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Activity guided fractionations led to the isolation of two antitumor compounds 5 alpha,8 alpha-epidioxy-24(R)-methylcholesta-6,22-dien-3 beta-D-glucopyranoside and 5,6-epoxy-24(R)-methylcholesta-7,22-dien-3 beta-ol from the methanol extract of Cordyceps sinensis. Two previously known compounds, ergosteryl-3-O-beta-D-glucopyranoside and 22-dihydroergosteryl-3-O-beta-D-glucopyranoside were also isolated. The structures of hitherto unknown sterols were established by 1D and 2D NMR spectroscopic techniques with the former synthesized in order to confirm the identity of the sugar moiety by chemical correlation. The glycosylated form of ergosterol peroxide was found to be a greater inhibitor to the proliferation of K562, Jurkat, WM-1341, HL-60 and RPMI-8226 tumor cell lines by 10 to 40% at 10 micrograms/ml than its previously identified aglycone, 5 alpha,8 alpha-epidioxy-24(R)-methylcholesta-6,22-dien-3 beta-ol.

Centipeda minima, a herb used medicinally to treat sinus infections in Nepal, was found to contain three antibacterial sesquiterpene lactones, identified as 6-O-methylacrylylplenolin, 6-O-isobutyroylplenolin, and 6-O-angeloylplenolin. 6-O-Methylacrylylplenolin had not been previously isolated from C. minima. All three had activity against Bacillus subtilis and Staphylococcus aureus, with 6-O-isobutyroylplenolin being the most active.

When applied in a mixed inoculum with tomato ringspot nepovirus (TomRSV), flavonoids and related compounds inhibited infectivity in Chenopodium quinoa. Compounds that showed strong anti-viral activity were: quercetin, quercetin 3-methyl ether, quercetin 7-methyl ether, quercetin 3,7,3′4′-tetramethyl ether, galangin 3-methyl ether, morin, robinin, quercetin 3,7,4′-trimethyl ether, quercetin 7,4′-dimethyl ether, 7,4′-di-O-benzol-quercetin 7-hydroxy-3,4′-dimethyl flavone, 6,3′-dihydroxy-4′-methyl aurone and fisetin 4′-methyl ether. Quercetin applied at a concentration of 5 μg ml−1 caused 70% inhibition of local lesion development. When quercetin was applied to leaves prior to inoculation, there was only slight induced resistance to infection. Quercetin at 5 μg ml−1 did not affect virus multiplication in protoplasts prepared from cucumber cotyledons and transfected with viral-RNA. In meristematic tip cultures, quercetin reduced virus titre by up to 89% over a period of 36 weeks whereas ribavirin caused a 25% reduction over the same period. It is proposed that flavonoids interfere with an early event in the virus life cycle resulting in decreased infectivity and titre in tissue culture.

GC-MS analyses of Agrobacterium signal compound mixtures from species belonging to a variety of flowering plant families revealed that the occurrence of virulence-inducing acetophenones may be restricted to members of the Solanaceae. Following wounding, species of Atropa, Datura, Hyoscyamus, Lycopersicon, Nicotiana, Scopolia and Solanum , produced a set of active C 6 C 2 compounds, whereas genera belonging to other families commonly produced sets of virulence-inducing C 6 C 1 and C 6 C 3 acids, esters and/or benzaldehydes. Prior to wounding there exists a small pool of acetophenone and C 6 C 1 acid glucosides in leaves of the Nicotiana species. After wounding, some of the acetophenones are generated by hydrolysis of the glucosides. Experiments with cycloheximide indicate that de novo biosynthesis also occurs. The enzyme systems required for the production of the acetophenones from phenylpropanoid precursors appear to be restricted in distribution amongst plant families.

Two host-plant-derived phenolic compounds (acetosyringone and α-hydroxyacetosyringone), which act as chemical signals for wide host range strains of Agrobacterium tumefaciens , have remained the only virulence ( vir ) gene inducing compounds identified from host plant tissues. Here we report the isolation of a vir -inducing phenolic compound from a number of Vitis cultivars, including a known host for limited host range A. tumefaciens , and its identification as syringic acid methyl ester (3,5-dimethoxy-4-hydroxybenzoic acid methyl ester). The presence of this compound in wound exudates does not provide a simple explanation for host range limitation of grapevine strains as it induces vir gene expression in both limited and wide host range strains of Agrobacterium .

