBC and OLP significantly and dose-dependently increased DNA breakage while BC and LP had no effect. Inclusion of BHT during incubation of cells with 40 μM OBC or OLP partially inhibited (ca. 40%, p<.05) the extent of comet formation. Intriguingly, OBC and OLP neither induce lipid peroxidation in Hs68 cells (measured as thiobarbituric acid-reactive substances released into the medium) nor increased the intracellular level of reactive oxygen species. Although it is presently unclear about what degradation products are formed, this study has demonstrated that, when oxidized, BC and LP lead to oxidative damage to both purified DNA and cellular DNA. The results suggest that such damage may contribute to the adverse effects of β-carotene reported in recent clinical studies and caution that it is important to prevent oxidation of BC and LP for human uses such as in supplemental studies.     

Ex-vivo and in vitro protective effects of kolaviron against oxygen-derived radical-induced DNA damage and oxidative stress in human lymphocytes and rat liver cells

The present study reports the protective effects of kolaviron, a Garcinia biflavonoid from the seeds of Garcinia kola widely consumed in some West African countries against oxidative damage to molecular targets ex-vivo and in vitro. Treatment with hydrogen peroxide (H2O2) at a concentration of 100 micromol/L increased the levels of DNA strand breaks and oxidized purine (formamidopyrimidine glycosylase (FPG) and pyrimidine (endonuclease III (ENDO III) sites) bases in both human lymphocytes and rat liver cells using alkaline single cell gel electrophoresis (the comet assay). Kolaviron was protective at concentrations between 30-90 micromol/L and decreased H2O2-induced DNA strand breaks and oxidized bases. Neither alpha-tocopherol nor curcumin decreased H2O2-induced DNA damage in this assay. In lymphocytes incubated with Fe3+/GSH, Fe3+ was reduced to Fe2+ by GSH initiating a free radical generating reaction which induced 11.7, 6.3, and 4.9 fold increase respectively in strand breaks, ENDO III and FPG sensitive sites compared with control levels. Deferoxamine (2 mmol/L), an established iron chelator significantly inhibited GSH/Fe3+-induced strand breaks and oxidized base damage. Similarly, kolaviron at 30 and 90 micromol/L significantly attenuated GSH/Fe3+-induced strand breaks as well as base oxidation. Kolaviron (100 mg/kg bw) administered to rats for one week protected rat liver cells against H2O2-induced formation of strand breaks, ENDO III, and FPG sensitive sites, Fe3+/EDTA/ascorbate-induced malondialdehyde formation and protein oxidation using gamma-glutamyl semialdehyde (GGS) and 2-amino-adipic semialdehyde (AAS) as biomarkers of oxidative damage to proteins. We suggest that kolaviron exhibits protective effects against oxidative damage to molecular targets via scavenging of free radicals and iron binding. Kolaviron may therefore be relevant in the chemoprevention of oxidant-induced genotoxicity and possibly human carcinogenesis.     

Radiation protection by Terminalia chebula: Some mechanistic aspects

Radioprotective ability of the aqueous extract of the fruit of Terminalia chebula (TCE) was evaluated for its antioxidant and radioprotective abilities. TCE (50 μg) was able to neutralise 1,1-diphenyl-2-picrylhydrazyl, a stable free radical by 92.9%. The free radical neutralizing ability of TCE was comparable to that of ascorbate (100 μM) 93.5% and gallic acid (100 μM) 91.5% and was higher than that of the diethyldithiocarbamate (200 μM) 55.4%, suggesting the free radical activity of TCE. TCE protected the plasmid DNA pBR322 from undergoing the radiation-induced strand breaks. Radiation damage converts the supercoiled form (ccc) of plasmid to open circular form (oc); the presence of TCE during radiation exposure protected the plasmid from undergoing these damages. The administration of TCE (80 mg/kg body weight, i.p.) prior to whole body irradiation of mice (4 Gy) resulted in a reduction of peroxidation of membrane lipids in the mice liver as well as a decrease in radiation-induced damage to DNA, as assayed by single-cell gel electrophoresis (comet assay). TCE also protected the human lymphocytes from undergoing the gamma radiation-induced damage to DNA exposed in vitro to 2 Gy gamma-radiation. These results suggest the radioprotective ability of TCE.     

