1 The insecticidal activity of the neotropical pepper Piper tuberculatum Jacq. and its isolated piperamides was studied. Bioassays with the mosquito Aedes atropalpus L. assessed the relative toxicity of the whole extract of Piper tuberculatum and four of the piperamides, which were isolated and identified, then prepared synthetically. 2 The results confirm that P. tuberculatum leaf extracts are as effective as black pepper seed extract and provide an alternative pepper insecticide from a more convenient source, the leaves. 3 Experiments with piperamides showed that the tertiary and quaternary mixtures have greater-than-additive toxicity compared to single compounds or binary mixtures. One of the four amide compounds, 4,5-dihydropiperlonguminine, was the most acutely toxic in mosquito larvae bioassays. 4 A study of piperamide levels from different P. tuberculatum populations in Costa Rica determined that they were relatively homogeneous. Piper tuberculatum from only one of the five sites had higher levels of one piperamide, 4,5-dihydropiperine, in both leaf and stem parts. One explanation for differences in the amide concentrations between populations is that one site is ecologically unique compared to the other four.

Extracts of 8 taxa of the genus Echinacea were found to have antiviral activity against Herpes simplex (HSV) virus Type I in vitro when exposed to visible and UV-A light. n-Hexane extracts of roots containing alkenes and amides were more active in general than ethyl acetate extracts containing caffeic acids. The most potent inhibitors of HSV were E. pallida var. sanguinea crude (70 % ethanol) inflorescence extract (MIC = 0.026 mg/mL), cichoric acid (MIC = 0.045 mg/mL) and Echinacea purpurea n-hexane root extract (MIC = 0.12 mg/mL).

The antifungal activity and 5-lipoxygenase-inhibiting activity of extracts of five wild and three commercially used taxa of the genus Echinacea were investigated. The near-UV mediated antifungal bioassays included clinically isolated Cryptococcus neoformans, two Candida albicans isolates (D10 and CN1A) with amphotericin B resistance, as well as established and emerging filamentous fungal pathogens (Trichophyton tonsurans, T. mentagrophytes, Microsporum gypseum and Pseudallescheria boydii). Root extracts of the eight Echinacea taxa showed antifungal activity against most of the pathogenic fungi. The inhibition of the 5-lipoxygenase (5-LOX) enzyme of the arachadonic acid pathway was determined by HPLC detection of a direct metabolic product (LTB 4 ) of 5-LOX derived from stimulated rat basophilic cells. Root extracts of the three commercial species of Echinacea (E. purpurea, E. pallida var. angustifolia, E. pallida var. pallida) inhibited the 5-LOX enzyme. E. pallida var. angustifolia was the most potent of the three. The results show that Echinacea spp. have significant antifungal and antiinflammatory activity.Pharmaceutical Biology Downloaded from informahealthcare.com by Emory University on 08/07/15For personal use only.