Carl A. Elliger

Flavonoids as larval growth inhibitors. Structural factors governing toxicity.

Various flavonoid types are known to confer resistance toward insect attack in several plant species. Thus, a C-glycosyl flavone isolated from the silk of a resistant variety of maize was shown to inhibit the growth o fthe corn earworm,Helio this zea[ 1, 2], and O-glycosyl flavones and aglycones are significant factors against the development of Heliothis virescens, H. zea and Pectinophora gossypiella on cotton flower buds [3, 4]. Similarly, flavonoid tannins are implicated as insect resistance factors of the oak tree and of the cotton plant as well [5, 6]. However, the pentahydroxy flavone, morin, which occurs naturally in mulberry actually stimulates the consumption of artificial diets by silkworm moth larvae [7], and a glycosylated flavone has also been shown to be responsible for the feeding of Agasicles beetles on alligatorweed [8]. Up to now only a relatively small number of structural variants among the flavonoids has been examined by insect bioassay, and an interpretation of these structural features has not been forthcoming. In order to clarify this topic, we

C-glycosylflavones from Zea mays that inhibit insect development.

Abstract A new C-glycosylflavone isolated from corn silk inhibits the growth and development of the corn earworm, Heliothis zea. This new compound was shown to be a 2″-O-α- l -rhamnosyl-6-C-(6-deoxy-xylo-hexos-4-ulosyl)luteolin. Also found co-occurring in corn silk were minor amounts of the corresponding 6-C-glycosylated analogs of chrysoeriol and apigenin.

Mutagenicity of flavones, chromones and acetophenones in Salmonella typhimurium: New structure—activity relationships

28 flavones and 11 structurally-related flavonoids, chromones, and acetophenones, were tested for mutagenicity in the Salmonella typhimurium his reversion assay. 7 flavones, all of which were hydroxy- or methoxy-substituted at position 8, were moderate to strong mutagens in strain TA100 in the presence of rat liver S9 mix. In each case, the response of strain TA98 was either not significant or was very much weaker than that observed in strain TA100. The activation by S9 is not mediated by the microsomal cytochrome P450 system, since activation was not diminished when microsomes were removed by centrifugation at 100 000 X g. The observed strain specificity and structural requirements for activity indicate a mutagenic mechanism different from that associated with previously reported mutagenic flavonols (3-hydroxy-flavones) which are most active in strain TA98. The most mutagenic flavone investigated, 5,7,8-trihydroxy-flavone (norwogonin), had a potency of 17 revertants/nmole. Simplification of the chemical structures to hydroxy-substituted chromone and acetophenone systems revealed similar strain specificity, hydroxylation requirements, and S9 dependence within these structural classes, suggesting a similar activation pathway and mutagenic mechanism. The greatest mutagenic potency was observed within the flavone series, but significant potency was retained by similarly hydroxylated chromones and acetophenones. No mutagenic activity was observed in the absence of the aryl ketone moiety.

Isolation of a toxic factor from jojoba meal.

Summary A new toxic glucoside from jojoba meal called simmondsin, has been isolated and identified as a 2-(cyanomethylene)-3-hydroxy-4,5-dimethoxycyclohexyl β-D-glucoside by application of conventional chemical fractionation and animal bioassay techniques. Preliminary rat and mouse toxicological data implicates the benzyl cyanide derivative of simmondsin as the toxicant.

Simmondsin, an unusual 2-cyanomethylenecyclohexyl glucoside from Simmondsia californica

Simmondsin, a monoglucoside extracted from seeds of the jojoba plant (Simmondsia californica), has been shown to be 2-(cyanomethylene)-3-hydroxy-4,5-dimethoxycyclohexyl β-D-glucoside (1). Analysis of the n.m.r. spectra of this compound and its penta-acetate permits assignment of the stereochemistry as well as establishing the point of attachment of the glucose.

p-vinylbenzeneboronic acid polymers for separation of vicinal diols

A relatively simple procedure was developed for preparing poly(p-vinylbenzeneboronic acid)-coated porous polystyrene beads which were shown to sorb and desorb vicinal diols reversibly through complex formation and to reject other hydroxy compounds. The complexing is highly pH dependent. By suitable adjustment of operating conditions, columns can be used for quantitative recovery of vicinal diols or can be used to separate mixtures of different vicinal diols chromatographically.

Deoxygenation of Aldehydes and Ketones with Sodium Cyanoborohydride

Abstract Treatment of hydroxy-substituted aromatic aldehydes and ketones with sodium cyanoborohydride yields the corresponding methylene compounds under conditions which favor intermediate carbonium ion formation.

Separation of plant polyphenolics by chromatography on a boronate resin

m-Aminophenylboronic acid attached to polyacrylamide beads by a short aliphatic chain strongly and selectively binds vicinal dihydroxyphenyl substituted compounds at pH 7–8. At lower pH these substances are released quantitatively thus affording a simple and rapid method for separation and purification of catecholic materials.

Minor petuniasterones from Petunia hybrida

Abstract Seven new steroids have been isolated from leaves and stems of Petunia hybrida . They are 30-hydroxy petuniasterone A (C-30 epimeric mixture), 1α-acetoxy-1,2-dihydropetuniasterone A (designated petuniasterone E), (22 R ,24 S )-7α,24-dihydroxy-22,25-oxidoergosta-1,4-dien-3-one (petuniasterone F), C-24 epimers of (22 R )-7α,22,24,25-tetrahydroxyergosta-1,4-dien-3-one (petuniasterones G 1 and G 2 and C-24 epimers of (22 R )-1-α-acetoxy-7α,22,24,25-tetrahydroxyergost-4-en-3-one (petuniasterones H 1 and H 2 ). The compounds which have 1-α-acetoxy groups may easily be converted into the corresponding A-ring dienes by mild base. The orthoesters and other side-chain variants may be formed from the 24,25-epoxy compounds which co-occur in the plant.

Ergostanoids from Petunia parodii

Abstract Leaves of Petunia parodii gave three new petuniolides, one of which has a 9,11-double bond. Of the other two, one has a 9β-OH with an 11,12-double bond and the second has a 9β, 19-cyclopropyl system as well as an 11β-OH and a 12-keto group. Also present are six new petuniasterones which arise from rearrangement of the D-ring epoxides, petuniasterones K and L. A 13,17- seco -petuniasterone was also present.