The aim of the present investigation was to appraise variation in the chemical composition and antimicrobial activity against phytopatogenic bacterial of essential oils from Azorella spinosa. Three samples of A. spinosa were collected in different date in the same area. The essential oils were obtained for hydro-destillation using a Clevenger-type apparatus. The chemical composition of essential oils were analysed using Gas chromatography-mass spectrometry showed variation in the yield and composition, the main detected compounds were monoterpenes such as limonene (10.66-12.30%), tricyclene (10.81-16.99%) and sabinene (9.10-11.49%), the most abundant sesquiterpene was γ-gurjenene (5.48-8.47%). The biological activity of essential oils from A. spinosa against wild phytopatogenic microorganisms showed selectivity over Pseudomonas syringae. This is the first report of the essential oil composition of A. spinosa, and confirms that natural products obtained from aromatic plants represent an important source of bioactive molecules that could be used as new alternatives for the treatment of phytopatogenic bacteria infections.

The MeOH extract of Piper ecuadorense Sodiro, Piperaceae, was chosen for metabolite isolation and elucidation due to the strong antifungal activity exhibited, measured by means of the broth microdilution method. Two known flavonoids: pinostrobin (1) and pinocembrin (2) were isolated from 4.16 g. of dichloromethane extract by column chromatography, using a gradient of hexane/EtOAc. A total of 20 mg of 1 were obtained from the fraction eluted with hexane-EtOAc 95:5 v/v, and 100 mg of 2 were obtained from the fraction eluted with hexane-EtOAc 85:15 v/v. The MIC values of the MeOH extract was 31.25 µg/mL for Trichophyton mentagrophytes ATCC® 28185 and 62.5 µg/mL for Trichophyton rubrum ATCC® 28188. The MIC value of pinocembrin was 125 µg/mL for Trichophyton mentagrophytes ATCC® 28185 and Trichophyton rubrum ATCC® 28188. Pinostrobin in antifungal test was not active against fungi tested.

The essential oil of the species Clinopodium nubigenum (Kunth) Kuntze, Lamiaceae, was analyzed by GC-MS and GC-FID, taking into account the more recent literature. Among the seventy compounds identified, the majority are oxygenated monoterpenoids. The essential oil, tested for antimicrobial activity, resulted effective in vitro against Candida albicans. From the aqueous MeOH extract of the aerial parts of the plant two nonvolatile compounds, named schizonepetoside A and schizonepedoside C, have been isolated. They are rare glycosyl terpenoids, which were previously isolated from only one plant, but never found before in the genus Clinopodium.