Contractile effect of the aqueous extract of Psidium guajava leaves on aortic rings in rat

Aqueous leaves extract of Psidium guajava significantly and dose-dependently (0.25-2 mg/ml) contracted aorta rings. The effect was evaluated also in presence of nifedipine and phentolamine. The sensitivity of the aortic rings to cumulative doses of P. guajava was significantly enhanced in the presence of phentolamine suggesting that the effect of P. guajava was to a large extent mediated by activation of alpha-adrenoceptor and to a lesser extent by acting via calcium ion channel.     

Guava (Psidium guajava L.) trees in a pasture: population model,sensitivity analyses,and applications

A preliminary demographic model is presented for a population of guava (Psidium guajava L.) trees in a pasture. In this paper special attention is devoted to describing both the calculation and testing of the parameters of the model. Some applications of the model are described. It is predicted that the guava population will gradually decline; low seedling survival (due to chemical control of pasture weeds) seems to be the factor governing this trend. Preliminary analyses of total gross energy production and economic income, with and without the guavas, favours the presence of the trees in pastures.     

Linalool production from the leaves of Bursera aloexylon and its antimicrobial activity

The oil of the leaves of Bursera aloexylon was found to contain a high linalool level (96.7 %). The antimicrobial activity tests indicated that the oil was effective against Rhodococcus equi (0.60 mg/ml) and Staphylococcus epidermides (0.15 mg/ml).     

Guava (Psidium guajava L.) trees in a pasture: population model,sensitivity analyses,and applications

A preliminary demographic model is presented for a population of guava (Psidium guajava L.) trees in a pasture. In this paper special attention is devoted to describing both the calculation and testing of the parameters of the model. Some applications of the model are described. It is predicted that the guava population will gradually decline; low seedling survival (due to chemical control of pasture weeds) seems to be the factor governing this trend. Preliminary analyses of total gross energy production and economic income, with and without the guavas, favours the presence of the trees in pastures.     

Antimicrobial activity of coupled hydroxyanthracenones isolated from plants of the genus Karwinskia

The in vitro activity of some isolated hydroxyanthracenones belonging to the genus Karwinskia against four bacteria, six filamentous fungi and four yeast are reported. These hydroxyanthracenones were found to possess antimicrobial activity, particularly against Streptococcus pyogenes, Candida albicans, C. boidinii, C. glabrata and Cryptococcus neoformans; minimal inhibitory concentrations range between 16 and 2 microg/ml.     

番石榴叶的化学成分与药理作用研究动态

简述国内外近年对番石榴叶化学成分与药理作用的研究动态,为该作物的应用研发提供有价值的参考。     

Four new flavonoids from the leaves of Morus mongolica

Four new flavonoids (1–4) were isolated from the leaves of Morus mongolica. The structures were determined on the basis of the spectroscopic methods including UV, IR, HR-ESI-MS, 1D and 2D NMR.     

Protective effect of flavonoids from Astragalus complanatus on radiation induced damages in mice

This study aimed to evaluate the radioprotective effect of flavonoids extracted from the seeds of Astragalus complanatus R.Br. (FAC) and their protective mechanism against radiation damage. FAC increased the survival rate of mice and made the damaged organ injured by ⁶⁰Co γ-irradiation recovered to normal appearance with the mechanism of enhancing immune function and blood-producing function in vivo. The molecule mechanism of FAC against radiation is involved in the reduction of DNA injury and mutation in vitro. Eleven monomers of the FAC were analyzed by HPLC. These results seem to support the use of FAC in relieving radiation damage.     

New flavane gallates isolated from the leaves of Plicosepalus curviflorus and their hypoglycemic activity

Two new flavane gallates were isolated from the leaves of Plicosepalus curviflorus. The structure of the new compounds was established as 2S,3R-3,3′,4′,5,7-pentahydroxyflavane-5-O-gallate (1) and 2S,3R-3,3′,4′,5,5′,7-hexahydroxyflavane-4′,5-di-O-gallate (2), respectively. In addition, seven known compounds (−)-catechin (3), quercetin (4), lupeol (5), β-sitosterol (6), pomolic acid (7), β-sitosterol 3-O-β-d-glucopyranoside (8) and 4-methoxycinnamic acid (9) were reported for the first time from the genus Plicosepalus. Compounds 1, 2 and 3 were investigated for their hypoglycemic activity and showed significant hypoglycemic activity in Swiss Albino mice.     

