R. Hiltunen

Characterisation of the antioxidant properties of de-odourised aqueous extracts from selected Lamiaceae herbs

Abstract De-odourised aqueous extracts of four commonly consumed herbs belonging to the Lamiaceae family, i.e. oregano ( Origanum vulgaris L.), rosemary ( Rosmarinus officinalis L.), sage ( Salvia officinalis L.) and thyme ( Thymus vulgaris L.), were investigated for their antioxidant properties. Various experimental models were used for the characterisation of the activity, including iron reduction capacity, DPPH , ABTS + and OH radical-scavenging activities and the capacity of the extracts to inhibit copper-induced oxidation of human low-density lipoproteins (LDL) ex vivo. The extracts showed varying degrees of reductive and radical scavenging capacity, and were capable of a marked prolongation of the lag-time in the LDL oxidation assay. The hierarchy of the observed antioxidant activity of the extracts was dependent on the type of assay used. The observed antioxidant characteristics were not fully related to the total phenolic contents of the extracts in any of the assays, but were presumably strongly dependent on rosmarinic acid, the major phenolic component present in this type of Lamiaceae extract.

Antimicrobial activity of some coumarin containing herbal plants growing in Finland.

Antimicrobial screening against selected Gram-positive and Gram-negative bacteria, yeasts, mold, as well as plant pathogenic fungi, with emphasis on method optimization was carried out on methanol extracts prepared from seven plants grown in Finland. Sensitivity to the extracts was found to vary considerably among the micro-organisms, the extract from Petroselinum crispum and Ruta graveolens showing the highest toxicity against Rhizoctonia solani. The growth of Heterobasidium annosum was inhibited, whereas that of Phytophtora (cactorum) was promoted by all the extracts. The antibacterial and antifungal activities of six natural coumarin compounds were weak, except for the inhibitory effect against Fusarium culmorum.

Analysis of fatty acids by gas chromatography, and its relevance to research on health and nutrition

Abstract Gas chromatography (GC) has been an indispensable analytical technique ever since the first exciting steps in the application of fatty acid determinations in oilseed plant breeding, biosynthesis and human metabolism. Present-day GC methods with high-quality capillary columns allow sensitive and reproducible fatty acid analyses, as well as the characterization of complex mixtures of geometric isomers when combined with other chromatographic separations and spectroscopic identification. Ordinary GC analysis is well suited for a detailed follow-up of the changes in human tissue fatty acids derived from dietary fats providing, however, that all the steps in the methodology are carefully optimized. Plasma fatty acids act as excellent indicators, and the use of substitute fats can be found as dose-dependent correlations. Analysis of phospholipid (PL) fatty acid composition is especially useful for recognizing the competitive capability of essential fatty acids present in a particular dietary fat. A clear response is observed even at the level of minor fatty acids, i.e. both increased and decreased use of trans fatty acids are indicated by changes in the most abundant octadecenoic trans isomers. In addition to the expected associations with serum lipids, plasma fatty acid data are also useful in monitoring relationships with lipid oxidation parameters. GC analysis of fatty acids still has its traditional uses, but it is now faced with new challenges. Since the effects that arise from even moderate amounts of dietary essential fatty acids cannot be neglected, continuing research aimed at their requirements is of prime importance. Modification of fatty acid compositions by metabolic engineering offers good possibilities for producing new oilseed crops with a more balanced α-linolenic/linoleic acid (LA) ratio, preferably combined with a high oleic acid (OA) content. In the future, particular attention has to be paid to the proportions of polyunsaturated fatty acids (PUFAs) in the diet, which are the factors that finally determine the apparently unique balance of tissue n −3 and n −6 fatty acids and eicosanoids decisive for human health.

Ethnobotanical and antimicrobial investigation on some species of Terminalia and Combretum (Combretaceae) growing in Tanzania

An ethnobotanical investigation on the medicinal uses of some species of Terminalia and Combretum (Combretaceae) was carried out in Mbeya, Tanzania during a 5-weeks field expedition. Of the sixteen species collected, Combretum fragrans F. Hoffm., Combretum molle G. Don., Combretum psidioides Welw., Combretum zeyheri Sond., Terminalia kaiserana F. Hoffm. and Terminalia sericea Burch ex. DC. have medical applications against various bacterial infections, such as gonorrhoea and syphilis, and against symptoms like diarrhoea, hypertension and even cancer. Antimicrobial screening of the crude extracts of the selected Combretum and Terminalia species was performed by the agar diffusion method. Among the most effective extracts were methanol extracts of the roots of Terminalia sambesiaca Engl. & Diels., T. kaiserana Guill. & Perrott., T. sericea Burch. ex DC., C. fragrans F. Hoffm. and Combretum padoides Engl. & Diels., all of which showed marked inhibition against Gram-positive bacteria, and were also good inhibitors of Enterobacter aerogenes. All four of the extracts of the roots of T. sericea tested, (methanol, ethanol, acetone and hot water) had good antimicrobial activity. A methanolic leaf extract of T. kaiserana was the only extract to have a bacteriocidic effect on Escherichia coli. Methanol root extracts of T. sambesiaca and methanol leaf extracts of T. sericea were the most effective against Candida albicans. The results of the antimicrobial screening support the ethnomedical uses of these plants.

