The main cytotoxic component in New Zealand collections of the liverwort Trichocolea mollissima was identified as methyl 4-[(5-oxogeranyl)oxy]-3-methoxybenzoate, a structure that has not been reported previously. Two double-bond isomers of this geranyl ether were present at lower levels. Reinvestigation of the benzoates from Japanese collections of Trichocolea tomentella led to the identification of four geranyl ethers (including two of the three compounds identified from T. mollissima), which had previously been assigned incorrect geranyl ester structures. One compound, previously reported as a 3,3-dimethylallyl ester, could not be reisolated from T. tomentella, but was found in a New Zealand collection of Trichocolea lanata. It was shown to be a 3,3-dimethylallyl ether by synthesis from methyl vanillate. Several of these compounds were active in cytotoxic and antifungal assays.

An in vitro nematode larval motility inhibition assay has been developed to screen plant extracts for anthelmintic activity against the sheep parasite Trichostrongylus colubriformis. The usefulness of this assay was verified by results for extracts of the liverwort Plagiochila stephensoniana and the shrub Pseudowintera colorata. The activity of these extracts was due to 4-hydroxy-3‘-methoxybibenzyl (1) (IC50 0.13 mg/mL) and polygodial (2) (IC50 0.07 mg/mL), respectively. Synthetic analogues of 1 displayed enhanced antiparasitic activity. (Z)-4-Hydroxy-3‘-methoxystilbene (3) had an IC50 of 0.06 mg/mL. The activity of an extract of the tree Phyllocladus aspeniifolius var. alpinus was due to the presence of polyphenolics, since treatment of the extract with polyvinylpolypyrrolidone or polyamide removed the activity. Keywords: Nematodes; anthelmintics; natural products; assay; plant extracts; Trichostrongylus colubriformis

Extracts of the leaves of the New Zealand native tree Pseudowintera colorata (Raoul) showed insecticidal and antifeedant activity against the webbing clothes moth, Tineola bisselliella (Hummel), and antifeedant activity against the Australian carpet beetle, Anthrenocerus australis (Hope). Assay-directed fractionation showed that two sesquiterpene dialdehydes, polygodial and 9-deoxymuzigadial, were responsible for these activities. Both compounds had similar antifeedant and insecticidal activity at rates from 3 to 0.4 mg/g wool in bioassays.

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A new sesquiterpene/quinol, with mild cytotoxic and antibacterial activity, has been isolated from a New Zealand collection of the liverwort Riccardia crassa. The structure of this compound, riccardiphenol C [3], was established by nmr spectroscopy. Closely related compounds previously isolated from a Japanese collection of R. crassa were not detected in this collection.