Volume 69, Issue 9-10

Three hitherto unknown di-O-xylosyl-C-glycosyl flavones were isolated from the leaves of Caesalpinia ferrea. The structures of all isolated compounds were elucidated by conventional methods and spectroscopic analysis, including 1D and 2D NMR, as well as by HRESIMS.

A new phenolic-type compound containing a nitrogenous, heterocyclic-fused ring from the fruit of the argan tree, Argania spinosa (Skeels L.), is described. This and another already known compound also isolated in the course of the work belong to an obscure and rare class of natural products, the amino phenolics.

series of 2-(p-substituted phenyl)-5-(2-{4-[(p-chloro-fluorophenyl)=phenyl] piperazin-1-yl}- acetamido)-benzoxazoles were synthesized and tested for their antimicrobial activities. The structures of the new derivatives were elucidated by spectral techniques. The minimum inhibitory concentrations (MIC) of the new benzoxazoles, along with those of previously synthesized analogues, were determined against standard bacterial and fungal strains and drug-resistant isolates, and compared with those of several reference drugs. The new benzoxazole derivatives were found to possess a broad spectrum of antimicrobial activity with MIC values of 32 - 1024 μg/ml. Although the standard drugs were more active against the tested pathogens, the activities of the new benzoxazoles and the reference drugs were largely similar against the drug-resistant isolates.

Previously we had isolated two prenylated flavanones and two prenylated dihydrochalcones, macatrichocarpins A-D (1 - 4), from the acetone extract of the leaves of Macaranga trichocarpa. Reexamination of the fractions containing minor components resulted in the isolation of four more flavonoid derivatives, including two new prenylated dihydrochalcones, oxymacatrichocarpin C (5) and isomacatrichocarpin C (6). The structures of these compounds were determined by the analysis of UV, NMR, and mass spectral data. The eight isolated flavonoids were tested on eight pathogenic bacteria and found to be mostly moderate antibacterial agents, with the lowest MIC value of 26.5 μM achieved by the flavanone macatrichocarpin A (1) against Bacillus subtilis.

Two endemic Cirsium species, C. leucopsis DC. and C. sipyleum O. Schwarz, and C. eriophorum (L.) Scop. growing in Turkey were investigated to establish their secondary metabolites, fatty acid compositions, and antioxidant and anticholinesterase potentials. Spectroscopic methods were used to elucidate the structures of thirteen known compounds (p-hydroxy-benzoic acid, vanillic acid, cisepoxyconiferyl alcohol, syringin, balanophonin, 1′-O-methyl-balanophonin, apigenin, kaempferol-3- O-β-D-glucopyranoside, kaempferol-3-O-α-L-rhamnopyranoside, taraxasterol, taraxasterol acetate, β-sitosterol, β-sitosterol-3-O-β-D-glucopyranoside). cis-Epoxyconiferyl alcohol and 1′-O-methylbalanophonin were isolated for the first time from Cirsium species. Palmitic acid (47:1%) was found to be the main fatty acid of C. leucopsis, linoleic acid in both C. sipyleum (42:1%) and C. eriophorum (37:8%). Assays of b-carotene bleaching, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium (ABTS) cation radicals, and superoxide anion radicals, as well as cupric reducing antioxidant capacity (CUPRAC) were used to determine the antioxidant activities of the extracts and isolated compounds. Vanillic acid, balanophonin, and kaempferol-3-O-α-L-rhamnopyranoside exhibited strong antioxidant activity. Taraxasterol was a potent inhibitor of acetyl- and butyrylcholinesterase activity, respectively.

The antihyperglycemic activity of the extracts and preparations of solid lipid nanoparticle suspensions of two mistletoes growing in Saudi Arabia, Plicosepalus acaciae and P. curviflorus, as well as their possible antioxidant effect were investigated in a type 2 diabetic animal model. Type 2 diabetes was induced in adult maleWistar rats by a high-fat diet followed by injection of streptozotocin (STZ). The diabetic rats were treated in parallel with pioglitazone hydrochloride (PIO), non-toxic extracts of P. acaciae and P. curviflorus, as well as three different solid lipid nanoparticle (SLN) suspension formulations prepared from each of the two extracts. Blood glucose level, insulin resistance, oxidative stress parameters, and antioxidant markers were determined. The total extracts of P. acaciae and P. curviflorus as well as the SLN formulations exhibited a significant blood glucose-lowering effect associated with antioxidant effects in the diabetic rats. The SLN preparation with the highest lipid content gave the best result. Reduction of hyperglycemia and insulin resistance in the diabetic rats was, at least partly, due to the antioxidant activities of the extracts and their SLN formulations.

