Antioxidant activity of uruguayan propolis. In vitro and cellular assays

The antioxidant capacity of propolis from the southern region of Uruguay was evaluated using in vitro as well as cellular assays. Free radical scavenging capacity was assessed by ORAC, obtaining values significantly higher than those of other natural products (8000 μmol Trolox equiv/g propolis). ORAC values correlated well with total polyphenol content (determined by Folin-Ciocalteu method) and UV absorption. Total polyphenol content (150 mg gallic acid equiv/g propolis) and flavonoids (45 mg quercetin equiv/g propolis) were similar to values reported for southern Brazilian (group 3) and Argentinean propolis. Flavonoid composition determined by RP-HPLC indicates a strong poplar-tree origin. Samples high in polyphenols efficiently inhibit low-density lipoprotein lipoperoxidation and tyrosine nitration. In addition, Uruguayan propolis was found to induce the expression of endothelial nitric oxide synthase and inhibit endothelial NADPH oxidase, suggesting a potential cardiovascular benefit by increasing nitric oxide bioavailability in the endothelium.     

Studies on plant regeneration and somaclonal variation in Saintpaulia ionantha Wendl. (African violet)

Efficient plant regeneration of Saintpaulia ionantha (African violet) has been obtained in the present study. MS medium supplemented with 1.0 mg L(-1) IAA and 2.0 mg L(-1) Zeatin resulted in 100% shoot regeneration and induced the highest number of shoots (average 15.0 +/- 0.8 shoots per explant) after being cultured for 8 weeks. The above hormone combination was optimum for shoot regeneration. Most of Saintpaulia ionantha plantlets derived from tissue culture system could be hardened and transferred to the greenhouse conditions with 84.0 +/- 1.6% success rate. However, regenerated plantlets of Saintpaulia ionantha (even after 12-months-old) failed to flower. Morphological characters of regenerated plantlets of Saintpaulia ionantha were observed and compared with in vivo (intact) plants. Regenerated plantlets showed some differences in morphological characters, such as height and leaf size, texture and colour, but the plantlets showed no variation in leaf arrangement and leaf margin. However, the morphological characters of the regenerated plantlets were found to be unstable.     

The effect of different hormones and incubation periods on in vitro proliferation of pineapple (Ananas comosus L.) Merr cv. smooth cayenne) shoot-tip culture

Seven different hormone treatments, namely 6-benzylaminopurine (BAP) at 2, 3 mg L(-1) was applied singly and in combination with Indole Acetic Acid (IAA) at 0.18, 0.8 and 1.8 mg L(-l), BAP at 3.3 mg L(-l) in combination with IAA at 1.8 and 3.3 mg L(-l) and triple combination of BAP at 2.3, IAA at 1.8 and Gibberellic acid (GA3) at 1.0 mg L(-1) were tested, over four different incubation periods of 30, 45, 60 and 75 days, for their effect in the proliferation and growth of Smooth cayenne pineapple shoot-tip culture. Combined application of BAP at 3.3 and IAA at 1.8 mg L(-1) induced the highest proliferation of 19 shoots/explant and the highest total of 121 and 125 shoots over 4 cycles of multiplication. Raising the IAA to 3.3 mg L(-1) resulted in the lowest proliferation and stunted shoots. Incorporation of GA3 improved the shoot length but caused drastic reduction in proliferation. The other treatments showed an intermediate effect.     

New phenantrene alkaloids from Cryptocarya crassinervia

The bark of Cryptocarya crassinervia provided two new phenantrene alkaloids, 2-hydroxyatherosperminine (1) and N-demethyl-2-methoxyatherosperminine (2).     

Agronomic characterization of diploid hybrid families derived from crosses between haploids of the common potato and three wild Argentinian tuber-bearing species

Five diploid hybrid families derived from crosses between haploids of three Argentinian cultivars and three diploid wild species,Solanum gourlayi, S. chacoense andS. spegazzinii, were evaluated in a field experiment in Balcarce. All plants were androsterile and, thus, could not be screened for 2n pollen production. Data on agronomic tuber traits were statistically analyzed. Differences among families were non-significant for tuber number/plant, but were significant for tuber weight/plant and dry matter content (with values above 21.0% in two of them). The relative frequencies of tubers in the categories established for size, skin texture, and eye depth were family dependent, but they were familiy independent in the categories established for tuber shape and skin color. Great morphological variability was detected for all the traits studied, and plants with high yield and high dry matter content were identified. These families can be used as sources of germplasm in breeding and to explore heterotic responses in 2x × 4x crosses, given the capacity of some plants to produce 2n eggs, as found in a related investigation.     

