Fusheng Jiang

Isolation and Identification of an Anti-tumor Component from Leaves of Impatiens balsamina

We have previously shown that ethanol or chloroform extracts of the leaves of Impatiens balsamina (LIB) have anti-tumor activity against the human hepatocellular carcinoma cell line HepG2. The ethanol extracts were separated into five fractions according to polarity. An MTT assay indicated that two of the fractions had anti-tumor activity and that the petroleum ether fraction (PEF) was the most active. But the available quantities of both the PEF and chloroform fractions (CHF) were limited, precluding further study. The chloroform extract (CHE) shared almost all the same spots with the PEF and CHF and was plentiful enough to carry out further separations. Thus, the CHE was further separated into six sub-fractions (CHE1~6) by column chromatography. A MTT assay showed that only the CHE2 fraction had a strong tumor inhibition ratio (IC50 = 6.47±0.05 mg/L), which was superior to that of curcumin (IC50 = 13.95±0.11 mg/L). However, TLC revealed that CHE2 was not pure and still contained two more components. After further separation and purification, followed by TLC and MTT assay confirmation, the final active component was isolated and identified as 2-methoxy-1,4-naphthoquinone by m.p., UV, MS and 13C- and 1H-NMR data. This is the first report demonstrating that 2-methoxy-1,4-naphthoquinone has intensive in vitro anti-tumor activity against HepG2 cells.

Antioxidant, Antityrosinase and Antitumor Activity Comparison: The Potential Utilization of Fibrous Root Part of Bletilla striata (Thunb.) Reichb.f.

This study was carried out to evaluate the utilization probability of the fibrous root part (FRP) of Bletilla striata, which was usually discarded and harvesting pseudobulb part (PSP). The chemical composition, total phenolic content, DPPH radical scavenging activity, Ferric-reducing antioxidant power and tyrosinase inhibition activity were compared between FRP and PSP. Antioxidant and pro-oxidant effect as well as antitumor effect of the extract of FRP and PSP were analyzed by in vitro cell system as well. Thin layer chromatography and high performance liquid chromatography analysis indicated that the chemical compositions in the two parts were similar, but the content in FRP was much higher than PSP. Meanwhile, the FRP extracts showed higher phenolic content, stronger DPPH scavenging activity, Ferric-reducing antioxidant capacity and tyrosinase inhibition activity. Sub-fraction analysis revealed that the distribution characteristic of phenolic components and other active constituents in FRP and PSP were consistent, and mainly deposited in chloroform and acetoacetate fractions. Especially, the chloroform sub-fraction (sch) of FRP showed extraordinary DPPH scavenging activity and tyrosinase inhibition activity, with IC50 0.848 mg/L and 4.3 mg/L, respectively. Besides, tyrosinase inhibition activity was even stronger than the positive compound arbutin (31.8 mg/L). Moreover, In vitro cell system analysis confirmed that FRP extract exerts comparable activity with PSP, especially, the sub-fraction sch of FRP showed better antioxidant activity at low dosage and stronger per-oxidant activity at high dosage, and both sch of FRP and PSP can dose-dependent induce HepG2 cells apoptosis, which implied tumor therapeutic effect. Considering that an additional 0.3 kg FRP would be obtained when producing 1.0 kg PSP, our work demonstrated that FRP is very potential to be used together with PSP.

Flavonoids from the leaves of Carya cathayensis Sarg. inhibit vascular endothelial growth factor-induced angiogenesis.

The total flavonoids (TFs) were isolated from the leaves of Carya cathayensis Sarg. (LCC), a well-known Chinese medicinal herb commercially cultivated in Tianmu Mountain district, a cross area of Zhejiang and Anhui provinces in China. Five flavonoids, i.e. cardamonin, pinostrobin chalcone (PC), wogonin, chrysin, and pinocembrin were the main components of the TFs. The TFs and these pure compounds suppressed vascular endothelial growth factor (VEGF)-induced angiogenesis as detected in the mouse aortic ring assay, and cardamonin showed the best effect among them. To further elucidate the mechanisms for suppressing angiogenesis of these flavonoids, assays of VEGF-induced proliferation and migration in human umbilical vein endothelial cells (HUVECs) were performed. The TFs, cardamonin, pinocembrin, and chrysin obviously suppressed both VEGF-induced HUVEC proliferation and migration. However, PC and wogonin not only slightly inhibited VEGF-induced proliferation but also remarkably suppressed those of migration in HUVECs. Our further study showed that cardamonin decreased the phosphorylation of ERK and AKT induced by VEGF with a dose-dependent manner in HUVECs. Our findings indicate that the TFs and these pure flavonoids may become potential preventive and/or therapeutic agents against angiogenesis-related diseases.

