Effect of Alstonia scholaris bark extract on testicular function of Wistar rats

Abstract Aim: To evaluate the antifertility effect ofAlstonia scholaris bark extract in male rats. Methods: In male Wistar rats Alstonia scholaris bark extract was given by oral route at a dose of 200 mg/day for 60 days. The fertility and testicular function were assessed by mating tests, sperm motility, sperm concentration, biochemical indices and testicular cell population dynamics. Results: Oral feeding with the extract at a dose of 200 mg/day for the period of 60 days did not cause body weight loss, while the weights of testes, epididymides, seminal vesicle and ventral prostate were significantly reduced. The production of step-19 spermatids was reduced by 79.6% in treated rats. The population of preleptotene and pachytene spermatocytes were decreased by 61.9% and 60.1%, respectively. Spermatogonia and Sertoli cell population were also affected. The seminiferous tubule and Leydig cell nuclear area were reduced significantly (P<0.01) when compared to the controls. Reduced sperm count and motility resulted in a total suppression of fertility. A significant fall in the protein and sialic acid content of the testes, epididymides, seminal vesicle and ventral prostate as well as glycogen content of testes were also noticed. The fructose content in the seminal vesicle was lowered whereas the testicular cholesterol was elevated as compared with the controls. The following compounds were obtained from the extract with chromatographic separation over Si-gel column: α-amyrin, β-amyrin, lupiol acetate, venenative, rhazine and yohimbine. Conclusion: At the dose level employed, Alstonia scholaris bark extract has a significant antifertility effect in male rats; the primary site of action may be post meiotic germ cells (Step 19 spermatids).

Monoterpenoid Indole Alkaloids from Inadequately Dried Leaves of Alstonia scholaris

Six new indole alkaloids,named alstoniascholarines L–Q(1–6),together with nineteen known analogues were isolated from the inadequately dried leaves of Alstonia scholaris.Their structures were elucidated on the basis of extensive analysis of spectroscopic data and by comparison of their physical and spectroscopic data with the literature values.In addition,the new alkaloids were tested for their cytotoxic and neurite outgrowth-promoting activities.

Acute and Sub-chronic Toxicity of Indole Alkaloids Extract from Leaves of Alstonia scholaris (L.) R. Br. in Beagle Dogs

Alstonia scholaris(L.)R.Br.,an evergreen tropical plant rich in indole alkaloids with significant physiological activity,is traditionally used to treat respiratory diseases in China.This study was conducted to establish the toxicity profile of the alkaloid extract(TA)of A.scholaris leaves in non-rodents.After oral administration of a single dose(4 g/kg.bw),a num-ber of transient symptoms,such as unsteady gait,drooling,emesis,and reddening of peri-oral mucosa,were observed,but no treatment-related mortality.A sub-chronic toxicity study with a range of doses of TA(20,60 and 120 mg/kg.bw)was conducted for a 13-week treatment period,followed by 4-week recovery observation.Except for emesis and drooling in majority of animals in 120 mg/kg.bw treatment group,no clinical changes were observed in TA-treated animals.Data from electrocardiography,bone marrow,urine,fecal,hematology and clinical chemistry analyses were comparable between TA-treated and control animals.No significant differences in the relative organ weights and histopathological characteristics were evident between the TA-treated and control groups.Accordingly,the non-observed-adverse-effect-level(NOAEL)of TA was established as 120 mg/kg.bw.Our results add further knowledge to the safety database for indole alkaloid extracts from A.scholaris with potential utility as novel drug candidates.

