Nagilactones

Podolactone A (29) happened to be the less toxic lactone, and the most active compounds are nagilactone D (4) and podolactone E (51). These podolactones did not produce mortality when applied topically to larvae or adults (5 pg per insect), which suggests that these compounds are not... 

Wih respect to the insecticide activity, Podocarpus macrophyllus is widely known in Japan for its resistance to termite attack. Saeki disclosed in 1970 that the termiticidal activity is entirely due to inumakilactone A (28) and another unidentified compound of similar structure, the former being more active [70]. This second compound was later reported to be nagilactone D (4). 

The methanolic extract of the leaves of P. gracilior (Kenya) caused mortality within 12 days after incorporation into a meridic artificial diet of several lepidopterous pest species. The toxic and growth inhibitory action of nagilactones C (3), D (4) and F (55) and podolide (39) towards these species are shown in Table 7. All tested podolactones are relatively potent growth inhibitors (ED50 4-30 ppm), while the concentration of the compounds that cause mortality was about two orders of magnitude... 

Table 7. Activities of nagilactones C, D and F and podolide towards different lepidopterous agricultural pest species.

The studies on the inhibitory effects of podolactones A (29) and E (51) and nagilactone E (36) were extended to a range of bioassays [73]. In some of these assays, the effects of the podolactones were compared to those of lycoricidinol and harringtonolide, plant growth inhibitors (Table... 

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