The structure of a piscicidal triterpenoid saponin (saponin A) isolated from the leaves of Maesa ramentacea has been shown to be 3-O-{[(α- l -rhamnopyranosyl(1 → 2)-α- l -rhamnopyranosyl(1 → 2)-β- d -galactopyranosyl(1 → 3)]-[β- d - glucopyranosyl(1 → 2)]-β- d -glucuronopyranosyl}barringtogenol C21, 22- O -diangeloate. Extensive use was made of homo- and heteronuclear 2D NMR techniques.

Agrobacterium tumefaciens is known to respond to the presence of certain phenolic compounds by expressing genes prerequisite for transformation of plant cells. One report has described the isolation and identification of virulence-inducing acetosyringone and hydroxyacetosyringone from a host plant. Since these compounds have never previously been reported from plant tissues and are not likely of widespread occurrence, it seems unlikely that these are the only signal compounds for this wide host range pathogen. We report here the structure-activity specificity of vir-induction, and present results which indicate that Agrobacterium is capable of detecting compounds which are ubiquitous or at least widespread amongst its host range. Also, the vir-inducing activities of the lignin precursors coniferyl and sinapyl alcohols are presented and discussed in terms of the biology of Agrobacterium.

Thiophene concentrations were measured in crown gall tissues produced by Agrobacterium tumefaciens infections (strains A208, A277) of Tagetes patula plants and compared with those of normal and transformed callus tissues. The results showed that it is not possible to predict the amounts of secondary motabolites produced as a result of transfers of genetic material from infected plants to crown galls and then to transformed callus tissues. There appears to be an accumulation of intermediates in some of the biosynthetic routes.

Six β-carboline alkaloids were screened for phototoxicity using yeast and bacterial bioassay systems. Five of the compounds tested showed various degrees of activity. The remaining compound, 6-methoxy-tetrahydroharman, was devoid of activity.

Sesquiterpene lactones are characteristic constituents of the Compositae but also occur sporadically in other angiosperm families and even in some liverworts. These bitter substances often contain as a major structural feature an α,β-unsaturated-γ-lactone, which in recent studies has been shown to be associated with anti-tumor, cytotoxic, anti-microbial and phytotoxic activity. They are known to poison livestock, to act as insect feeding deterrents and to cause allergic contact dermatitis in humans. This review highlights the present state of knowledge on the biological activities and mechanism of action of some sesquiterpene lactones.

The metabolism of vulpinic acid by an unclassified soil micro-organism was studied. A new compound, 2,5-diphenyl-3-hydroxy-4-oxo-2-hexendioic acid (DHOHA) was isolated from the reaction mixture of a cell-free preparation and pulvinic acid. The existence of a hydrolase which catalyses the conversion of vulpinic acid to pulvinic acid was detected in cell-free preparation, and an inducible lactone hydrolase capable of converting pulvinic acid to DHOHA was purified 130-fold and characterized. This enzyme had a MW of ca 34 000, a K m for pulvinic acid at pH optimum (pH 7.0) less than 10 − 6 M, p I = 5.0, and was inhibited by p -chloromercuriphenylsulfonate and diethylpyrocarbonate. The enzyme was highly specific for pulvinic acid. The initial degradative steps proposed for this organism are vulpinic acid → pulvinic acid → DHOHA.

The two dihydroflavonols, 3,5,4′-trihydroxy-7-methoxyflavanone and 3,5,4′-trihydroxy-7,3′-dimethoxyflavanone, and naringenin were isolated from aerial parts of Artemisia dracunculus. The mass spectrum of 3,5,4′-trideuteroxy-7-methoxyflavanone is described as an example of the usefulness of deuteration in the analysis of certain flavonoids.

An aromatic 3,4-oxygenase with a broad spectrum of substrate specificity has been partially purified from acetone-dried powders of the fungus, Tilletiopsis washingtonensis . The enzyme catalyzed the oxidation of 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxymandelic acid, 3,4-dihydroxycinnamic acid, 3,4-dihydroxyphenylpropionic acid and 3,4-dihydroxyphenylalanine. The lactone of the primary fission product of 3,4-dihydroxyphenylacetic acid (β- carboxymethyl -cis-cis muconic acid ) was isolated as a dimethyl ester and identified as β- carboxymethylmuconolactone .

A variety of fungi were shown to degrade phloridzin to phloretin, phloroglucinol and phloretic acid. Phloretic acid in turn was metabolized to p -hydroxybenzoic acid. Aspergillus niger yielded cell-free preparations which catalyzed the hydrolysis of phloretin to phloroglucinol and phloretic acid.

