Structure-antifungal activity relationship of cinnamic acid derivatives

A structure-antifungal activity relationship (SAR) study of 22 related cinnamic acid derivatives was carried out. Attention was focused on the antifungal activities exhibited against Aspergillus flavus, Aspergillus terreus, and Aspergillus niger. (E)-3-(4-methoxy-3-(3-methylbut-2-enyl)phenyl)acrylic acid (16) exhibited antifungal activity against A. niger, comparable to that of miconazole and a significant antifungal effect against A. flavus and A. terreus as well. A structure-activity relationship (SAR) study of related cinnamic acid derivatives has allowed a model to be proposed for the recognition of the minimal structural requirements for the antifungal effect in this series.     

Free radical scavenging and antioxidative activity of caffeic acid amide and ester analogues: structure-activity relationship.

The structure-activity relationships of synthetic caffeic acid amide and ester analogues as potential antioxidants and free radical scavengers have been investigated. The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) scavenging activity of the test compounds was N-trans-caffeoyl-L-cysteine methyl ester (5) > N-trans-caffeoyldopamine (4) > N-trans-caffeoyltyramine (3) > N-trans-caffeoyl-beta-phenethylamine (2) > Trolox C (8) > caffeic acid phenethyl ester (1) > caffeic acid (6) > ferulic acid (7). This established that the radical scavenging activity of the compounds increased with increasing numbers of hydroxyl groups or catechol moieties and also with the presence of other hydrogen-donating groups (-NH, -SH). The antioxidative activity of the compounds was also investigated in an emulsified linoleic acid oxidation system accelerated by 2,2'-azobis(2-amidinopropane) dihydrochloride. The order was 1 > 2 > 4 > 3 > or = 5 > 6 > 8 > 7. Therefore, in the emulsion system, the antioxidative activity of the test compounds depends not only on the hydroxyl groups or catechol rings but also on the partition coefficient (log P) or hydrophobicity of the compounds. This supports the concept that hydrophobic antioxidants tend to exhibit better antioxidative activity in an emulsion system.     

Structure-activity relationships of derivatives of fusapyrone, an antifungal metabolite of Fusarium semitectum

Fusapyrone (1) and deoxyfusapyrone (2) are two 3-substituted-4-hydroxy-6-alkyl-2-pyrones isolated from Fusarium semitectum that have considerable antifungal activity against molds. Because of their low zootoxicity and selective action they are potentially utilizable along with biocontrol yeasts for control of postharvest crop diseases. Seven derivatives of 1 (3 and 5-10) and one derivative of 2 (4) were obtained by chemical modifications of the glycosyl residue, the 2-pyrone ring, the aliphatic chain, or a combination thereof, and a structure-activity correlation study was carried out with regard to their zootoxicity and antifungal activity. Derivatives 7-10, as well as 1, were slightly zootoxic in Artemia salina (brine shrimp) bioassays, whereas pentaacetylation of 1 into 3, 5, and 6 resulted in a strong increase in toxicity. Compound 4, the tetraacetyl derivative of 2, was as toxic as 2. Because the structural changes of 1 that resulted in an increase of biological activity in A. salina bioassay were those that affected mainly the water solubility of the molecule, it appears that toxicity is related to hydrophobicity. Compounds 1 and 2 showed strong antifungal activity toward Botrytis cinerea, Aspergillus parasiticus, and Penicilliun brevi-compactum (minimum inhibitory concentration at 24 h = 0.78-6.25 microg/mL). Among derivatives 3-10, only compounds 7, 9, and 10 retained some activity, limited to B. cinerea and at high concentration (25-50 microg/mL). None of the compounds 1-10 inhibited the growth of the biocontrol yeasts Pichia guilliermondii and Rhodotorula glutinis at the highest concentration tested (50 microg/mL).     