Antitumor constituents from the leaves of Carya cathayensis

This study aimed to find cytotoxic chemical constituents from Carya cathayensis leaves (LCC) by using various chromatographic procedures. Identification of the chemical constituents was carried out by various spectroscopic techniques and classical chemical methods. The cytotoxic activity of the constituents was assayed on HeLa and HepG2 cell lines by staining with 3-(4,5-dimethylthiahiazol-2-y1)-2,5-di-phenytetrazolium bromide (MTT). Six flavanoids, namely (1) pinostrobin, (2) pinostrobin chalcone, (3) wogonin, (4) cardamonin, (5) alpinetin and (6) tectochrysin were identified from this species. Compounds 2–6 were isolated from this kind of plant for the first time. MTT results showed that wogonin has a moderate cytotoxic activity with IC50 values of 17.03 ± 2.41 and 44.23 ± 3.87 µM against HeLa and HepG2 cell lines, respectively. According to the correlation of primary the structure and activity, 8-methoxy substituent in these flavones may be a major factor of the antitumor activity.

Revaluation of the association between vascular endothelial growth factor gene 936 C/T polymorphism and breast cancer risk

We read with interest the article by Yang et al. [1], which investigated the association between vascular endothelial growth factor(VEGF) gene 936 C/T polymorphism and breast cancer risk with a meta-analysis. The results indicated that T allele was not associated with decreased risk of breast cancer (odds ratio = 0.87; 95% confidence interval 0.75–1.02). And the subgroup analysis by ethnicity showed the similar results. However, there were several methodological issues should be addressed. First, the authors didn’t assess Hardy–Weinberg equilibrium (HWE) in controls of all included studies for 936 C/T polymorphism. Deviation from HWE usually reflects existence of genotyping errors, population stratification, or selection bias in the controls [2]. So we assessed HWE in controls of the individual studies (Table 1). These results indicated that the study by Lin et al. [3] deviated from HWE in controls and it should be excluded. Second, for the study by Jacobs et al. [4], the genotypes in controls presented by Yang et al. were not in accordance with those provided by the original publication; and they should be 353/118/8 for CC, CT and TT genotypes, respectively. Third, in the ‘‘Results’’ section, the authors claimed that ‘‘Among the seven publications, six presented the numbers of CC, CT, and TT genotypes separately whereas one study showed only CC genotype and combined CT ? TT genotypes.’’, then they only presented the result under dominant model (CT ? TT vs. CC). Actually, all the studies presented the genotype frequency of CC, CT, and TT, respectively (Table 1). Therefore, we excluded the study by Lin et al. [3], corrected the data for the study by Jacobs et al. [4], and then presented the results for the association between VEGF gene 936 C/T polymorphism and breast cancer risk under all genetic models in order to show more information (Figs. 1, 2, 3, 4). These results suggested that VEGF gene 936 C/T polymorphism was not significantly associated with breast cancer risk.

Biodistribution of curcumin and its derivatives new aspects for curcumin administration

Curcumin, a polyphenolic compound derived from dietary spice turmeric, possesses diverse pharmacologic effects including antioxidant, anti-ininflammatory, antitumor and chemoprotective effects. However, its clinical applications were initially limited by its poor absorption, rapid metabolism and rapid systemic elimination. To improve the bioavailability of curcumin, new approaches have to be taken. Three curcumin derivatives (mPEG2k-Gly-Cur, mPEG2k-Gly-Cur-OA and Cur-OA2) were synthesized in this paper, and their biodistribution was analyzed by HPLC technique. In mice, all compounds were administered i.v. (equal to free curcumin 20 mg/kg), and the results confirmed the rapid clearance of free curcumin in blood and liver, but it was beyond our expectation to observe the remarkable lung tissue accumulation effect of curcumin, with Cmax= 193.12 µg/g after 30 min of administration, and can still be detected with 8.25 µg/g after 4 h. PEGylation can extend the circulation half-life of curcumin, but the effect was limited attributed to the low molecular weight of PEG. PEG co-modify with Oleic acid can increase liver uptake of curcumin. Oleic acid alone esterified curcumin can significantly increase curcumin level in liver, and can be detected with 15.77 µg/g after 4 h. In conclusion, our finding suggested that free curcumin have the lung accumulation property, which implied lung disease therapeutic effect; and it would also be suitable for curcumin to explore pulmonary delivery system so as to increase its bioavailability. Additionally, Oleic acid esterification method could be another way to enhance curcumin activity in certain specific organs, especially in liver.

An antitumor activity endophytic fungus a33 isolated from Viscum Coloratum of Chinese

An endophytic fungus having antitumor activity was isolated from Viscum Coloratum of Chinese. On the basis of its morphological and 18S rDNA sequence, the fungus was identified as Lasiodiplodia theobromae and designated as A33. The broth of A33 showed effectively antitumor acitivity. In addition, TNF mRNA exoression was upregulated after treatment with A33 for 6h compared to the untreated group. Isolation of such a fungus may provide a promising alterative approach to produce antitumor agent, and A33 could serve as a potential material for fungus engineering to improve antitumor agent production.

