Acute toxicity evaluation, antibacterial, antioxidant and immunomodulatory effects of Melastoma malabathricum

Melastoma malabathricum (MM) is a well-known plant in Malaysian traditional medicine, locally known as senduduk. Its ethanol and aqueous extracts have been used in the present investigation to study the immunomodulatory role on human peripheral blood mononuclear cell (PBMC), and the DPPH, ABTS and FRAP free radical scavenging activities were also measured. Total flavonoids and total phenolic contents were assayed and the antibacterial effect was tested against four species of bacteria; two Gram-positive (Staphylococcus aureus and Streptococcus agalactiae) and two Gram-negative (Escherichia coli and Klebsilla pneumonia). The tests were carried out using the disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Moreover, the acute toxicity was evaluated in vivo on the ethanol extract of MM to establish its safety when administered orally. In our results, both extracts of MM showed abilities to scavenge DPPH and ABTS free radicals, IC(50) values: (11.599 ± 0.84, 10.573 ± 0.58 μmol/L) and (62.657 ± 0.78, 63.939 ± 0.48 μmol/L) for ethanol and aqueous extracts respectively. Indeed the ethanol extract evidenced high phenolic content (384.33 ± 0.005 mg/g), flavonoids contents (85.8 ± 0.009 mg/g) and ferric reducing antioxidant power (33,590 ± 0.038 mmol/g), with high activity against S. aureus and S. agalactiae (11 ± 0.3 and 12 ± 0.6 mm inhibition zones). Likewise, the percentage of peripheral blood mononuclear cells (PBMC) viability was increased in response to MM, IC(50) values (1.781 ± 1.2 and 6.545 ± 0.93 μg/mL) for ethanol and aqueous extracts, respectively. In addition, our results showed that the MM extract is safe even at a high dose of 5,000 mg/kg and has no oral toxicity. These findings suggest the excellent medicinal bioactivity of MM and explain the popularity of this plant in the folk medicine as a remedy for different illnesses.     

Effects of Pithecellobium jiringa ethanol extract against ethanol-induced gastric mucosal injuries in Sprague-Dawley rats

Current anti-gastric ulcer agents have side effects, despite the progression and expansion of advances in treatment. This study aimed to investigate the gastroprotective mechanisms of Pithecellobium jiringa ethanol extract against ethanol-induced gastric mucosal ulcers in rats. For this purpose, Sprague Dawley rats were randomly divided into five groups: Group 1 (normal control) rats were orally administered with vehicle (carboxymethyl cellulose), Group 2 (ulcer control) rats were also orally administered with vehicle. Group 3 (positive control) rats were orally administered with 20 mg/kg omeprazole, Groups 4 and 5 (experimental groups) received ethanol extract of Pithecellobium jiringa ethanol extract at a concentration of 250 and 500 mg/kg, respectively. Sixty minutes later, vehicle was given orally to the normal control group, and absolute ethanol was given orally to the ulcer control, positive control and experimental groups to generate gastric mucosal injury. The rats were sacrificed an hour later. The effect of oral administration of plant extract on ethanol-induced gastric mucosal injury was studied grossly and histology. The level of lipid peroxidation (malondialdehyde-MDA), superoxide dismutase (SOD) and gastric wall mucus were measured from gastric mucosal homogenate. The ulcer control group exhibited severe gastric mucosal injury, and this finding was also confirmed by histology of gastric mucosa which showed severe damage to the gastric mucosa with edema and leucocyte infiltration of the submucosal layer. Pre-treatment with plant extract significantly reduced the formation of ethanol-induced gastric lesions, and gastric wall mucus was significantly preserved. The study also indicated a significant increase in SOD activity in gastric mucosal homogenate, whereas a significant decrease in MDA was observed. Acute toxicity tests did not show any signs of toxicity and mortality up to 5 g/kg. The ulcer protective effect of this plant may possibly be due to its preservation of gastric wall mucus along with increased SOD activity and reduction of oxidative stress (MDA). The extract is non-toxic, even at relatively high concentrations.     

农田周围杂草带中普通田鼠种群数量的季节变动特征及杂草带年龄和植被之间的关系

本文中我们采用标志重捕方法从2003到2004年11月,对栖息在野花带的普通田鼠种群结构和数量动态进行比较系统的研究.结果表明,这两年中种群密度夏季最大分别达到410个体/ha和641个体/ha,春季最少分别达到166个体/ha和153个体/ha,从7月份开始增长,8月份种群密度减少并在11月份开始重新增长.种群中雌性个体数量比较多,雌性在种群中的居留时间比较长同时存活率比雄性高,这种现象导致种群数量的季节变化.种群周转率比较高,在两个捕鼠期间种群中的80%个体被更新,这表明普通田鼠在野花带中的活动非常活跃,不断与周围的其它种群进行交流,提高种群对环境的适应能力.种群中雌雄个体的领域之间没有年间变化,它们的活动领域比较小,领域长度2003年平均为11米,最长为37.5米,2004年平均为13米,最长为52米.本研究中我们没有找到环境因素和种群数量动态之间的相关关系.     

Semigroup method for a deteriorating system with multiple vacations of a repairman

Semigroup Forum - By using the method of functional analysis, especially $$C_0$$ -semigroup theory and spectral theory of linear operators we prove the well-posedness and the existence of a unique...     

Synthesis, Analgesic, and Antiparkinsonian Profiles of Some Pyridine, Pyrazoline, and Thiopyrimidine Derivatives

Summary. A series of substituted pyridine, pyrazoline, and thiopyrimidine derivatives were synthesized from 3-acetylpyridine, which was prepared from nicotinic acid as a naturally starting material. The pharmacological screening showed that many of these compounds have good analgesic and antiparkinsonian activities comparable to Voltarene^? and Benzatropine^? as reference drugs. The structure assignment of the new compounds is based on chemical and spectroscopic evidence. The detailed synthesis, spectroscopic data, and pharmacological properties for synthesized compounds are reported.