对二甲苯对皱纹盘鲍肝胰腺细胞DNA的损伤

为研究对二甲苯对皱纹盘鲍肝胰腺的毒性作用,设置4个浓度(0.5、1.0、1.5和2.0 mg·L^-1)和对照组,开展为期21 d的对二甲苯对皱纹盘鲍的亚慢性毒性试验,采用彗星试验技术进行皱纹盘鲍肝胰腺细胞DNA损伤分析,采用CASP分析软件对拖尾率、彗星尾长、彗尾DNA相对含量、Olive矩等损伤指标进行统计。结果表明: 与对照组相比,各染毒组皱纹盘鲍肝胰腺细胞DNA均受到损伤,且损伤程度存在显著性差异。随着染毒浓度的增加,肝胰腺细胞DNA受损程度加重,高浓度甚至可以引发细胞凋亡,呈现一定的剂量-损伤效应。中浓度对二甲苯短时间暴露即可对皱纹盘鲍肝胰腺细胞造成DNA损伤,随着暴露时间延长,细胞DNA受损程度加重,呈现一定的时间-损伤效应。但长时间暴露细胞DNA各损伤指标有所减小,这可能与细胞自身的DNA修复机制和生物体解毒系统的代谢机制有关。研究表明,对二甲苯可对皱纹盘鲍肝胰腺细胞产生氧化损伤,导致DNA断裂,高浓度的对二甲苯长时间暴露可导致其细胞凋亡。     

Simulated acid rain induces lipid peroxidation and membrane damage in foliage

Abstract. Exposure of young bean foliage to acid rain induces free-radical-mediated lipid peroxidation and causes the same disruptive changes in the molecular organization of membrane lipid-bilayers that are observed during natural leaf senescence. Young plants were misted daily for 7d with simulated acid rain for a 2h period. Wide angle X-ray diffraction revealed the presence of gel-phase lipid in a fraction containing predominantly chloroplast membranes isolated from treated leaves, and the lipid-phase transition temperature of these membranes rose from below −30°C to ∼ 36°C over the treatment period. The formation of gel-phase lipid is known to be associated with lipid peroxidation, and it is therefore significant that production of ethane and levels of malondialdehyde in the leaves, which are both products of lipid peroxidation, rose throughout the treatment period. There was also increased production of ethylene and superoxide radical, which are typical responses of plant tissue to toxicity.     

Effects of homogeneous and inhomogeneous static magnetic fields combined with gamma radiation on DNA and DNA repair

The aim of this study was to reveal whether static magnetic fields (SMFs) influence the repair of radiation‐damaged DNA on leukocytes or has any effect on DNA. After 4 Gy of ⁶⁰Co‐γ irradiation, some of the samples were exposed to inhomogeneous SMFs with a lateral magnetic flux density gradient of 47.7, 1.2, or 0.3 T/m by 10 mm lateral periodicity, while other samples were exposed to homogeneous SMF of 159.2 ± 13.4 mT magnetic flux density for a time period of 0.5 min, 1, 2, 4, 6, 18, 20, or 24 h. Another set of samples was exposed to the aforementioned SMFs before gamma irradiation. The following three groups were examined: (i) exposed to SMF only, (ii) exposed to SMF following irradiation by ⁶⁰Co‐γ, and (iii) exposed to SMF before ⁶⁰Co‐γ irradiation. The analysis of the DNA damage was made by single‐cell gel electrophoresis technique (comet assay). Statistically significant differences were found at 1 h (iSMF), 4 h (hSMF), and 18 h (hSMF) if samples were exposed to only SMF, compared to control. When the SMF exposure followed the ⁶⁰Co‐γ irradiation, statistically significant differences were found at 1 h (iSMF) and 4 h (hSMF). If exposure to SMF preceded ⁶⁰Co‐γ irradiation, no statistically significant difference was found compared to 4 Gy gamma‐irradiated group. Bioelectromagnetics 31:488–494, 2010. © 2010 Wiley‐Liss, Inc.     

