Two plants, often found growing in local abundance yet unused, were examined in the course of the study reported herein. The first part of this study was an examination of the seeds of Smyrnium olusatrum L., finding that petroselinic acid (an uncommon isomer of oleic acid) previously reported could be readily obtained as both the glycerol triester and the free acid in high purity. A ¹³C-NMR method was developed that could rapidly determine the petroselinic acid content quantitatively in crude extracts and to confirm purity with a reasonably high level of accuracy. It is proposed that, through field studies and extrapolation of data obtained, the potential yield as a commercial oilseed crop could exceed that of crops currently grown for oil content. In addition, a minor, non-fatty
component of the seeds was identified and found to inhibit the crystallisation of saturated components in synthetic mixtures of triglycerides. This may have applications in food or lubricant formulations. The second part of the study examines the potential uses of Hedera helix L. ( common ivy). High levels of fatty acids in the seeds, dominated by petroselinic acid, were established quantitatively by ¹³C-NMR and confirmed by gas chromatography of the butyl esters; the latter technique repeatedly found that a rare fatty acid (hexadecadienoic acid) was present in both the seed and pericarp oils, albeit at levels below 1%. Overall, the extractable fatty acid components of the fruits were found to contain levels comparable to oilseeds of commerce, both on a dry matter basis. In addition, triterpenoid saponins were also found to be present in most growing structures of H helix at high levels in the leaves (10-15 %) and even higher in the whole fruits (around 25 %). These were readily extracted and it was established, by analysis of crude extracts, derivatives and comparison with standards, that hederagenin was the principal core structure of these saponins, known as an aglycone. Crude extracts and modified mixtures of the extracts were found to have high beneficial activity in vitro and in vivo as crop and timber protectants at extremely low concentrations. The concentrations in crude formulations were comparable to or exceeding that of regimes used commercially. The mode of action is discussed. Two patents have been filed as a result of these studies.
Keywords: Smyrnium olusatrum; Hedera helix; petroselinic acid; hexadecadienoic acid; saponins; triterpenes; Phytophthora infestans, molluscicide; fungicide.