Antioxidative activity of propolis extract in yeast cells

The antioxidative activities of propolis and its main phenolic compounds, caffeic acid, p-coumaric acid, ferulic acid, and caffeic acid phenethyl ester, were investigated in the yeast Saccharomyces cerevisiae. After 1 h of exposure of the yeast cells, their intracellular oxidation was measured using 2',7'-dichlorofluorescein. Yeast cells exposed to 96% ethanolic extracts of propolis in DMSO (EEP) showed decreased intracellular oxidation, with no significant differences seen for the individual phenolic compounds. However, cellular uptake was seen only for a moderately polar fraction of EEP (E2) and caffeic acid phenethyl ester. The EEP antioxidative activity thus resulted from this E2 fraction of EEP. The influence of EEP was also investigated at the mitochondrial proteome level, by analyzing its profile after 1 h of exposure of the yeast cells to EEP and E2. Changes in the levels of antioxidative proteins and proteins involved in ATP synthesis were seen.     

Effect of EDTA alone and in combination with polygodial on the growth of Saccharomyces cerevisiae

The antifungal activity of ethylenediaminetetraacetic acid (EDTA) against Saccharomyces cerevisiae was significantly affected by various conditions such as inoculum size, pH, and metal ions (Mg(2+), Ca(2+)). EDTA was found to be effective against this yeast at the inoculum size of 10(5) colony forming units (CFU)/mL with the minimum inhibitory concentration of 400 mug/mL and the minimum fungicidal concentration of 6400 mug/mL, but it was not effective at 10(7) CFU/mL up to 6400 mug/mL. The fungicidal activity of EDTA against S. cerevisiae was significantly enhanced in combination with polygodial. Isobolograms, fractional inhibitory concentration, and fractional fungicidal concentration indices were used for evaluating the interaction between combined compounds. This synergistic effect is likely due to polygodial's destructive action on the cellular membrane, which facilitates the transmembrane transport of foreign compounds (EDTA) into yeast cells. Once inside the cells, EDTA forms chelation with divalent metals such as Mg(2+) and Ca(2+), which are required by various essential enzymes.     

Isolation and characterization of rosmarinic acid oligomers in Celastrus hindsii Benth leaves and their antioxidative activity

Antioxidative compounds were isolated from the 50% methanol extract of dried leaves of Celastrus hindsii. Eight phenolic compounds (1-8) were finally obtained by reversed-phase high-performance liquid chromatography, and their structures were elucidated by nuclear magnetic resonance spectrometry and mass spectrometry analyses. They were the five known compounds, rutin (1), kaempferol 3-rutinoside (2), rosmarinic acid (3), lithospermic acid (4), and lithospermic acid B (6), and three novel oligomers of rosmarinic acid, a dimer (5) and two trimers (7 and 8). The major components in the extract were rosmarinic acid (3) and lithospermic acid B (6). These phenolic compounds were shown to have antioxidative activities against the autoxidation of methyl linoleate in bulk phase and the radical-initiated peroxidation of soybean phosphatidylcholine in liposomes. In the liposomal peroxidation, the number of phenolic hydroxyl group in each molecule was correlated with the effectiveness of antioxidative activity.     

Tyrosinase inhibitors of Pulsatilla cernua root-derived materials

The inhibition of mushroom tyrosinase by Pulsatilla cernua root-derived materials was evaluated. The bioactive components of Pulsatilla cernua root were characterized by spectroscopic analyses as 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid, which exhibited potent antityrosinase activity. The ID50 values of 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid were 0.97 and 0.33 mM, respectively. The compounds isolated from Pulsatilla cernua roots exhibited noncompetitive inhibition against oxidation of L-DOPA by mushroom tyrosinase. This activity was compared with that of three cinnamic acid derivatives and four well-known tyrosinase inhibitors. The ID50 of 4-hydroxy-3-methoxycinnamic acid exhibited superior activity relative to anisaldehyde, anisic acid, benzoic acid, benzaldehyde, cinnamic acid, and cinnamaldehyde; but antityrosinase inhibitors and cinnamic acid derivatives, except for cinnamyl alcohol, were slightly more effective than 3,4-dihydroxycinnamic acid. In the case of benzaldehyde and cinnamaldehyde, the aldehyde group is, apparently, a key group in eliciting potent inhibitory activity, whereas anisaldehyde is more effective than anisic acid. Methoxy substitutions, such as 2-methoxycinnamic acid, 3-methoxycinnamic acid, and 4-methoxycinnamic acid, enhanced inhibition of tyrosinase activity. As a naturally occurring tyrosinase inhibitor, 3,4-dihydroxycinnamic acid and 4-hydroxy-3-methoxycinnamic acid may be useful as new agents to inhibit the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) by mushroom tyrosinase.     