Acute and Chronic Toxicity of Indole Alkaloids from Leaves of Alstonia scholaris (L.) R. Br. in Mice and Rats

Alstonia scholaris(L.)R.Br.(Apocynaceae)is an evergreen tree that has been used to treat lung diseases.In this study,the toxicity profile of indole alkaloids from leaves of A.scholaris was investigated.In acute toxicity tests,mice were adminis-tered total alkaloids(TA)and five indole alkaloids.In a chronic toxicity test,rats were continuously administered TA(50,100,and 300 mg/kg bw)for 13 weeks,followed by a 4-week recovery.A single administration of TA affected the behavior of mice,and at 12.8 g/kg bw,prone position,shortness of breath,wheezing,and convulsion were observed.The half-lethal dose(LD50)in mice was 5.48 g/kg bw,almost 2740 times the clinical dose in humans.Among the five indole alkaloids,the maximum tolerance dose in mice ranged from 0.75 to 4 g/kg bw.The TA-treated rats did not die and showed no adverse effects or dose-dependent changes in weight or food and water consumption,despite fluctuations in hematological and bio-chemical parameters compared with historical data.Furthermore,both gross and histopathological observations revealed no abnormalities in any organ.With daily oral administration to rats,the non-observed-adverse-effect-level of TA was 100 mg/kg bw.The results indicate that TA is safe for clinical use.

Genotoxicity and Safety Pharmacology Studies of Indole Alkaloids Extract from Leaves of Alstonia scholaris (L.) R. Br.

Indole alkaloids extract(IAAS)was prepared from leaves of Alstonia scholaris(L.)R.Br.,an evergreen tropical plant widely distributed throughout the world.This plant has been used historically by the Dai ethnic people of China to treat respiratory diseases.This study evaluated the genotoxicity and safety pharmacology of IAAS to support clinical use.The bacterial reverse mutation(Ames)test,in vitro mammalian chromosomal aberration test,and in vivo mammalian erythrocyte micronucleus(MN)test were performed to evaluate genotoxicity.Mice were administered IAAS(240,480,or 960 mg/kg bw)once orally to observe adverse central nervous system effects.Furthermore,beagle dogs were administered IAAS(10,30,60 mg/kg bw)once via the duodenum to evaluate its effects on the cardiovascular and respiratory systems.IAAS with or without S9-induced metabolic activation showed no genotoxicity in the Ames test up to 500μg/plate,in the mammalian chromosomal aberration test up to 710μg/mL,or in the MN test up to 800 mg/kg bw.No abnormal neurobehavioral effects were observed in mice following treatment with up to 960 mg/kg bw of IAAS.Moreover,blood pressure,heart rate,electrocardiogram parameters,and depth and rate of breathing in anesthetized beagle dogs did not differ among the IAAS doses or from the vehicle group.These data indicated that IAAS did not induce mutagenicity,clastogenicity,or genotoxicity,and no pharmaco-toxicological effects were observed in the respiratory,cardiovascular,or central nervous systems.Our results increased understanding of safety considerations associated with IAAS,and may indicate that IAAS is a possible drug candidate.

Anti-microbial Effects In Vitro and In Vivo of Alstonia scholaris

Alstonia scholaris could be used as a traditional medicinal plant in China for the treatment of acute respiratory,which might be caused by respiratory tract infections.The investigation tested the anti-infective effects of total alkaloids extract(TA)from leaves of A.scholaris,and as a result,TA inhibited herpes simplex virus type 1(HSV-1),respiratory syncytial virus(RSV)and influenza A virus(H1N1)in vitro respectively.In addition,the survival days of mice were prolonged,and the lung weights and mortality of mice were decreased significantly,after oral administrated TA in H1N1 and beta-hemolytic streptococcus infectious models in vivo respectively.The finding supported partly the traditional usage of A.scholaris in the treatment of respiratory infections.

Four new corynanthe-type alkaloids from the roots of Alstonia scholaris

Four new corynanthe-type alkaloids,meloslines C–F(1–4),together with four known ones(5–8)were isolated from the roots of Alstonia scholaris.Their structures including absolute configurations were elucidated by extensive spectroscopic analysis and electronic circular dichroism(ECD)calculation.Compounds 1 and 2 exhibited potent vasorelaxant activity on endothelium-intact renal arteries precontracted with KCl.