Radiation protection of DNA by ferulic acid under in vitro and in vivo conditions

The effect of ferulic acid was studied on γ-radiation-induced relaxation of plasmid pBR322 DNA and induction of DNA strand breaks in peripheral blood leukocytes and bone marrow cells of mice exposed to whole body γ-radiation. Presence of 0.5 mM ferulic acid significantly inhibited the disappearance of supercoiled (ccc) plasmid pBR322 with a dose modifying factor (DMF) of 2.0. Intraperitoneal administration of different amounts (50, 75 and 100 mg/kg body weight) of ferulic acid 1 h prior to 4 Gy γ-radiation exposure showed dose-dependent decrease in the yield of DNA strands breaks in murine peripheral blood leukocytes and bone marrow cells as evidenced from comet assay. The dose-dependent protection was more pronounced in bone marrow cells than in the blood leukocytes. It was observed that there was a time-dependent disappearance of radiation induced strand breaks in blood leukocytes (as evidenced from comet parameters) following whole body radiation exposure commensuration with DNA repair. Administration of 50 mg/kg body weight of ferulic acid after whole body irradiation of mice resulted disappearance of DNA strand breaks at a faster rate compared to irradiated controls, suggesting enhanced DNA repair in ferulic acid treated animals. (Mol Cell Biochem xxx: 209–217, 2005)     

Lipid peroxide induced DNA damage: protection by turmeric (Curcuma longa)

Summary Liposomal lipid peroxidation and peroxide induced DNA damage were investigated. Inhibition of lipid peroxidation was studied using 400 µM uric acid, -carotene, -tocopherol, curcumin and butylated hydroxyanisole (BHA). Curcumin, the active principle of turmeric (Curcuma longa), was as effective an antioxidant as BHA. An aqueous extract of turmeric was also found to be an effective inhibitor. The inhibition obtained using this aqueous extract, incorporated into the liposome itself, was 70% at 300 ng/µ1 This indicates the presence of yet another antioxidant in turmeric besides the lipophilic curcumin. The aqueous antioxidant extended 80% protection to DNA against peroxidative injury at 100 ng/µl. This component of turmeric is being characterised and investigated as an antioxidant/anticlastogen and as an antipromoter.Abbreviations GT₁b Trisialoganglioside - TBS Tris Buffered Saline - PBS Phosphate Buffered Saline - TBA Thio Barbituric acid - BHA Butylated Hydroxy Anisole - EDTA Ethylene Diamine Tetra Acetic Acid     

The protective effect exerted by ascorbic acid on DNA fragmentation of human leukocytes induced by Lachesis muta muta venom

The objective of this study was to evaluate the genotoxic and mutagenic effects of the toxins present in Lachesis muta muta's venom on human peripheral blood leukocytes and the protective potential of ascorbic acid on DNA fragmentation. The venom of L. muta muta was incubated in different concentrations (1, 2.5, 5, 7.5, 10, 15, 20, 30, 40, 50, 60, and 120 µg/mL) with human blood to evaluate DNA fragmentation using the comet, agarose gel electrophoresis, and micronucleus assays. In these concentrations evaluated, the venom of L. muta muta induced genotoxicity (comet assay and agarose gel electrophoresis) and mutagenicity (micronucleus test), but they were not cytotoxic, as they did not change the rate of cell proliferation after cytokinesis blockade with cytochalasin B. The ascorbic acid significantly inhibited the genotoxicity induced by L. muta muta venom in the proportions evaluated (1:0.1 and 1:0.5, venom/ascorbic acid - w/w). Thus, future studies are needed to elucidate the protective mechanisms of ascorbic acid on the genotoxic effects induced by toxins present in snake venoms.     

Enzymatic synthesis of gallic acid from tannic acid with an inducible hydrolase of Enterobacter spp

Gallic acid acts as a precursor molecule to synthesize various tannin molecules. These are plant polyphenols and were proved to be good anti-oxidant, anti-cancerous, anti-inflammatory, anti-microbial compounds. In order to fully exploit prominent biological activities of specific tannins and to develop tannin-based new medicines, it is necessary to obtain their pure preparations with an aim of high yield and specificity. In the present study, gallic acid is synthesized by the hydrolysis of tannic acid using a microbial based transformation process. The microorganism was isolated and identified. The ability of the isolated microorganism to covert tannic acid into gallic acid was determined by HPLC and enzyme production.

• Highlights

• The present investigation signifies the role of Enterobacter spp. in various processes:

• ??To synthesize gallic acid (a precursor for food oxidant such as propyl gallate) and a bacteriostatic antibiotic (trimethoprim).

• ??To protect the environment from tannery’s discharge through the process of biodegradation.

• ??To reduce the toxicity of tannins in animal feed.