植物乳杆菌抑制黄曲霉活性代谢物的初步研究

植物乳杆菌（Lactobacillus plantarum）能够抑制黄曲霉生长,但起主要抑菌作用的物质尚未明确。该研究采用非靶向代谢组学技术比较分析了8株抑菌活性较好（S组）和8株抑菌活性较差（W组）的L. plantarum发酵上清液。结果显示,两组L. plantarum发酵上清液的代谢组存在显著差异（P<0.05）。通过数据库比对鉴定得到咪唑乙酸、酪氨酸等30个显著差异代谢物（P<0.05）,其中有机酸、脂肪酸等酸性物质较多为22个。通过与已报道的乳酸菌产生的抗真菌物质相比较,找到十八烷酸、吲哚乙酸等结构一致或结构类似物,表明上清液中酸性物质起主要的抑菌作用,且其抑菌活性依赖于低 pH 值的酸性环境。在L. plantarum产生的主要有机酸中,乳酸、乙酸、丙酸的抑菌活性良好,其抑制黄曲霉活性从大到小依次为丙酸、乙酸、乳酸。当乙酸浓度为2.64g/L、丙酸浓度为1.76 g/L时,可完全抑制浓度为106个/mL的黄曲霉孢子生长。综合表明,植物乳杆菌代谢物中有机酸和脂肪酸为主要抑菌物质,且抑菌活性随酸性物质浓度增大而增强。     

Synthesis and antifungal activities of novel 5-amino-6-arylamino-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives

A novel approach was developed to regioselectively synthesize new 5-amino-6-arylamino-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one 5 derivatives via a tandem aza-Wittig and annulation reactions of iminophosphorane 2, aromatic isocyanates, and hydrazine in 52-92% isolated yields. The compounds 5 reacted with triethyl orthoformate to give 1,8-2H-pyrazolo[3,4-d][1,2,4]triazolo[1,5-a]pyrimidin-4-ones 6 in good yields (62-94%). Their structures were clearly confirmed by spectroscopy data (IR, (1)H NMR, MS), elemental analysis, or X-ray diffraction crystallography. The results of preliminary bioassay indicated that the compounds 5 and 6 possessed high antifungal activity against Botrytis cinerea Pers and Sclerotinia sclerotiorum. Compounds 5 showed much better antifungal activities when R was Me instead of PhCH 2. Especially, compounds 6c, 6g, and 6i inhibited Sclerotinia by 100% at the concentration of 50 mg/L and by 83, 83, and 82% at the dosage of 10 mg/L, respectively.     

In vitro potential antioxidant activity of (1-->3),(1-->6)-beta-D-glucan and protein fractions from Saccharomyces cerevisiae cell walls

(1-->3),(1-->6)-Beta-D-Glucan, a cell wall polysaccharide in many microorganisms, fungi and algae, is a well-known biological response modifier. Recently, it was found that (1-->3)-beta-D-glucan from Saccharomyces cerevisiae also exhibits antioxidative capabilities. In this study the antioxidative activity of the cell wall fractions of brewer's yeast was investigated. Particular emphasis was put on the question to which extent glucan is responsible for the antioxidative activity of the cell walls and how the other cell wall components might contribute. For the experiments yeast cell walls from brewery fermentations were used. Glucan was isolated by a three-step extraction procedure including a combination of hot water and enzymatic treatment. The level of (1-->3),(1-->6)-beta-D-glucan in the cell walls was analyzed enzymatically. The antioxidant activity was determined by electron paramagnetic resonance spectrometry and Trolox equivalent antioxidant capacity assay. The results show that the antioxidative activity of yeast cell wall proteins exceeds that of beta-glucan greatly. Especially aromatic side chains and free thiols from denatured proteins seem to work as antioxidants.     

