Cytotoxicity Evaluation and Isolation of a Chroman Derivative from Phyllanthus amarus. Aerial Part Extract

Abstract

Chemical and cytotoxicity examinations of the crude methanol extract of the aerial parts of Phyllanthus amarus. Schum. et Thonn. (Euphorbiaceae) were investigated. The cytotoxicity property of the P. amarus. was evaluated in vitro., using the human ovarian A2780 cancer cell. Bioassay-guided fraction of the crude extract (IC₅₀ value of 31.2 µg/mL) showed that the dichloromethane fraction was most toxic with an IC₅₀ value of 22.7 µg/mL, whereas the polar methanol fraction was least cytotoxic with an IC₅₀ value of 31.2 µg/mL. This led to the isolation of a new chroman derivative from the dichloromethane fraction. On the basis of nuclear magnetic resonance and mass spectral data, the structure of the chroman was established as 4,4,8-trimethoxy chroman. The compound exhibited very little or no in vitro. cytotoxicity with an IC₅₀ of 16.2 µg/mL, relative to actinomycin, the reference compound, with an IC₅₀ of 2.0 ng/mL. It can therefore be concluded that the aerial parts of P. amarus., an extensively used plant remedy in various African and Asian Pacific ethnomedicines, is relatively nontoxic.     

Influence of Emblica officinalis aqueous extract on growth and antioxidant defense system of human hepatoma cell line (HepG2)

Context: Amla [Emblica officinalis Gaertn. (Euphorbiaceae)], a major constituent of several herbal formulations, is a well-known hepatoprotectant. Despite its extensive use, mechanistic understanding of its antioxidant action is rather limited.

Objective: In the current study, we investigated the effects of E. officinalis extracts (from dried fruits) on cellular oxidative state using a hepatocyte cell line (HepG2). We hypothesize that E. officinalis aqueous extracts have potency to modulate basal oxidative markers and enhance endogenous antioxidant defenses.

Materials and methods: Cells were incubated with aqueous extracts of E. officinalis (1–100 μg/ml) for varied time points (4–24?h) and biochemical markers of oxidative stress were determined in cell lysate.

Discussion: Aqueous extracts of E. officinalis at 100 μg/ml can significantly modulate the basal levels of oxidative markers and enhance antioxidant defenses of the cells.

Conclusions: Our findings clearly indicate the propensity of E. officinalis aqueous extracts to improve endogenous antioxidant defenses in HepG2 cells. Although further studies are required to assess their efficacy under experimentally induced oxidative, our data suggest that the hepatoprotective effects of E. officinalis reported earlier may be largely due to its potential to enhance the antioxidant defenses in vivo.

Results: Because E. officinalis up to 100 μg/ml concentrations had no effect on cell viability; it was considered noncytotoxic. Incubation with E. officinalis for 24?h resulted in significant diminution in the levels of lipid hydroperoxide (18–42%) and reactive oxygen species (11–29%). Furthermore; E. officinalis increased the levels of glutathione (GSH; 18–32%); antioxidant capacity (19–31%); and activities of antioxidant enzymes (superoxide dismutase; 25–41%; catalase; 39–50%; GSH peroxidase; 20–35%; GSH reductase; 26–35%; and GSH S-transferase; 12–30%).     

金丝桃素、叶下珠、茵陈体外抗巨细胞病毒效应的比较

目的:探讨金丝桃素单体、苦味叶下珠水溶液浸出物、茵陈水溶性提取物体外抗人巨细胞病毒(HCMV AD169)的作用.方法:采用细胞病变(CPE)抑制法观察金丝桃素单体、苦味叶下珠水溶液浸出物、茵陈水溶性提取物对HCMV AD169毒株的抑制作用,使用MTT比色法检测细胞的损伤程度,并利用吸光度(A)值评价这三种中药抗HC...     

叶下珠复方Ⅱ号对小鼠H22肝癌移植瘤生长的抑制作用

目的观察叶下珠复方Ⅱ号对小鼠H22肝癌移植瘤生长的抑制作用,并探讨其可能的作用机制。方法取昆明小鼠40只,建立小鼠H22肝癌移植瘤模型,分为模型组、叶下珠复方Ⅱ号高剂量组（37.5g/kg）、低剂量组（18.75g/kg）和环磷酰胺（20mg/kg）治疗组。叶下珠复方Ⅱ号高、低剂量组均灌胃给药,环磷酰胺组采用腹腔注射,每日1次,连续8d。末次给药24h后,测定瘤体质量,计算抑瘤率;检测血清IL-2和TNF-а含量。结果叶下珠复方Ⅱ号高、低剂量组瘤重明显低于模型组,差异均有显著性意义（P〈0.01）,但与环磷酰胺组比较,差异均无显著性意义（P〉0.05）。叶下珠复方Ⅱ号高、低剂量组的抑瘤率分别为67%和58%,与环磷酰胺组接近。叶下珠复方Ⅱ号高剂量组血清IL-2水平明显高于模型组（P〈0.05）。叶下珠复方Ⅱ号高、低剂量组血清TNF-а水平明显低于模型组,差异有显著性意义（P〈0.05）。结论叶下珠复方Ⅱ号有较好的抑制小鼠H22肝癌移植瘤生长作用,作用机制与调节免疫,升高IL-2水平和抑制TNF-а水平有关。     