Effects of a novel isoflavonoid from the stem bark of Alstonia scholaris against fructose-induced experimental cataract

Objective: The present study investigated the anticataract activity of a novel isoflavonoid, isolated from stem bark of Alstonia scholaris, against fructose-induced experimental cataract.Methods: The bioactivity of fractions extracted from A. scholaris, an isolated isoflavonoid(ASII) was screened using in vitro(goat lens) and in vivo(albino rats) experimental cataract models. For the in vivo evaluation, albino rats(12–15 weeks old) were divided into five groups(n = 6). Group I(normal)received 0.3% carboxymethyl cellulose solution(10 m L/[kgád], p.o.). Group II(control) received 10%(w/v)fructose solution in their drinking water. Groups III–V received ASII at three different doses, 0.1, 1.0 and10 mg/(kgád), concurrently with 10%(w/v) fructose solution. Treatment was given daily for 8 consecutive weeks. During the protocol, systolic blood pressure, diastolic blood pressure, blood glucose level and lenticular opacity were monitored at 2-week intervals. Pathophysiological markers(catalase, superoxide dismutase, glutathione peroxidase, reduced glutathione and malondialdehyde) in eye lenses were examined at the end of the 8-week treatment period.Results: The results of in vitro study showed that A. scholaris extract and the active fraction(A3) reduced the lenticular opacity as compared to toxic control group. The in vivo study showed that 8-week administration of ASII(0.1, 1.0 and 10 mg/[kgád], p.o.) led to significant reduction in blood pressure and blood glucose level and retarded the initiation and evolution of cataractogenesis, compared to the fructoseinduced cataract model control. Additionally, ASII treatment led to significant improvement in lens antioxidants(catalase, superoxide dismutase, glutathione peroxidase and reduced glutathione) and decreased lens malondialdehyde, compared to the control group(group II).Conclusion: Results revealed that administration of ASII played a crucial role in the reduction of cataract formation in diabetic and hypertensive models.

编辑学者化与编辑引领学术:两样的赋能,一样的迷思

学者化和引领学术除了皆是学术期刊编辑的自我赋能,在更深的层面上还有更多共同之处:主体都是因编辑职业化而告别学者身份独立掌控了学术期刊的编辑,都面临着自身身份和与学者关系的重建,学者化和引领学术既是身份重建的目标、也是与学者关系的基础,反复言说,不仅是自我激励,更是让学者接受其设计的新关系的游说,故而都将已是事实的、对学术期刊的独立掌控作为言说的依凭,并视之为新身份、新关系不可变更的前提。实际上,两者构建的新身份和新关系不仅起点相同,看似不同的目标,指向也是一致的,学者化不会是终点而只能是阶段性目标,它的逻辑结果必然是引领学术,故而与其说殊途同归,不如说原本就是同路人。从各自所立的“flag”皆无法逻辑自洽可知,这是一条永远也无法抵达终点的路,故而唯有走出学者化和引领学术的迷思,回归学术共同体,才是编辑和掌控于其手中学术期刊的根本进路。

桂东常见几种绿化树种大苗育苗平衡施肥研究

研究高密度(行间距0.5m×0.5m)种植下,杜英(Elaeocarpus decipiens Hemsl)、秋枫(Bischofla javanica)、小叶榄仁(Terminalia mantaly)、蓝花楹(Jacaranda mimosifoia)、海红豆(Adenantherpavonina Linn.)和盆架子(Alstonia scholaris)6个树种绿化大苗圃地土壤理化性质变化规律,探索适合各树种绿化大苗育苗的施肥配方,为绿化苗圃科学施肥提供理论依据。结果表明:(1)各树种在梧州市生长表现良好,年均胸径生长量均高于1cm,除海红豆外,其它树种树高年均生长量均高于1m。(2)6个树种对不同矿质元素需求比例不同。(3)6个树种育苗林地土壤物理性质差别大,其中,盆架子和秋枫林地土壤偏紧,蓝花楹林地土壤紧实,对于盆架子、秋枫与蓝花楹圃地,应加强松土或多施有机肥。