a b s t r a c tThe purpose of this study was to develop and characterize biodegradable nanospheres containing essential oils from Zanthoxylum rhoifolium leaves and evaluate its insecticidal effect in Bemisia tabaci populations. The essential oil from Z. rhoifolium leaves exhibited an average yield of 0.03% and presented ␤-elemene (31.26%), D-germacrene (18.16%), ␤-caryophyllene (12.09%), ␦-elemene (7.63%), ␤-cedrene (6.69%), bicyclogermacrene (4.57%) and E-caryophyllene (3.63%) as main components. The PCL nanospheres containing this essential oil exhibited encapsulation efficiency higher than 96%, pH close to 5, particle diameter smaller than 500 nm and zeta potential values of approximately −20 mV. The in vitro release profile was characteristic of biphasic release, i.e., a fast initial release, followed by slow release for 12 h or more. The biological assay results were also significant and as such both the in natura and nanoencapsulated essential oils resulted in reductions as high as 95% in the number of eggs and nymphs compared with our control. Collectively these results suggest that both in natura and nanoencapsulated essential oils from Z. rhoifolium leaves can potentially be used in B. tabaci control in association with integrated pest management practices.

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Tooth decay is a major public health problem which affects a large number of people in several countries. Even though more than 700 bacterial species have been detected in the oral cavity, Streptococcus and Lactobacillus stand out as the genera that cause tooth decay and other periodontal diseases. In this study, essential oils from Citrus aurantifolia leaves (CL-EO) and fruit peel (CP-EO) were obtained by hydrodistillation by a Clevenger-type apparatus whereas their chemical composition was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Limonene (77.5 %), linalool (20.1 %), citronellal (14.5 %) and citronellol (14.2 %) were the main constituents found in the essential oils from C. aurantifolia leaves and fruit peel. Antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both CL-EO and CP-EO displayed some activity against all oral pathogens under investigation; MIC values ranged from 20 to 200 µg/mL. CL-EO and CP-EO not only had promising activity against Streptococcus mutans (MIC = 20 µg/mL) and Lactobacillus casei (31.25 µg/mL), but also displayed antibacterial activity against all studied cariogenic bacteria. Efficacy of essential oils against S. mutans and L. casei is noteworthy and should be further investigated.

RESUMO Campomanesia adamantium é muito utilizada na medicina popular no tratamento de hipertensão, reumatismo e diabetes. Objetivou-se com o presente trabalho avaliar o rendimento, a composição química, e as atividades antimicrobiana e antioxidante do óleo essencial de folhas de C. adamantium submetidas a diferentes métodos e tempos de secagem. O delineamento utilizado foi inteiramente casualizado, com oito tratamentos e três repetições. O óleo essencial foi extraído por hidrodestilação das folhas e analisado por CG-EM. O tipo de secagem das folhas de C. adamantium influenciou no teor e na composição química do óleo essencial. Os constituintes espatulenol, óxido cariofileno e germacreno-B apresentaram maior concentração na maioria das procedências avaliadas. O óleo essencial das folhas de C. adamantium apresentou moderada atividade antibacteriana em relação a todos os micro-organismos testados. A atividade antioxidante se deu empregando-se o método de redução do radical estável DPPH, sendo observada fraca atividade antioxidante por meio do ensaio utilizado.

Diversas espécies do gênero Solanum apresentam glicoalcalóides e flavonóides com grande variedade de atividades biológicas. O flavonóide tiliroside (1), uma fração rica em glicoalcalóides denominada GB e o glicoalcalóide solasonina (2) foram obtidos dos tricomas de galhos jovens e frutos de Solanum crinitum Lam e o alcalóide estereoidal solasodina (3), extraído das partes aéreas de S. jabrense Agra & M. Nee, tiveram sua atividade citotóxica avaliada frente a células do carcinoma de Ehrlich e da leucemia humana K562. O efeito antiproliferativo destas substâncias mostrou comportamento dose-dependente após avaliação através do método do MTT, para ambos os casos. Os resultados indicaram atividade citotóxica para 1, GB e 2, com IC 50 = 69,50 µM, 19,5 µg mL -1 e 74,20 µM, respectivamente, quando ensaiadas frente ao carcinoma de Ehrlich, e IC 50 = 118,40 µM, 13,65 µg mL -1 , 60,35 µM e 76,92 µM para 1, GB, 2 e 2a (derivado peracetilado da solasonina) frente a leucemia K562. A baixa atividade da aglicona solasodina (3) indicou a importância da presença dos açúcares na estrutura do glicoalcalóide e permitiu postular a substância 2, presente na fração rica em glicoalcalóides (GB), como um dos principios ativos. Além disso, os resultados mostraram a possibilidade de biomonitoramento através do ensaio do MTT na busca de metabólitos com atividade citotóxica.Steroidal alkaloids, flavonoids and their glycosides occurring in numerous species of Solanum genus are known to possess a variety of biological activities. The flavonoid tiriloside (1), a rich in glycoalkaloids total fraction named GB and the glycoalkaloid solasonine (2) isolated from thricomes of young branches and fruits from Solanum crinitum Lam, and the aglycone solasodine (3) isolated from Solanum jabrense Agra & M. Nee, were assayed against murine Ehrlich carcinoma and human K562 leukaemia cultured cells. The exposure in vitro of these cancer cells to these products resulted in a dose-dependent growth inhibition evaluated by the MTT method. The results indicated significant cytotoxic activities with IC 50 = 69.50 µM, 19.5 µg mL -1 , and 74.20 µM for 1, GB and 2, respectively, against Ehrlich carcinoma, and IC 50 = 186.50 µM, 13.65 µg mL -1 and 76.92 µM, for 1, GB, 2 and 2a, respectively, against K562 leukaemia cells. The low activity of the aglycone 3 indicates that the role of the sugar moiety is very important in the cytotoxic activity of glycoalkaloid solsonine. The cytotoxic activity revealed by the GB fraction may be attributed to the presence of 2. Additionally, these results show the viability of the MTT assay for monitoring phytochemical bioactive compounds. K562 Leukaemia Vol. 13, No. 6, 2002 Kolaviron for the treatment of various diseases, including hepatitis and laryngitis, 3 and several Leguminosae plants containing isoflavonoids with potent estrogenic activity. 4 Many plants in the Solanaceae family accumulate steroidal alkaloids based on a C 27 cholestane skeleton, e.g. solasodine and tomatidine. These compounds are essentially nitrogen analogues...