Effect of sequential subcultures on in vitro proliferation capacity and shoot formations pattern of pineapple (Ananas comosus L. Merr.) over different incubation periods

In vitro obtained shoots of pineapple (Ananas comosus L. Merr.) cv Smooth cayenne was cultured on MS medium enriched with 6-benzylaminopurine (BAP) at 3.25 mg l⁻¹ (14.43 μM) and indole acetic acid (IAA) at 1.75 mg 1⁻¹ (9.40 μM) and subcultured for four times at four different incubation periods (30, 45, 60 and 75 days). By the fourth subculture, irrespective of incubations periods, the explants lost 50% of its shoot formation capacity. Longer incubation resulted on higher rate and total shoots than a shorter incubation, however, the magnitude of that different varied over subcultures. The difference in shoots formation between the explants incubated for 30 and 75 days was 6 shoots at first, increased to 21 at the third and declined to 11 shoots at the fourth subculture. Over a period of 75 days, the majority of shoots formation occurred during the first 30 days (35%) at a rate of 1.5 shoot per week and the last 15 days (40%) at a rate of 3.8 shoot per week. In the period between 30 and 60 days, 15% of shoots at rate of 1.8 and 10% at rate of 1.0 shoot per week formed during the first and the second 15 days interval, respectively. Over four consecutive subcultures, explants incubated for 30 days produced the lowest total (1028 shoots) and that incubated for 75 days produced the highest total (120,917 shoots) from a single explant. No significant differences in total were observed between explants incubated for 45 and 60 days over the first three subcultures. However, by the fourth subculture the total of 60 days (14,288 shoots) was two times higher (7163 shoots) than that of 45 days long incubation.     

Assessment of the pharmacological interactions between the nematodicidal fenbendazole and the flukicidal triclabendazole: In vitro studies with bovine liver microsomes and slices

Parasitic diseases have a significant impact on livestock production. Nematodicidal drugs, such as fenbendazole (FBZ) or its oxidized metabolite oxfendazole (OFZ), can be used along with the trematodicidal triclabendazole (TCBZ), to broaden the spectrum of anthelmintic activity. However, co‐exposure to these compounds could lead to drug–drug (D‐D) interactions and eventually alter the clinical profile of each active principle. The aim of this study was to assess the presence of such interactions by means of two in vitro models, namely bovine liver microsomal fractions and bovine precision‐cut liver slices (PCLSs). To this end, an in vitro assessment involving incubation of FBZ and TCBZ or a combination of FBZ and TCBZ was carried out. Results with microsomal fractions showed a 78.4% reduction (p = .002) in the rate of OFZ production upon co‐incubation, whereas the sulfoxide metabolite of TCBZ (TCBZSO) exhibited a decreasing tendency. With PCLS, OFZ accumulation in the incubation medium increased 1.8‐fold upon co‐incubation, whereas TCBZSO accumulation decreased by 28%. The accumulation of FBZ and OFZ in the liver tissue increased upon 2‐hr co‐incubation, from 2.1 ± 1.5 to 18.2 ± 6.1 (p = .0009) and from 0.4 ± 0.1 to 1.3 ± 0.3 nmol (p = .0005), respectively. These results confirm the presence of D‐D interactions between FBZ and TCBZ. Further studies are needed to determine the extent of involvement of drug‐metabolizing enzymes and membrane transporters in interactions between compounds largely used in livestock production systems.     

Antimicrobial activity of Viola tricolor herb

The antimicrobial activity of infusion, decoction, ethanol extract and fractions obtained by successive extraction of Viola tricolor herb with dichloromethane, ethyl acetate and methanol was evaluated. The infusion, decoction and ethanol extract were found to be most effective against the tested microorganisms.     

Triterpenes and steroids from the leaves of Aglaia exima (Meliaceae)

A study on the leaves of Aglaia exima led to the isolation of one new and seven known compounds: six triterpenoids and two steroids. Their structures were elucidated and analyzed mainly by using spectroscopic methods; 1D and 2D NMR, mass spectrometry, UV spectrometry and X-ray. All the triterpenoids and steroids were measured in vitro for their cytotoxic activities against eight cancer cell lines; lung (A549), prostate (DU-145), skin (SK-MEL-5), pancreatic (BxPC-3), liver (Hep G2), colon (HT-29), breast (MCF-7) and (MDA-MB-231). The new cycloartane triterpenoid, 24(E)-cycloart-24-ene-26-ol-3-one 1, showed potent cytotoxic activity against colon (HT-29) cancer cell line (IC₅₀ 11.5 μM).