Structure-function analysis of the vanillin molecule and its antifungal properties

The aim of the present study was to evaluate which structural elements of the vanillin molecule are responsible for its observed antifungal activity. MICs of vanillin, its six direct structural analogues, and several other related compounds were determined in yeast extract peptone dextrose broth against a total of 18 different food spoilage molds and yeasts. Using total mean MICs after 4 days of incubation at 25 degrees C, the antifungal activity order was 3-anisaldehyde (1.97 mM) > benzaldehyde (3.30 mM) > vanillin (5.71 mM) > anisole (6.59 mM) > 4-hydroxybenzaldehyde (9.09 mM) > phenol (10.59 mM) > guaiacol (11.66 mM). No correlation was observed between the relative antifungal activity of the test compounds and log P(o/w). Furthermore, phenol (10.6 mM) was found to exhibit a greater activity than cyclohexanol (25.3 mM), whereas cyclohexanecarboxaldehyde (2.13 mM) was more active than benzaldehyde (3.30 mM). Finally, the antifungal order of isomers of hydroxybenzaldehyde and anisaldehyde was found to be 2- > 3- > 4- and 3- > 2- > 4-, respectively. In conclusion, the aldehyde moeity of vanillin plays a key role in its antifungal activity, but side-group position on the benzene ring also influences this activity. Understanding how the structure of natural compounds relates to their antimicrobial function is fundamentally important and may help facilitate their application as novel food preservatives.     

Metabolites from Aspergillus fumigatus, an endophytic fungus associated with Melia azedarach, and their antifungal, antifeedant, and toxic activities

Thirty-nine fungal metabolites 1-39, including two new alkaloids, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6) and 3-hydroxyfumiquinazoline A (16), were isolated from the fermentation broth of Aspergillus fumigatus LN-4, an endophytic fungus isolated from the stem bark of Melia azedarach. Their structures were elucidated on the basis of detailed spectroscopic analysis (mass spectrometry and one- and two-dimensional NMR experiments) and by comparison of their NMR data with those reported in the literature. These isolated compounds were evaluated for in vitro antifungal activities against some phytopathogenic fungi, toxicity against brine shrimps, and antifeedant activities against armyworm larvae (Mythimna separata Walker). Among them, sixteen compounds showed potent antifungal activities against phytopathogenic fungi (Botrytis cinerea, Alternaria solani, Alternaria alternata, Colletotrichum gloeosporioides, Fusarium solani, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. vasinfectum, and Gibberella saubinettii), and four of them, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6), fumitremorgin B (7), verruculogen (8), and helvolic acid (39), exhibited antifungal activities with MIC values of 6.25-50 μg/mL, which were comparable to the two positive controls carbendazim and hymexazol. In addition, of eighteen that exerted moderate lethality toward brine shrimps, compounds 7 and 8 both showed significant toxicities with median lethal concentration (LC(50)) values of 13.6 and 15.8 μg/mL, respectively. Furthermore, among nine metabolites that were found to possess antifeedant activity against armyworm larvae, compounds 7 and 8 gave the best activity with antifeedant indexes (AFI) of 50.0% and 55.0%, respectively. Structure-activity relationships of the metabolites were also discussed.     

Synthesis and antiviral activities of amide derivatives containing the alpha-aminophosphonate moiety

Starting from (substituted-)benzaldehydes, the title compounds 6 were synthesized through five step reactions. Benzaldehydes were treated with ammonium hydroxide, followed by dialkyl phosphite, to give dialkyl N-(arylmethylene)-1-amino-1-aryl methylphosphonates ( 3). Phosphonates 3 were then easily hydrolyzed to give dialkyl 1-amino-1-aryl-methylphosphonates 5. Target compounds 6 were then obtained by the reaction of 5 and substituted benzoic or cinnamic acid. Their structures were clearly verified by spectroscopic data (IR, 1H, 13C, and 31P NMR, and elemental analysis). These compounds were shown to be antivirally active in the bioassay. It was found that title compounds 6g, 6l, and 6n had the same inactivation effect of TMV (EC 50 = 54.8, 60.0, and 65.2 microg/mL, respectively) as commercial product Ningnanmycin (EC50 = 55.6 microg/mL). To the best of our knowledge, this is the first report on the synthesis and antiviral activity of amide derivatives containing an alpha-aminophosphonate moiety.     