A hydroponic culture experiment was conducted to study the effect of copper toxicity on root morphology, ultrastructure, and copper accumulation in Moso bamboo (Phyllostachys pubescens). Root ultrastructure of Moso bamboo was studied by transmission electron microscopy and scanning electron microscopy. Application of 200 μM Cu resulted in an accumulation of 810 mg kg -1 dry weight and 91 mg kg -1 dry weight Cu in roots and shoots, respectively. The majority of the plants did not survive the application of 400 μM Cu. Biomass production declined consistently with application of each additional increment of Cu. Root growth was more severely inhibited than shoot growth. Cu adversely affected the root morphology of the plants, however, root surface area and number of root tips increased slightly at low levels of Cu. Root cell ultrastructure and organelles changed significantly under Cu stress, in particular, cell walls, mitochondria, and xylem parenchyma were affected.

Cucurbita maxima (CM) seed oil is commonly used in Indian folk medicine to treat various ailments. We have investigated the effect of CM seed oil on memory impairment induced by scopolamine in rats. Male adult Wistar rats were administered scopolamine 1 mg/kg body weight, i.p. or 1:25 mg/kg body weight, s.c. to induce memory impairment. The nootropic agent piracetam 100 mg/kg body weight, i.p. and CM seed oil 100 and 200 mg/kg body weight, p.o. were administered daily for five consecutive days. The memory function was evaluated in the Morris water maze (MWM) test, the social recognition test (SRT), the elevated plus maze (EPM) test, and the pole climbing test (PCT). Acetylcholinesterase (AChE) activity and oxidative stress parameters were estimated in the cortex, hippocampus, and cerebellum of the brains after completion of the behavioural studies. The effects of scopolamine on the levels of the tumour necrosis factor alpha (TNF-α) transcript were also investigated. Scopolamine caused memory impairment in all the behavioural paradigms along with a significant increase in the AChE activity and oxidative stress in the brain. Scopolamine also caused a significant increase in the expression of TNF-α in the hippocampus. CM seed oil exhibited antiamnesic activity as indicated by a significant reduction in the latency time in the MWM test and decreased social interaction during trial 2 in the SRT. Further, treatment with CM seed oil significantly decreased the AChE activity and malondialdehyde levels and increased the glutathione level in brain regions. CM seed oil also significantly decreased the expression of TNF-α in the hippocampus. The effect of CM seed oil on behavioural and biochemical parameters was comparable to that observed in rats treated with piracetam. These results indicate that CM seed oil may exert antiamnesic activity which may be attributed to the inhibition of AChE and inflammation as well as its antioxidant activity in the brain.

Norway spruce (Picea abies) debarking water is an aqueous extract obtained as waste from the debarking of logs at paper mills. The debarking water contains a mixture of natural compounds that can exhibit diverse biological activities, potentially including fungicidal activity on some species of wood-decaying fungi. Thus, we investigated the growth rates of such fungi on agar plates to which debarking water extracts had been added. The experiment included five wood-decaying fungi, viz. Gloeophyllum sepiarium, Oligoporus lateritius, Ischnoderma benzoinum, Junghuhnia luteoalba, and Phlebia sp. Growth reduction was observed for all species at the highest tested concentrations of freeze-dried and ethanol-extracted debarking water, the ethyl acetate-soluble fraction and the diethyl ether-soluble fraction. However, the magnitude of the effect varied between different species and strains of individual species. The brown-rot fungi G. sepiarium and O. lateritius were generally the most sensitive species, with the growth of all tested strains being completely inhibited by the ethyl acetate-soluble fraction. These results indicate that development of antifungal wood-protecting agents from debarking water could potentially be a way to make use of a low-value industrial waste.