Enhancement of scopolamine production in Hyoscyamus muticus L. hairy root cultures by genetic engineering

Abstract. In order to test the possibility of enhancing the production of pharmaceutically valuable scopolamine in transgenic cultures, the 35S-h6h transgene that codes for the enzyme hyoscyamine-6β-hydroxylase (EC 1.14.11.11) was introduced into Hyoscyamus muticus L. strain Cairo (Egyptian henbane). This plant was chosen for its capability to produce very high amounts of tropane alkaloids (up to 6% of the dry weight in the leaves of mature plant). To our knowledge, this is the first time such a large population of transgenic cultures has been studied at the morphological, chemical and genetic levels. A great variation was observed in the tropane alkaloid production among the 43 positive transformants. The best clone (KB7) produced 17 mg/l scopolamine, which is over 100 times more than the control clones. However, conversion of hyoscyamine to scopolamine was still incomplete. The expression of h6h was found to be proportional to the scopolamine production, and was the main reason behind the variation in the scopolamine/hyoscyamine ratio in the hairy-root clones. These results indicate that H. muticus strain Cairo has a potential for even more enhanced scopolamine production with more efficient gene-expression systems.

Metabolism of berry anthocyanins to phenolic acids in humans.

We studied the metabolism of berry anthocyanins to phenolic acids in six human subjects by giving them bilberry-lingonberry puree with and without oat cereals. Puree + cereals contained 1435 micromol of anthocyanins and 339 micromol of phenolic acids. The urinary excretion of measured 18 phenolic acids increased 241 micromol during the 48 h follow-up after the puree + cereals supplementation. The excretion peak of dietary phenolic acids was observed at 4-6 h after the puree + cereals supplementation and 2 h earlier after the supplementation of the puree alone. Homovanillic and vanillic acids were the most abundant metabolites, and they were partly produced from anthocyanins. No gallic acid, a fragmentation product of delphinidin glycosides, was detected, and only a very low amount of malvidin glycosides was possibly metabolized to syringic acid. Although anthocyanins were partly fragmented to phenolic acids, still a large part of metabolites remained unknown.

Comparison of hydrodistillation and supercritical fluid extraction for the determination of essential oils in aromatic plants

Abstract Supercritical fluid extraction (SFE) and hydrodistillation were compared as methods to extract essential oils from savory, peppermint and dragonhead. Despite the high solubilities of essential oil components in supercritical CO2, the extraction rates were relatively slow with pure CO2 (ca. 80% recovery after 90 min). However, a 15-min static extraction with methylene chloride as modifier followed by a 15-min dynamic extraction with pure CO2 yielded high recoveries which agreed well with the results Of hydrodistillation performed for 4 h. Spike recovery studies demonstrated that compounds as volatile as monoterpenes can be quantitatively ( > 90%) collected off-line from the SFE effluent. SFE recovered some organic compounds from each of the samples that were not extracted by hydrodistillation, most notably C27, C29, C31, and C33 n-alkanes.

Bioactivity of certain Egyptian Ficus species

The fruit extracts of Ficus sycomorus L., F. benjamina L., F. bengalensis L. and F. religiosa L. were screened for bioactivity. F. bengalensis and F. religiosa demonstrated activity in the brine shrimp test (Artemia salina) which indicates toxicity, whereas F. sycomorus and F. benjamina showed no activity. All the fruit extracts exhibited antitumor activity in the potato disc bioassay. None of the tested extracts showed any marked inhibition on the uptake of calcium into rat pituitary cells GH4C1. The extracts of the four tested Ficus species had significant antibacterial activity, but no antifungal activity. The results of this preliminary investigation support the traditional use of these plants in folk medicine for respiratory disorders and certain skin diseases.

Extraction of clove using pressurized hot water

Subcritical water extraction was used to extract eugenol and eugenyl acetate from clove at various temperatures and pressures where water was in either the liquid or gas (steam) phase. Several solid phase materials were tested in order to quantitatively and selectively collect the analytes after the water extraction. Quantitative collection of eugenol and eugenyl acetate could be achieved using a C18 solid phase trap. The extraction kinetics with subcritical water was very fast at high temperatures (250°C and 300°C), giving a 100% recovery after 15 min for eugenol and eugenyl acetate, compared to extraction at 125°C, where the same recovery was achieved only after 80 min extraction. In addition, both eugenol and eugenyl acetate proved to be stable at the highest extraction temperature (300°C) used in this study. Copyright

Chemical and Antioxidant Evaluation of Indian Gooseberry (Emblica officinalis Gaertn., syn. Phyllanthus emblica L.) Supplements

Indian gooseberry (Emblica officinalis Gaertn.) (Euphorbiaceae) has a distinguished history in Ayurveda medicine and is ascribed a number of medicinal properties and as a dietary supplement, its use is increasing in Western countries. It is thought that its beneficial properties are a function of its antioxidant potency. The study investigated the chemistry and antioxidant properties of four commercial E. officinalis fruit extracts in order to determine if there are any qualitative–quantitative differences. All extracts produced positive responses in the total phenol, total flavonoid and total tannin assays. The presence of predominantly (poly)phenolic analytes, e.g. ellagic and gallic acids and corilagin, was confirmed by RP‐HPLC coupled with photodiode array detection. Despite ascorbic acid being a major constituent of E. officinalis fruits, the furanolactone could not be identified in one of the samples. The extracts demonstrated varying degrees of antioxidative efficacy. The extract designated IG‐3 was consistently amongst the most effective extracts in the iron(III) reduction and 1,1‐diphenyl‐2‐picrylhydrazyl and superoxide anion radical scavenging assays while the extract designated IG‐1 demonstrated the best hydroxyl radical scavenging activity. All extracts appeared to be incapable of chelating iron(II) at realistic concentrations. Copyright