This study evaluated the antibacterial and antiproliferative activities of the essential oil of Psidium guajava leaves (PG-EO), traditionally used in folk medicine. The essential oil was obtained from fresh leaves by hydrodistillation, using a modified Clevenger apparatus. The major PG-EO chemical constituents were identified by GC-MS and GC-FID as being β-caryophyllene (16.1%), α-humulene (11.9%), aromadendrene oxide (14.7%), δ-selinene (13.6%), and selin-11-en-4α-ol (12.5%). The antibacterial activity of the essential oil of P. guajava leaves was determined in terms of its minimum inhibitory concentrations (MIC) using the broth microdilution method in 96-well microplates. PG-EO had moderate activity against Streptococcus mutans (MIC = 200 µg/mL), S. mitis (MIC = 200 µg/mL), S. sanguinis (MIC = 400 µg/mL), S. sobrinus (MIC = 100 µg/mL), and S. salivarius (MIC = 200 µg/mL). The antiproliferative activity was evaluated against different tumor cell lines: breast adenocarcinoma (MCF-7), human cervical adenocarcinoma (HeLa), and human gliobastoma (M059J). A normal human cell line (GM07492A, lung fibroblasts) was included. The antiproliferative activity was evaluated using the XTT assay and the results were expressed as IC50. The essential oil showed significantly lower IC50 values against MCF-7 and M059J lines than that obtained for the normal line, showing selectivity. Our results suggest that the essential oil of Psidium guajava L. has promising biological activities and can be considered a new source of bioactive compounds.

Globally, the fungus Sclerotinia sclerotiorum is considered as one of the most important phytopathogens, since it affects the production of several economically important crops. Further, it is difficult to control, thus increasing the use of pesticides. Therefore, the search for new substances, especially those extracted from plants, has received special attention to control this plant pathogen. The objective of the present study was to evaluate the yield and chemical composition of the essential oil extracted from the fresh leaves of guava collected during the rainy and dry seasons, and also to evaluate its toxicity against S. sclerotiorum. The experiment was a completely randomized design with five treatments and six replicates. The essential oil was extracted by hydrodistillation of the leaves and analyzed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. The main compounds identified in the essential oil were trans-caryophyllene and ?-humulene. The essential oil at a concentration of 300 ?L exhibited 90% inhibition of the mycelial growth of S. sclerotiorum. This confirmed the antifungal potential of the essential oil of the guava leaves during both the sampling seasons.

Many essential oils (EOs) of different plant species possess interesting antimicrobial effects on buccal bacteria and antioxidant properties. Eugenia klotzschiana Berg (pêra-do-cerrado, in Portuguese) is a species of Myrtaceae with restricted distribution in the Cerrado. The essential oils were extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC-MS. The major compounds were α-copaene (10.6 %) found in oil from leaves in natura, β-bisabolene (17.4 %) in the essential oil from dry leaves and α-(E)-bergamotene (29.9 %) in oil from flowers. The antioxidant activity of essential oils showed similarities in both methods under analysis (DPPH and ABTS˙+) and the results suggested moderate to high antioxidant activity. The antibacterial activity was evaluated by determining minimum inhibitory concentrations (MICs), using the microdilution method. MIC values below 400 µg/mL were obtained against Streptococcus salivarius (200 µg/mL), S. mutans (50 µg/mL), S. mitis (200 µg/mL) and Prevotella nigrescens (50 µg/mL). This is the first report of the chemical composition and antibacterial and antioxidant activities of the essential oils of E. klotzschiana. These results suggest that E. klotzschiana, a Brazilian plant, provide initial evidence of a new and alternative source of substances with medicinal interest.