A new natural spiro heterocyclic compound and the cytotoxic activity of the secondary metabolites from Juniperus brevifolia leaves

A new natural spiro compound 3,4-dehydrotheaspirone and the known arctiol [1β,6α-dihydroxy-4(14)-eudesmene] were isolated from Juniperus brevifolia. Arctiol is reported for the first time in the Juniperus genus. Their structures were established by 1D, and 2D NMR and MS spectra. Antimicrobial and cytotoxic activities of 1 and several secondary metabolites ,,,,,,,,, previously isolated by our group from J. brevifolia were evaluated and some SAR has been established. The 18-hydroxydehydroabietane (4) displayed great antiproliferative activity against cancer cell lines tested, namely HeLa, A-549 and MCF-7. Compound 4 also presented a significant bactericidal effect against Bacillus cereus at different concentrations tested.     

Two new benzophenone glycosides from the fruit of Psidium guajava L.

The ripe edible fruits of Psidium guajava L. was phytochemically investigated, three benzophenone glycosides, 2, 6-dihydroxy-3, 5-dimethyl-4-O-β-D-glucopyranosyl-benzophenone (1), 2, 6-dihydroxy-3-methyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-benzophenone (2), 2, 6-dihydroxy-3, 5-dimethyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-benzophenone (3) were isolated by means of chromatography, and their structures were elucidated on the basis of mass spectrometry, ¹H NMR, ¹³C NMR, HSQC and HMBC data. Compounds 1 and 2 were new benzophenone glycosides, and here we report the complete spectroscopic assignments for 3.     

Antimicrobial activity of flowers from Anthemis cotula

The flavonoid containing total extract of Anthemis cotula flowers, tested at the concentration of 200 μg/ml, showed interesting antimicrobial activity against both Gram-negative and Gram-positive microorganisms.     

Antioxidant compounds from Ebenus pinnata

Activity-guided fractionation of the methanol extract of Ebenus pinnata aerial parts led to the isolation of ombuoside (1), kaempferol 3-O-rutinoside (2), rutin (3), catechin (4), and picein (5), along with beta-sitosterol and beta-sitosterol glucoside. Compounds 1-4 showed significant antioxidant activity in the DPPH, and TEAC, reducing power assays.     

Four new neolignans from the leaves of Tripterygium wilfordii

Four new neolignans, wilfordiols A-D (1-4), together with five known compounds (5-9), were isolated from an aqueous extract of the dried leaves of Tripterygium wilfordii. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRESIMS, and CD experiments. The anti-inflammation activities of compounds 1-9 were evaluated by the inhibitory effect on NO production, in vitro.     

Study on the antimicrobial activity of Hymatanthus sucuba

The antimicrobial activity of Hyamatantus sucuba roots methanol extract, fractions prepared from this extract (n-hexane, CHCl(3), EtOAc, and n-butanol) and some isolated compounds were evaluated against some Gram(+) and Gram(-) bacteria and yeasts.     

Antimicrobial and phytochemical studies on Pedilanthus tithymaloides

The antibacterial and antifungal properties of ethanolic extract of the leaves of Pedilanthus tithymaloides and some of its constituents were investigated by the dilution method.     

Cytotoxic activity of lignans from Hibiscus cannabinus

The antimicrobial and cytotoxic activities of six lignans isolated from the core and bark acetone extracts of Hibiscus cannabinus have been investigated. Two compounds (2 and 3) showed strong cytotoxic activity against HeLa, Hep-2 and A-549 cell lines while compound 5 showed moderate activity on HeLa cells when they were in advanced stage of cellular division. The compounds did not exhibit antimicrobial activity.     

Antidiarrheal activity of dehydroleucodine isolated from Artemisia douglasiana

Dehydroleucodine (DhL), a sesquiterpene lactone obtained from Artemisia douglasiana, was screened for antidiarrheal effects. DhL inhibited castor oil-induced diarrhea in mice by judged by a decrease in the number of wet faeces in the DhL-treatment groups. DhL significantly reduced intestinal transit in mice. Yohimbine and phentolamine counteracted the inhibitory effect of DhL. It is suggested that alpha(2)-adrenergic receptors mediate the effect of DhL in intestinal motility. DhL reduced also intraluminal accumulation of fluid. Thus, the antidiarrheal activity of DhL is possibly related, at least in part, to its inhibitory action against gastrointestinal motility and the inhibition of enteropooling property.     

Phytochemical and antimicrobial activities of the Daniellia oliveri leaves

The n-butanol soluble part and four chromatographic fractions of the aqueous ethanolic extract of the leaves of Daniellia oliveri were investigated for antimicrobial properties. All fractions showed activity against Staphylococcus aureus. A chromatographic fraction showed significant activity against the fungus Tricophyton rubrum.     

Antimicrobial activity of Loranthus micranthus harvested from kola nut tree

Various solvent extracts of Loranthus micranthus exhibited varying degrees of antimicrobial activity. Only the petroleum ether extract showed antifungal activity. The methanol extract showed the best antimicrobial activity against Escherichia coli and Bacillus subtilis.