Cannabigerol: a bibliometric overview and review of research on an important phytocannabinoid

Phytochemistry Reviews - Cannabigerol (CBG) is one of the major phytocannabinoids present in Cannabis sativa L. but is presumed to be an artefact or degradation product of cannabigerolic acid...     

Propolis: chemical diversity and challenges in quality control

Phytochemistry Reviews - Propolis is a resinous natural product produced by honeybees using beeswax and plant exudates. The chemical composition of propolis is highly complex, and varies with...     

AFLP analysis of genetic relationships between barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) landraces from north Shewa in Ethiopia

Local cultivars adapted to specific environmental conditions are the chief source of seed for farmers in Ethiopia and deserve research priority. The aim of this study was, therefore, to determine the genetic relationships between different barley landraces, from north Shewa in Ethiopia so as to differentiate genotypes known by different local names and facilitate their conservation and use in breeding new varieties. Five AFLP primer combinations were analyzed for 19 barley landraces and five malting varieties. The number of scoreable fragments amplified by each AFLP primer combination varied from 49 to 118 with an average of 84.5 and polymorphic fragments for each primer combination varied from 27 to 77 with an average of 58.5. The average percent polymorphism was 69.9% with values ranging from 55.1% to 75.8%. Cluster analysis placed the accessions and malting varieties into one main group while all the farmers’ cultivars, with the exception of two, were in the other main group. It was shown that sampling of germplasm at a given locality might not represent the whole array of genetic variability of locally grown famers’ cultivars. A comprehensive study of all the farmers’ barley cultivars, grown in different parts of Ethiopia, is required to maximize the efforts of germplasm conservation and utilization in national and regional breeding programs.     

The ethnobotany,leaf anatomy,essential oil variation and biological activity of Pteronia incana (Asteraceae)

The only available ethnobotanical information on Pteronia incana has been recorded by the Montagu Museum in the Western Cape Province of South Africa. It was reported that the plant is used to treat influenza, fever, kidney ailments and backache. In common with other species of Pteronia, the plant contains an essential oil reminiscent of pine turpentine oil with β-pinene, limonene, 1,8-cineole, myrcene, spathulenol, p-cymene and methyleugenol as main compounds present in all or most of the samples, with smaller amounts of α-pinene, sabinene, γ-terpinene, terpinen-4-ol, biclogermacrene, globulol and α-bisabolol in some of the distillates. We investigated the oil composition of 11 individual plants collected at three geographically distant localities but found limited variation, both within and between populations. Leaf sections of P. incana showed that it is anatomically similar to P. divaricata in the presence of a secretory duct associated with the main vascular bundle (and often other bundles as well), in addition to glandular and non-glandular trichomes on both leaf surfaces. One yeast (Cryptococcus neoformans), two Gram-negative bacteria (Moraxella catarrhalis and Klebsiella pneumoniae) and one Gram-positive bacterium (Mycobacterium smegmatis) were selected for antimicrobial activity studies using the minimum inhibitory concentration (MIC) microtitre plate method. The results showed that methanol:dichloromethane (MeOH:CH₂Cl₂) extracts were active against M. smegmatis (lowest MIC values of 0.5–0.8 mg/ml) and C. neoformans (lowest MIC values of 0.5–2.0 mg/ml). The essential oil was most active against C. neoformans (lowest MIC value of 0.3 mg/ml). These results provide a scientific rationale for the use of P. incana in Cape herbal medicine.     

Ethnobotany,leaf anatomy,essential oil composition and antibacterial activity of Pteronia onobromoides (Asteraceae)

Available ethnobotanical information on Pteronia onobromoides (first recorded in 1685) indicates that the plant was once of considerable cultural and commercial importance and that it was powdered, mixed with fat, and applied to the skin for cosmetic and/or medicinal purposes. Sâb, as well as Son or San, are considered to be the original Nama names for this aromatic bush and also the origin of various names for San people, such as Sonqua and Bushman. A study of the leaf anatomy showed that essential oil is produced in globose oil glands situated below some of the vascular bundles in the spongy parenchyma, adjacent to the palisade parenchyma. The oil is relatively complex but contains a combination of myrcene, limonene, 1,8-cineole and p-cymene as main compounds, with smaller amounts of sabinene, trans-linalooloxide, linalool, terpinen-4-ol, α-terpineol, eugenol, thymol and α-phellandrene. Dichloromethane extracts exhibited antibacterial activity (especially against Staphylococcus epidermidis) with MIC values as low as 0.83 mg/ml. Other solvent extracts and the essential oil itself were less active. The results show that the traditional method of mixing powdered leaves with fat and applying it to the skin may have had deodorant, disinfectant and medicinal benefits.     

Red blood cell fatty acid profile of chronic renal failure patients receiving maintenance haemodialysis treatment

Increased prostaglandins (PGs) are associated with many inflammatory pathophysiological conditions; and are synthesized from arachidonic acid by either of 2 enzymes, cyclooxygenase-1 (COX-1) or -2 (COX-2). Recent epidemiologic, expression, and pharmacologic studies suggest COX-2 derived metabolites also play a functional role in the maintenance of tumor viability, growth and metastasis. Archival and/or prospectively collected human tissues were prepared for immunohistochemistry, and representative cases assayed via Western blot, RT-PCR, or TAQman analysis. Consistent overexpression of COX-2 was observed in a broad range of premalignant, malignant, and metastatic human epithelial cancers. COX-2 was detected in ca. 85% of the hyperproliferating, dysplastic, and neoplastic epithelial cells, and in the existing and angiogenic vasculature within and adjacent to hyperplastic/neoplastic lesions. These data collectively imply COX-2 may play an important role during premalignant hyperproliferation, as well as the later stages of invasive carcinoma and metastasis in various human epithelial cancers.     

Distribution and chemotaxonomic significance of flavonoids inAloe (Asphodelaceae)

A chemotaxonomic study of practically all the species of the genusAloe showed that flavonoids occur as major compounds in 31 out of a total of 380 species investigated. Flavanones and dihydroflavonols are present in the exudate of species inAloe ser.Rhodacanthae andSuperpositae and also in a number of the endemic species from Madagascar. Flavones occur as the only major compound in the leaf extracts of the sects.Leptoaloe andGraminialoe. In ser.Macrifoliae and inLomatophyllum, the sister genus ofAloe, isovitexin co-occurred with theC-glucosylanthrone aloin. The chemotaxonomic implication of these results are discussed together with the significance of the taxonomic and chemogeographical distribution of flavonoids inAloe. With a few rare exceptions, the leaf compounds from two different biogenetic pathways (polyketide pathway and flavonoid pathway) are mutually exclusive. Since flavonoids are restricted to the basal groups inAloe, we conclude that flavonoids are plesiomorphic characters inAloe reflecting ancient phylogenetic and biogeographic links.     

6'-O-Coumaroylaloesin from Aloe castanea--a taxonomic marker for Aloe section Anguialoe

The structure of 6'-O-coumaroylaloesin [2-acetonyl-8-(6-O-coumaroyl-beta-D-glucopyranosyl)-7-hydrox y-5-methylchromone], a mono-ester chromone derivative in which only the 6-position of the glucosyl moiety is esterified, was determined by spectroscopic methods. The compound is a unique chemotaxonomic character restricted to the six species in Aloe section Anguialoe.