余甘子提取物抗氧化作用研究

通过Fenton反应产生羟基自由基,光照核黄素体系产生氧自由基,以分光光度法测定余甘子提取物对羟基自由基、氧自由基的清除作用,以及对羟基自由基诱导脂质氧化的抑制作用。结果余甘子提取物对.OH的最大清除率分别为79.4%、63.2%,对脂质氧化最高抑制率为61.0%,余甘子提取物具有良好的清除自由基和抗氧化作用。     

盐炙对广西余甘子清除2种自由基作用的谱效关系影响

目的:分析盐炙对广西余甘子清除2种自由基作用的谱效关系影响。方法:通过HPLC法建立了13批广西不同产地余甘子盐炙前后的指纹图谱,并测定清除DPPH自由基和ABTS⁺自由基作用,采用改进的灰色关联度分析法分析谱效关系。结果:盐炙后,清除DPPH自由基新增了11个特征共有峰,清除ABTS⁺自由基新增了12个特征共有峰,清除这2种自由基的作用增强,特征共有峰34(诃子联苯酸)、峰42(鞣花酸)等盐炙后峰面积均增大。结论:清除这2种自由基作用的增强,是广西余甘子盐炙后新产生和含量增加的化学成分组成的化学组分群共同作用的结果,为阐明广西余甘子盐炙后抗氧化活性的物质基础提供了实验依据和新的思路,也为日后其盐炙品的质量评价提供了参考。     

余甘子抗免疫性肝纤维化大鼠的作用(Ⅱ)

目的 :观察余甘子对猪血清所致免疫性肝纤维化大鼠的影响。 方法 :采用大鼠ip猪血清,造成大鼠肝纤维化,ig余甘子提取物,检测丙氨酸转移酶(ALT)、门冬氨酸转移酶(AST)、白蛋白(Alb)、球蛋白(GLO)、总蛋白(TP)的含量,计算肝脏系数,并观察肝组织病理形态学变化。 结果 :余甘子提取物能够减少ALT,AST,GLO,TP的含量,升高Alb含量,纠正蛋白倒置,降低肝脏系数;改善肝组织病理损伤。 结论 :余甘子对猪血清致大鼠肝纤维化模型具有较好的保护作用。     

高效液相色谱法测定广西余甘子叶中槲皮素和山奈酚的含量

目的:建立广西余甘子叶中槲皮素及山奈酚的含量测定方法。方法:采用HPLC法,色谱柱为ThermoHypersilBDSC18(4.6mm×250mm,5μm);流动相为乙腈-0.1%磷酸(27∶73);流速为1.0mL·min-1;柱温为30℃;检测波长为360nm。结果:槲皮素在0.06～1.2μg之间;山奈酚在0.021～0.43μg,峰面积与进样量呈良好的线性关系;槲皮素和山奈酚的加样回收率分别为98.83%,101.58%,RSD分别为2.73%,2.21%(n=6)。结论:该方法简便可行,重复性好,结果准确,可作为广西余甘子叶中槲皮素和山奈酚的含量测定方法。     

余甘子对肿瘤细胞抑制作用及免疫调节的研究

目的 :运用中药血清药理学的研究方法,研究余甘子对S180荷瘤小鼠肿瘤存活率、主要免疫器官及红细胞免疫调节能力的影响。 方法 :余甘子采用鲜果榨汁经冷冻干燥保存。建立小鼠肿瘤模型,模型小鼠随机分组,小鼠末次给药后摘眼球取血,分离红细胞、淋巴细胞,进行肿瘤红细胞淋巴细胞混合花环实验;观察不同剂量给药组对小鼠肿瘤抑制率及脾、胸腺指数的影响。 结果 :与模型对照组比较,余甘子大剂量组红细胞促淋巴细胞黏附肿瘤细胞能力及抑制肿瘤存活率具极显著差异性;与阳性对照组比较,各剂量组对免疫器官的影响均具显著差异性。 结论 :余甘子在抑制肿瘤生长的同时,对免疫器官有极好的保护作用。     

叶下珠复方对人肝癌HePG_2细胞增殖及细胞信号传导通路的影响

目的观察叶下珠复方药物血清对人肝癌HePG2细胞体外增殖的抑制作用并探讨其机制。方法用叶下珠复方药物血清处理HePG2人肝癌细胞株,MTT法检测该药对肝癌细胞株增殖的抑制作用,用流式细胞仪检测该复方诱导肿瘤细胞凋亡情况。通过RT-PCR检测该药对细胞信号传导和转录激活因子3(STAT3)及其下游靶基因bcl-2的表达。结果叶下珠复方药物血清对HePG2细胞有抑制增殖和促进凋亡作用,该抑制作用与药物呈时间浓度关系。不同浓度的叶下珠复方处理HePG2细胞后bcl-2、stat3的mRNA水平明显下调(P0.05)。结论叶下珠复方在体外能抑制肝癌细胞增殖,促进其凋亡,其机制可能与抑制肿瘤细胞增殖的不同信号通路有关。