Inspired by vitamin A for anti-ageing: Searching for plant-derived functional retinoid analogues.

Background: Cosmetic treatments that inspire one's appearance to resemble their younger portrait often utilize ingredients that confer acute effects, particularly hydration by creating hydrophobic barriers or transient elevation of barrier water content. But superior therapies successfully promote morphogenesis of the dermal-epidermal junction, inspiring extracellular matrix (ECM) formation. This can be achieved by agonism of the very well-known retinoid nuclear receptors using the endogenous ligand all-trans retinoic acid (tRA), tRA precursors or plant-based functional analogues, with reduced side effects. Aims Materials and Methods: While there are already many promising cosmetic ingredients available from the world's flora, higher potency is favoured, so increasing known candidates is a worth undertaking. Functional analogues of retinoic acid can be identified by culturing fibroblasts with lipophilic candidates from the plant kingdom and assessing gene-arrays. Modern approaches to validating these findings include the coculturing of fibroblasts with keratinocytes as a measure to predict the potential effects of crosstalk. Results and Discussion: In this regard, the most promising plant-derived candidates are of terpene or meroterpene origin, including derivatives of squalene and phytol. Surprisingly pimaric or abietic acids and labdane diterpenes are also noteworthy agonists of the retinoic acid receptor, stimulating collagen expression in dermal fibroblasts. Conclusion: There are numerous derivatives of these terpenes available from the world's flora and research conducted thus far encourages further screening of these chemical candidates.

Synthesis of CDE molecular fragments related to sendanin mediated by titanocene(III).

A practical, brief, and diastereoselective synthesis of limonoid CDE fragments from a readily available starting material is described. The key step was the titanocene(III)-promoted cyclization of unsaturated epoxylactones, readily prepared from α-cyclocitral. In this way, we confirm the viability of our procedure for the synthesis of a limonoid model with different functionalization patterns. We also report the antifeedant activity of epoxylactones 18 and 19, which show significant antifeedant activity against Spodoptera littoralis and Spodoptera frugiperda, two insect species with different feeding ecologies.

Antibacterial compounds from the mushroom Ganoderma colossum from Nigeria.

Three colossolactones (colossolactone E, colossolactone B and 23-hydroxycolossolactone E) were isolated and characterized from an n-hexane:dichloromethane (2:7) extract of Ganoderma colossum using chromatographic techniques. The antimicrobial activity of the three compounds was then tested against Gram-positive and Gram-negative bacteria. The activity was evaluated by the thin-layer chromatography agar overlay method. The results showed that colossolactone E and 23-hydroxycolossolactone E were active against Bacillus subtilis and Pseudomonas syringae. Colossolactone B was not active against the bacteria. Their structures were elucidated by spectroscopic methods. Potency of the compounds against bacteria tested supports the use of this mushroom in therapeutic medicine.

Therapeutic uses of Aloe L. (Asphodelaceae) in southern Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: The African-Arabian succulent genus Aloe L. (Aloaceae/Asphodelaceae) is represented by approximately 120 infrageneric taxa in southern Africa, including A. ferox Mill., a species long used in commercial natural products. AIMS OF THE STUDY: To assess the documented ethnobotanical knowledge and biocultural value of utility in the genus in southern Africa. MATERIALS AND METHODS: A survey of over 350 multidisciplinary publications was undertaken. RESULTS: Local uses for medicine and wellbeing were identified for over half the species of Aloe occurring in the Flora of Southern Africa region. The most frequently cited medicinal uses were the treatment of infections and internal parasites, digestive ailments and injuries. Numerous species were recorded for their social uses, notably as ingredients in tobacco snuff. CONCLUSION: The exceptional infrageneric diversity of Aloe, and extensive therapeutic uses in southern Africa, indicate its cultural importance in the subcontinent. These factors highlight the need for the conservation of the species as well as their potential as a source of natural products.

Antimicrobial activity of some Ganoderma species from Nigeria.

