Chemical Composition and Antimicrobial Activity of Geniosporum rotundifolium Briq and Haumaniastrum villosum (Bene) AJ Paton (Lamiaceae) Essential Oils from Tanzania

Purpose: To determine the chemical composition and antimicrobial potential of essential oils from two aromatic plants of Tanzania, Geniosporum rotundifolium Briq. and Haumaniastrum villosum (Benè) A.J. Paton (Lamiaceae).Method: Essential oils from the aerial parts of the plants were extracted by hydro-distillation for 3 h using a Clevenger type of apparatus. The constituents were analyzed by gas chromatography – mass spectrometry (GC/MS).The minimum inhibitory concentrations of the essential oils were determined for eight bacterial strains and three pathogenic fungi using agar dilution method.Results: The constituents of G. rotundifolium oil were mainly oxygenated derivatives of mono- and sesquiterpenes; spathulenol (12.46 %), α-terpineol (4.65 %) and germacrene-D (3.71 %) were the most abundant. Those of H. villosum oil were predominantly sesquiterpenes (72.61 %) with caryophyllene oxide (19.01 %), humulene epoxide II (11.95 %), β-bourbonene (5.7 %), α-humulene (5.63 %) and β- caryophyllene (5.39 %) being more abundant. The oil of G. rotundifolium exhibited weak to moderate activity against the bacterial species but showed no activity against the test fungi. However, H. villosum oil showed very promising activity against all the test microorganisms (MIC 0.08 – 10.34 mg/mL).Conclusion: The major components of G. rotundifolium essential oil were oxygenated derivatives of mono- and sesquiterpenes whereas those of H. villosum were sesquiterpenes. All tested microorganisms were susceptible to H. villosum oil.Keywords: Geniosporum rotundifolium, Haumaniastrum villosum, Essential oils, Chemical composition, Antimicrobial activit

Chemical analysis of Greek pollen - Antioxidant, antimicrobial and proteasome activation properties

<p>Abstract</p> <p>Background</p> <p>Pollen is a bee-product known for its medical properties from ancient times. In our days is increasingly used as health food supplement and especially as a tonic primarily with appeal to the elderly to ameliorate the effects of ageing. In order to evaluate the chemical composition and the biological activity of Greek pollen which has never been studied before, one sample with identified botanical origin from sixteen different common plant taxa of Greece has been evaluated.</p> <p>Results</p> <p>Three different extracts of the studied sample of Greek pollen, have been tested, in whether could induce proteasome activities in human fibroblasts. The water extract was found to induce a highly proteasome activity, showing interesting antioxidant properties. Due to this activity the aqueous extract was further subjected to chemical analysis and seven flavonoids have been isolated and identified by modern spectral means. From the methanolic extract, sugars, lipid acids, phenolic acids and their esters have been also identified, which mainly participate to the biosynthetic pathway of pollen phenolics. The total phenolics were estimated with the Folin-Ciocalteau reagent and the total antioxidant activity was determined by the DPPH method while the extracts and the isolated compounds were also tested for their antimicrobial activity by the dilution technique.</p> <p>Conclusions</p> <p>The Greek pollen is rich in flavonoids and phenolic acids which indicate the observed free radical scavenging activity, the effects of pollen on human fibroblasts and the interesting antimicrobial profile.</p