Geoffrey C. Kite

Ayurvedic drugs and their plant sources

Ayurvedic Drugs and Their Plant Sources , Ayurvedic Drugs and Their Plant Sources , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Infraspecific taxonomy and essential oil chemotypes in sweet basil, Ocimum basilicum

Essential oil compositions of fresh and freeze-dried leaves were determined for 16 accessions of Ocimum basilicum belonging to different varieties to see whether they could be used as infraspecific taxonomic characters. One accession of O. x citriodorum was also studied. Some 30 monoterpenoids, sesquiterpenoids and phenylpropanoids were identified, the major components (more than 20% of the total essential oil composition in one or more accessions) being geranial and neral in O. x citriodorum, and linalool, methyl chavicol, eugenol, methyl eugenol and geraniol in O. basilicum. Based on a combination of the latter compounds, five major essential oil profiles could be distinguished in the accessions studied for O. basilicum. These profiles were largely the same for fresh and freeze-dried material of the same plant, although in the dried leaves, methyl chavicol and eugenol concentrations had generally declined in comparison to those of linalool. There appeared to be little correlation between essential oil patterns and varietal classification within O. basilicum. In view of the chemical heterogeneity of O. basilicum and its use as an essential oil-producing crop, culinary herb, medicinal plant and insect-controlling agent, in all of which chemicals play an important role, the infraspecific classification of this taxon should take chemical characters into consideration. A system for the classification of essential oil chemotypes in O. basilicum is proposed.

The application of atmospheric pressure chemical ionisation liquid chromatography–mass spectrometry in the chemotaxonomic study of flavonoids: characterisation of flavonoids from Ocimum gratissimum var. gratissimum

Liquid chromatography coupled to mass spectrometry (LC-MS), using atmospheric pressure chemical ionisation (APCI), was found to complement data obtained from diode array detection enabling common flavonoids in Ocimum gratissimum var. gratissimum to be characterised at the analytical level without complete purification, or even to be characterised in crudely purified ethanolic extracts. Xanthomicrol, cirsimaritin, rutin, kaempferol 3-O-rutinoside and vicenin-2 were identified as the major flavonoids, whereas luteolin 5-O-glucoside, luteolin 7-O-glucoside, apigenin 7-O-glucoside, vitexin, isovitexin, quercetin 3-O-glucoside and isothymusin were detected as minor constituents. First-order positive ion APCI-MS provided not only the pseudomolecular ion of flavonoid O-glycosides, but also an ion corresponding to the aglycone and an intermediate ion if more than one sugar was attached to the flavonoid. Information on the type and sequence of sugars was therefore obtained without the need to undertake MS2 product ion analyses. Product ion analysis was useful for confirming the glycoside fragmentation observed in first-order MS, especially with co-eluting compounds, and for obtaining fragmentation patterns of either free aglycones or the aglycone moiety of flavonoid O-glycosides; the latter could be used to support the aglycone identification achieved from the UV spectra. Negative ion APCI-MS was found useful for flavone C-glycosides and gave very characteristic product ions due to fragmentation of the C-sugars. For flavonoid O-glycosides analysed in the negative ion mode, there was evidence that the position and nature of the attached sugars could influence the aglycone product ion formed by MS2 analysis and hence its product ion spectrum. APCI is considered to be a more useful ion source than electrospray in the chemotaxonomic study of flavonoids. Copyright

The floral odour of Arum maculatum

Non-invasive headspace analyses of the odour produced by inflorescences of Arum maculatum L. still attached to plants growing wild in southern England revealed that the major components were 2-heptanone, indole (each comprising 8–23% of the volatiles) and germacrene B (10–14%). p-Cresol (0.2–6%) was also a notable odorous component amongst the 56 compounds present, however, simple amines, reported in previous invasive studies, could not be detected. Although the major odorous organ was the spadix appendix, microheadspace analyses revealed that the germacrene B originated entirely within the spathe chamber, probably from the fertile portion of the spadix. The main pollinator was confirmed as females of Psychoda phalaenoides L. and a comparison of the inflorescence volatiles with those produced by cow dung, the normal breeding microhabitat of the pollinator, identified p-cresol as the major common component.

Inflorescence odours of Amorphophallus and Pseudodracontium (Araceae)

Abstract The inflorescence odours of 18 species of Amorphophallus and two species of Pseudodracontium were analysed by headspace techniques and compared to the limited data on potential pollinators. The odours of species with ‘gaseous’ or carrion smells had a simple chemical composition, consisting mainly of dimethyl oligosulphides. The odours of other Amorphophallus species having different smells were also generally dominated by one or two compounds: e.g. trimethylamine in A. brachyphyllus, isocaproic acid in A. elatus, 4-methoxyphenethyl alcohol in A. albispathus, and isoamyl acetate with ethyl acetate in A. haematospadix. The production of odours containing dimethyl oligosulphides appears to be a common feature of sapromyophilous flowers that attract carrion insects.

α-Homonojirimycin [2,6-dideoxy-2,6-imino-d-glycero-l-gulo-heptitol] from omphalea diandra L.: isolation and glucosidase inhibtion

Abstract The isolation of α-homonojirimycin [2,6-dideoxy-2,6-imino-D-glycero-L-gulo-heptitol] from Omphalea diandra is described; α-homonojirimycin is an inhibitor of several α-glucosidases.