Chiral gamma-aryl-1H-1,2,4-triazole derivatives as highly potential antifungal agents: Design, synthesis, structure, and in vitro fungicidal activities

A novel series of chiral gamma-aryl-1H-1,2,4-triazole derivatives as highly potential antifungal agents have been designed and synthesized conveniently by using the chiral auxiliary as a controlling reagent. All of the compounds exhibit moderate to high ee values reaching up to 99%, and the preliminary bioassay results demonstrated that most of the target compounds take on a significantly wide spectrum activity against Fusarium oxysporium, Rhizoctonia solani, Botrytis cinereapers, Gibberella zeae, Dothiorella gregaria, and Colletotrichum gossypii species.     

Chemical and biological characterization of cinnamic acid derivatives from cell cultures of lavender (Lavandula officinalis) induced by stress and jasmonic acid

Cell cultures of lavender (Lavandula officinalis) were analyzed for the metabolite profile under normal growth conditions and under stress as well as after jasmonic acid treatment. The main compound synthesized was rosmarinic acid, which was also secreted into the culture medium. Different solvent extraction methods at different pH values altered the profile slightly. Anoxic stress induced the synthesis of a cinnamic acid derivative, which was identified as caffeic acid by gas chromatography-mass spectrometry. Caffeic acid was also induced after treatment of the cell cultures with jasmonic acid. Although the antioxidative activity of both compounds, rosmarinic acid and caffeic acid, was confirmed in an assay using 2,2-diphenyl-1-picrylhydrazyl (DPPH), it was demonstrated that both substances have a low cytotoxic potential in vitro using acute myeloid leukemia (HL-60) cells. The potential of the system for finding new bioactive compounds is discussed.     

Design and syntheses of novel phthalazin-1(2H)-one derivatives as acetohydroxyacid synthase inhibitors

A series of 2-substituted-8-(4,6-dimethoxypyrimidin-2-yloxy)-4-methylphthalazin-1-one derivatives, 7a-7w, were designed via an ortho-substituent cyclization strategy to discover a new herbicidal lead structure. These compounds were synthesized by a seven-step route using 3-hydroxy-acetophenone as a starting material. Determination of the Ki values against wild-type A. thaliana acetohydroxyacid synthase (AHAS) (EC 4.1.3.18) indicated that some of the compounds displayed good enzyme inhibition activity comparable to that of KIH-6127. The further preliminary bioassay data on weeds showed that the synthesized compounds exhibited typical injury symptoms of AHAS-inhibiting herbicides, and some of them showed broad-spectrum and high herbicidal activities in postemergence treatments against Echinochloa crusgalli, Digitaria sanguinalis, Setaria viridis, Brassica juncea, Amaranthus retroflexus, and Chenopodium album at an application rate of 150 g ai/ha. To our knowledge, this is the first report of methylphthalazin-1-one derivatives as AHAS inhibitors.     

Phenolic compounds from the leaf extract of artichoke (Cynara scolymus L.) and their antimicrobial activities

A preliminary antimicrobial disk assay of chloroform, ethyl acetate, and n-butanol extracts of artichoke (Cynara scolymus L.) leaf extracts showed that the n-butanol fraction exhibited the most significant antimicrobial activities against seven bacteria species, four yeasts, and four molds. Eight phenolic compounds were isolated from the n-butanol soluble fraction of artichoke leaf extracts. On the basis of high-performance liquid chromatography/electrospray ionization mass spectrometry, tandem mass spectrometry, and nuclear magnetic resonance techniques, the structures of the isolated compounds were determined as the four caffeoylquinic acid derivatives, chlorogenic acid (1), cynarin (2), 3,5-di-O-caffeoylquinic acid (3), and 4,5-di-O-caffeoylquinic acid (4), and the four flavonoids, luteolin-7-rutinoside (5), cynaroside (6), apigenin-7-rutinoside (7), and apigenin-7-O-beta-D-glucopyranoside (8), respectively. The isolated compounds were examined for their antimicrobial activities on the above microorganisms, indicating that all eight phenolic compounds showed activity against most of the tested organisms. Among them, chlorogenic acid, cynarin, luteolin-7-rutinoside, and cynaroside exhibited a relatively higher activity than other compounds; in addition, they were more effective against fungi than bacteria. The minimum inhibitory concentrations of these compounds were between 50 and 200 microg/mL.     