     

Effect of endothelin-1 induced ischemia on peroxidative damage and membrane properties in rat striatum synaptosomes

Synaptosomes obtained from rat striata lesioned by central injection of endothelin-1 (ET-1) were analyzed for the levels of lipid peroxidation products, the susceptibility to lipid peroxidation, the phospholipid and free fatty acid composition and the activity of Na⁺,K⁺-ATPase one hour after ET-1 treatment. The intrastriatal injection of ET-1 promoted an increase of endogenous thiobarbituric reactive substances (TBARS), as index of free radical mediated lipid damage, and a greater susceptibility to iron/ascorbate-induced lipid peroxidation. The pattern of free fatty acids showed a significant decrease of arachidonic and docosahexaenoic acid consequent to ET-1 treatment. The analysis of lipid composition showed a significant loss of phospholipids: among phospholipid species, sphingomyelin and phosphatidylethanolamine plasmalogen were particularly reduced by ET-1 treatment. The activity of membrane-bound Na⁺,K⁺-ATPase was also significantly reduced in synaptosomes obtained from ET-1 lesioned striata. Taken together these results indicate a significant modification of synaptosomal membrane of ET-1 treated rat striata, possibly due to a free radical mediated damage.     

Biochemical changes induced by accelerated aging in sunflower seeds. I. Lipid peroxidation and membrane damage

When stored at 42°C and 100% relative humidity for 1 to 8 days, sunflower seeds (Helianthus annuus L. cv. Rodeo) aged prematurely and lost 25% of their initial viability. A ten-fold increase in conjugated dienes as well as a decrease of unsaturated fatty acids in diacylglycerol and polar lipids fractions were observed after 8 days of accelerated aging, demonstrating the occurrence of lipid peroxidation in prematurely aged sunflower seeds. However, the viability remained relatively high. The absence of membrane damage in seeds and of lipid peroxidation in isolated microsqmes suggested that lipid peroxidation concerned mainly lipid reserves. These results suggest that, at least within the first 8 days of treatment, the lipid reserve in sunflower seeds might act as a detoxifying trap, protecting membranes from excessive damage.     

Decreased DNA repair rates and protection from heat induced apoptosis mediated by electromagnetic field exposure

In this study, we demonstrate that electromagnetic field (EMF) exposure results in protection from heat induced apoptosis in human cancer cell lines in a time dependent manner. Apoptosis protection was determined by growing HL-60, HL-60R, and Raji cell lines in a 0.15 mT 60 Hz sinusoidal EMF for time periods between 4 and 24 h. After induction of apoptosis, cells were analyzed by the neutral comet assay to determine the percentage of apoptotic cells. To discover the duration of this protection, cells were grown in the EMF for 24 h and then removed for 24 to 48 h before heat shock and neutral comet assays were performed. Our results demonstrate that EMF exposure offers significant protection from apoptosis (P<.0001 for HL-60 and HL-60R, P<.005 for Raji) after 12 h of exposure and that protection can last up to 48 h after removal from the EMF. In this study we further demonstrate the effect of the EMF on DNA repair rates. DNA repair data were gathered by exposing the same cell lines to the EMF for 24 h before damaging the exposed cells and non-exposed cells with H2O2. Cells were allowed to repair for time periods between 0 and 15 min before analysis using the alkaline comet assay. Results showed that EMF exposure significantly decreased DNA repair rates in HL-60 and HL-60R cell lines (P<.001 and P<.01 respectively), but not in the Raji cell line. Importantly, our apoptosis results show that a minimal time exposure to an EMF is needed before observed effects. This may explain previous studies showing no change in apoptosis susceptibility and repair rates when treatments and EMF exposure were administered concurrently. More research is necessary, however, before data from this in vitro study can be applied to in vivo systems.     

Fungal endophytes from Acer ginnala Maxim: isolation, identification and their yield of gallic acid

Aims:  The aim of the study was to isolate the endophytic fungi from Acer ginnala and screen isolates rich in gallic acid.
Methods and Results:  After epiphytic sterilization, 145 fungal endophytes were isolated from the stem, annual twig and seed of Acer ginnala . The endophytes were grouped into ten different taxa, Phomopsis sp., Neurospora sp., Phoma sp., Epicoccum sp., Penicillium sp., Alternaria sp., Fusarium sp., Trichoderma sp., Cladosporium sp. and a species of Pleosporales Incertae Sedis , by their morphological traits and ITS-rDNA sequence analysis. The content and yield of gallic acid of 141 isolates were determined by HPLC. On average, the species of Pleosporales Incertae Sedis had the highest content and yield of gallic acid (13·28 mg g⁻¹ DW; 119·62 mg l⁻¹), while Alternaria sp. had the lowest.
Conclusions:  Of 141 fungal endophytes from A. ginnala , Phomopsis sp. isolate SX10 showed both the highest content and the highest yield of gallic acid (29·25 mg g⁻¹ DW; 200·47 mg l⁻¹).
Significance and Impact of the Study:  Endophytic fungi isolated from A. ginnala may be used as potential producers of gallic acid and other compounds with biological activities, or functioned as elicitors to produce natural compounds.     