HPLC/MS analysis and anxiolytic-like effect of quercetin and kaempferol flavonoids from Tilia americana var. mexicana

AIM OF THE STUDY Around the world, Tilia species have been used in traditional medicine for their properties as tranquilizer. Furthermore, Mexican species of Tilia have been grouped as Tilia americana var. mexicana, but their specific content in flavonoids is poorly described. In this study, inflorescences of Mexican Tilia were collected in three different regions of Mexico to compare their flavonoid content and anxiolytic-like response. MATERIALS AND METHODS Flavonoid content was analyzed by using an HPLC-MS technique. For anxiolytic-like response, Tilia inflorescences extracts (from 10 to 300 mg/kg, i.p.) were tested in experimental models (open-field, hole-board and plus-maze tests, as well as sodium pentobarbital-induced hypnosis) in mice. RESULTS HPLC-MS analysis revealed specific peaks of flavonoid composition demonstrating some differences in these compounds in flowers and bracts depending on the region of collection. No differences in the neuropharmacological activity among these samples of Tilia were found. Moreover, their effects were associated with quercetin and kaempferol glycosides. CONCLUSIONS Dissimilarities in the flavonoid composition of Mexican Tilias might imply that these species must be re-classified in more than one species, not as a unique Tilia americana var. mexicana. Since quercetin and kaempferol aglycons demonstrated anxiolytic-like response and that no difference in the pharmacological evaluation was observed between these three Mexican Tilias, we suggest that this pharmacological effect of Tilia inflorescences involves these flavonoids occurrence independently of the kind of glycosides present in the samples reinforcing their use in traditional medicine in several regions of Mexico.

Leaf flavonoid glycosides as chemosystematic characters in Ocimum

Abstract Thirty-one accessions of nine species belonging to three subgenera of Ocimum (basil, family Lamiaceae) were surveyed for flavonoid glycosides. Substantial infraspecific differences in flavonoid profiles of the leaves were found only in O. americanum , where var. pilosum accumulated the flavone C -glycoside, vicenin-2, which only occurred in trace amounts in var. americanum and was not detected in cv. Sacred. The major flavonoids in var. americanum and cv. Sacred, and also in all other species investigated for subgenus Ocimum , were flavonol 3- O -glucosides and 3- O -rutinosides. Many species in subgenus Ocimum also produced the more unusual compound, quercetin 3- O -(6″- O -malonyl)glucoside, and small amounts of flavone O -glycosides. The level of flavonol glycosides produced was reduced significantly in glasshouse-grown plants, but levels of flavone glycosides were unaffected. A single species investigated from subgenus Nautochilus , O. lamiifolium , had a different flavonoid glycoside profile, although the major compound was also a flavonol O -glycoside. This was identified as quercetin 3- O -xylosyl(1‴→2″)galactoside, using NMR spectroscopy. The species investigated from subgenus Gymnocimum , O . tenuiflorum (= O. sanctum ), was characterised by the accumulation of flavone O -glycosides. These were isolated, and identified as the 7- O -glucuronides of luteolin and apigenin. Luteolin 5- O -glucoside was found in all nine species of Ocimum studied, and is considered to be a key character for the genus.

The chemotaxonomic significance of two bioactive caffeic acid esters, nepetoidins A and B, in the Lamiaceae.

A survey of leaf surface constituents in the family Lamiaceae using HPLC with diode array detection revealed the presence of two characteristic phenolic compounds in many species. The distribution of these phenolics in the Lamiaceae was found to be of taxonomic significance, as they were present in the great majority of species investigated for the subfamily Nepetoideae, including representatives of the well-known genera of culinary herbs, mint, rosemary, sage, thyme and basil. In contrast, they were absent from species of the other subfamilies of Lamiaceae studied and from the related families Verbenaceae, Scrophulariaceae, Acanthaceae and Buddlejaceae. The compounds were isolated from Plectranthus crassus and identified by NMR spectroscopy as the known caffeic acid esters (Z,E)-[2-(3,5-dihydroxyphenyl)ethenyl] 3-(3,4-dihydroxyphenyl)-2-propenoate and (Z,E)-[2-(3,4-dihydroxyphenyl)ethenyl] 3-(3,4-dihydroxyphenyl)-2-propenoate, for which the trivial names nepetoidins A and B are proposed. The presence of this pair of caffeic acid esters adds another character to the chemical, palynological and embryological features distinguishing the Nepetoideae from the other subfamilies of Lamiaceae and related families, and supports the view that the Nepetoideae are a specialised and monophyletic group within the family. Nepetoidin B was shown to have a greater antioxidant activity than gallic, rosmarinic and caffeic acids, and showed activity as an insect phagostimulant. Both compounds were antifungal.

Applications of phytochemical and in vitro techniques for reducing over-harvesting of medicinal and pesticidal plants and generating income for the rural poor

Plants provide medicine and pest control resources for millions of poor people world-wide. Widespread harvesting of medicinal and pesticidal plants puts pressure on natural populations, thus severely compromising their contribution to the income and well-being of traders and consumers. The development of in vitro propagation techniques appropriate for developing countries will provide a robust platform for effective propagation and cultivation of endangered plants. This review focuses on advances in the application of phytochemical and in vitro tools to identify and rapidly propagate medicinal and pesticidal plants. Problems of over-harvesting can be alleviated and ex situ cultivation in agroforestry systems can be facilitated through improving seed germination, in vitro cloning and the use of mycorrhizal fungi. We also present a case for effective use of phytochemical analyses for the accurate identification of elite materials from wild stands and validation of the desired quality in order to counter loss of efficacy in the long run through selection, propagation or ex situ management in agroforestry systems. Future prospects are discussed in the context of medicinal activity screening, sustainable propagation, on-farm planting, management and utilization.