Insulin-releasing properties of a series of cinnamic acid derivatives in vitro and in vivo

Cinnamic acid derivatives are naturally occurring substances found in fruits, vegetables, and flowers and are consumed as dietary phenolic compounds. In the present study, cinnamic acid and its derivatives were evaluated for insulin secreting activity in perfused rat pancreas and pancreatic beta-cells (INS-1) as well as an increase in [Ca(2+)]i in vitro. The presence of m-hydroxy or p-methoxy residues on cinnamic acid was a significantly important substituent as an effective insulin releasing agent. The introduction of p-hydroxy and m-methoxy-substituted groups in cinnamic acid structure (ferulic acid) displayed the most potent insulin secreting agent among those of cinnamic acid derivatives. In particular, the stimulatory insulin secreting activities of test compounds were associated with a rise of [Ca(2+)]i in INS-1. In perfused rat pancreas, m-hydroxycinnamic acid, p-methoxycinnamic acid, and ferulic acid (100 microM) significantly stimulated insulin secretion during 10 min of administration. The onset time of insulin secretion of those compounds was less than 1 min and reached its peak at 4 min that was about 2.8-, 3.3-, and 3.4-fold of the baseline level, respectively. Intravenous administration of p-methoxycinnamic acid and ferulic acid (5 mg/kg) significantly decreased plasma glucose and increased insulin concentration in normal rats and maintained its level for 15 min until the end of experiment. Meanwhile, m-hydroxycinnamic acid induced a significant lowering of plasma glucose after 6 min, but the effects were transient with plasma glucose concentration, rapidly returning to basal levels. Our findings suggested that p-methoxycinnamic acid and ferulic acid may be beneficial for the treatment of diabetes mellitus because they regulated blood glucose level by stimulating insulin secretion from pancreatic beta-cells.     

Insect pest management agents: hormonogen esters (juvenogens)

The chemical part of this investigation focused on designing structures and synthesizing a series of six new esters (juvenogens), derived from biologically active insect juvenile hormone bioanalogues (juvenoids, JHAs) and unsaturated short-chain linear and branched fatty acids for possible application as biochemically targeted insect hormonogen agents. The structures of the new compounds were assigned on the basis of a detailed NMR analysis of their (1)H and (13)C NMR spectra. The biological part of this investigation focused on introductory biological screening tests with these compounds against the red firebug (Pyrrhocoris apterus), termites (Reticulitermes santonensis and Prorhinotermes simplex), and the blowfly (Neobellieria bullata). The biological activity of the juvenogens was studied in relation to the fatty acid functionality in the structures. Notable biological activity in topical tests and medium activity in peroral tests was found for the juvenogens 3 and 7 with P. apterus. The compounds 6 and 8 showed the lowest activity in both topical and oral assays with P. apterus. Considerable effect of all tested juvenogens was observed in P. simplex; however, the juvenogens 5 and 6 (derivatives of the only branched short-chain fatty acid) showed no activity against R. santonensis. The effect of the compounds 3-8 on larval hatching of N. bullata was only moderate (larval hatching 80-90%); however, the proliferation effect caused by 5, 6, and 8 is more pronounced than the effect caused by 3, 4, and 7.     

Phytotoxic Eremophilanes from Ligularia macrophylla

Systematic bioassay-guided fractionation of the methylene chloride extract of the roots from Ligularia macrophylla was performed to identify both phytotoxic and antifungal compounds. Four phytotoxic eremophilanes (furanoeremophilan-14beta,6alpha-olide, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane, eremophil-7(11)-ene-12,8alpha;14beta,6alpha-diolide, and 3alpha-angeloyloxybakkenolide A) and two antifungal fatty acids (linoleic acid and alpha-linolenic acid) were isolated. The X-ray crystal structure determination of 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane is reported here for the first time. All four eremophilanes substantially inhibited growth of the monocot Agrostis stolonifera (bentgrass) while demonstrating little activity against the dicot Lactuca sativa (lettuce) at 1000 microM. In a dose-response screening of all compounds for growth inhibitory activity against Lemna paucicostata, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane was the most active with an IC50 of 2.94+/-0.16 microM. This compound also caused the greatest reduction of photosynthetic electron flow; however, its mode of action remains to be determined. Evaluation of isolated compounds for activity against the Formosan subterranean termite, Coptotermes formosanus, is also reported. At a concentration of 0.5% (wt/wt), 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane significantly reduced the consumption of filter paper by C. formosanus.