Poly (ethylene glycol) prodrug for puerarin and its characteristic evaluation

A puerarin prodrug was prepared pharmaceutically by covalently linking puerarin to a drug carrier monomethoxy-polyethylene glycol (mPEG, MW=2000Da ) via a glycine (Gly) spacer. And the products were validated by UV, FI-IR and 1H NMR. We evaluated the hemolytic property of the prodrug, the results showed that it produced minimal hematotoxicity as often shown by puerarin injectible. And the protective effect of prodrug on acute myocardial ischemia model implied better therapeutic effect than puerarin injectible. Our data suggest that the puerarin PEG conjugation is a promising prodrug that exhibits better aqueous solubility, much less side effects and more effective than puerarin.

Tumor necrosis factor-α 308 G/A polymorphism in breast cancer risk

To the Editor, We read with great interest the two recent meta-analysis of the association between Tumor necrosis factor(TNF)-a 308G/A polymorphism and breast cancer risk [1, 2] and the two related letters [3, 4] which commented on the two articles. The meta-analysis by Fang et al. [1] included 11 studies with 10,184 breast cancer cases and 12,911 controls, and the results suggested that TNF-a308G allele might be a modestly risk factor for the development of breast cancer among Caucasian and the overall. However, the other one by Shen et al. [2] comprised 13 studies involving 10,236 cases and 13,143 controls, and the results indicated that TNF-a308A allele might slightly decrease the risk of breast cancer among Caucasian, but not among the overall. The partial difference (for the overall population) on the conclusions between two studies is due to the eligible studies they identified. As commented by Chen et al. [3] and Zhou et al. [4], the article by Fang et al. contained one study not in Hardy–Weinberg equilibrium [5] and omitted two eligible studies [6, 7]; while the article by Shen et al. [2] included one duplicate study [8]. These findings suggested that the incomprehensive search of publications would bias the results. In addition, we have three further comments on the Rebuttal Comments by Fang et al. [3] and Shen et al. [4]. First, Fang et al. [3] mentioned that the study by Kohaar et al. [6] did not supply the frequencies of GA and AA genotypes. In fact, this information was provided in the main text (see the fourth paragraph of the ‘‘Result’’ section). Second, the opinions of Shen et al. [4] suggested that PubMed searching might be enough to indentify the eligible studies. We agree that PubMed database is one of the most comprehensive sources of medicine information worldwide, while its coverage is incomplete like any database [9, 10]. Other databases, such as ISI Web of Knowledge, Embase, and even non-English databases also should be searched to avoid the introduction of selection bias and language bias [10, 11]; or at least, both Medline and hand searching should be used when the meta-analysis is performed [10]. Third, the reference number in the ‘‘References for Rebuttal letter’’ section is not in accord with that in the main text of Rebuttal letter [4].

Are polymorphisms of the ataxia telangiectasia mutated gene associated with breast cancer risk

To the Editor, We read with great interest the recent article by Lu et al. [1] which assessed the association between polymorphisms of the ataxia telangiectasia mutated (ATM) gene and breast cancer risk with a meta-analysis involving five studies of 2,604 cases and 1,973 controls. This was an important investigation as the association has been inconsistent based on the previous individual studies. The results of metaanalysis indicated that for ATM 5557G[A polymorphism (also known as D1853N or rs1801516), AA genotype significantly decreased the risk of breast cancer compared with GA and GG genotypes [odds ratio (OR) = 0.67, 95% confidence interval (CI) 0.51–0.89]. However, another recent meta-analysis by Gao et al. [2] including nine studies of 4,191 cases and 3,780 controls suggested that ATM 5557G[A polymorphism was not significantly associated with breast cancer risk (AA vs. GA ? GG: OR = 0.78, 95% CI 0.59–1.04). After carefully reading the two articles, we noted several methodological issues in the study by Lu et al. [1]. First, although the authors [1] claimed that they used comprehensive databases to search the potential eligible studies, they omitted at least five studies [3–7] that met their inclusion criteria for ATM 5557G[A polymorphism, which did make the strength of the association be inaccurate. However, as the study by Tapia et al. [3] was not in Hardy–Weinberg equilibrium (HWE) in controls, it should be excluded in the final meta-analysis. In addition, the meta-analysis by Gao L et al. [2] omitted one eligible study [8] and included one ineligible study [3]. Therefore, we re-assessed the association between ATM 5557G[A polymorphism and breast cancer (Fig. 1). Our results suggested that AA genotype was associated with decreased risk of breast cancer, compared with GA and GG genotypes in Caucasians (OR = 0.69, 95% CI 0.54–0.89). Second, there were several mistakes in Tables 1 and 2. For example, in Table 1, the Iranian population in the study by Mehdipour et al. [8] and the Israel population in the study by Koren et al. [9] did not belong to Asians, in fact, they were both Caucasians. In Table 2, the P value and the corresponding CI of OR were not in agreement with each other for three studies [9–11]. Third, the genotype frequencies of ATM IVS1 ? 19A[T polymorphism in controls of the study by Tamimi et al. [12] deviated from HWE, and this study should be excluded in the final meta-analysis.