Isolation and characterization of Stigmasta-7, 22-dien-3-ol (α-Spinasterol) from Entada africana stem bark crude extract

The phytochemical investigation of the stem bark extracts of Entada africana led to the isolation and characterization of Stigmasta-7,22-dien-3-ol from the dichloromethane soluble portion of acetone/methanol (1:1v/v) crude extract. The powdered stem bark sample of Entada africana was defatted with hexane and extracted with acetone/methanol (1:1v/v) mixture. The dichloromethane soluble fraction was purified on a low pressure column containing silica gel 60 (60-200 mesh). The purification afforded an isolate coded Enac3 (85 mg) with Rf value of 0.404 in hexane/ethyl acetate (4:1). The isolate was characterized using IR, NMR data and in comparison with literature. Analysis of spectroscopic data and literature comparison suggests Enac3 as stigmasta-7, 22-dien-3-ol. The isolation of stigmasta-7, 22-dien-3-ol from the stem bark of Entada africana suggests the presence of useful bioactive principles which could be exploited for medicinal purposes.

Tannin Content of the Bark and Branch of Caatinga Species

This research aimed to determine the concentration of tannins in the bark and in the branches of ten species of Caatinga occurrence. The Folin-Denis colorimetric method was used to determine the phenol content and the tannins are precipitated using a protein. The tannin content was obtained by the difference between the supernatant and the non-tannic phenol content. The data were subjected to the Shapiro-Wilk normality’s test and after, to Analysis of Variance using a 2x10 factorial design and Turkey’s test was used to detect differences. For bark sample, the species Parapiptadenia zehntneri, Parapiptadenia rigida and Libidibia ferrea presented the three highest percentages among the studied species, being 10.84%, 10.74% and 10.27%, respectively. For branch sample, Aspidosperma pyrifolium presented the highest percentage of tannins among the ten species, with 9.15% of these substances. It is possible to suggest the use of other parts of the tree to extract the tannins, such as the branches and their bark, offering an alternative for the extraction that is usually made from the main trunk and providing sustainability to the Caatinga.

Simulation of fuel bed ignition by wildland firebrands

A 3-D mathematical model of fuel bed (FB) ignition initiated by glowing firebrands originating during wildland fires is proposed. In order to test and verify the model, a series of experiments was conducted to determine the FB ignition time by a single pine bark and twig firebrand (Pinus sylvestris). Irrespective of the pine bark sample sizes and experimental conditions, the ignition of the FB was not observed. Conversely, pine twigs, under certain parameters, ignited the FB in the range of densities (60–105 kg m−3) and with the airflow velocity of ≥2 m s−1. The results of the mathematical modelling have shown that a single pine bark firebrand ≤5 cm long with a temperature of T ≤ 1073 K does not ignite in the flaming mode the FB, and only the thermal energy of larger particles is sufficient for flaming ignition of the adjacent layers of the FB. The analysis of the results has shown that the firebrand length is a major factor in the initiation of ignition. Comparison of the calculated and observed FB ignition times by a single firebrand have shown that our modelling accords well with the experimental results.

Natural Populations of Saccharomyces kudriavzevii in Portugal Are Associated with Oak Bark and Are Sympatric with S. cerevisiae and S. paradoxus

ABSTRACT Here we report the isolation of four Saccharomyces species (former Saccharomyces sensu stricto group) from tree bark. The employment of two temperatures (10°C in addition to the more commonly used 30°C) resulted in the isolation of S. kudriavzevii and S. uvarum, two species that grow at low temperatures, in addition to S. cerevisiae and S. paradoxus. A clear bias was found toward the bark of certain trees, particularly certain oak species. Very often, more than one Saccharomyces species was found in one locality and occasionally even in the same bark sample. Our evidence strongly suggests that (markedly) different growth temperature preferences play a fundamental role in the sympatric associations of Saccharomyces species uncovered in this survey. S. kudriavzevii was isolated at most of the sites sampled in Portugal, indicating that the geographic distribution of this species is wider than the distribution assumed thus far. However, the Portuguese S. kudriavzevii population exhibited important genetic differences compared to the type strain of the species that represents a Japanese population. In this study, S. kudriavzevii stands out as the species that copes better with low temperatures.

UJI AKTIFITAS ANTIKANKER EKSTRAK ETANOL KULIT BATANG Bruguiera gymnorhiza TERHADAP SEL MEYLOMA

Mangrove vegetation especially tanjang (Bruguiera gymnorhiza) known as a kind of plant that used as an ingredients for traditional medicine. Bioactive compound in tanjang bark has potential medical. Although there is no previous experiment about tanjang bark, few compounds from Bruguiera genus has been experimented and has an activity as an anti-cancer and anti-tumor. The purpose of this experiment is to conduct sitotoxicity tanjang bark against Meyloma cell. Tanjang bark sample that used obtained from Tritih beach at Cilacap. Tanjang bark that has been cleaned and dried is cut and then crused until it obtain powder. The powder is been maceration with 96% ethanol and been evaporation. The extract that obtain is used in sitotoxicity test using MTT (3-(4,5-dimethylthiazoil-2-il)-2,5-diphenil tetrazolium bromide) method toward Meyloma cell after 24 hour of incubation using several concentration variation. Tanjang bark extract in ethanol has LC50 value 508.19 mg/ml. Morphology analyze and nuclear staining shows that there is apoptosis activity even in small amount. The result shows that tanjang bark extract has a potency as an anti-cancer toward Meyloma cell.