Recruitment of HRDC domain of WRN and BLM to the sites of DNA damage induced by mitomycin C and methyl methanesulfonate

The HRDC (helicase and RNase D C-terminal) domain at the C-terminal of WRNp (Werner protein) (1150-1229 amino acids) and BLMp (Bloom protein) (1212-1292 amino acids) recognize laser microirradiation-induced DNA dsbs (double-strand breaks). However, their role in the recognition of DNA damage other than dsbs has not been reported. In this work, we show that HRDC domain of both the proteins can be recruited to the DNA damage induced by MMS (methyl methanesulfonate) and MMC (methyl mitomycin C). GFP (green fluorescent protein)-tagged HRDC domain produces distinct foci-like respective wild-types after DNA damage induced by the said agents and co-localize with γ-H2AX. However, in time course experiment, we observed that the foci of HRDC domain exist after 24 h of removal of the damaging agents, while the foci of full-length protein disappear completely. This indicates that the repair events are not completed by the presence of protein corresponding to only the HRDC domain. Consequently, cells overexpressing the HRDC domain fail to survive after DNA damage, as determined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay. Moreover, 24 h after removal of damaging agents, the extent of DNA damage is greater in cells overexpressing HRDC domain compared with corresponding wild-types, as observed by comet assay. Thus, our observations suggest that HRDC domain of both WRN and BLM can also recognize different types of DNA damages, but for the successful repair they fail to respond to subsequent repair events.     

Repair of DNA damage induced by gamma radiation and UV and gamma mimetics in virus-infected human cells

The method of chromatography of cell lysates on the columns with hydroxyapatite (HAP) and the method of ultracentrifugation of cell lysates in neutral sucrose gradient were used to study the mutagen-induced repair activity of human cells HEp-2 noninfected and chronically infected with measles and rubella viruses in order to determine the sedimentation properties of complexes containing DNA. Gamma-radiation, bleomycin, 4-nitroquinoline-1-oxide, and mitomycin C were used as DNA damaging agents. It was shown that the chronic infectious process inhibited repair of DNA damages induced by 4-nitroquinoline-1-oxide and mitomycin C and did not influence repair of DNA lesions caused by gamma-radiation and bleomycin.     

In vitro anti‐enterovirus 71 activity of gallic acid from Woodfordia fruticosa flowers

Aims: The anti‐enterovirus 71 (EV71) activity of six Nepalese plants’ extracts and gallic acid (GA) isolated from Woodfordia fruticosa Kurz (family; Lythaceae) flowers were evaluated in Vero cells. Methods and Results: The anti‐EV71 activity of tested compounds was evaluated by a cytopathic effect reduction method. Our results demonstrated that flowers’ extracts of W. fruticosa exerted strong anti‐EV71 activity, with a 50% inhibitory concentration (IC₅₀) of 1·2 μg ml^?1 and no cytotoxicity at a concentration of 100 μg ml^?1, and the derived therapeutic index (TI) was more than 83·33. Rivabirin showed no antiviral activity against EV71. Furthermore, GA isolated from W. fruticosa flowers exhibited a higher anti‐EV71 activity than the extract of W. fruticosa flowers, with an IC₅₀ of 0·76 μg ml^?1 and no cytotoxicity at a concentration of 100 μg ml^?1, and the derived TI was 99·57. Conclusions: This study demonstrated that flower extracts of W. fruticosa possessed anti‐EV71 activity and GA isolated from these flowers showed stronger anti‐EV71 activity than that the extracts. Significance and Impact of the Study: Our results suggest that the GA from W. fruticosa flowers may be used as a potential antiviral agent.     

The metabolism of gallic acid and hexahydroxydiphenic acid in plants: Biogenetic and molecular taxonomic considerations

The distinctive and unique features of gallic acid metabolism in plants are discussed and recent observations on new metabolites are presented. The potential application of these results to taxonomic questions is outlined.