The biosynthesis of shanorellin (2,6-dimethyl-3-hydroxymethyl-5-hydroxy-1,4-benzoquinone), an extracellular product of Shanorella spirotricha Benjamin (Ascomycetes), has been found to follow the acetate—polymalonate pathway. Studies with carbon-14 indicate that both methyl groups are derived from methionine.

Twenty-two species of Gaultheria were examined for phenols and phenolic acids obtained by hydrolysis of ethanolic extracts. Most species yielded p -hydroxybenzoic, o -pyrocatechuic, protocatechuic, gentisic, vanillic, p -coumaric, caffeic and ferulic acids. Thirteen species contained derivatives of salicylic acid as well; the glycoside gaultherin was isolated from two of these. The three species of the section Amblyandra yielded catechol as the major phenol in hydrolyzates of ethanolic extracts. Catechol-β- D -glucopyranoside was isolated from one of these. The relationship of these phenolic compounds to one another is discussed.

A survey of Equisetum species found in British Columbia showed that they all contained flavonoid di- and tri-glycosides especially those of kaempferol and, to a lesser extent, those of quercetin. Three other minor flavonoids were identified as gossypitrin, herbacitrin and apigenin-4′-glucoside.

Peak production of phenylalanine and tyrosine ammonia lyase activity occurs during late logarithmic phase in the growth of batch cultures of the yeast, Sporobolomyces roseus . There is some evidence that two enzymes are involved although the production and activity of each enzyme appears to be under common control. Replacement media containing either phenylalanine or tyrosine stimulate production of both enzymes whereas cinnamic acid represses their formation. The activities of both enzymes are also inhibited by cinnamic or p -coumaric acids.

The ability of plant tissues to degrade aromatic rings (of phenylalanine, cinnamic acid, tryptophan) in the absence of micro-organisms has been established using plant tissue cultures (Ruta, Melilotus).

Cultures of Polyporus hispidus grown on a liquid medium with glucose as the principal carbon source produced the yellow pigment hispidin (4-hydroxy-6-(3,4-dihydroxystyryl)-2-pyrone) (II). Tracer studies showed that DL -phenylalanine, DL -tyrosine, cinnamate, p-coumarate and caffeate were incorporated into the hispidin molecule without scrambling of the label. Good incorporation of acetate and roalonate into the pyrone portion of the molecule was observed. The related styrylpyrone, bis-noryangonin (4-hydroxy-6-(4-hydroxystyryl)-2-pyrone) (1) was also detected in extracts of cultured mycelium and a cell-free enzyme preparation was obtained which catalyzed the hydroxylation of bis-noryangonin to hispidin.

Flavanones and dihydroflavonols exhibit characteristic fragmentation patterns that can be utilized in their differentiation. Electron-impact and high resolution mass spectrometry are used to establish the patterns and identities of the characteristic ions.

The isolation and identification of shanorellin (I) (2,6-dimethyl-3-hydroxymethyl-5-hydroxy-1,4-benzoquinone) from the culture medium of an ascomycete, Shanorella spirotricha (Benjamin) is described.

Tracer studies in Gaultheria adenothrix have shown salicylic acid to be the best precursor of catechol.

During the isolation of shanorellin (2,6-dimethyl-3-hydroxymethyl-5-hydroxy-1,4-benzoquinone) from the culture media of Shanorell spirotricha Benjamin, three other p -benzoquinones have been obtained and identified. These are a monoacetate and an ethyl ether of shanorellin as well as a dimer with an ether linkage at the primary alcohol function. These three new benzoquinones are proved to be artifacts derived from shanorellin during the isolation process.

We have isolated two dithiapolyacetylenes from the roots of Chaenactis douglasii and from the plant roots as well as root cultures of Eriophyllum lanatum , namely 1-(2-methylethyn)-4-(hex-1,3-diyn-4-ene)-2,3-dithiacyclohexa-4,6-diene, and 1-(4-methylbut-1,3-diyn)-4-(but-1-yn-3-ene)-2,3-dithiacyclohexa-4,6-diene. We propose the trivial names thiarubrine A and thiarubrine B for these compounds.

Phenylalanine ammonia-lyase (PAL) has been detected in an Ascomycete, Nectria cinnabarina. Growth in light increases levels of PAL in some but not all Basidiomycetes.

E/Z Photoisomerism, in UV-A, of cell wall ferulate and diferulate-carbohydrate esters is suggested as a mechanism for transduction of light energy leading to changes in wall structure and hence water flux, turgor pressure and growth. Unilateral light would cause phototropism.