The crude n-hexane:diethyl ether, chloroform:acetone and methanol extracts of four species of Ganoderma (Ganoderma colossum (Fr.) C. F. Baker, G. resinaceum Boud., G. lucidum (cf.) (Curtis) P. Karst. and G. boninense (cf.) Pat.), from Nigeria, were tested for antimicrobial activity. The three solvent extracts of all the species of Ganoderma were active against Pseudomonas syringae and Bacillus subtilis, whereas none of the extracts were active against Cladosporium herbarum. Preliminary thin layer chromatography chemical tests on these extracts of Ganoderma showed that they contained compounds that stained blue-violet and blue or green when sprayed with anisaldehyde-sulphuric acid or Dragendorff, respectively. The profile of compounds in the extracts showed some variation among the four species.

Toxicity and behavioural effects of diet-borne alkaloids on larvae of the black blowfly, Phormia regina.

Larvae of the black blowfly, Phormia regina (Meigen) (Diptera: Calliphoridae) were exposed for 24 h to artificial diets that contained one of the following alkaloids: arecoline, caffeine, nicotine, quinine, sparteine or strychnine at either 1000 or 100 p.p.m. Each of the alkaloids caused reduced weight gain, relative to a control population in a no-choice bioassay and, with the exception of quinine, all alkaloids caused reduced larval weights in a choice bioassay. Larvae were unable to move away from diets containing arecoline (1000 and 100 p.p.m) and congregated away from diets containing 1000 p.p.m. quinine. Arecoline (1000 p.p.m) and both concentrations of nicotine caused significant mortality of larvae. Over a longer period (120 h), 10 and 1 p.p.m. nicotine resulted in significant numbers of larvae congregating away from a treated diet. Ten p.p.m. nicotine caused reduced weight gain over 120 h, although larvae provided with a choice were less affected. Exposure of larvae to dried residues of nicotine for 2 h did not affect subsequent development.

Two novel assays for the detection of haemin-binding properties of antimalarials evaluated with compounds isolated from medicinal plants.

Forty-two compounds isolated from nine plants used within South America for the treatment of malaria were tested for haemin binding using two novel, rapid screening methods. The data obtained were analysed with respect to IC(50) values for in vitro toxicity to Plasmodium falciparum trophozoites. One method, a multiwell assay based on the inhibition of the interaction of haemin with glutathione (GSH), is sensitive in the 10 microM range, takes c. 1 h and is suitable for either a high throughput screen or rapid assay during natural product isolation. Of 19 compounds showing antiplasmodial activity (IC(50) < 40 microM), 16 (84%) showed >40% inhibition of GSH-haemin reaction. The sensitivity and specificity of the assay were 0.85 and 0.82, respectively. The positive predictive value was 0.81 and the negative predictive value 0.86. A more sensitive assay (0.1 microM range) is based on the reversal by haemin-binding compounds of the haemin inhibition of the L-dopachrome-methyl ester tautomerase activity of human macrophage migration inhibitory factor. This assay gives a better idea of the affinity of interaction and uses very small amounts of test compound. The log[RI(50)] of eight of the compounds that tested positive in the above assays together with those of quinine and chloroquine showed a positive correlation with log[antiplasmodial IC(50)] for strain T9-96 (r = 0.824) and strain K1 (r = 0.904). Several of the antimalarial compounds that bind haemin are isoquinolines, a class not shown previously to interact with haemin.

Can larvae of the pod-borer, Helicoverpa armigera (Lepidoptera: Noctuidae), select between wild and cultivated pigeonpea Cajanus sp. (Fabaceae)?

Experiments were conducted to observe the feeding and food selection-behaviour of different instars of the pod-borer Helicoverpa armigera (Hübner) in response to choices between the cultivated and a wild species of Cajanus. First and second instars fed upon a cultivated variety of Cajanus cajan in preference to a wild species, C. scarabaeoides and on flowers of C. cajan, rather than pods or leaves of C. cajan. First and second instars preferred pods of C. scarabaeoides with trichomes removed to pods with trichomes present. All instars fed upon pods of C. cajan rather than those of C. scarabaeoides. Solvent extraction of the pod surfaces affected the feeding of larvae, in some instances. They preferred the unextracted pods of C. cajan; the extracted pod of C. scarabaeoides (first and second instars) or the unextracted pod of C. scarabaeoides (fourth and fifth instars). Glass-fibre disc bioassays showed that the methanol, hexane and water extracts from the pod-surface of C. cajan stimulated the feeding of fifth instars. The experiments have shown that characteristics of C. cajan, such as either the compounds present or the type and distribution of trichomes on the plant surfaces, can determine the susceptibility of C. cajan to pod-borer larvae.